Food As Medicine: Sorrel

Want to add some lemony tang to your dish and receive essential vitamins and minerals at the same time? Garden sorrel can do the trick. All things in moderation, though. Oxalic acid contained in sorrel can lead to the formation of kidney stones if consumed in excess.

History and Traditional Use

Range and Habitat

Garden sorrel (Rumex acetosa, Polygonaceae) is a wild, perennial herb characterized by slender stems supporting bright green, spear-shaped leaves, with distinctive backwards-reaching lobes.1,2 Sorrel grows in patches that average in height from 20-36” and produce small red-brown flowers, which bloom in early summer and produce tiny, hard fruits.3 Sorrel is easy to cultivate and grows best in cool, temperate climates, as well as grasslands, coastal dunes, and cliffs.1 In addition to R. acetosa, another species of sorrel, French sorrel (R. scutatus), is used for culinary purposes.4 This article will profile the history, uses, and components of R. acetosa.

Sorrel is native to Europe and northern Asia, and evidence of cultivation dates back to 4,000 BCE.2 In the Middle Ages, sorrel was a prominent vegetable throughout Europe and was also cultivated by ancient Egyptians, Greeks, and Romans. Often referred to as the lemon of the leaf crops, the sour-tasting leaves are the most commonly consumed part of the plant.2,5 Sorrel’s stem and flower were also used in medicinal applications.2 Sorrel’s species name, acetosa, is Latin for “vinegary,” indicating the plant’s acidic taste.6


Phytochemicals and Constituents

Sorrel is a nutrient-dense green, containing important vitamins and minerals, such as vitamin A, vitamin C, sodium, potassium, magnesium, calcium, and iron.2Vitamin A is a fat-soluble vitamin that supports healthy vision, bone growth, and a strong immune system.7Vitamin C is a water-soluble vitamin, essential for its role in collagen synthesis and its antioxidant properties. Sodium, potassium, and magnesium are the most abundant minerals within human cells, and each plays a role in electrolyte and fluid balance. Calcium is a structural component of the skeletal matrix, and iron is necessary for oxygen delivery and DNA synthesis.

Flavan-3-ols and other phenolic compounds in sorrel leaves provide additional benefits.8-10 Phenolic compounds have protective effects against inflammation and cell damage and interfere with tumor and estrogen receptor activities.10 The main phenolic compounds present in R. acetosa include resveratrol (41.27 µg/g), vanillic acid (130.29 µg/g), sinapic acid (5,708.48 µg/g), and catechin (75.46 µg/g). Sorrel leaves also contain beta-carotene, though not in therapeutic levels.11


Historical and Commercial Uses

Documented uses of sorrel include domestic remedies, and extend to complex medicinal therapies.2 Sorrel leaf juice has been used in fragrances and for stain removal, and sorrel leaves are a popular ingredient in French cuisine.

Sorrel leaves are considered acidic, astringent, and cooling.6 Sorrel has been used as a laxative and a topical treatment for skin disorders, sore throats, and warts.11 Sorrel leaf also was used for its diuretic properties to induce water excretion and to manage fevers.1,5,12 Due to its high concentration of vitamin C, sorrel has been used as a therapeutic food for conditions caused by vitamin C deficiencies, such as scurvy.1Furthermore, common garden sorrel was used as a treatment for constipation, cramping, and diarrhea, since the plant demonstrates soothing effects on the stomach and intestines.8,9 The astringent properties of the seeds were used to treat hemorrhages.12

Currently, sorrel is used as an ingredient in herbal medicinal remedies, such as Sinupret (Bionorica SE; Neumarkt, Germany), a proprietary blend of botanicals, indicated for sinusitis and bronchitis.7 Tablets contain 18-36mg of sorrel leaf and stem extract, in addition to four other herbs: elderflower (Sambucus nigra, Adoxaceae), primrose flower and calyx (Primula veris, Primulaceae), European vervain leaf and stem (Verbena officinalis, Verbenaceae), and yellow gentian root (Gentiana lutea, Gentianaceae).

Modern Research

Currently, studies on sorrel offer promising results in the areas of digestion, infection prevention, topical skin treatments, and anti-proliferative activity.10,12,13

A recent in vivo and in vitro study evaluated the traditional use of R. acetosa to treat stomach discomforts and distress in animal models.12 A 70% methanol extract from sorrel leaves was found to have a high acute toxicity dosage (i.e., large amounts were well tolerated and exhibited no adverse effects), relaxed the gastrointestinal tract or produced gastrointestinal contractions depending on the dose, and exhibited anti-emetic properties. These findings support the traditional use of sorrel as a constipation aid that stimulates a bowel movement.

Anti-diarrheal properties may be linked to the presence of calcium-binding components and tannins in sorrel.8,9,12Oxalic acid binds with and thereby reduces available free calcium for receptor stimulation. This leads to reduced muscle contraction and may alleviate diarrhea.12Tannins exert an astringent effect, which may help alleviate not only conditions such as diarrhea, but also chronic upper respiratory infections, by reducing excess fluid.9

Phytochemical extracts from other buckwheat families (Polygonaceae) members exhibit antiviral and anticancer effects, specifically extracts from R. acetosella, or sheep sorrel. Sheep sorrel has a history of use as an ingredient in the formula known as Essiac tea, which purportedly is based on the traditions of the indigenous Ojibwa Native American tribe.11 Garden sorrel shows similar antiviral and anticancer effects. An in vivo trial discovered that an extract of R. acetosa reduced influenza A viral invasion of host cells, and further reduced viral growth.14 Antiviral reactions are primary effects of rich polyphenol concentration. In sorrel, these polyphenols mainly include flavonols, proanthocyanidins, and hydrolysable tannins. These compounds may prevent the assembly and maturation (growth and development) of certain viruses, an important step in infection control.

Additional documentation supports anti-proliferative (tumor cell growth preventing) activities seen with R.acetosa preparations.10,13 Prevention of cell growth, specifically tumor cells, was found at concentrations of 75 and 100 µg/mL of a 90% aqueous methanol extract.10

In vitro and in vivo trials displayed antimicrobial and antiviral properties. Sinupret was able to reduce viscosity, or thickness, of mucus in animal models and produce an anti-inflammatory response. Sorrel’s contributions to anti-inflammation are credited to an increased response by immune cells. Few adverse side effects related to sorrel have been reported, and include gastrointestinal disorders and correlated allergic reactions.7

47777071 - sorrel also called spinach dock a nutritious plant
Consumer Considerations

Oxalic acid within sorrel produces a bitter taste, which makes sorrel a valuable ingredient for adding a tart, lemony flavor to various dishes. However, oxalic acid is a potential cause for concern in regard to renal function.11 Crystalized calcium oxalate (which forms when oxalic acid combines with calcium) can lead to the formation of kidney stones and may also accumulate in the heart, circulatory vessels, and lungs.15 In addition, oxalic acid’s ability to bind to micronutrients, such as iron and calcium, decreases its absorption.11,13 Furthermore, oxalates may irritate the digestive system when consumed in large amounts.16 For these reasons, consumption of sorrel should be monitored for special populations affected by renal and arthritic conditions, as well as those with gastrointestinal disorders.1,11

Oxalic acid is concentrated at 300mg per 100 grams of sorrel.11 The majority is found within the leaves, followed by marginal amounts in stems.13 The concentration of oxalates depends on the plant’s growing conditions, such as soil and climate.8 Moreover, tannins in sorrel leaves are concentrated between 7-15%.11When consumed in large amounts, tannins may cause stomach upset and/or kidney and liver damage.

Fortunately, oxalic acid concentration decreases to negligible amounts with light cooking.11 For example, sorrel soup has a lower oxalic acid concentration compared to pesto made with fresh sorrel leaves.13 Also, the oxalic acid concentration increases proportionately to the size and length of the leaf, making young, tender leaves a better choice for those people affected by these conditions.


Nutrient Profile17

Macronutrient Profile: (Per 1 cup chopped raw sorrel)

29 calories
3 g protein
4 g carbohydrate
1 g fat

Secondary Metabolites: (Per 1 cup chopped raw sorrel)

Excellent source of:
Vitamin A: 5320 IU (106.4% DV)
Vitamin C: 63.8 mg (106.3% DV)
Magnesium: 137 mg (34.3% DV)
Manganese: 0.5 mg (25% DV)

Very good source of:
Iron: 3.2 mg (17.8% DV)
Dietary Fiber: 4 g (16% DV)
Potassium: 519 mg (14.8% DV)
Vitamin B6: 0.2 mg (10% DV)

Good source of:
Phosphorus: 83.8 mg (8.4% DV)
Thiamin: 0.1 mg (6.7% DV)
Calcium: 58.5 mg (5.9% DV)
Riboflavin: 0.1 mg (5.9% DV)

Also provides:
Folate: 17.3 mcg (4.3% DV)
Niacin: 0.7 mg (3.5% DV)

DV = Daily Value as established by the US Food and Drug Administration (FDA), based on a 2,000-calorie diet.


Recipe: Green Potato Salad

Adapted from Blue Apron18

Ingredients:

  • 2 pounds yellow potatoes, such as Yukon Gold, diced into bite-sized pieces
  • 6 ounces fresh spinach
  • 6 ounces fresh sorrel leaves
  • 2 green onions, thinly sliced
  • 2 stalks celery, thinly sliced
  • 1/2 cup sour cream or Greek yogurt
  • 1 tablespoon prepared horseradish (or to taste)
  • Salt and pepper to taste

Directions:

  1. Place the potatoes in a

    sauce pan

    and cover with water. Bring to a boil, salt the water, then cook until potatoes are tender and easily pierced with a fork, approximately 15 minutes.

  2. Lift the potatoes out, reserving the water, and set aside in a bowl. Add the greens to the boiling water and cook for 30 seconds to a minute, or until wilted. Drain the spinach into a strainer, pressing to release as much water as possible.

  3. Roughly chop the greens, then add to the potatoes.

  4. Add remaining ingredients to the bowl and toss thoroughly to combine. Season with salt and pepper. Salad may be served warm, at room temperature, or after chilling.

References

  1. Rumex acetosa (common sorrel). Kew Royal Botanic Gardens website. Available here. Accessed April 28, 2016.
  2. Van Wyk B-E. Food Plants of the World: An Illustrated Guide. Portland, Oregon: Timber Press, Inc.; 2006.
  3. Bown D. The Herb Society of America: New Encyclopedia of Herbs and Their Uses. London, UK: Dorling Kindersley Ltd.; 2001.
  4. Real Food Right Now and How to Cook It: Sorrel. Grace Communications Foundation website. Available here. Accessed April 28, 2016.
  5. Felter HW, Lloyd JU. King’s American Dispensatory. 18th edition. Cincinnati, OH: Ohio Valley Co.; 1898. Available here. Accessed April 28, 2016.
  6. Onstad D. Whole Foods Companion: A Guide for Adventurous Cooks, Curious Shoppers & Lovers of Natural Foods. White River Junction, VT: Chelsea Green Publishing Company; 1996.
  7. Oliff HS, Blumenthal M. Scientific and Clinical Monograph for Sinupret. Austin, TX: American Botanical Council; 2009.
  8. Kemper KJ. Sorrel (Rumex acetosa L.). Boston, MA: The Longwood Herbal Task Force; 1999.
  9. Bicker J, Petereit F, Hensel A. Proanthocyanidins and a phloroglucinol derivative from Rumex acetosaL. Fitoterapia. 2009;80(8):483-495.
  10. Kucekova Z, Mlcek J, Humpolicek P, Rop O, Valasek P, Saha P. Phenolic compounds from Allium schoenoprasumTragopogon pratensis and Rumex acetosa and their antiproliferative effects. Molecules. 2011;16(11):9207-9217.
  11. Vasas A, Orbán-Gyapai O, Hohmann J. The Genus Rumex: Review of traditional uses, phytochemistry and pharmacology. J Ethnopharmacol. 2015;175:198-228.
  12. Hussain M, Raza SM, Janbaz KH. Pharmacologically mechanistic basis for the traditional uses of Rumex acetosa in gut motility disorders and emesis. Bangladesh J Pharmacol. 2015;10(3):548.
  13. Tuazon-Nartea J, Savage G. Investigation of oxalate levels in sorrel plant parts and sorrel-based products. Food Nutr Sci. 2013;4(8):838-843.
  14. Derksen A, Hensel A, Hafezi W, et al. 3-O-galloylated procyanidins from Rumex acetosa L. inhibit the attachment of influenza A virus. PLoS One. 2014;9(10).
  15. Oxalic acid. J.R. Organics website. Available here. Accessed May 5, 2016.
  16. Elpel T. Botany in a Day: The Patterns Method of Plant Identification. Pony, MT: HOPS Press, LLC; 2013.
  17. Basic report: 11616 Dock, raw. Agricultural Research Service, United States Department of Agriculture website. Available here. Accessed April 28, 2016.
  18. Seared Salmon and “Green” Potato Salad with Pickled Mustard Seeds. Blue Apron website. Available here. Accessed April 28, 2016.
Advertisements

Food as Medicine: Pecan (Carya illinoinensis, Juglandaceae)

Pecan (Carya illinoinensis) is a member of the Juglandaceae family, which also includes other economically important North American trees, such as hickory (Carya spp.) and walnut (Juglans spp.).1,2 Fossil records show that the pecan tree can live up to a thousand years, and its existence predates human settlements in North America.3 Pecan can grow to a height of 150 feet with a seven-foot diameter.2-4 The deciduous, lanceolate leaves are alternate and odd-pinnately compound and are typically made up of 9-17 leaflets.4In the spring, the tree produces both male and female inconspicuous flowers that are often wind-pollinated.5,6 During the summer, the “fruit” of the tree grows in clusters of 3-6 one-inch oblong brown-shelled nuts, called endocarps, that contain two seeds that are referred to and sold in the market as pecans.4,5

The pecan tree initially requires well-drained soil with an adequate water supply; however, once established, it is drought-tolerant.7 Pecan trees are native to North America, and typically grow in the southern and midwestern regions of the United States and in the northern regions of Mexico.2,8Eighty percent of the world’s supply of pecans is grown and produced in the United States,2 but other countries, such as Mexico, Brazil, Peru, Israel, China, South Africa, and Australia also produce pecans on a large commercial scale.4,7 In the United States, pecans are grown and harvested commercially in 14 states. More than 75% of US pecans come from Georgia, New Mexico, and Texas, which produced 76 million, 67 million, and 61 million pounds, respectively, in 2014.9,10

Among tree nut consumption in the United States, pecans rank third behind almonds (Prunus dulcis, Rosaceae) and English walnuts (Juglans regia, Juglandaceae), respectively.10 In 2014, the global pecan crop totaled 264.2 million pounds or 132,075 US tons and was valued at $517 million, a 12% increase from 2013. In terms of pecan exports, Hong Kong and Vietnam remain the primary markets for in-shell pecans from the United States. Canada and the Netherlands are the primary markets for shelled pecans from the United States.

Phytochemicals and Constituents

Pecans contain essential fatty acids, 17 different vitamins and minerals, and phenols and phytosterols.4They are calorie-dense and have a high-fat content.7 Of all culinary nuts (though the pecan nutmeat is botanically considered a drupe), pecans have the second-highest fat content after macadamia (Macadamiaspp., Proteaceae).11 Pecans are low in saturated fats but are a rich source of monounsaturated fatty acids (MUFAs), primarily oleic acid, and polyunsaturated fatty acids (PUFAs), predominantly linoleic acid (omega-6).4 Diets with higher intakes of MUFAs and PUFAs and lower intakes of saturated and trans fats correlate with a lower risk for cardiovascular disease (CVD).

Compared to other nuts, pecans have an especially high antioxidant content.12 Specifically, pecans contain bioactive compounds such as phenols, condensed tannins (e.g., proanthocyanidins, or PACs), hydrolyzable tannins (e.g., derivatives of gallic and ellagic acids), and tocopherol isomers that contribute to their antioxidant activity.12,13

Phenolic acids, such as gallic acid, may inhibit the growth of a variety of bacteria.14 PACs exhibit antimutagenic properties and antioxidant effects,1 specifically by inhibiting lipid oxidation in both foods and in human cells.15 A study that analyzed phenolic compounds from 18 different pecan cultivars in the United States found that the most abundant antioxidants present were PACs, as well as gallic and ellagic acids and their derivatives.12

Pecan shells have also been tested for bioactive compounds and reportedly contain higher amounts of phenolic compounds than the actual pecan nutmeat.13 Current research is exploring the use of teas prepared with pecan nut shells to treat liver damage in rat models, which may expand the role of pecans in the human diet.16 However, no human research has been conducted regarding the therapeutic use of pecan shells, so additional research is warranted to ensure safety.

Pecans are an excellent source of tocopherols, which are forms of lipid-soluble vitamin E, and exist as four different isomers: alpha, beta, gamma, and delta.4 Foods that are sources of vitamin E typically contain alpha-tocopherol and gamma-tocopherol. Pecans have unusually high gamma-tocopherol content: around 25 mg of gamma-tocopherol per 100 grams. Gamma-tocopherol has been observed to act as a stronger antioxidant in vivo than alpha-tocopherol.17 In addition, it has been suggested that gamma-tocopherol may also detoxify reactive nitrogen oxide species, and thus reduce inflammation in the body.

In addition, pecans contain phytosterols, also known as plant sterols, primarily in the forms of beta-sitosterol and stigmasterol, which may help lower cholesterol levels.12,18 In the small intestine, phytosterols compete with cholesterol for absorption and thus inhibit the body’s uptake and reuptake of cholesterol in the bloodstream. This can improve serum cholesterol levels and may reduce low-density lipoprotein (LDL) cholesterol by up to 10-14%.4 Different cultivars and the degree of ripening in pecans yield varying quantities of phytosterols, but all varieties provide these plant sterols.19

Historical and Commercial Uses

The word “pecan” likely comes from an Algonquian language. French traders recorded the word as pacanesor pecanes, which later evolved into its current common name.8 Native Americans consumed and stored pecans, but also traded them for furs and other goods.2 The low-water and high-calorie contents of pecans help them survive long storage.20 A historical record from the mid-1500s by the Spanish explorer Álvar Núñez Cabeza de Vaca revealed that Native Americans in south Texas would gather pecans in autumn and then grind them and soak them in water to make a milky beverage to sustain them throughout the winter.4This liquid also formed the base of a fermented beverage called powcohicora. Native Americans also used ground pecan meal to thicken stews and roasted the pecans for sustenance on long journeys.3

In addition to using the pecan nuts as a food source, the Kiowa tribe of the Great Plains area of the United States used decoctions of the tree bark to treat tuberculosis.21 The Comanche Nation used a poultice of pulverized pecan tree leaves as a topical treatment for ringworm-infected skin.

Although it can be used as a source of wood,3 the pecan tree is primarily grown and commercialized for its nuts. In order to reduce waste, different uses for pecan shells are being researched more extensively. Pecan shell mulch is available in areas that produce pecans commercially; however, its high tannin content may inhibit the growth of certain plant species. In addition, pecan shells can be used like wood chips to smoke and barbeque meats.

Due to its wide distribution throughout the state and long history of cultivation, the pecan tree became the official state tree of Texas in 1919.3 Texas also officially recognized pecan as its state health nut in 2001, and named pecan pie as the state pie in 2013.22

Modern Research

Currently, most research conducted on pecan consists of epidemiological or population-based studies that analyze correlations between nut consumption and lowered risk of CVD.23 However, there have been some in vitro and clinical research studies that have investigated the effects of pecan consumption in regards to antioxidant capacity.

Cardiovascular Health

Nut consumption has been linked to lowered risk of cardiovascular events such as heart attacks.4,23Epidemiological studies suggest a 37% decreased risk for coronary heart disease when nuts are consumed at least four times a week compared to infrequent or no nut consumption.24 A systematic review and meta-analysis of 61 trials confirmed that increased intake of tree nuts was associated with lower total cholesterol, LDL cholesterol, apolipoprotein B (Apo B, the main protein constituent of LDL cholesterol), and triglyceride levels.25 The review also found that nut consumption correlated with markedly lower Apo B levels in patients with diabetes versus patients without diabetes. Because people with diabetes are at an increased risk for CVD, this finding is significant and should be explored further.

In a crossover study, participants were randomly assigned to consume either a pecan-enriched diet or the National Cholesterol Education Program Step 1 diet for four weeks. The participants switched diets for the following four weeks. When consuming the pecan-rich diet, participants demonstrated a decrease in concentrations of Apo B and an increase in Apo A1, which stimulates an uptake of high-density lipoprotein (HDL) cholesterol, beyond the values observed in the Step 1 diet.26 Decreased LDL and increased HDL cholesterol levels were also observed in participants while consuming the pecan diet. In addition, the pecan-enriched diet resulted in decreased plasma triglycerides.

A study assessed postprandial (post-meal) plasma antioxidant capacity in human subjects after pecan consumption, and found that participants who consumed 90 grams (about three servings) of whole pecans or pecans blended with water had significantly higher hydrophilic and lipophilic plasma oxygen radical absorbance capacity (ORAC; which measures antioxidant capability in blood), decreased LDL oxidation, and increased plasma catechin concentrations, compared to the control meal that matched the pecans in caloric, fluid, and macronutrient contents.27 This demonstrates the bioavailability and potential antioxidant action in humans after consuming pecans.

Similarly, a randomized controlled, crossover trial assessed the impact of the addition of pecans to the diet on cholesterol levels and antioxidant capacity. Twenty-four healthy participants were assigned to either a control diet with no pecans or a pecan-enriched diet for four weeks, and then switched diets for another four weeks.15 The results showed that during the consumption of the pecan-enriched diet, participants significantly increased serum gamma-tocopherol (normalized to total cholesterol) while decreasing plasma LDL levels and inhibiting lipid peroxidation and degradation. Total antioxidant activity was not significantly different between groups.

Type 2 Diabetes

Though the mechanism of action is not fully understood, an inverse relationship has been observed between nut consumption and risk for developing type 2 diabetes.28 The Nurse’s Health Study suggested that a higher intake of MUFAs and PUFAs may contribute to improved insulin sensitivity.

For individuals with type 2 diabetes, it appears that nut consumption has a neutral impact on blood glucose and insulin levels.28 This makes nuts a healthy option for people with diabetes looking to lower their risk of CVD while having minimal impact on their blood glucose levels. Though the caloric intake associated with adding nuts to the diet is a concern, especially for those with, or at risk for, type 2 diabetes, the evidence that increased nut intake is associated with weight gain is inconclusive. Some studies show slight weight gain and others show weight maintenance or even loss with the addition of nuts to a calorie-controlled diet.28,29

Consumer Considerations

Like many other nuts, pecans contain phytic acid, which can block or reduce absorption of important minerals, including calcium, magnesium, iron, and zinc.4 The process of soaking or drying the pecans prior to consumption can reduce the phytic acid content. Pecans are also high in oxalates, so individuals with a history of calcium oxalate kidney stones should consider limiting intake of pecans to prevent complications.

Pecans are in the class of tree nuts, which are fairly common food allergens. It is estimated that about 1% of the population (about three million people) in the United States suffers from tree nut and/or peanut (Arachis hypogaea, Fabaceae) allergies.4 These allergies can cause severe reactions, such as life-threatening anaphylaxis. Individuals with tree nut allergies should, therefore, avoid consumption of or exposure to pecans, and always read food ingredient labels to determine if there is any possible contamination from the processing facility.

Although more common in peanuts and Brazil nuts (Bertholletia excelsa, Lecythidaceae), nuts like pecans are susceptible to contamination with a mold called Aspergillus flavus, which produces aflatoxins, which are among the most carcinogenic substances known, and also have the potential to lead to mental impairment in children.4 To avoid this mold, it is important to purchase high-quality nuts from reputable grocery stores that keep them in a dry, cool environment. Because of their high-fat content, shelled pecans have a shorter shelf life than pecans in the shell and become rancid easily, so it is best to consume them soon after shelling or properly store them in the refrigerator or freezer.4,11 Purchasing them in the shell and roasting them at home can also safeguard against this fungal growth.11

Nutrient Profile30

Macronutrient Profile: (Per 1 ounce [approx. 28.4 grams])

196 calories
2.6 g protein
3.9 g carbohydrate
20.4 g fat

Secondary Metabolites: (Per 1 ounce [approx. 28.4 grams])

Excellent source of:

Manganese: 1.3 mg (65% DV)
Vitamin E: 7.6 mg (36.7% DV)

Very good source of:

Thiamin: 0.2 mg (13.3% DV)
Dietary Fiber: 2.7 g (10.8% DV)

Good source of:

Magnesium: 34 mg (8.5% DV)
Phosphorus: 79 mg (7.9% DV)

Also provides:

Iron: 0.7 mg (3.9% DV)
Potassium: 116 mg (3.3% DV)
Vitamin B6: 0.06 mg (3% DV)
Riboflavin: 0.04 mg (2.4% DV)
Calcium: 20 mg (2% DV)
Niacin: 0.3 mg (1.5% DV)
Folate: 6 mcg (1.5% DV)
Vitamin K: 1 mcg (1.3% DV)

Trace amounts:

Vitamin C: 0.3 mg (0.5% DV)
Vitamin A: 16 IU (0.3% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000-calorie diet.

Recipe: Pecan Pie Energy Bites

Courtesy of Gluten Free Vegan Pantry31

Ingredients:

  • 2 cups Medjool dates, pitted
  • 1 1/2 cups pecans
  • 1/2 cup rolled oats
  • 1 teaspoon cinnamon
  • 2 tablespoons maple syrup

Directions:

  1. Process dates in a food processor on high for about 45 seconds, or until a date ball begins to form.

  2. Add pecans and process for another 1-2 minutes.

  3. Add remaining ingredients, scraping down the sides of the processor bowl if necessary, and process for another 1-2 minutes.

  4. Using a small ice cream scoop or 1-tablespoon measure, portion

    out

    the mixture and roll into balls. Place on a parchment paper-lined baking sheet and place in the refrigerator for 15-20 minutes.

  5. Store in an airtight container in the refrigerator for up to a week.

References

  1. Villarreal-Lozoya JE, Lombardini L, Cisneros-Zevallos L. Phytochemical constituents and antioxidant capacity of different pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivars. Food Chemistry. 2007;102:1241-1249.
  2. National Geographic Society. Edible: An Illustrated Guide to the World’s Food Plants. Lane Cove, Australia: Global Book Publishing; 2008.
  3. Pecan Tree: Texas State Tree. State Symbols USA website. Available at: www.statesymbolsusa.org/symbol-official-item/texas/state-tree/pecan-tree. Accessed October 16, 2017.
  4. Murray M. The Encyclopedia of Healing Foods. New York, NY: Atria Books; 2005.
  5. Plants Profile for Carya illinoinensis (pecan). United States Department of Agriculture website. Available at: http://plants.usda.gov/core/profile?symbol=cail2. Accessed October 16, 2017.
  6. Cheatham S, Johnston MC, Marshall L. The Useful Wild Plants of Texas, the Southeastern United States, the Southern Plains, and Northern Mexico. Volume 3. Austin, TX: Useful Wild Plants, Inc; 2009.
  7. Van Wyk B-E. Food Plants of the World. Portland, OR: Timber Press; 2006.
  8. Hall GD. Pecan food potential in prehistoric North America. Economic Botany. 2000;54(1):103-112.
  9. Lillywhite J, Simonsen J, Heerema R. US consumer purchases and nutritional knowledge of pecans. Horttechnology. 2014;24(2):222-230.
  10. Pecans. Agricultural Marketing Resource Center website. August 2015. Available at: www.agmrc.org/commodities-products/nuts/pecans/. Accessed October 16, 2017.
  11. Wood R. The New Whole Foods Encyclopedia. New York, NY: Penguin Books; 1999.
  12. Robbins K, Gong Y, Wells M, et al. Investigation of the antioxidant capacity and phenolic constituents of US pecans. Journal of Functional Foods. 2015;15:11-22.
  13. de la Rosa L, Vazquez-Flores A, Pedraza-Chaverri J, et al. Content of major classes of polyphenolic compounds, antioxidant, antiproliferative, and cell protective activity of pecan crude extracts and their fractions. Journal of Functional Foods. 2014;7:219-228.
  14. Prado A, Aragao A, Fett R, et al. Phenolic compounds and antioxidant activity of pecan (Carya illinoinensis (Wangenh.) K. Koch) kernel cake extracts. Grasas Y Aceites (España). 2009;(5):458.
  15. Haddad E, Jambazian P, Karunia M, et al. A pecan-enriched diet increases γ-tocopherol/cholesterol and decreases thiobarbituric acid reactive substances in plasma of adults. Nutrition Research. 2006;26:397-402.
  16. Müller L, Pase C, Burger M, et al. Hepatoprotective effects of pecan nut shells on ethanol-induced liver damage. Experimental and Toxicologic Pathology: Official Journal of the Gesellschaft Für Toxikologische Pathologie. 2013;65(1-2):165-171.
  17. Christen S, Woodall AA, Shigenaga MK, et al. γ-tocopherol traps mutagenic electrophiles such as NOx and complements α-tocopherol: Physiological implications. Proceedings of the National Academy of Sciences of the United States of America.1997;94:3217–3222.
  18. Alasalvar C, Bolling BW. Review of nut phytochemicals, fat-soluble bioactives, antioxidant components and health effects. British Journal of Nutrition. 2015;113 Suppl 2:S68-S78.
  19. Bouali I, Trabelsi H, Berdeaux O, et al. Analysis of pecan nut (Carya illinoinensis) unsaponifiable fraction. Effect of ripening stage on phytosterols and phytostanols composition. Food Chemistry. 2014;164:309-316.
  20. Pecan. Texas Texas Beyond History website. Available at: www.texasbeyondhistory.net/st-plains/nature/images/pecan.html. Accessed October 16, 2017.
  21. Moerman D. Native American Ethnobotany. Portland, OR: Timber Press; 1998.
  22. Texas State Symbols. Texas State Library and Archives Commission website. August 30, 2017. Available at: www.tsl.texas.gov/ref/abouttx/symbols.html. Accessed November 9, 2017.
  23. O’Neil C, Keast D, Fulgon V, Nicklas T. Tree nut consumption improves nutrient intake and diet quality in US adults: an analysis of National Health and Nutrition Examination Survey (NHANES) 1999-2004. Asia Pacific Journal of Clinical Nutrition. 2010;19(2):142-150.
  24. Kelly J, Sabaté J. Nuts and coronary heart disease: an epidemiological perspective. British Journal of Nutrition. 2006;96 Suppl 2:S61-S67.
  25. Del Gobbo L, Falk M, Feldman R, et al. Effects of tree nuts on blood lipids, apolipoproteins, and blood pressure: systematic review, meta-analysis, and dose-response of 61 controlled intervention trials. American Journal of Clinical Nutrition. 2015;102(6):1347-1356.
  26. Rajaram S, Burke K, Connell B, et al. A monounsaturated fatty acid-rich pecan-enriched diet favorably alters the serum lipid profile of healthy men and women. Journal of Nutrition. 2001;131(9):2275-2279.
  27. Hudthagosol C, Haddad E, McCarthy K, et al. Pecans acutely increase plasma postprandial antioxidant capacity and catechins and decrease LDL oxidation in humans. Journal of Nutrition. 2011;141(1):56-62.
  28. Lovejoy J. The impact of nuts on diabetes and diabetes risk. Current Diabetes Reports. 2005;5(5):379-384.
  29. Morgan W, Clayshulte B. Pecans lower low density lipoprotein cholesterol in people with normal lipid levels. Journal of the American Dietetic Association. 2000;100:312-318.
  30. Basic Report: 12142, Nuts, pecans. National Nutrient Database for Standard Reference Release 28. United States Department of Agriculture Agricultural Research Service. Available at: https://ndb.nal.usda.gov/ndb/foods/show/3681. Accessed October 16, 2017.
  31. Pecan pie energy bites – vegan + gluten free. Gluten Free Vegan Pantry website. April 24, 2015. Available at: www.glutenfreeveganpantry.com/pecan-pie-energy-bites-vegan-gluten-free/. Accessed October 19, 2017.

 

Food as Medicine: Chia (Salvia hispanica, Lamiaceae)

Chia (Salvia hispanica, Lamiaceae) is an annual herb native to Mexico and Guatemala that requires fertile, well-drained soil and subtropical climate conditions to set seed in the late summer months of July and August.1-4 Chia is the most common name for this plant, but it is also sometimes called Spanish sage, lime-leaf sage, Mexican chia, and black chia.2,4 The plant grows to three feet (0.9 meters) tall when mature, and has opposite, serrated leaves that are 1.5-3 inches (3.8-7.6 cm) long and 1-2 inches (2.5-5 cm) wide, and produces small white or purple flowers on the tips of its terminal stems.2,4,5 Chia’s leaves contain essential oil that acts as a defense mechanism to repel insects.2 The edible part of the chia plant is the seeds,5-7which are small (2 mm in length), flat, and oval-shaped.2 Although dark chia seeds are predominantly gray with dark spots,7 they can also appear white, black, black spotted, or dark brown, and may differ slightly in size and weight.2,5

Phytochemicals and Constituents

Chia seed has high levels of protein, omega-3 fatty acids, fiber, and specific vitamins and minerals.2,7 The seed also contains all essential amino acids and is high in antioxidants.8 A gram of chia seeds contains about 0.28 g fiber, 0.21 g protein, and 0.6 g/g of the omega-3 fatty acid alpha-linolenic acid (ALA), which is the highest proportion of ALA of any known plant source.9 Chia seed and its oil have an abundance of polyunsaturated fatty acids (PUFAs). ALA is the most predominant fatty acid found in chia, followed by the omega-6 fatty acids linoleic acid and oleic acid.

Omega-6 fatty acids have pro-inflammatory, hypertensive, and prothrombotic properties.5Omega-3 fatty acids, however, are associated with numerous health benefits and have anti-inflammatory, anti-diabetic, lipid-lowering, cardioprotective, and hepatoprotective properties. For maintenance of good health, omega-3 fatty acids should be incorporated in the diet at higher amounts than omega-6 fatty acids. The omega-3:omega-6 ratio found in chia seeds is about 3:1.6,7 The amount of oil within chia seed ranges from 25-40%.2,5

In comparable serving sizes, the protein content of chia seeds exceeds that of seeds such as amaranth (Amaranthus spp., Amaranthaceae) and quinoa (Chenopodium quinoa, Chenopodiaceae).2 The primary determinant of a high-quality protein is its digestibility or the amount of protein absorbed by the body relative to the amount consumed. For chia seed flour, protein digestibility is nearly 80%, which is comparable to processed cereal grains such as wheat (Triticum aestivum, Poaceae) and oats (Avena sativa, Poaceae); however, chia contains a much higher percentage of protein per serving than these grains.10Furthermore, chia seed contains high levels of the amino acids glutamic acid, arginine, and aspartic acid.2In addition to an abundance of these non-essential amino acids, chia seed contains all nine essential amino acids that the body is unable to produce and is therefore considered a complete protein, unlike other plant protein sources such as chickpeas (Cicer arietinum, Fabaceae). Chia seed contains low concentrations of prolamins (< 15%), which suggests that it can be safely incorporated into the diet of patients with celiac disease.2,10

Approximately two tablespoons (one ounce or about 28 grams) of chia seed provides almost 40% of an average person’s daily fiber intake, as recommended by the US Food and Drug Administration (FDA). Total dietary fiber includes both soluble and insoluble forms that are important for reducing the risk of cardiovascular disease, diabetes, and certain types of cancer.2 Compared to other foods, chia seed contains more dietary fiber than an equivalent volume of flax (Linum usitatissimum, Linaceae) seed. High fiber intake also promotes gastrointestinal and digestive health.

Chia seeds and oil are not only known for their macronutrient and micronutrient contents, but also for their antioxidant properties.7 Phenolic compounds present in chia have been found to protect against certain diseases, such as cardiovascular disease and diabetes.11 The most important polyphenols found in chia seeds and seed oil include chlorogenic and caffeic acids, which play a crucial role in the protection against free radicals and inhibit fat, protein, and DNA peroxidation.2,11,12 The flavonols myricetin, quercetin, and kaempferol are other active compounds present in chia seeds.7 Flavonols are known for their antioxidant, cytotoxic, anti-inflammatory, and anti-thrombotic effects.5,13 Researchers have found that these polyphenols and others found in chia seed and seed oil (e.g., rosmarinic, protocatechuic, and gallic acids) have a high antioxidant capacity.12,14

Historical and Commercial Uses

Chia has been used by Mesoamerican cultures for more than 1,000 years for medicinal, culinary, artistic, and religious purposes.7,15 The Chumash and Cahuilla peoples in the coastal southern regions of California cultivated chia for its seeds, which were collected, hulled, and winnowed by hand.16 After the introduction of wheat, chia was still a preferred crop, and small amounts of chia flour were used to improve the flavor of wheat flour.

The seed of the chia plant is the part most often used for medicinal purposes, but the root and aerial parts were also used occasionally.15 Prior to Spanish colonization in the 16th century, chia seed was used by native tribes to provide energy, treat respiratory infections, and for obstetrics treatment. Prized by Aztec warriors in central Mexico, chia seeds were eaten to promote endurance and consumed with bread prior to battle or with water before running long distances.8

The Diegueño people of Baja California took chia seeds on journeys, kept a few seeds in the mouth and periodically chewed them to maintain their strength.16 One tablespoon of chia seed was believed to be sufficient to feed a person for a day. After the 16th century, a mucilaginous paste made from chia seeds and water was used therapeutically to treat eye obstructions and infections.17 Medical uses of chia seed prior to Spanish colonization included soothing skin conditions, treating gastrointestinal conditions, lowering fevers, and as a poultice for open wounds.15,16

The chia seed has been used for culinary purposes in multiple forms: whole, ground (flour), mucilage, and oil.7,15 Seeds were ground into flour and used to make biscuits, cakes, and a porridge called pinole.16 Traditional foods, such as tortillas and tamales, were made from chianpinolli, or roasted and ground chia seed.15,17 Chia flour was used to make an array of beverages during the height of the Aztec Empire, but modern use of this tradition has declined.15 The most recognized use of chia seeds in the 18th and 19th centuries was infusing chia seeds in water, which was believed to make the alkaline desert water taste more palatable. “Chia fresca,” or “agua de Chia,” was also a popular, thirst-quenching beverage that combined chia seeds with fruit juices.15-17

Chia seed oil was also used for artistic purposes, primarily in paints and lacquers to create a glossy finish on clay or gourd vessels.15 The oil was also used as the basic ingredient for ceremonial face or body paint. Chia-infused beverages were historically consumed during ceremonies, festive occasions, and holy observances. Other religious uses included the use of chia flour to make dough that was formed into the shape of the goddess Chicomecoatl, the “maker and giver of things necessary to live,” as an offering. With the rediscovery of chia as an important food source, modern uses of chia seed and oil focus on its omega-3 fatty acid content for nutritional supplementation, and it is sold commercially as cold-pressed seed oil or whole seeds as ingredients for baked goods, snacks, bread, yogurt, and bars.2

In 1977, the Chia Pet, small hollow-bodied animal figurines made out of terra cotta, became a registered trademark of Joseph Enterprises, Inc.18 Moistened chia seeds are applied to the grooved ridges on the outside of the figurine, and water is added to the hole inside the figurine to help the seeds germinate. Within days, the figure grows a thick coat of chia sprouts. For more than 30 years, Chia Pets have offered customers amusement and an introductory lesson to the practice of cultivating plants.

Modern Research

Cardiovascular Disease Risk Factors

The nutrient profile and bioactive compounds found in chia seed and oil have demonstrated cardioprotective effects by reducing disease risk factors in humans. Hypertension, a known risk factor for developing cardiovascular disease, is generally asymptomatic and can be difficult to control with drug therapies alone. Diet interventions can offer a complementary approach.19 Supplementation with ground chia seed for 12 weeks was shown to reduce blood pressure in individuals with treated and untreated hypertension. Participants in the study were randomly assigned to one of three groups: consumption of chia with previously used medications (CHIA-MD), chia without medications (CHIA-NM), or a placebo group with medications (PLA-MD). Subjects in the two treatment groups consumed 35 grams of chia flour per day. The PLA-MD group received 35 grams of roasted wheat bran as a placebo. Researchers found that the two chia groups had significantly reduced diastolic and systolic blood pressures from baseline. The CHIA-MD group also had significantly reduced total blood pressure from baseline.

A 2015 systematic review investigated current literature on consumption of whole or ground chia seeds and its effect on preventing or managing risk factors associated with heart disease, such as hypertension, diabetes, dyslipidemia, and obesity.20 The review focused on seven clinical trials published between 2007 and 2013. The chia seed preparations used in the studies varied in quantity (4-50 grams per day) and type (e.g., whole or milled). There were also differences in sample size, methodology, and participant characteristics (e.g., diabetic, obese, hypertensive). Therefore, the authors state that the findings on chia consumption and the effects of reducing cardiovascular risk factors are inconclusive. They recommend additional randomized, double-blind, placebo-controlled clinical trials on the consumption of chia to obtain reliable results and to determine an appropriate dose for cardioprotective benefits.

Obesity is a condition that has been associated with a state of chronic oxidative stress. Reactive oxygen species damage cell proteins, lipids, and DNA, and can result in impaired function and potentially cell death. Obesity also impedes the body’s enzymatic antioxidant system, reducing the activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase.24 Additionally, obesity correlates with a reduction in levels of protective thiols, vitamins, minerals, and polyphenols. A study on chia seed’s efficacy for weight loss and decreasing disease risk factors in overweight adults found increases in plasma ALA levels. However, consumption of chia seed in high doses (50 grams per day) had no effect on weight loss or changes in disease risk factors related to cardiovascular disease (e.g., blood pressure, high-density and low-density lipoprotein, total cholesterol, or blood triglyceride levels).21Another randomized, double-blind, placebo-controlled study assessed the effectiveness of chia seed (whole or ground) supplementation for changing disease risk factors for overweight women.22 For 10 weeks, participants consumed 25 grams per day of ground or whole chia seeds or a placebo. Multiple outcome measures were assessed, and researchers observed a 58% and 39% increase in plasma ALA and eicosapentaenoic acid (EPA) levels, respectively, in the ground chia treatment group.

Glucose Levels

The use of chia as a food ingredient holds promise in the area of so-called “functional foods.” A 2013 study observed the effects of bread supplemented with chia seed flour on post-prandial (after-meal) blood sugar levels in healthy adults. Thirteen healthy adults consumed nine test meals that included bread supplemented with different doses (seven, 15, and 24 grams) of whole or ground chia.23 Bread without chia was used as the control. Researchers concluded there was a significant dose-dependent effect on blood glucose levels for both whole and ground seeds compared to the control, but no differences were evident between the same doses of the whole and ground seed groups. This may indicate that the quantity of seeds given in the diet will demonstrate hypoglycemic properties and not the form in which chia is ingested. The seeds used in the study were a specific varietal bred from black chia and proved effective for reducing blood glucose levels, but future research is needed to further investigate the benefits of different chia strains.

Antioxidant Properties

Chia’s antioxidant potential was analyzed in a 2015 rat study.24 Results demonstrated that daily consumption of chia seed and chia seed oil enhanced plasma antioxidant levels through catalase, glutathione peroxidase and thiol level reduction. Chia seed and seed oil intake resulted in a significant reduction in plasma levels of 8-isoprostane, the most specific biological indicator for assessing oxidative stress in vivo. High levels of 8-isoprostane can occur with a diet high in fat and fructose and result in pro-oxidative effects. This may be the mechanism by which chia seed and seed oil produce a hypolipidemic effect. Lipid peroxidation in rat livers was not reversible; however, levels of glutathione reductase were increased as well as thiol levels, resulting in improved antioxidant status.

Other Uses

Carbohydrate-loading refers to the practice of increasing dietary intake of carbohydrates prior to athletic events that last more than 90 minutes. This intake results in a greater capacity of muscle glycogen stores and aids in improved athletic performance.8 A 2011 study compared performance test results of six male marathon runners who were given two different carbohydrate-loading treatments: a commercial sports drink and the same commercial sports drink supplemented with chia. The runners participated in two trials in a crossover, counterbalanced, repeated-measure design with a two-week washout period between testing to allow participants to recover from the intense exercise and to avoid any carry-over effects from the treatments. While the researchers found no statistical difference between the control and the test groups in performance parameters, the athletes in the chia group significantly decreased their dietary intake of sugar while boosting intake of omega-3 fatty acids, which indicates that the chia drink may be a healthier option for athletes who choose to carbohydrate-load.

Chia seed oil is also used topically. Approximately 30% of patients with diabetes or end-stage renal disease (ESRD) suffer from skin disorders including pruritus, which is characterized by itchy, dry skin and inflammatory lesions caused by scratching.13 This study followed five patients with these conditions (three with diabetes; two with ESRD) and five patients without these conditions who all exhibited xerotic pruritus (abnormally dry, itchy skin) for eight weeks. A topical oil and water emulsion containing 4% chia seed oil were applied to the affected skin. Lotion without chia seed oil was used on participants as a placebo. After eight weeks of application, statistically significant improvements in skin hydration, chronic itching, and prurigo nodularis (hard, itchy lumps on the skin) were observed in the treatment group with diabetes and ESRD, while similar significant improvements in skin hydration and epidermal permeability were also observed in the group of patients without these conditions.

Consumer Considerations

Consumption of whole or ground chia seed has shown no evidence of toxicity or allergenic effects.2However, the Dietary Guidelines for Americans, eighth edition, issued by the US Department of Health and Human Services and US Department of Agriculture listed a standard portion size of chia as one tablespoon (or roughly 50 grams) per day.25 This may be due to clinical studies that have not exceeded a dose of 50 grams per day, and thus the potential adverse effects have not been adequately studied above this amount.

The PUFA content, as well as the low concentration of tocopherol and phenolic compounds, account for the low oxidative stability of chia oil. Within 300 days, a 30% drop in the tocopherol content of chia seed oil was observed.9 The antioxidant capacity of chia oil is relatively low due to the hydrophilic nature of the phenolic compounds within the chia seed. Despite chia seed’s rich omega-3 and omega-6 content, there is a technological disadvantage in the production of chia seed oil in regards to its stability and short shelf life, especially when exposed to light or oxygen. Chia seed oil is best kept in the refrigerator after opening and should be used quickly to gain its full range of nutrients.

Nutrient Profile26

Macronutrient Profile: (Per 1-ounce seeds)

138 calories
4.7 g protein
11.9 g carbohydrate
8.7 g fat

Secondary Metabolites: (Per 1-ounce seeds)

Excellent source of:

Manganese: 0.8 mg (40% DV)
Dietary Fiber: 9.8 g (39.2% DV)
Phosphorus: 244 mg (24.4% DV)
Magnesium: 95 mg (23.8% DV)

Very good source of:

Calcium: 179 mg (17.9% DV)
Thiamin: 0.2 mg (13.3% DV)
Niacin: 2.5 mg (12.5% DV)
Iron: 2.2 mg (12.2% DV)

Also provides:

Folate: 14 mcg (3.5% DV)
Potassium: 115 mg (3.3% DV)
Riboflavin: 0.05 mg (3% DV)

Trace amounts of:

Vitamin C: 0.5 mg (0.8% DV)
Vitamin E: 0.14 mg (0.7% DV)
Vitamin A: 15 IU (0.3% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000-calorie diet.

Strawberries-and-Cream-Chia-Pudding-4-2

Recipe: Strawberries and Cream Chia Pudding

Adapted from Emily Han27

Ingredients:

  • 8 ounces fresh strawberries
  • 3/4 cup coconut milk
  • 2 tablespoons honey
  • 1/2 teaspoon vanilla extract
  • 1/2 teaspoon grated lime zest
  • 1/4 cup chia seeds

Directions:

  1. Combine the strawberries, coconut milk, honey, vanilla, and lime zest in a blender. Puree until smooth. Taste and add more honey, if desired.

  2. Place the chia seeds in a large bowl and add the strawberry mixture. Whisk thoroughly to combine. Let the mixture stand for 10 minutes, then whisk again.

  3. Cover and refrigerate for at least four hours and up to three days. Stir before serving. The pudding will set up thicker the longer it sits.

References

  1. Salvia hispanica – L. Plants for a Future website. Available at: www.pfaf.org/user/Plant.aspx?LatinName=Salvia+hispanica. Accessed August 24, 2017.
  2. Muñoz LA, Cobos A, Diaz O, Aguilera JM. Chia seed (Salvia hispanica): An ancient grain and a new functional food. Food Reviews International. 2013;29:394-308.
  3. Taxon: Salvia hispanica L. US National Plant Germplasm System website. Available at: https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?32939. Accessed August 24, 2017.
  4. Kaiser C, Ernst M. Center for Crop Diversification Crop Profile: Chia. Lexington, KY: University of Kentucky College of Agriculture, Food and Environment. February 2016.
  5. Ali NM, Yeap SK, Ho WY, Beh BK, Tan SW, Tan SG. The promising future of chia, Salvia hispanica L. Journal of Biomedicine and Biotechnology. 2012;171956.
  6. Porras-Loaiza P, Jiménez-Munguía MT, Sosa-Morales ME, Palou E, López-Malo A. Physical properties, chemical characterization and fatty acid composition of Mexican chia (Salvia hispanica L.) seeds. International Journal of Food Science and Technology. 2014;49:571-577.
  7. Valdivia-López MA, Tecante A. Chia (Salvia hispanica): A review of native Mexican seed and its nutritional and functional properties. Advances in Food and Nutrition Research. 2015;75:54-71.
  8. Illian TG, Casey JC, Bishop PA. Omega 3 chia seed loading as a means of carbohydrate loading. Journal of Strength and Conditioning Research. 2011;25(1):61-65.
  9. Bodoira RM, Penci MC, Ribotta PD, Martínez ML. Chia (Salvia hispanica L.) oil stability: Study of the effect of natural antioxidants. LWT – Food Science and Technology. 2017;75:107-113.
  10. Kačmárová K, Lavová B, Socha P, Urminská D. Characterization of protein fractions and antioxidant activity of chia seeds (Salvia hispanica L.). Potravinarstvo. 2016;10(1):78-82.
  11. Pandey KB, Rizvi SI. Plant polyphenols as dietary antioxidants in human health and disease. Oxidative Medicine and Cellular Longevity. 2009;2(5):270-278.
  12. da Silva Marineli R, Moraes ÉA, Lenquiste SA, Godoy AT, Eberlin MN, Maróstica Jr MR. Chemical characterization and antioxidant potential of Chilean chia seeds and oil (Salvia hispanica L.). LWT – Food Science and Technology. 2014;59:1304-1310.
  13. Jeong SK, Park HJ, Park BD, Kim I. Effectiveness of topical chia seed oil on pruritus of end-stage renal disease (ESRD) patients and healthy volunteers. Ann Dermatol. 2010;22(2):143-148.
  14. Martínez-Cruz O, Paredes-López O. Phytochemical profile and nutraceutical potential of chia seeds(Salvia hispanica L.) by ultra high performance liquid chromatography. Journal of Chromatography A. 2014;1346:43-48.
  15. Cahill J. Ethnobotany of chia, Salvia hispanica L. (Lamiaceae). Economic Botany. 2003;57(4):604-618.
  16. Immel DL. Plant Guide: Chia. Washington DC: United States Department of Agriculture Natural Resources Conservation Service. 2003.
  17. Hershey DR. Don’t just pet your chia. Science Activities. 1995;32(2):8-12.
  18. Edwards O. Chia Pet. Smithsonian Magazine. December 2007. Available at: www.smithsonianmag.com/arts-culture/chia-pet-180308610/. Accessed August 24, 2017.
  19. Toscano LT, Oliveira da Silva CS, Toscano LT, Monteiro de Almeida AE, Santos AdC, Silva AS. Chia flour supplementation reduces blood pressure in hypertensive subjects. Plant Foods Hum Nutr. 2014;69:392-398.
  20. de Souza Ferreira C, de Sousa Fomes LdF, Santo da Silva GE, Rosa G. Effect of chia seed (Salvia hispanica L.) consumption on cardiovascular risk factors in humans: a systematic review. Nutrición Hospitalaria. 2015;32(5):1909-1918.
  21. Nieman DC, Cayea EJ, Austin MD, Henson DA, McAnulty SR, Jin F. Chia seed does not promote weight loss or alter disease risk factors in overweight adults. Nutrition Research. 2009;29:414-418.
  22. Nieman DC, Gillitt N, Jin F, et al. Chia seed supplementation and disease risk factors in overweight women: a metabolomics investigation. J Alt Complement Med. 2012;18(7):700-708.
  23. Ho H, Lee AS, Jovanonvski E, Jenkins AL, DeSouza R, Vuksan V. Effect of whole and ground Salba seeds (Salvia hispanica L.) on postprandial glycemia in healthy volunteers: A randomized controlled, dose-response trial. Eur J Clin Nutr. 2013;67:786-788.
  24. da Silva Marineli R, Lenquiste SA, Moraes ÉA, Maróstica Jr. MR. Antioxidant potential of dietary chia seed and oil (Salvia hispanica L.) in diet-induced obese rats. Food Research International. 2015;76:666-674.
  25. US Department of Health and Human Services and US Department of Agriculture. 2015-2020 Dietary Guidelines for Americans. 8th ed. December 2015. Available at: http://health.gov/dietaryguidelines/2015/guidelines. Accessed September 14, 2017.
  26. Basic Report: 12006, Seeds, chia seeds, dried. United States Department of Agriculture Agricultural Research Service website. Available at: https://ndb.nal.usda.gov/ndb/foods/show/3610. Accessed August 23, 2017.
  27. Han E. Dairy-Free Dessert Recipe: Strawberries & “Cream” Chia Pudding. The Kitchn website. May 8, 2013. Available at: www.thekitchn.com/recipe-strawberry-chia-pudding-recipes-from-the-kitchn-189016. Accessed August 23, 2017.
  28. Bauman H, Bates K. Food as Medicine: Strawberry (Fragaria x ananassa, Rosaceae). HerbalEGram. 2015;12(5). Available at: http://cms.herbalgram.org/heg/volume12/05May/FaM_Strawberry.html. Accessed September 11, 2017.

Food as Medicine Horseradish (Armoracia rusticana, Brassicaceae)

History and Traditional Use

Range and Habitat

Horseradish (Armoracia rusticana, Brassicaceae) is a hardy perennial native to southeastern Europe and western Asia. Today, it is grown in the temperate regions of Europe, Asia, and North and South America, as well as some parts of Africa and New Zealand.1 The plant grows in clumps with bright green leaves that radiate out from the main taproot, which is cultivated as a food ingredient.2 Small, white, four-petaled flowers grow from a stalk that can reach two to three feet or higher when flowering.2 Young leaves two to three inches in length also can be harvested for use in salads.3

Horseradish is easy to cultivate and often will continue to thrive even during periods of neglect.4 While technically a perennial, it is best treated as an annual or biennial crop due to the root’s tendency to become woody and unpalatable with age. Once established, horseradish grows well in full sun and slightly moist soil.1


Phytochemicals and Constituents

Glucosinolates, sulfur-containing secondary metabolites, give horseradish its characteristic spicy flavor.5Horseradish contains eight different glucosinolates, of which sinigrin, gluconasturtiin, glucobrassicin, and neoglucobrassicin are the most common.5 Once inside the body, glucosinolates are broken down into powerful derivatives called isothiocyanates and indoles, which are believed to be the main cancer-preventive constituents of horseradish and other cruciferous vegetables (i.e., vegetables of the family Brassicaceae).1,6

Horseradish also contains minerals such as phosphorous, calcium, magnesium, and potassium.Freshly grated roots contain minimal fat, are low in calories, and rich in vitamin C. Cooking horseradish can strip it of its nutritional value, so it is best used fresh.1


Historical Uses

Horseradish root has been ground into a spice, prepared as a condiment, and used medicinally for more than 3,000 years. It was used topically by both the Greeks and Romans as a poultice to ease muscle pain, such as backaches and menstrual cramps.3 Internally, it was used to relieve coughs and as an aphrodisiac.4 Starting in the Middle Ages (ca. 1000-1300 CE), horseradish was incorporated into the Jewish Passover Seder as one of the maror, or bitter herbs.In the 16th century, Europeans began using horseradish in sauces and condiments as well as for its medicinal applications.

Historically, horseradish was used to treat a wide variety of illnesses including asthma, coughs, colic, toothache, and scurvy (due to its vitamin C content). Grated horseradish poultices were used to ease pain associated with gout and sciatica, and also were infused in milk to clarify the skin and remove freckles.3Currently, horseradish is consumed regularly in the form of ready-to-use sauces and dips.2 In 2005, the Horseradish Information Council reported that in the United States, 24 million pounds of horseradish roots were processed into six million gallons of prepared horseradish sauce.3


Modern Research & Uses

The chemoprotective role of horseradish’s gluconsinolate content against various types of cancers in humans has been widely studied.8,9 A hydrolyzed form of the glucosinolate sinigrin has been shown to suppress the growth of cancerous tumors in vitro and protect against further DNA damage.9,10 One hypothesis is that glucosinolates may work by enhancing the liver’s ability to detoxify carcinogens.10 Using a rat model, researchers found that sinigrin affects many organs involved in carbohydrate and lipid metabolism, including the liver, pancreas, and intestine.11 Sinigrin also reduced lipid levels in the blood, suggesting that it could be beneficial in reducing elevated triglyceride levels after meals, a risk factor for coronary artery disease.11

Horseradish also contains allyl isothiocyanate, which is a well-recognized antimicrobial agent against a variety of organisms including pathogens like Escherichia coli (E. coli), a common food-borne pathogen, and Helicobacter pylori (H. pylori), a bacteria known to cause stomach ulcers and increase the risk for gastric cancer.12 Due to its antibiotic properties, horseradish can be used to treat urinary tract infections and destroy bacteria in the throat that can cause bronchitis, coughs, and other related problems.13 In a recent study, isothiocyanates extracted from horseradish showed antimicrobial activity against ten different oral microorganisms.14 Although broccoli (Brassica oleracea var. italica), Brussels sprouts (B. oleracea var. gemmifera), and other cruciferous vegetables also contain these compounds, horseradish has up to ten times more glucosinolates than other members of the family Brassicaceae.10

Horseradish root was approved as a nonprescription medicine ingredient by the German Commission E for treatment of infections of the respiratory tract and as supportive treatment in urinary tract infections.13 In the United States, horseradish root is the active ingredient of Rasapen, a urinary antiseptic drug.13Horseradish is considered a strong diuretic and, coupled with its antibacterial properties, acts to flush out harmful bacteria or other inflammatory agents in the bladder sooner than they normally would be eliminated.10

Isothiocyanates in horseradish root are released when hydrolyzed by other active enzymes, which are activated only when the root is scratched.15 Fumes released from grating or cutting the root can irritate the membranes of the eyes and nose, and therefore horseradish should be prepared in a well-ventilated room and care should be taken in its use.


Nutrient Profile


Macronutrient Profile:
 (Per 1 tablespoon [15 g] raw horseradish)

Calories: 7

Protein: 0.18 g

Carbohydrates: 1.69 g

Fat: 0.1 g

Secondary Metabolites: (Per 1 tablespoon [15 g] raw horseradish)

Good source of:
Vitamin C: 3.7 mg (6.2% DV)

Vitamin K: 0.2 mcg (2.5% DV)

Folate: 9 mcg (2.25% DV)

Dietary fiber: 0.5 g (2% DV)

Potassium: 37 mg (1.1% DV)

Magnesium: 4 mg (1% DV)

Calcium: 8 mg (0.8% DV)

Zinc: 0.12 mg (0.8% DV)

Vitamin B6: 0.01 mg (0.5%DV)

Phosphorus: 5 mg (0.5% DV)

Niacin: 0.06 mg (0.3% DV)

DV = Daily Value, as established by the US Food and Drug Administration, based on a 2,000-calorie diet.

Recipe: Kale and Potato Hash

Recipe courtesy of EatingWell magazine16


Ingredients:

  • 8 cups torn kale leaves
  • 2 tablespoons freshly grated horseradish
  • 1 medium shallot, minced
  • 1/2 teaspoon freshly ground pepper
  • 1/4 teaspoon kosher salt
  • 2 cups shredded cooked potatoes
  • 3 tablespoons extra virgin olive oil

Directions:

  1. Place kale in a large microwave-safe bowl, cover, and microwave until wilted, about 3 minutes. Drain, cool slightly and finely chop.

  2. Meanwhile, mix horseradish, shallot, pepper, and salt in a large bowl. Add the chopped kale and potatoes; stir to combine.

  3. Heat oil in a large nonstick skillet over medium heat. Add the kale mixture, spread into an even layer, and cook, stirring every 3 to 4 minutes and returning the mixture to an even layer, until the potatoes begin to turn golden brown and crisp, 12 to 15 minutes total.

References

  1. Small E, ed. Culinary Herbs. Ottawa, ON: NRC Research Press; 1997.
  2. Van Wyk B-E. Food Plants of the World: An Illustrated Guide. Portland, OR: Timber Press; 2005.
  3. The Essential Guide to Horseradish. The Herbal Society of America website.  Available here. Accessed January 5, 2015.
  4. National Geographic Society. Edible: An Illustrated Guide to the World’s Food Plants. Washington, DC: National Geographic Society; 2008.
  5. Alnsour M, Kleinwächter M, Böhme J, Selmar D. Sulfate determines the glucosinolate concentration of horseradish in vitro plants (Armoracia rusticana Gaertn., Mey. & Scherb.). J Sci Food Agric. 2013;93(4):918-923.
  6. Rinzler CA. The New Complete Book of Herbs, Spices, and Condiments: A Nutritional, Medical, and Culinary Guide. New York, NY: Checkmark Books; 2001.
  7. US Department of Agriculture. USDA National Nutrient Database for Standard Reference, Release 27. Available here. Accessed January 5, 2015.
  8. Hayes JD, Kelleher MO, Eggleston IM. The cancer chemopreventive actions of phytochemicals derived from glucosinolates. Eur J Nutr. 2008;47(2):73-88.
  9. Bonnesen C, Eggleston IM, Hayes JD. Dietary indoles and isothiocyanates that are generated from cruciferous vegetables can both stimulate apoptosis and confer protection against DNA damage in human colon cell lines. Cancer Res. 2001;61(16):6120-6130. Available here. Accessed January 5, 2015.
  10. Patel DK, Patel K, Gadewar M, Tahilyani V. A concise report on pharmacological and bioanalytical aspect of sinigrin. Asian Pac J Trop Biomed. 2012;2(1):S446-S448.
  11. Okulicz M. Multidirectional time-dependent effect of sinigrin and allyl isothiocyanate on metabolic parameters in rats. Plant Foods Hum Nutr. 2010;65(3):217-224.
  12. Luciano FB, Holley RA. Enzymatic inhibition by allyl isothiocyanate and factors affecting its antimicrobial action against escherichia coli O157:H7. Int J Food Microbiol. 2009;131(2): 240-245.
  13. Blumenthal M, Goldberg A, Brinkmann J, eds. Herbal Medicine: Expanded Commission E Monographs.Austin, TX: American Botanical Council and Newton, MA: Integrative Medicine Communications; 2000.
  14. Park HW, Choi KD, Shin IS. Antimicrobial activity of isothiocyanates (ITCs) extracted from horseradish (Armoracia rusticana) root against oral microorganisms. Biocontrol Sci. 2013;18(3):163-168. Available here. Accessed January 5, 2015.
  15. Duke JA, ed. CRC Handbook of Medicinal Spices. Boca Raton, FL: CRC Press; 2002.
  16. Kale and Potato Hash. EatingWell. October/November 2005. Available here. Accessed January 13, 2005.

Food as Medicine: Kiwifruit (Actinidia deliciosa, Actinidiaceae)

Kiwifruit (Actinidia deliciosa, Actinidiaceae), also known by the less common name “Chinese gooseberry,” is one of 50 known species within the genus Actinidia.1 These species are climbing, woody vines with large, heart-shaped leaves and cream-colored flowers that bloom in the spring. The flowers are dioecious, with male and female blossoms found in separate individuals. The kiwifruit matures in early winter and typically has brown fuzzy skin. Depending on the species, the flesh is either green or yellow, but all species are filled with small black, edible seeds.1 While A. deliciosa accounts for about 90% of kiwifruit in international trade, two other species are cultivated and sold commercially: A. Chinensis and A. arguta.2 Actinidia deliciosa is the common green kiwifruit.3 The most common cultivar of A. chinensis is “Hort16A,” known by the brand name ZESPRI, or “gold kiwifruit.”4Actinidia arguta is referred to as “baby kiwi” or “grape kiwi” due to the small size of its fruits.2Actinidia species are native to southwestern China, but they are now cultivated in New Zealand, the United States, Italy, France, Chile, and Japan.5

Phytochemicals and Constituents

Kiwifruit provides fiber, potassium, folate, phosphorus, copper, and vitamins A, C, E, and K.3,6 In fact, one kiwifruit provides more than the Recommended Dietary Allowance (RDA) of vitamin C for adults and almost 35% of the RDA of vitamin K. Vitamin C has numerous health benefits, including anticarcinogenic and immune-regulating properties.3,7 In addition, it plays a role in the formation of collagen, a major component of connective tissue, skin, and bones. Vitamin C intake also has been shown to help mitigate a number of conditions, including cardiovascular disease and inflammation.8 Vitamin E is an antioxidant that stops the oxidation of low-density lipoprotein (LDL) cholesterol and protects cell membranes against damage caused by reactive oxygen species.9 Vitamin E also helps maintain the structure and function of skeletal, cardiac, and smooth muscles. Vitamin K regulates blood clotting, aids in the transfer of calcium through the body, and supports bone health, reducing the risk of osteoporosis and bone fractures due to age.10

Kiwifruit is also a good source of fiber, which contributes to its laxative effect. Additionally, the lignins in cellulose (a form of dietary fiber) are believed to have antimutagenic properties due to their ability to increase the adsorption of aromatic amines in the gut, thus preventing them from entering the bloodstream. Aromatic amines can act as carcinogens after they have been metabolized by the liver.3

One of the interesting compounds present in kiwifruit is actinidin, an enzyme that helps to hydrolyze proteins. Due to the actinidin content of kiwifruit, other fruits and dairy products will soften or curdle upon prolonged contact with the chopped fruit, so kiwifruit should be added at the last minute to fruit salads and other mixed preparations. Actinidin has been shown to improve digestion by assisting with protein digestion and digestive motility.11 Kiwifruit contains numerous other bioactive compounds, including organic acids, plant pigments, and polyphenols. The primary organic acid in kiwi is citric acid, but it also contains malic, quinic, gallic, and oxalic acids. Organic acids provide the fruits with significant antioxidant properties.

Some of the plant pigments present in kiwifruit include carotenoids and chlorophyll, and some cultivars also contain anthocyanins.11 The carotenoids include beta-carotene, lutein, violaxanthin, and 9’-cis-neoxanthin.3 When compared with other commonly consumed fruits, kiwifruit is the richest source of lutein, which is a carotenoid that is highly concentrated in the macula of the eye and is associated with lowering risk of cataracts. All Actinidia species contain chlorophylls a and b, but levels are much lower in the gold kiwi variety. Some kiwifruits also contain anthocyanins, but they are not a significant component of the antioxidant capacity of the fruit. Glutathione is another important antioxidant present in kiwifruit, and it not only prevents oxidative damage of cells but also helps to keep vitamins C and E in their active form, regenerating their antioxidant capacities.11

Historical and Commercial Uses

Kiwifruit is featured in Chinese literature dating back to the 15th century.12 The kiwifruit was originally called mi hou tao, or “monkey peach,” because monkeys would eat the fruit in the wild.4 Traditionally, both the root and the fruit of A. chinensis were used in traditional Chinese medicine and are known as xiao yang tao. The root of A. Chinensis contains antiangiogenic phytochemicals including triterpenes, polyphenols, and anthraquinones, and it has been noted in the Chinese pharmacopeia as being useful for treating many diseases, such as stomach, rectal, and breast cancers, as well as hepatitis viral infections.12-14 The fruit of A. Chinensis was used as a juice to quench thirst, aid digestion, clear heat, and reduce irritability, inflammation, and vomiting.3,14

Other Actinidia species were used for their therapeutic effects as well. Historically, A. macrosperma was used to stimulate the immune system and A. polygama was used as an anti-inflammatory agent and to counteract allergies due to its anti-asthmatic effect.3,15

Modern Research

Clinical trials for kiwifruit primarily have focused on its effects on the digestive, immune, and cardiovascular systems. Preliminary research has also investigated the antioxidant properties of kiwifruit and its possible inhibitory effect on cancerous cell growth.

Gastrointestinal System

Clinically, kiwifruit has been shown to have a laxative effect. Daily consumption of the fruit improved the frequency and ease of bowel movements and improved stool bulk and softness in healthy older adults.3 In another study, researchers found that daily kiwifruit intake relieved symptoms in subjects suffering from chronic constipation, with no reports of adverse effects like diarrhea.3 Additionally, a trial in healthy subjects who were not experiencing constipation found no adverse gastrointestinal effects from daily consumption of kiwifruit.16

These gastrointestinal benefits are attributed to the lubricating effects of kiwifruit’s pectin and the enzyme actinidin, which combine with the enzymes in the stomach and the small intestine to improve digestion.4The pectin and fiber present in kiwifruits also function as prebiotics. Prebiotics help to modify the composition of the bacterial flora in the gut so that healthy bacteria are stimulated and harmful bacteria are suppressed. An in vitro study looked at the prebiotic effect of the pectin present in kiwifruit compared to other prebiotics like inulin, guar gum, and citrus pectin. The pectin in kiwifruit was more effective than these prebiotics in reducing the intestinal adhesion of harmful bacteria and increasing the adhesion of beneficial bacteria.17 In a mouse study on irritable bowel disease (IBD), extracts of both green and golden kiwifruit were administered, resulting in a potent anti-inflammatory effect. These results indicate that further research should be done exploring the medicinal properties of kiwifruits in the treatment of IBD.18

Antibacterial and Immunological Activity

In an in vitro study, essential oil from A. macrosperma produced inhibitory effects against a number of common bacteria, including Escherichia coli and Staphylococcus aureus, as well as three common fungal species.3 In a mouse study, kiwifruit extract was shown to alter innate and acquired immunity when the mice were injected with cholera and diphtheria/tetanus vaccines.15 This could have implications for improving immunity in vaccinated individuals, particularly children and other high-risk populations.

Other animal studies have shown that extracts of A. arguta may have anti-allergenic effects, implying a potential for the use of kiwi extracts as therapies for allergy conditions like bronchial asthma or eczema.3 A human trial observed the effects of daily intake of golden kiwifruit on both older adults (older than 65 years) and young children (ages 2-5) in relation to cold and flu-like illnesses. For the adults, those who ate four kiwifruits daily had symptoms for fewer days over the course of a cold than the adults who ate two bananas (Musa acuminata, Musaceae) daily. In the preschool children, the odds of getting a cold or the flu decreased by almost half in the children who ate two kiwifruits daily instead of one banana.4

Cardiovascular System

There is some evidence that kiwifruit may have the ability to affect risk factors for cardiovascular disease, like blood pressure, plasma triglycerides, and platelet aggregation. A human study showed that eating two to three kiwifruits per day reduced triglyceride levels by 15% and reduced platelet aggregation response by18% compared to control.19Multiple studies have shown that daily kiwi consumption improves not only triglyceride levels but also the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol. One clinical trial studied male smokers who ate three kiwis per day for eight weeks. The patients had significantly reduced blood pressure and angiotensin-converting enzyme (ACE) activity (a component of the blood pressure-regulation process), especially those with hypertension. A number of in vitro studies support the claim that kiwifruit reduces platelet aggregation, but clinical trials are conflicting and more human studies are needed to confirm this effect.4

Antioxidant and Cytotoxic Properties

The vitamin and phytochemical composition of kiwifruit give it powerful antioxidant properties. An in vivo study showed that kiwifruit juice ingestion increased plasma antioxidant capacity within 30 minutes and that these levels were sustained for up to 90 minutes. Though this was not a long-term study, this may have implications for kiwifruit’s ability to fight oxidative stress.3 Similar findings were established through two human studies in the United Kingdom, which showed that kiwifruit consumption improved antioxidant status of both the plasma and lymphocytes of participants. One of these studies also showed that kiwifruit seemed to stimulate DNA repair. A pilot study was performed to extrapolate on this possibility and the results showed that kiwi aided DNA repair for an average of 13 hours after ingestion.7

Though vitamin C is known for its antioxidant power, it also has a synergistic effect on iron absorption. In a study of young women with mild anemia (iron deficiency), participants who consumed two golden kiwifruits with an iron-fortified cereal daily had significantly improved iron levels compared to participants who ate the cereal with a banana. The vitamin C content, along with the carotenoids lutein and zeaxanthin present in kiwifruits, are likely responsible for this outcome.4

There is a great deal of investigation into the role of antioxidants and other phytochemicals in the prevention of cancerous cell growth, but despite kiwifruit’s history of use in traditional Chinese medicine, there are few clinical trials establishing the connection of the fruit and its constituents with cancer prevention or treatment. In vitro studies have shown that extracts of Actinidia species may be toxic to cancer cells. Additionally, mice studies have shown that kiwifruit juice inhibits the growth of sarcoma cells.12 Another mouse study showed that catechin in the stems of A. arguta and the juice of A. deliciosa increased bone marrow proliferation, which may have implications for reducing the adverse effects of chemotherapy treatments. There has also been evidence suggesting that the prebiotic effect of fiber found in foods may change the bacteria in the colon, providing protection against colon cancer.3

Consumer Considerations

Though it is poorly understood, there is an allergy risk associated with the fruits of Actinidia species. Allergic reactions can range from mild itching of the throat, mouth, and lips, and swelling to anaphylaxis, though it is more common for reactions to be mild. The more severe reactions typically occur in children.4The prevalence of allergies to Actinidia fruits may vary geographically; in France, Finland, and Sweden, kiwifruit is one of the top ten most common allergens.16 Allergies to kiwifruit are often cross-reactive with other common allergens such as pollens, rye (Secale cereale, Poaceae), hazelnut (Corylus avellana, Betulaceae), chestnut (Castanea spp., Fagaceae), banana, and avocado (Persea Americana, Lauraceae). Heat treatment and industrial homogenization have been shown to greatly reduce the allergic reactivity of green kiwi. These treatments are often performed on processed products like beverages and jams.20

Kiwifruit contains oxalate, which is from the salt of oxalic acid. Oxalates can cause oral irritation in some individuals, and they can be risky for individuals with a history of calcium oxalate-containing kidney stones. Oxalate in high concentrations can also reduce the bioavailability of calcium, magnesium, and iron in the body.3 Though kiwifruit contains more than 10 mg of oxalate per serving (enough to be considered high levels), it would require daily consumption of large quantities of kiwifruit for the levels of oxalates in the body to become dangerous. Additionally, oxalate content decreases during storage.16

Nutrient Profile21

Macronutrient Profile: (Per one fruit [approx. 69 grams])

42 calories
0.8 g protein
10.1 g carbohydrate
0.4 g fat

Secondary Metabolites: (Per one fruit [approx. 69 grams])

Excellent source of:

Vitamin C: 64 mg (106.7% DV)
Vitamin K: 27.8 mcg (34.8% DV)

Good source of:

Dietary Fiber: 2.1 g (8.4% DV)
Potassium: 215 mg (6.1% DV)
Vitamin E: 1 mg (5% DV)

Also, provides:

Folate: 17 mcg (4.3% DV)
Manganese: 0.07 mg (3.5% DV)
Magnesium: 12 mg (3% DV)
Calcium: 23 mg (2.3% DV)
Phosphorus: 23 mg (2.3% DV)
Vitamin B6: 0.04 mg (2% DV)
Thiamin: 0.02 mg (1.3% DV)
Niacin: 0.24 mg (1.2% DV)
Riboflavin: 0.02 mg (1.2% DV)
Vitamin A: 60 IU (1.2% DV)
Iron: 0.2 mg (1.1% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000-calorie diet.

Recipe: Kiwi, Lemon, and Rosemary Shrub

Courtesy of Jerry James Stone22

Ingredients:

  • 1 1/2 pounds kiwifruit
  • 2 slices of lemon
  • 1 sprig of rosemary
  • 1 cup sugar
  • 1 cup champagne vinegar

Directions:

  1. Peel and thinly slice the kiwifruit. Arrange a layer of kiwifruit in a quart-sized jar and sprinkle with sugar. Repeat the layering until all the sugar and fruit is in the jar. Seal and let stand for five hours.

  2. Add the lemon, rosemary, and vinegar to the jar. Seal and shake to combine and dissolve the sugar, then let stand for 24 hours.

  3. Strain the mixture through a sieve into a clean quart-sized jar. Seal and refrigerate. To serve, mix two tablespoons of the shrub with sparkling water in an ice-filled glass.

References

  1. The National Geographic Society. Edible: An Illustrated Guide to the World’s Food Plants. Washington, DC: The National Geographic Society; 2008.
  2. Wojdyło A, Nowicka P, Oszmiański J, Golis T. Phytochemical compounds and biological effects of Actinidia fruits. J Funct Foods. 2017;30:194-202. doi:10.1016/j.jff.2017.01.018.
  3. Hunter DC, Skinner MA, Ferguson AR, Stevenson LM. Kiwifruit and health. In: Bioactive Foods in Promoting Health: Fruits and Vegetables. Auckland, New Zealand; 2010:565-580. doi:10.1016/B978-0-12-374628-3.00037-2.
  4. Stonehouse W, Gammon CS, Beck KL, Conlon C, von Hurst PR, Kruger R. Kiwifruit: our daily prescription for health. Can J Physiol Pharmacol. 2013;91(6):442-447. doi:10.1139/cjpp-2012-0303.
  5. van Wyk B-E. Food Plants of the World: An Illustrated Guide. Portland, OR: Timber Press; 2005.
  6. Murray M, Pizzorno J, Pizzorno L. The Encyclopedia of Healing Foods. New York, NY: Atria Books; 2005.
  7. Rush E, Ferguson LR, Cumin M, Thakur V, Karunasinghe N, Plank L. Kiwifruit consumption reduces DNA fragility: a randomized controlled pilot study in volunteers. Nutr Res. 2006;26(5):197-201. doi:10.1016/j.nutres.2006.05.002.
  8. Carr AC, Pullar JM, Moran S, Vissers MCM. Bioavailability of vitamin C from kiwifruit in non-smoking males: determination of “healthy” and “optimal” intakes. J Nutr Sci. 2012;1:e14. doi:10.1017/jns.2012.15.
  9. Weil A, Becker B. Facts about vitamin E. Weil website. August 2016. Available at: www.drweil.com/vitamins-supplements-herbs/vitamins/facts-about-vitamin-e/. Accessed June 21, 2017.
  10. Ehrlich SD. Vitamin K. University of Maryland Medical Center website. July 16, 2013. Available at: www.umm.edu/health/medical/altmed/supplement/vitamin-k. Accessed June 22, 2017.
  11. Drummond L. Chapter three — The composition and nutritional value of kiwifruit. Adv Food Nutr Res. 2013;68:33-57. doi:http://dx.doi.org/10.1016/B978-0-12-394294-4.00003-1.
  12. Motohashi N, Shirataki Y, Kawase M, et al. Cancer prevention and therapy with kiwifruit in Chinese folklore medicine: A study of kiwifruit extracts. J Ethnopharmacol. 2002;81(3):357-364. doi:10.1016/S0378-8741(02)00125-3.
  13. Zhu WJ, Yu DH, Zhao M, et al. Antiangiogenic triterpenes isolated from Chinese herbal medicine Actinidia chinensis Planch. Anti-Cancer Agents Med Hist. 2013;13(2):195-198. doi:10.2174/187152013804711146.
  14. Hsu HY. Oriental Materia Medica: A Concise Guide. Long Beach, CA: Oriental Healing Arts Institute; 1986.
  15. Shu Q, Mendis De Silva U, Chen S, et al. Kiwifruit extract enhances markers of innate and acquired immunity in a murine model. Food Agric Immunol. 2008;19(2):149-161. doi:10.1080/09540100802117198.
  16. Singletary K. Kiwifruit. Nutr Today. 2012;47(3):133-147. doi:10.1097/NT.0b013e31825744bc.
  17. Parkar SG, Redgate EL, Wibisono R, Luo X, Koh ETH, Schröder R. Gut health benefits of kiwifruit pectins: Comparison with commercial functional polysaccharides. J Funct Foods. 2010;2(3):210-218. doi:10.1016/j.jff.2010.04.009.
  18. Edmunds SJ, Roy NC, Love DR, Laing WA. Kiwifruit extracts inhibit cytokine production by lipopolysaccharide-activated macrophages, and intestinal epithelial cells isolated from IL10 gene deficient mice. Cell Immunol. 2011;270(1):70-79. doi:10.1016/j.cellimm.2011.04.004.
  19. Park YS, Leontowicz H, Leontowicz M, et al. Comparison of the contents of bioactive compounds and the level of antioxidant activity in different kiwifruit cultivars. J Food Compos Anal. 2011;24(7):963-970. doi:10.1016/j.jfca.2010.08.010.
  20. Nishiyama I. Fruits of the Actinidia genus. Adv Food Nutr Res. 2007;52(6):293-324. doi:10.1016/S1043-4526(06)52006-6.
  21. Basic Report: 09148, Kiwifruit, green, raw. United States Department of Agriculture Agricultural Research Service website. May 2016. Available at: https://ndb.nal.usda.gov/ndb/foods/show/2253. Accessed June 22, 2017.
  22. Stone JJ. Kiwi, lemon & rosemary shrub (drinking vinegar). Jerry James Stone website. December 4, 2013. Available at: jerryjamesstone.com/recipe/kiwi-lemon-rosemary-shrub-drinking-vinegar/. Accessed June 22, 2017. [Editor’s note: The linked webpage contains profanity.]