Food as Medicine: Burdock (Arcitum lappa, Asteraceae)

HerbalEGram: Volume 15, Issue 1, January 2018 Editor’s Note: Each month, HerbalEGram highlights a conventional food and briefly explores its history, traditional uses, nutritional profile, and modern medicinal research. We also feature a nutritious recipe for an easy-to-prepare dish with each article to encourage readers to experience the extensive benefits of these whole foods. With this series, we hope our readers will gain a new appreciation for the foods they see at the supermarket and frequently include in their diets. The basic materials for this series were compiled by dietetic interns from Texas State University in San Marcos and the University of Texas at Austin through the American Botanical Council’s (ABC’s) Dietetic Internship Program, led by ABC Education Coordinator Jenny Perez. We would like to acknowledge Perez, ABC Special Projects Director Gayle Engels, and ABC Chief Science Officer Stefan Gafner, PhD, for their contributions to this project. By Hannah Baumana and Bethany Diazb a HerbalGram Associate Editor b ABC Dietetics Intern (Texas State University, 2017) Overview Burdock (Arctium lappa, Asteraceae), also known as great burdock, is a biennial plant in the sunflower family that grows well in full or partial sun and flourishes in undisturbed areas.1 Wild burdock can be found in forests, along roadsides or streams, farmlands, and waste areas. Native to Eurasia, burdock has been naturalized across the world and has a wide history of use in many countries as food and/or medicine.2 This weed-like plant grows well from coast to coast across the northern part of the United States and southern Canada.1 One of the distinct features of burdock is its sturdy stalk that can grow from two to six feet in height and its large, coarse, heart-shaped green leaves that extend out from alternating stems.3 Burdock blooms from mid-summer to early fall starting in its second year of maturity, and produces purple-pink flowers atop the globular bristle heads that are often called burrs.2 The root can reach a depth of approximately two feet and contains the greatest amount of nutrients during the plant’s first year. The root is long, hard, and slender with a carrot-like shape. When the brown outer layer is peeled away, the inside of the root is white and has an earthy, mildly bitter taste. Phytochemicals and Constituents Burdock root is a nutrient-dense food that is low in calories and fat. The root is a good source of protein, calcium, phosphorus, potassium, and folate.4,5 Each of these nutrients plays an important part in human metabolism, growth, and development. Potassium is necessary for electrolyte and pH balance, while folate is involved in amino acid metabolism, red blood cell formation, and DNA synthesis.6 In addition, burdock root is also a great source of fiber in the form of prebiotic inulin, which supports gastrointestinal health. Inulin has also been associated with the anti-diabetic properties of burdock root. Like most root vegetables, burdock is predominantly composed of complex carbohydrates. However, in burdock root, fructose is the dominant monosaccharide in the plant and contains repeating units of fructose and glucose, which contribute to the high oligosaccharide and polysaccharide content known as fructo-oligosaccharides (FOSs).7,8 Inulin is a water-soluble form of fiber that has been studied for its physiological effects on the gut microbiome. Inulin acts as a prebiotic, which allows the beneficial microorganisms to flourish in the gut and generate useful short-chain fatty acids. It also lowers the pH of the intestines, which helps prevent the establishment and growth of pathogenic bacteria.8 Research suggests that the diversity of beneficial gut bacteria and the ratio of beneficial microorganisms to pathogenic microorganisms significantly contribute to healthy weight management, support the immune system through the regulation and enhancement of white blood cell activity, and reduce blood triglyceride and cholesterol levels. Burdock root contains numerous phytochemicals, such as lignans, triterpenoids, and polyacetylenes.3,9 A variety of these constituents have been shown to promote blood circulation and are linked to antidiabetic medicinal properties, such as increasing insulin uptake, which improves glucose tolerance.10 Burdock root also contains caffeic acid and its derivatives chlorogenic acid and cynarin, as well as the flavonoids quercetin, luteolin, and the lignans arctiin and arctigenin, which have demonstrated cytotoxic, anti-inflammatory, and free radical scavenging properties.11-13 Arctigenin is one of the most-studied bioactive compounds in burdock root and has been investigated both in vitro and in animals for its anti-inflammatory benefits and potential anti-tumor properties. Arctigenin has been shown to decrease inflammation in humans by inhibiting the gene expression of proteins that regulate white blood cell activity and T-lymphocytes.14 A 2017 mouse study examined arctigenin’s effects on prostate cancer and reported that when given 50 mg/kg of arctigenin daily prior to tumor implantation, the mice experienced anti-tumor effects including a reduction in tumor growth factors, which suppressed overall tumor growth. This suggests that arctigenin, and thus the use of burdock root, may have a place in preventive medicine and dietary therapy.15 Historical and Commercial Uses When burdock became naturalized in North America, it became a dietary and medicinal ingredient for indigenous tribes.16 Numerous tribes, including the Iroquois, Cherokee, and Delaware, used burdock root to treat rheumatism and as a blood cleanser.17 Some tribes also used burdock root to treat skin disturbances. Another common use of burdock root among tribes was for the treatment of venereal diseases. The Iroquois ate burdock root as a vegetable, drying and storing the root for colder months. Burdock has been used for its medicinal properties for thousands of years in many parts of Europe, China, and Japan. In Japan, burdock root (called gobo) is a common food and is used as a remedy in a traditional herbal medicine practice known as Kampo.2 As a traditional medicine, burdock is used as a diuretic and also as a so-called “blood purifier,” or alterative.2,18,19 As a diuretic, burdock root can increase urination and is used to flush out the urinary tract system and decrease the occurrence of minor liver- and kidney-related complications.17 As an alterative, burdock root is used to enhance the body’s natural detoxification processes and has a 100-year history of use in folk and indigenous medicine as a cancer treatment. In the 1920s, burdock root was an important herbal component of two folk medicine cancer treatment formulas known as the Hoxsey and Essiac formulas.18 In modern times, burdock is used by Western herbalists as a nutritive prebiotic that supports healthy skin, moves lymph, and enhances detoxification and elimination functions.18 Burdock root is indicated for skin conditions such as acne, psoriasis, atopic dermatitis, and cystitis. The root is preferred for chronic skin conditions, while the seed is preferred for treating acute skin eruptions such as boils and sties.2,18 Other therapeutic conditions for burdock include gout, rheumatoid arthritis, and anorexia nervosa.9 In addition, burdock root’s bittersweet flavor can stimulate appetite and improve bowel function.20 As an herbal medicine, burdock root is most often prepared as a tea, but can also be made into extracts and tinctures, or powdered and encapsulated. The first-year root of burdock is the most commonly consumed plant part, though the young leaves are often eaten in salads or lightly steamed.3,21 Similar to carrots, a biennial plant grown as an annual root crop, burdock is cultivated in Japan as an annual root vegetable and is frequently included in soups, stews, salads, and pickles. Although it is a common vegetable in Japan, and occasionally used in some culinary practices in parts of Europe, burdock is little known outside these cultures.2,3 However, it is growing in popularity as both a food and medicine. Modern Research While clinical evidence on the use of burdock root is limited, much of the research focuses on inflammatory markers and response pathways. Chronic skin conditions like eczema and psoriasis, gastrointestinal diseases, rheumatoid arthritis, and gout can be linked to persistent inflammation in the body. A placebo-controlled clinical study demonstrated a significant reduction in osteoarthritis pain in participants who consumed burdock root tea three times daily for six weeks.22 In addition, those in the treatment group also experienced significantly increased Knee Injury & Osteoarthritis Outcome scores and decreased Timed Up and Go scores compared to control. These results indicate that those in the burdock tea group had reduced arthritis symptoms, pain, and fall risk and increased mobility and quality of life. Another clinical study on burdock root and osteoarthritis reported anti-inflammatory and antioxidative results. Patients with osteoarthritis were given six grams of burdock root, delivered as a tea, daily for 42 days. At the end of the experiment, blood samples and biochemical analyses showed a significant reductions in the clinical inflammatory markers interleukin-6 (IL6) and C-reactive protein (CRP) compared to baseline.23 It is important to note that all patients in this study were given acetaminophen and glucosamine as part of their “drug” regimen (glucosamine is technically not a drug, but a dietary supplement, i.e., depending on the regulatory regime in which it is sold and used). Other clinical studies provide evidence that burdock can significantly improve dry skin and wrinkles.24,25 However, these studies used the fruit rather than the root or did not disclose which part of the plant was used. Rat studies have demonstrated the gastroprotective properties of burdock root, seed, and leaf extracts, including healing gastric ulcers, a dose-dependent response for the healing of gastric mucosa,26 inhibiting gastric ulcer formation,27 and decreasing the inflammatory response associated with colitis.28 An in vitro study on the anti-inflammatory response related to atopic dermatitis found that burdock root extract had stimulatory effects on immune cells and inhibited the antigen-induced mRNA expression and production of cytokines related to allergic and atopic reactions.29 Extracts of burdock root with concentrations of 10 µg/mL and 100 µg/mL enhanced proliferation of splenocyte cells that were induced with T-cell immunogenicity. A down-regulation of IL-4 and IL-5 was exhibited with the 100 µg/mL extract, supporting the anti-allergic and anti-inflammatory effects of burdock root. Burdock root extracts have also exhibited antioxidant and cytotoxic effects. One study that experimented with eight different burdock root extracts reported that the hydroethanolic mixture (594 grams of fresh milled burdock root, 1:5 ratio with 70% ethanol) had high amounts of phenolic compounds and the greatest free radical scavenging activity. The study also reported that the dichloromethane extract (276 grams of fresh milled roots, 1:5 ratio) showed cytotoxic properties against specific cancer cell lines.13 Preliminary studies also suggest that burdock root has the ability to benefit patients with type 2 diabetes. In an animal study, daily supplementation with burdock root extract not only increased the levels of insulin produced, but also helped control body weight and facilitated favorable changes in blood lipid profiles such as reducing triglyceride and very low-density lipoprotein (VLDL) cholesterol levels and increasing high-density lipoprotein (HDL) cholesterol levels.30 In addition, when compared to the control group, the treatment group exhibited an increase in liver enzymes and a decrease in leptin levels. This study also had two groups of healthy rats that were not induced with diabetes but were given the same amount of burdock root extract as their diabetic counterparts. These two groups of rats also saw significant changes in lipid profiles and insulin levels, which suggest that burdock root may also be beneficial to patients who are pre-diabetic or have metabolic syndrome. A two-part study reported that burdock root extract in vitro caused an increase in glucose uptake with insulin present and decreased liver glucose production by inhibiting the liver enzyme glucose-6 phosphatase. The in vivo phase, conducted with rats, demonstrated a decrease in blood glucose as well as a decrease in the amount of insulin secreted for the animals that were given 50 or 100 µg /mL of dried burdock root extract.10 This indicates that burdock root extract may be a promising natural remedy for patients with uncomplicated type 2 diabetes. Obesity is a risk factor for many disease states including type 2 diabetes and heart disease. A rat study found that daily supplementation with burdock root for four weeks lead to a reduction in body weight.31 Rats that were fed 500 mg/kg or 1,000 mg/kg of burdock root a day weighed less than the rats in the control group that did not consume any burdock. This study also investigated the mechanisms behind the weight management properties and reported that lipid synthesis was suppressed by downregulating or inhibiting various enzymes that are part of lipid metabolism and decreased overall cellular lipid content. This study provides introductory evidence for an alternative method to weight management in humans. Burdock root may also prevent liver damage from environmental toxicity. Rats with liver injuries ingested 900 mg/kg of burdock root for one day or consumed 300 mg/kg of burdock three times a day for seven days. Both experimental groups showed a decrease in serum levels of the liver enzymes SGOT and SGPT and an increase in glutathione levels.32 Furthermore, additional reviews have found that the root of burdock helps to decrease lipid deposits into the liver caused by alcohol or high-fat diets as well as initiate hepatoprotective mechanisms that increase antioxidant activity.2,8 Consumer Considerations Burdock root is well-tolerated by most individuals, though those with a sensitivity to foods high in the prebiotic inulin, such as Jerusalem artichokes (Helianthus tuberosus, Asteraceae), artichokes (Cynara scolymus, Asteraceae), asparagus (Asparagus officinalis, Asparagaceae), or leeks (Allium ampeloprasum, Amaryllidaceae), may experience temporary gas or bloating post-consumption.18 No significant adverse effects have been reported with burdock root apart from rare cases of anaphylactic shock; however, patients should discontinue use and notify their health care provider if they suspect an allergic reaction.20 Burdock root has not been reported to have any negative interactions with other herbs or medications. However, since burdock root has been used traditionally to increase urine output, taking additional diuretics while using burdock is not recommended.33 Patients should ensure adequate hydration while taking burdock medicinally due to its diuretic effect. Nutrient Profile5 Macronutrient Profile: (Per 1 cup of peeled root [approx. 118 grams]) 85 calories 1.8 g protein 20.5 g carbohydrate 0.2 g fat Secondary Metabolites: (Per 1 cup of peeled root [approx. 118 grams]) Excellent source of: Potassium: 363 mg (7.7% DV) Dietary Fiber: 3.9 g (13% DV) Vitamin C: 3.5 mg (3.9% DV) Calcium: 48 mg (3.7% DV) Very good source of: Iron: 0.9 mg (5% DV) Vitamin E: 0.5 mg (3.3% DV) Vitamin K: 1.9 mcg (1.6% DV) Good source of: Thiamin: 0.01 mg (0.9% DV) Riboflavin: 0.04 mg (3.1% DV) Niacin: 0.4 mg (2.5% DV) Vitamin B6: 0.3 mg (17.6% DV) Folate: 27 mcg (6.8% DV) Also provides: Phosphorus: 60 mg (4.8% DV) Magnesium: 45 mg (10.7% DV) Manganese: 0.3 mg (13.0% DV) DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000-calorie diet. Recipe: Burdock Kinpira Courtesy of Chichi Wang34 When shopping for burdock, choose plump, crisp roots, gently scrub to remove dirt, and briefly soak in acidulated water (one teaspoon lemon juice or vinegar to one liter water) to prevent browning or oxidation. To store, wrap in a damp paper towel, refrigerate, and use within a week. Ingredients: 2 burdock roots approximately one foot in length 1 tablespoon vegetable oil 2 tablespoons soy sauce 1 tablespoon sake or mirin 2 tablespoons sugar Directions: Wash and peel burdock root. Cut the root into four-inch segments, the quarter lengthwise. Place the prepared root in acidulated water to prevent discoloration. Place a sauté pan over medium heat and add the oil. Sauté root for four to six minutes until lightly browned. Add soy sauce, sake, and sugar to pan. Simmer for five minutes, until the root is cooked through but still crunchy. Serve at room temperature or cold. References Doll J, Doll J. Common Burdock. 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BMC Complement Altern Med. 2013;13(1):330. doi:10.1186/1472-6882-13-330. Knott A, Reuschlein K, Mielke H, et al. Natural Arctium lappa fruit extract improves the clinical signs of aging skin. J Cosmet Dermatol. 2008;7(4):281-289. doi:10.1111/j.1473-2165.2008.00407.x. da Silva LM, Allemand A, Mendes DAGB, et al. Ethanolic extract of roots from Arctium lappa L. accelerates the healing of acetic acid-induced gastric ulcer in rats: Involvement of the antioxidant system. Food Chem Toxicol. 2013;51:179-187. doi:10.1016/j.fct.2012.09.026. Li XM, Miao Y, Su QY, Yao JC, Li HH, Zhang GM. Gastroprotective effects of arctigenin of Arctium lappa L . on a rat model of gastric ulcers. Biomedical Reports. 2016;5:589-594. doi:10.3892/br.2016.770. de Almeida ABA, Sánchez-Hidalgo M, Martín AR, et al. Anti-inflammatory intestinal activity of Arctium lappa L. (Asteraceae) in TNBS colitis model. J Ethnopharmacol. 2013;146(1):300-310. doi:10.1016/j.jep.2012.12.048. Sohn E, Jang S, Joo H, et al. Anti-allergic and anti-inflammatory effects of butanol extract from Arctium lappa L. Clinical and Molecular Allergy. 2011:9(4)1-12. Ahangarpour A, Heidari H, Oroojan AA, Mirzavandi F, Nasr Esfehani K, Dehghan Mohammadi Z. Antidiabetic, hypolipidemic and hepatoprotective effects of Arctium lappa root’s hydro-alcoholic extract on nicotinamide-streptozotocin induced type 2 model of diabetes in male mice. Avicenna J Phytomedicine. 2017;7(2):169-179. Kuo D, Hung M, Hung C, et al. Body weight management effect of burdock (Arctium lappa L.) root is associated with the activation of AMP-activated protein kinase in human HepG2 cells. Food Chem. 2012;134(3):1320-1326. doi:10.1016/j.foodchem.2012.03.023. Lin S-C, Lin C-H, Lin C-C, et al. Hepatoprotective effects of Arctium lappa Linne on liver injuries induced by chronic ethanol consumption and potentiated by carbon tetrachloride. J Biomed Sci. 2002;9(5):401-409. doi:10.1007/BF02256533. Burdock. University of Maryland Medical Center website. June 22, 2015. Available at: www.umm.edu/health/medical/altmed/herb/burdock. Accessed September 1, 2017. Wang C. Seriously Asian: Burdock Root Recipe. Serious Eats website. May 2010. Available at: www.seriouseats.com/recipes/2010/05/seriously-asian-stir-fried-burdock-root-kinpira-pickled-burdock-recipe.html. Accessed January 3, 2018.