Wednesday, 30 May 2018
Food as Medicine Beets
HerbalEGram: Volume 13, Issue 1, January 2016 (Beta vulgaris, Chenopodiaceae) 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 (TSU) in San Marcos and the University of Texas at Austin (UT) through the American Botanical Council’s (ABC’s) Dietetic Internship Program, led by ABC Education Coordinator Jenny Perez. We would like to acknowledge Jenny 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 Lindsey Dureeb a HerbalGram Assistant Editor b ABC Dietetics Intern (TSU, 2013) History and Traditional Use Range and Habitat The garden, or sugar, beet (Beta vulgaris, Chenopodiaceae) is an annual vegetable which forms a dense cluster of dark green leaves attached to a large, bulbous root.1 Both greens (aerial parts) and roots are edible. Beets typically are grown in the spring and fall; they thrive in cool seasons. In warmer climates, beets are grown in the winter as well. The leaves can grow up to 18 inches tall, though they are best harvested at two to three inches. The plant produces red-tinged green flowers. Though red beetroots are most commonly available commercially, golden and “candy cane” red and white roots also exist. The United States, France, Poland, Germany, and Russia currently are the leading producers of beets.2 Selective breeding has produced several different varietals of Beta vulgaris, including sugar beet (used for sugar extraction), mangel-wurzel (used as livestock fodder), and Swiss chard (B. vulgaris subsp. cicla).1 Current research suggests that these varietals may help post-exercise muscle recovery, improve blood pressure, and combat dyslipidemia. Phytochemicals and Constituents Beets are nutritionally diverse, low in calories, cholesterol-free, and fat-free. Beet greens also are edible and contain calcium, vitamin A and carotenoids, vitamin C, and iron. 100 grams of beet greens contain 50% of the United States Department of Agriculture’s (USDA’s) Recommended Daily Allowance for vitamin C.2 Beetroots are a good source of folic acid, fiber, potassium, and manganese.3 They are also rich in niacin, vitamin B-6, pantothenic acid, iron, copper, magnesium, and manganese. Like carrots, the color of beetroots indicates the different nutrient compounds contained within. Red beets contain phytochemicals called betalains*, which can also be found in Swiss chard, rhubarb (Rheum rhabarbarum, R. rhaponticum, Polygonaceae), and prickly pear cactus (Opuntia ficus-indica, Cactaceae).4 Betanin, one of the most-studied betalains, has been shown to provide anti-inflammatory support in vitro and in animal models. Red beets contain 300-600 mg/kg of betanin, which gives this variety its signature ruby-red color. This is slightly unusual, since most red-colored foods owe their pigmentation to anthocyanins, another prevalent group of compounds with antioxidant actions. However, betanin has exceptionally high antioxidant activity, exhibiting 1.5-2 times more activity than its anthocyanin counterparts. Golden, or yellow, beetroots have greater concentrations of lutein than red beets. In the human body, lutein is found in high concentrations in the retina of the eye, and may help protect the eye from abnormal light sensitivity and degenerative diseases such as cataracts and macular degeneration. Beet greens contain higher levels of lutein and zeaxanthin, a similar carotenoid that also promotes healthy vision. Historical and Commercial Uses Beets were first cultivated in the Mediterranean region and have a history of use that dates back over 4,000 years.5 Modern cultivated beets are descendants from a wild plant called the sea beet (B. vulgaris subsp. maritima), which grew wild in North Africa and on the Mediterranean coast.1 Initially, humans consumed only the greens, and the root was used for medicinal purposes or animal fodder. Greek and Roman authors, including Theophrastus (3rd century BCE), Hippocrates (4th century BCE), Dioscorides (1st century CE), and Pliny the Elder (1st century CE), noted a wide variety of ailments they claimed could be cured or prevented by beetroot and greens consumption.6 The primary medicinal use of the beet was to detoxify the blood and cleanse the kidneys, liver, bowel, and gallbladder. Beets also were believed to contain aphrodisiac qualities, and carvings of beets were found on excavated frescoes from Greek brothels.7 Other conditions thought to be treated using beets included leprosy, wounds and skin disorders, dandruff, digestive issues, and earaches.6 Trade throughout Europe spread the growth of beets beyond the Mediterranean area, and the roots eventually evolved into the sweeter, more edible modern plant.4 The popularity of beets increased around the 16th century due to this careful cultivation. The high sugar content of the root made beets a significant economic crop in Europe in the 19th century as an alternative sweetener in the place of sugarcane (Saccharum officinarum, Poaceae). Currently, about 20-30% of the world’s sugar production comes from sugar beets.7 Today, the root and greens are consumed as a food product.8 The root can be prepared by boiling, roasting, baking, or pickling. Raw roots often are added to salads and soups. The greens can be prepared as any other bitter green, such as collard greens (Brassica oleracea, var. acephala, Brassicaceae). Beet juice and extract also are used as natural alternatives to red food dye and in various cosmetic products.9 Modern Research Current research shows that supplementation with beet juice has been shown to play a role in human exercise tolerance and recovery. One human study concluded that beet juice supplementation reduced the negative effects associated with muscle hypoxia after exercise.10 Muscle hypoxia occurs when adequate oxygen is not available for normal muscle activity. This impairs exercise tolerance and energy production from muscles. Another clinical trial reported that supplementation of beetroot juice for three days prior to strenuous exercise reduced the amount of oxygen spent and increased exercise endurance by reducing the time of muscle failure onset.11 This effect remained true during moderate exercise as well. Beets can affect blood pressure and dyslipidemia (a high level of cholesterol, triglycerides, or both in the blood), due to their high nitrate concentration. Dietary nitrates are converted to nitrites, which are known vasodilators (compounds which cause blood vessels to expand), in the body upon ingestion. Consumption of beet juice thus increases the concentration of plasma nitrites in the blood, which decreases blood pressure in healthy adults. When studying this effect, scientists also concluded that beet juice is protective against endothelial (related to the inner lining of arteries) damage, finding a decrease in systolic blood pressure by 6 mmHg after supplementation with beetroot juice.12 The nitrates in beets also aid in smooth muscle relaxation, further adding to its value as an exercise supplement.2 Professional and amateur athletes are increasingly adding beetroot juice to their exercise regimen, claiming an increase in stamina and decision-making speed following a promising 2015 study.13 Researchers concluded that after a week of supplementation with beet juice, healthy male subjects showed increased reaction time and athletic performance during a sprinting exercise.14 Another study showed a significant decrease in blood pressure, with a change of 10.4 mmHg systolic and 8 mmHg diastolic measurements, due to the high nitrate concentration in beets. This study also suggested that beets can prevent endothelial dysfunction and inhibit platelet aggregation. These effects were attributed to the ingestion of nitrates that are converted to nitrites and then reduced to nitric oxide in the stomach.15 Supplementation of beetroot, combined with hawthorn (Crataegus spp, Rosaceae) berry, increased plasma nitrate and nitrite concentrations, and significantly reduced triglyceride levels in 72% of participants with elevated triglycerides.16 Health Considerations Eating a moderate amount of red beetroots or products colored with red beet extract may cause some individuals to experience a temporary reddening of the urine.4 This is known as “beeturia” and is not harmful. However, it may also be an indication of abnormal iron levels in the body or of a problem with iron metabolism, as those with these pre-existing conditions are more likely to experience “beeturia.” Both root and greens of beets contain a high amount of oxalates, which may exacerbate conditions such as kidney stones. However, since beets also contain a high ratio of minerals to oxalates, the amount of bioavailability may be lower than foods with similar oxalic contents.17,18 * Betalains were first named as a unique set of pigments in 1968 by Andre Dreiding and the late Professor Tom J. Mabry, PhD, of the Department of Botany at the University of Texas at Austin. A world-renowned phytochemist and scholar, Mabry passed away in November 2015. Among his many academic distinctions and memberships, he was a former member of the ABC Advisory Board. Nutrient Profile3 Macronutrient Profile: (Per 100g [approx. 3/4 cup] raw beetroot) 43 calories 1.61 g protein 9.56 g carbohydrate 0.17 g fat Secondary Metabolites: (Per 100g [approx. 3/4 cup] raw beetroot) Excellent source of: Folate: 109 mcg (27.25% DV) Very good source of: Manganese: 0.32 mg (16% DV) Dietary Fiber: 2.8 g (11.2% DV) Good source of: Potassium: 325 mg (9.3% DV) Vitamin C: 4.9 mg (8.17% DV) Magnesium: 23 mg (5.75% DV) Also provides: Iron: 0.8 mg (4.44% DV) Phosphorus: 40 mg (4% DV) Vitamin B6: 0.07 mg (3.5% DV) Riboflavin: 0.04 mg (2.35% DV) Zinc: 0.35 mg (2.33% DV) Thiamin: 0.03 mg (2% DV) Niacin: 0.33 mg (1.65% DV) Calcium: 16 mg (1.6% DV) DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000 calorie diet. Recipe: Roasted Beets with Orange-Balsamic Glaze Ingredients: 1/2 pound fresh beets 2 tablespoons olive oil Salt and pepper to taste 1/2 cup balsamic vinegar 2 tablespoons freshly-squeezed orange juice 2 teaspoons sugar Directions: 1. Heat oven to 350°F. Wash beets, scrubbing off any excess dirt, and trim off greens, if present. 2. Place beets in the middle of a large sheet of aluminum foil. Coat with olive oil, then sprinkle with salt. Wrap beets in the foil and roast for about 1 hour, checking every 15 minutes after 1 hour of cooking time, until beets are easily pierced with a knife. 3. Peel the skin off beets while they are still warm, but cool enough to handle. Take care with preparing cooked beets, as their vibrant red color will stain some surfaces and fabrics. 4. Prepare the glaze by combining vinegar, orange juice, and sugar in a small saucepan over medium-high heat. Bring to a boil, then turn heat down to maintain a simmer until the mixture has thickened and coats the back of a spoon. 5. To serve, thinly slice beets, then drizzle with glaze. References Beta vulgaris. Missouri Botanical Garden website. Available here. Accessed December 15, 2015. Murray M. The Encyclopedia of Healing Foods. New York, NY: Atria Books; 2005. Basic Report: 11080, Beets, raw. Agricultural Research Service, United States Department of Agriculture website. Available here. Accessed December 15, 2015. Mateljan G. World’s Healthiest Foods: Essential Guide for the Healthiest Way of Eating. Seattle, WA: George Mateljan Foundation; 2006. Vegetable Profile: Beets. University of Maryland College of Agriculture and Natural Resources website. Available here. Accessed January 4, 2016. Biancardi E, Panella LW, Lewellen RT. Beta maritima: The Origin of Beets. New York, NY: Springer-Verlag; 2012. Avey, T. The History Kitchen: Discover the History of Beets. PBS.org. October 8, 2014. Available here. Accessed December 15, 2015. First beets yielded only greens. Texas A&M Agrilife Extension website. Available here. Accessed January 4, 2016. Gliszczynska-Swiglo A, Szymusiak H, Malinowska P. Betanin, the main pigment of red beet: molecular origin of its exceptionally high free radical-scavenging activity. Food Addit Contam. 2006;23(11):1079-1087. Vanhatalo A, Fulford J, Bailey S, et al. Dietary nitrate reduces muscle metabolic perturbation and improves exercise tolerance in hypoxia. J Physiol. 2011;589(22):5517-5528. Bailey S, Winyard P, Vanhatalo A, et al. Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans. J Appl Physiol. 2009;107(4):1144-1155. Kapil V, Milsom A, Okorie M, et al. Inorganic nitrate supplementation lowers blood pressure in humans. Role for nitrite-derived NO. Hypertension. 2010;65:274-281. Gray N. Faster sprints and better decisions: Beetroot juice backed for increased sports performance. Nutraingredients.com. September 21, 2015. Available here. Accessed January 4, 2016. Thompson C, Wylie LJ, Fulford J, et al. Dietary nitrate improves sprint performance and cognitive function during prolonged intermittent exercise. European Journal of Applied Physiology. 2015;115(9):1825-1834. Webb A, Patel N, Loukogeorgakis S, et al. Acute blood pressure lowering, vasoprotective, and antiplatelet properties of dietary nitrate via bioconversion to nitrite. Hypertension. 2008;51:784-790. Zand J, Lanza F, Garg H, et al. All-natural nitrite and nitrate containing dietary supplement promotes nitric oxide production and reduces triglycerides in humans. J Nut Res. 2011;21(4):262-269. Liebman M, Al-Wahsh IA. Probiotics and other key determinants of dietary oxalate absorption. Adv Nutr. 2011;2:254-260. Available here. Accessed December 23, 2015. Hanson CF, Frankos VH, Thompson WO. Bioavailability of oxalic acid from spinach, sugar beet fibre and a solution of sodium oxalate consumed by female volunteers. Food Chem Toxicol. 1989;27(3):181-4.