Beets (Beta vulgaris) may not be on everyone’s “favorite foods” list, but these ruby roots are hard to top when it comes to healthy eating. Beets have been a staple of inland diets for centuries and are now gaining attention as a sports performance-boosting food, and more.
Nutrients Found in Beets
Beets are a source of beneficial nutrients including betaine (trimethylglycine or TMG), betalains, betacyanin, betanin, folate, fiber, and iron. Like all plant foods, beets contain antioxidants, particularly in the peel, where their phenolic compounds are most concentrated.1,2 The red varieties of the root appear to have the greatest antioxidant activity.3 An analysis of commonly consumed vegetables that included fresh and frozen spinach, leek, white cabbage, Chinese cabbage, and beets found that beets had the highest concentration of beneficial nitrates, which leafy green vegetables otherwise contribute to the diet.4
Protection from Harmful Free Radicals
In rats exposed to the carcinogen carbon tetrachloride, pretreatment with beetroot juice for 28 days resulted in less liver lipid peroxidation and a decreased decline in antioxidant enzymes in comparison with no pretreatment.5 Pretreated animals had three times the activity of the antioxidant enzyme superoxide dismutase (SOD) compared to those that did not receive beetroot. Beetroot product have also demonstrated an antioxidant effect in the cells of obese individuals.6
Effects on Blood Pressure, Arterial and Vascular Health
A number of investigations have found an association between beetroot and lower blood pressure. A study involving 14 healthy humans compared the effects of beetroot juice and water. Three hours after ingestion, beetroot juice was associated with an average reduction in blood pressure of 10.4/8 mm Hg, accompanied by an increase in plasma nitrite (an indicator of blood vessel dilation) converted from beet’s nitrate content. Beetroot juice was also associated with a decrease in platelet aggregation and protection against the induction of endothelial dysfunction. Interruption of the conversion of nitrate to nitrite prevented these effects. “Certain vegetables possess a high nitrate content, and we hypothesized that this might represent a source of vasoprotective nitric oxide via bioactivation,” write Andrew J. Webb and colleagues. “These findings suggest that dietary nitrate underlies the beneficial effects of a vegetable-rich diet and highlights the potential of a ‘natural’ low cost approach for the treatment of cardiovascular disease.” 7
Among individuals with peripheral arterial disease (PAD), the consumption of beetroot juice resulted in an ability to walk 18% longer before experiencing claudication pain, a 17% increase in peak walking time, and a decrease in diastolic blood pressure compared to a placebo. “These findings support the hypothesis that nitrite-related nitric oxide signaling increases peripheral tissue oxygenation in areas of hypoxia and increases exercise tolerance in PAD,” Aarti A. Kenjale and colleagues write.8
A randomized, double-blind trial that compared the effects of nitrate-rich beetroot juice to nitrate-depleted beetroot juice in 69 participants with untreated high cholesterol resulted in improved flow-mediated dilatation (which is a measure of vascular function) and other benefits after six weeks among those who received nitrate-rich juice.9
A meta-analysis of 16 crossover trials with a total of 254 participants concluded that beetroot juice and nitrate supplementation were associated with a significant reduction in systolic blood pressure.10 Another meta-analysis, that included 9 crossover trials and 3 parallel trials with a total of 246 participants confirmed an association between beetroot and inorganic nitrate intake and improvement in vascular fuction.11
Among Europeans, beetroot juice is a popular addition to standard cancer therapy.12 Green beets contain apigenin, vitexin, vitexin-2-O-xyloside and vitexin-2-O-rhamnoside, while red beetroots provide betaxanthins and betacyanins, which, in addition to their antioxidant and anti-inflammatory activities, have anti-proliferative effects in cancer cells.13 Two decades ago, Cancer Letters published the finding of an inhibitory effect for beet root extract against Epstein-Barr virus, as well as skin and lung cancer cells.14 Further investigation by the researchers uncovered a protective effect for beetroot in mice in which skin and liver tumors were initiated.“The most interesting observation is that the cancer chemopreventive effect was exhibited at a very low dose used in the study and thus indicating that beetroot warrants more attention for possible human applications in the control of malignancy,” G. J. Kapadia and colleagues conclude.15
A study in breast and prostate cancer cells found cytotoxic effects that were attributed to the pigment betanin, a constituent of beetroot extract.16 Although the ability of the extract was less than that of the chemotherapy doxorubicin, the researchers involved in the study recommend the evaluation of the addition of beetroot to the drug to reduce chemotherapy side effects. Other research suggests the use of beetroot to prevent hypertension resulting from anthracycline chemotherapy.17
Beets’ best known current use is in sports. A double-blind crossover study that evaluated the effects of six days of beetroot juice consumption found a decrease in oxygen cost with exercise as well as a reduction in systolic blood pressure compared to a placebo.18
Another crossover study involving nine competitive cyclists that compared the effects of beetroot juice to nitrate-depleted beetroot juice resulted in an increase in power output and performance during four kilometer and 16.1 kilometer cycling time trials in association with nitrate-containing juice.19 Other research by the team that compared the effects of six days of beetroot juice intake to six days of beetroot juice that was nitrate-depleted found a decrease in the oxygen cost of walking, moderate intensity running, and severe intensity running among those who received beetroot that contained nitrate, as well as increased time to exhaustion during severe intensity running.20 “The novel findings of Lansley et al. have several clinical implications,” commented Leonardo F. Ferreira and Bradley J. Behnke in an accompanying editorial. “A dietary therapy that lowers blood pressure and increases exercise tolerance may obviate the use of expensive drugs with potentially deleterious side effects . . . we can be cautiously optimistic that a relatively simple approach for treating cardiovascular perturbations and exercise intolerance is within our sight.”21
An analysis of 23 articles that provided data on beetroot juice supplementation concluded that beetroot can improve cardiorespiratory endurance in athletes by increasing efficiency which improves performance.22
Future research will undoubtedly uncover more exciting benefits for this humble root.
“Beetroot supplementation is a new and exciting area of research that to date has been shown to induce favorable effects in several facets of health and disease,” conclude Tom Clifford and colleagues in a 2015 review. “This indicates that beetroot supplementation holds promise as an economic, practical, and important natural dietary intervention in clinical settings. Because of beetroot’s high biological activity, there are still several unexplored areas in which supplementation might confer health benefits. This includes but is not limited to; pain reduction, cognitive function, vascular function, insulin resistance, cancer, and inflammation, especially in older and diseased populations.”23
- Kähkönen MP et al. J Agric Food Chem. 1999 Oct;47(10):3954-62.
- Kujala TS et al. J Agric Food Chem. 2000 Nov;48(11):5338-42.
- Wettasinghe M et al. J Agric Food Chem. 2002 Nov 6;50(23):6704-9.
- Petersen A et al. Food Addit Contam. 1999 Jul;16(7):291-9.
- Kujawska M et al. J Agric Food Chem. 2009 Mar 25;57(6):2570-5.
- Zielińska-Przyjemska M et al. Phytother Res. 2009 Jan;23(1):49-55.
- Webb AJ et al. Hypertension. 2008 Mar;51(3):784-90.
- Kenjale AA et al. J Appl Physiol (1985). 2011 Jun;110(6):1582-91.
- Velmurugan S et al. Am J Clin Nutr. 2016 Jan;103(1):25-38.
- Siervo M et al. J Nutr. 2013 Jun;143(6):818-26.
- Lara J et al. Eur J Nutr. 2016 Mar;55(2):451-459.
- Obrist R et al. Dtsch Med Wochenschr. 1986 Feb 21;111(8):283-7.
- Ninfali P et al. Phytother Res. 2017 Jun;31(6):871-884.
- Kapadia GJ et al. Cancer Lett. 1996 Feb 27;100(1-2):211-4.
- Kapadia GJ et al. Pharmacol Res. 2003 Feb;47(2):141-8.
- Kapadia CG et al. Anticancer Agents Med Chem. 2011 Mar;11(3):280-4.
- Kuriakose RK et al. Oxid Med Cell Longev. 2016;2016:8139861.
- Bailey SJ et al. J Appl Physiol (1985). 2009 Oct;107(4):1144-55.
- Lansley KE et al. Med Sci Sports Exerc. 2011 Jun;43(6):1125-31.
- Lansley KE et al. J Appl Physiol (1985). 2011 Mar;110(3):591-600.
- Ferreira LF et al. J Appl Physiol (1985). 2011 Mar;110(3):585-6.
- Domínguez R et al. Nutrients. 2017 Jan 6;9(1).
- Clifford T et al. Nutrients. 2015 Apr 14;7(4):2801-22.