Research project for my nutrition controversies class:
Beets, It’s What’s for Breakfast My friend Bronwen introduced me to the beet smoothie. As she scrubbed a fist sized beet, cut it into quarters and tossed it into a blender, she told me about her recent turn to veganism and roller-derby. For a long time, she struggled to maintain her energy throughout the 3-4 hour practice; until she discovered the recipe for beet smoothie online. From that point forward she made beets part of her Tuesday evening derby ritual.
Curious, I started looking into the benefits of juicing, and stumbled upon an article in Runner’s World Magazine about juicing. It mentioned a study on athletes involving beet juice and the effects on endurance performance, which is something I can benefit from as I train for my marathon. But the studies didn’t stop there; it seems that beets are getting a lot of attention in the world of nutritional science. Findings are also showing benefits in lowering blood pressure and maintaining liver health. In 2009, Andrew M. Jones, Stephen J. Bailey, Paul Winyard, Anni Vanhatalo, Jamie R. Blackwell, Fred J. DiMenna, Daryl P. Wilkerson, Joanna Tarr, and Nigel Benjamin studied the effects of beet juice on athletes. Nine men between ages 19-38 were given 500 milliliters of beet juice or black currant juice for six consecutive days. On the last three days, they took part in increasingly long and difficult cycling tests. Those who had been given the beet juice had a longer time to exhaustion, lower blood pressure, and were able to pedal harder than those who had the black currant juice.
There is a gamut of articles citing the Jones et al study on beets and athletics. The study itself is under scrutiny from the scientific community because of the very small size of the the actual study and the funders of the project--a beetroot juice company in Britain. However, the findings correlate with other studies on the effects of beet juice on the cardiovascular system. A study in Hypertension magazine (A. J. Webb, N. Patel, S. Loukogeorgakis, M. Okorie, Z. Aboud, S. Misra, R. Rashid, P. Miall, J. Deanfield, N. Benjamin, R. MacAllister, A. J. Hobbs, A. Ahluwalia, 2008) showed that drinking 500mL of beet juice “substantially reduced” blood pressure in healthy adults.
Beets contain high levels of inorganic dietary nitrates. These nitrates are changed into nitrites as they enter the body. Bacteria in the saliva convert the nitrate into nitrite. The nitrites are swallowed and enter the stomach where they are then converted into nitric oxide (NO) or circulate in the blood as nitrites. Blood pressure has been shown to drop in direct correlation to the increase of nitrites in the blood. “Nitrite is a potent vasodilator” (Webb et al, 2008). This process begins about half an hour after the beets are ingested, and peaks about an hour and a half later. The effects begin to decrease over the next 24 hours. There are ongoing studies on the pharmaceutical benefits for people with cardiovascular disease. “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” (Webb et al, 2008)
Nitrites help protect against endothelial dysfunction (when the inside lining of blood vessels have a problem expanding or contracting with blood flow and cannot function properly). The study also shows that men are more likely to reap the benefits of drinking their beets. Men and women were given similar amounts per kilogram. Women already have a lower basal blood pressure, higher nitrite levels, and lower body mass than men. After drinking beet juice, the plasma nitrite levels increased in both men and women, those increases were more prominent in women than in men . However the rate of reduced blood pressure was higher in men. It is thought that the apparent lack of effect from increased nitrite levels in women has to do with the saturation of basal plasma nitrite levels. The difference in the way women utilize nitrites is thought to have something to do with differing bacteria colonizing tongues (Vikas Kapil, Alexandra B. Milsom, Michael Okorie, Sheiva Maleki-Toyserkani, Farihah Akram, Farkhanda Rehman, Shah Arghandawi, Vanessa Pearl, Nigel Benjamin, Stavros Loukogeorgakis, Raymond MacAllister, Adrian J. Hobbs, Andrew J. Webb, Amrita Ahluwalia, 2010) Beets also lend themselves to aiding liver function.
A study in Hungary (Váli L, Stefanovits-Bányai E, Szentmihályi K, Fébel H, Sárdi E, Lugasi A, Kocsis I, Blázovics A., 2007) showed that rat given a treatment of beets in their chow had better resilience than their non-treated counterparts after both had the blood flow diverted from their livers for 45 minutes and reperfused for 15 minutes. Rats who had eaten beets showed that enzymatic antioxidants increased significantly indicating that the beets had a positive effect. “Beets thin bile, allowing it to flow more freely through the liver and into the small intestine.” (Blessing, 2011--this reference is a bit sketchy--her references were scant and inconclusive)
Multiple alternative medicine sites offer techniques to cleanse the liver utilizing beets. Very little could be found on the benefits of a liver cleanse; however, it is persistent throughout the alternative medicine culture. In fact several more trusted sites warn against adverse effects caused by these cleanses. Some sites (like WebMD.com) noted that the liver is very good at removing toxins on it’s own, and cleanses were in essence pointless and sometimes harmful (the jury is still out on this one for me--I know how potent beets can be as a general systems bulldozer).
Beets are a good source of folate to assist in new tissue growth, magnesium for energy metabolism, vitamin C for healthy immune function, iron to oxygenate the blood, and potassium for proper fluid balance (Sizer, Whitney, 2011). Despite their high carbohydrate content, they are also high in fiber and low in saturated fats. Beets are a loaded with antioxidants for staving off cancer. But wait a moment, aren’t nitrates and nitrites in food a cause for cancer? Studies in the 1970’s showed an increase of cancer in lab animals who were fed sodium nitrate. However, there is no human data to prove this, a fact that processed meat companies are now exploiting and scientists are striving to figure out.
All in all, Bronwyn was onto something: beets are a great way to get energy and micronutrients. They are packed with nitrates which bacteria in the saliva turn to nitrites. Nitrites are shown increase the body’s ability to work hard in athletics and to lower blood pressure in healthy adults. Research is being done to find out how beets affect the liver. I will continue to add them to smoothies, roast them for dinner, and saute them in citrus juice for salads. And, in case you were wondering, here is Bronwen’s recipe for a Beet smoothie.
Recipe for Beet Smoothie
1 organic beet, greens removed, scrubbed and quartered
3 dates
2 cups frozen strawberries
1 slice of lemon, peel included
2 cups coconut water (more or less as the blender needs to flow smoothly
Combine in blender and blend until smooth
Resources
Juicy Details Fresh-squeezed fruits and veggies are tasty–but do they live up to the hype? Liz Applegate Ph.D. August 2012 “Runner’s World”
Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans; Stephen J. Bailey, Paul Winyard, Anni Vanhatalo, Jamie R. Blackwell, Fred J. DiMenna, Daryl P. Wilkerson, Joanna Tarr, Nigel Benjamin, Andrew M. Jones, October 2009. “Journal of Applied Physiology”
Mother Was Right: Eat Your Vegetables and Do Not Spit! When Oral Nitrate Helps With High Blood Pressure, David A. Wink, Nazareno Paolocci, February, 2008 “Hypertension” Acute Blood Pressure Lowering, Vasoprotective, and Antiplatelet Properties of Dietary Nitrate via Bioconversion to Nitrite. A. J. Webb, N. Patel, S. Loukogeorgakis, M. Okorie, Z. Aboud, S. Misra, R. Rashid, P. Miall, J. Deanfield, N. Benjamin, R. MacAllister, A. J. Hobbs, A. Ahluwalia. Hypertension, 2008
Endothelium/Endothelin “Inorganic Nitrate Supplementation Lowers Blood Pressure in Humans Role for Nitrite-Derived NO,” Vikas Kapil, Alexandra B. Milsom, Michael Okorie, Sheiva Maleki-Toyserkani, Farihah Akram, Farkhanda Rehman, Shah Arghandawi, Vanessa Pearl, Nigel Benjamin, Stavros Loukogeorgakis, Raymond MacAllister, Adrian J. Hobbs, Andrew J. Webb, Amrita Ahluwalia; Hypertension, June 2010
Beet Juice & Liver Detoxification, Jill Blessing, http://www.livestrong.com/article/297215-beet-juice-liver-detoxification/ , Jun 14,2011Nutrition Concepts and Controversies California Edition, F.S Sizer and E.N. Whitney, 2011
Liver-protecting effects of table beet (Beta vulgaris var. rubra) during ischemia-reperfusion. Váli L, Stefanovits-Bányai E, Szentmihályi K, Fébel H, Sárdi E, Lugasi A, Kocsis I, Blázovics A. February 2007 “Nutrition”
