Can beets improve athletic performance and increase VO2 max?
The beet is a nutrient-dense vegetable containing vitamins, minerals and other antioxidants. But the greatest health benefits of beets are a result of a group of phytonutrients called betalains. Betalains provide the vegetable’s vibrant red/ violet or yellow colors: yellow beets contain a betalains called betaxanthins (vulgaxanthin, specifically) while red beets contain betalains called betacyanins (betanin, specifically). These nutrients have been shown to provide antioxidant, anti-inflammatory, and detoxification support (phase 2 detox steps involving glutathione). Although you can see betalain pigments in other foods such as the stems of chard or rhubarb, most of the health benefits of beets are due to the high concentration of betalains found in the peel and flesh.
Why Beets for Athletes? Nitrogen and Nitrates!
Aside from the antioxidant and anti-inflammatory effects, betalains are also jammed packed with nitrogen. Why is nitrogen important? Nitrogen is an essential element for humans. All amino acids necessary for protein formation contain nitrogen as does the DNA in genes. Nitrogen can be obtained from various sources, including plants that contain nitrates (celery, spinach, parsley, fennel, cabbage, turnips, etc.) But among all the plant foods, the one with the highest concentration of nitrates is… beets.
Through a chain reaction in the human body, nitrates are converted into nitric oxide, a powerful vasodilator. Though the effects are brief (nitric oxide is quickly destroyed in the body), they are substantial:
- Increases blood flow to skeletal muscles, allowing more oxygen flow and control of muscle contractions
- Increases VO2 max, endurance and strength (eases mitochondrial load to raise energy production)
- Regulates blood pressure by dilating arteries
- Assists in gastric motility
- Assist the immune system in fighting off bacteria
It has long been known that the production of nitric oxide (NO) occurs via synthesis from l-arginine, an amino acid. However, increasing research over the last 10 years has demonstrated a less complicated method for the body to breakdown nitrate to nitrite via food consumption. The nitrite in food is converted to NO in the acidic environment of the stomach. Unlike the production of NO from l-arginine, the production of NO from nitrate does not require any cofactors and is independent of oxygen.
Beets for Athletes in Endurance Sports
There have been quite a few studies performed investigating the health benefits of beets for athletes – specifically in regards to performance and endurance.
A study published in the Journal of Applied Physiology in 2009 found that individuals who drank beet juice experienced up to a 16% increase in endurance compared to those who did not. Both the group drinking beet juice and a control group who were drinking a placebo were given a series of endurance tests including cycling on a stationary bike; those who had taken the beet juice performed for an average of 92 seconds longer than those on the placebo and were shown to cover the same equivalent distance as the other group in 2% less time.
Another study using trained cyclists had participants consume 500mL of beetroot juice (6.2mmols of nitrate) 2 ½ hours before exercise. The participants then proceeded to do two time trials – a 4km and a 16km ride. In the 4km time trials, there was a 2.8% improvement, and on the 16km time trial there was a 2.7% improvement in time. The cyclists exhibited a 7-11% improvement in power output with no increase in oxygen cost of exercise. Plasma nitrite levels increased before exercise with the beetroot juice. It should also be noted that resting systolic blood pressure also dropped, while having no affect on the diastolic blood pressure.
In another study, subjects ate either 200 grams of baked beetroot or a placebo (cranberry relish) before completing a 5-kilometer treadmill time trial test. The researchers wanted to know if eating 200grams of beetroot (about 2 medium-sized beetroots) before exercise would have any significant improvement on running times. They found that the group who consumed the beetroot had increased running velocity by 3%.
Learn More → Nutrition for Endurance Athletes: Evidence-Based Protocols
References: J Appl Physiol (1985). 2009 Oct;107(4):1144-55.  Med Sci Sports Exerc. 2011; 43(6): 1125-1131.  J Acad Nutr Diet. 2012 Apr;112(4):548-552.  Nat Rev Drug Discov. 2008 Feb;7(2):156-67.  J Appl Physiol (1985). 2013 Aug 1;115(3):325-36.