Monday, January 27, 2014

Nutritional considerations to performance: Beet juice and Nitrate supplementation

 By: Grant Harrison, MS. Source Endurance Senior Consultant

When you look back at how you won your last race, you probably think about all the hard work in training that led you up to that point, how well you and your teammates read the race, or perhaps a tactically sound move that put you atop the podium. We are quick to give credit to the more tangible elements to training and racing but what about our diet? Most of us have never said, “My diet was awesome, my teammates put me in a good spot to win, and my training was effective,” right?
On a daily basis, the types, quantities, and qualities of foods we eat have an effect on the intensities or durations at which we are able to train and race. Most cycling and endurance sport athletes have a good understanding of how to fuel their workouts and how to be good stewards to their body through diet. That said, the importance of proper nutrition and supplementation should not be undermined as optimal performance hinges on a balanced diet and proper supplementation.  Nutritional supplements have made their way into endurance sports as we understand how many of them directly affect how well we are able perform.

Recently, an emerging body of research has looked at the effectiveness of beetroot juice and/or nitrate supplementation as a way to improve performance. As dietary nitrate supplementation has shown to reduce resting blood pressure. Dietary nitrates have also shown to increase muscle blood flow, regulation of muscular contractions, glucose uptake, and cellular respiration.
Building upon these findings, recent research has focused on how dietary nitrate supplementation may improve sub-maximal exercise, sever maximal exercise, and exercise at altitude.

During sub-maximal intensity exercise, the effects of a 6-day nitrate supplementation have shown reduced VO2 (volume of oxygen consumed) when compared to a nitrate deficient placebo. What this means is that our muscles are more efficient at producing energy aerobically and therefore are able to perform more work at any given sub-maximal level of oxygen consumption. Figure 1. shows the data collected by Muggeridge, et al. (2014)

The same study had participants perform a 10-Km time trial under the same conditions as time to completion and power were measured across the placebo and nitrate supplementation groups. The results of the study showed significant differences in both power and time to completion between the two groups (Figure 2.).

Another study conducted by Kelly, J., Vanhatalo, A., Wilkerson, D., Wylie, L., and Jones, A., (2013), also analyzed the effects of nitrate supplementation on four different severe-intensity exercise bouts all to exhaustion. Three of the four exercise bouts elicited a significant difference between the nitrate supplementation group and the placebo group (figure 3.) with the most intense exercise bout not showing statistical significance though an improvement was observed for the nitrate supplement group.

The results from these studies should give athletes a solid reason to investigate the performance benefits of beetroot juice and/or nitrate supplementation. Like any other product, the consumer should seek out a product that works best for them with the least amount of drawbacks. Given the apparent scientific consensus that beetroot juice and nitrate supplements lead to increases in performance, it would be expected that many endurance athletes will use dietary nitrate products not only in acute doses, but as a regular staple to improve overall health and effectiveness of training. Finally, Muggeridge, D., et al (2014), propose that NO- production as a direct consequence of dietary nitrate supplementation may offset the
reduction in NO- during hypoxia and minimize the negative consequences on exercise performance at altitude. Muggeridge also contends that individuals living in low altitude locations would seek the most benefit from supplementing as NO- levels tend to be elevated in high-altitude dwellers.

As many products exist on the market for this supplement, Source Endurance client Chris Lowry of La Crosse, WI has been enjoying the benefits of beetroot in its organic form. Lowry incorporates an amino acid blend with raw organic juiced beets and other fruits before and after his workouts.

Cermak, N., Gibala, M., & Van Loon, L., (2012). Nitrate Supplementation's Improvement of 10-km time-trial performance in trained cyclists. International Journal Of Sport Nutrition & Exercise Metabolism, 22(1), 64-71.

Kelly, J., Vanhatalo, A., Wilkerson, D. P., Wylie, L. J., & Jones, A. M. (2013). Effects of nitrate on the power-duration relationship for severe-intensity exercise. Medicine & Science In Sports & Exercise, 45(9), 1798-1806.

Larsen F., Ekblom B., Sahlin K., Lundberg J., Weitzberg E. (2006) Effects of dietary nitrate on blood pressure in healthy volunteers.The New England Journal of Medicine, 355:2792–3.

Muggeridge, D., F. Howe, C., Spendiff, O., Pedlar, C., James, P., & Easton, C., (2014). A single dose of beetroot juice enhances cycling performance in simulated altitude. Medicine & Science In Sports & Exercise, 46(1), 143-150.

Stamler JS, Meissner G. (2001) Physiology of nitric oxide in skeletal
muscle. Physiology Review. 81:209–37.

Webb A., Patel N., Loukogeorgakis S., et al. (2008) Acute blood pressure
lowering, vasoprotective, and antiplatelet properties of dietary

nitrate via bioconversion to nitrite. Hypertension, 51:784–90.