Similarly, another study had athletes ingest 500 mL of 8 mmol
concentrated beetroot juice for six days and then performed
exercise tests on days four, five, and six. Results showed an
increase in time to exhaustion and an increase in oxygen uptake
on all days tested (1). An alternate study provided athletes with
the beetroot juice supplement only on the days of testing (on
four separate occasions) and found significant benefits as well
(7). Although the results of the previous study were beneficial
for single-dose supplementation, it should be noted that the
athletes were supplemented more than one time and continued
to show beneficial effects after the study. As a result, continuous
supplementation as opposed to one-time dosage of beetroot juice
is supported.
ARE THERE OTHER FOODS BESIDES BEETROOT?
Beetroot is not the only food that contains inorganic nitrates,
which may provide these potential benefits. Dark green, leafy
vegetables like spinach also contain a fair amount of nitrates;
however, most research has focused on beetroot juice. In order to
get the 8 mmol of nitrates (the optimal amount shown to have a
beneficial effect), an individual would need to consume 200 – 300
g of spinach, or approximately 10 cups (4). This amount is a lot of
spinach to eat before a workout and may be an impractical way to
obtain nitrates.
The question may arise that if it is the nitrates in the beetroot juice
that provide these benefits, then why not just consume nitrates
directly instead of the juice? A lot of speculation has surrounded
the consumption of nitrates since previous studies have linked
them to cancer. As a result, it has led to strict regulation of nitrate
concentrations in food and water. Current research is beginning
to show the benefits of some nitrate-rich foods, which is leading
to further investigation within this area (4). Researchers may also
argue that beetroot juice does not just contain nitrates; it also
contains substances like betaine and antioxidants, which are being
tested to determine if any beneficial effects on exercise exist in
addition to the nitrates. Therefore, it cannot be concretely stated
that it is the nitrates alone in the beetroot juice that attribute to all
of these benefits (2). However, benefits were seen within the cited
studies.
BOTTOM LINE
Consuming beetroot juice prior to high-intensity exercise may help
improve a workout by increasing the amount of time before lactic
acid builds up. Currently, there are multiple products that are sold
in health food stores that are concentrated to 8 mmol nitrate in 70
mL (or 2.3 oz) bottles, which may be consumed prior to exercise.
REFERENCES
1. Bailey, SJ, Winyard, P, Vanhatalo, A, Blackwell, JR,
Wilkerson, DP, Tarr, J, Benjamin, N, and Jones, AM. Dietary nitrate
supplementation reduces the O2 cost of low-intensity exercise and
enhances tolerance to high-intensity exercise in humans. Journal
of Applied Physiology 107: 1144-1155, 2009.
2. Breese, BC, McNarry, MA, Marwood, S, Blackwell, JR, Bailey,
SJ, and Jones, AM. Beetroot juice supplementation speeds O2
uptake kinetics and improves exercise tolerance during severeintensity exercise initiated from an elevated metabolic rate.
American Journal of Physiology Regulatory Integrative and
Comparative Physiology 305: 1441-1450, 2013.
3. Bryan, NS and Hord, NG. Dietary nitrates and nitrites. In:
Bryan, N (Ed.), Food Nutrition and the Nitric Oxide Pathway.
Lancaster, PA: Destech Pub Inc; 59-77, 2010.
4. Cermak, NM, Gibala, MJ, and van Loon, LJ. Nitrate
supplementation’s improvement of 10-km time-trial performance
in trained cyclists. International Journal of Sport Nutrition and
Exercise Metabolism 22: 64-71, 2012.
5. Cermak, NM, Res, P, Stinkens, R, Lundberg, JO, Gibala, MJ, van
Loon, LJ. No improvement in endurance performance following
a single dose of beetroot juice. International Journal of Sport
Nutrition and Exercise Metabolism 22: 470-478, 2012.
6. Thompson, KG, Turner, L, Prichard, J, Dodd, F, Kennedy, DO,
Haskell, C, Blackwell, JR, and Jones, AM. Influence of dietary
nitrate supplementation on physiological and cognitive response
to incremental cycle exercise. Respiratory, Physiology, and
Neurobiology 13: 412-416, 2013.
7. Wylie, LJ, Kelly, J, Bailey, SJ, Blackwell, JR, Skiba, PF, Winyard,
PG, Jeukendrup, AE, Vanhatalo, A, and Jones, AM. Beetroot juice
and exercise: Pharmacodynamics and dose-response relationships.
Journal of Applied Physiology 3: 325-336, 2013.
ABOUT THE AUTHOR
Debra Wein is a recognized expert on health and wellness and
designed award-winning programs for both individuals and
corporations around the United States. She is the President and
Founder of Wellness Workdays, Inc., (www.wellnessworkdays.com)
a leading provider of worksite wellness programs. In addition, she
is the President and Founder of the partner company, Sensible
Nutrition, Inc. (www.sensiblenutrition.com), a consulting firm of
registered dietitians and personal trainers, established in 1994, that
provides nutrition and wellness services to individuals. She has
nearly 20 years of experience working in the health and wellness
industry. Her sport nutrition handouts and free weekly email
newsletters are available online at www.sensiblenutrition.com.
Kelly Murphy is a Registered and Licensed Dietitian working
for the Dallas, TX office of Sensible Nutrition Inc., a nutrition
consulting firm that provides one-on-one nutrition counseling. She
has extensive experience with nutrition and wellness as well as
athletics. Murphy obtained her undergraduate degree from Cornell
University, where she was a four-year varsity athlete. She enjoys
combining her passions for both athletics and nutrition to help
indiv