WebMD Medical News
Louise Chang, MD
Sept. 27, 2011 (San Diego) -- Runners and other exercisers hoping to improve their performance might consider a detour to the produce aisle.
Eating beetroot before a workout gave runners a modest edge in speed during a 5K run when they were close to the finish line, new research shows.
The baked beetroot won out over the cranberry relish that served as a comparison, says Margaret Murphy, RD, a Chicago dietitian who conducted the research as a graduate student at St. Louis University.
''With the beetroot, they were 41 seconds faster at the finish," and that could make the difference between a win or not among competitive amateur runners, she says.
The study was presented at the American Dietetic Association's Food & Nutrition Conference & Expo here in San Diego.
For exercise performance, "there has been a lot of interest in beetroot juice for the last couple of years," Murphy tells WebMD. A study from the U.K., for instance, found that exercisers could work out longer if they drank beetroot juice.
Other research has found that beetroot juice can help reduce blood pressure.
Beetroot is rich in substances called nitrates. Nitrates are converted into nitric oxide by the body. The nitric oxide dilates blood vessels. That results in improved oxygen delivery.
"You are going to have more ability to sustain aerobic activity," Murphy says.
Murphy decided to study the whole vegetable rather than the juice.
She assigned 11 men and women, all recreationally fit athletes, to eat the beetroot or the cranberry relish, in random order, once before a 5K run. The tests were done a week apart. The average age of the exercisers was 25.
They each ate 200 grams, about 7 ounces, of beetroot. That amount has about 500 milligrams of nitrates.
After the beetroot, exercisers had overall times that were 3% faster compared to their times after eating cranberry relish, and 5% faster during the last mile, she found.
Beetroots can be found in the produce section of the market. They look a bit like radishes.
The beetroot recipe is simple, Murphy tells WebMD.
She gave the men and women the beetroot about 45 minutes before they jogged because they came into the study after fasting. However, for those who want to try it, she suggests eating it about two and a half hours before an event.
The new research adds to accumulating data about the effect of beetroot on exercise performance, says Daniel Kim-Shapiro, PhD, professor of physics at Wake Forest University. He is an expert on nitric oxide and has found that drinking beet juice boosts blood flow to the brain in older people.
He reviewed the data but was not involved in the study.
''Data is just beginning to emerge that actual exercise performance is enhanced," he says.
He offers some caveats. Eating nitrate in the form of beet juice or the vegetable instead of supplements ''is probably safest," he says. He warns exercisers not to confuse nitrate from foods with nitrite salt, sold over the Internet and potentially hazardous.
Moderation is key, Kim-Shapiro says. He has heard of exercisers drinking beet juice to boost performance and then getting sick to their stomachs during exercise.
Kim-Shapiro reports being a co-author on a patent application on the use of nitrite salts for heart disease and receiving royalties from the licensing of the application.
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.
SOURCES:Margaret Murphy, RD, dietitian, Chicago.Daniel Kim-Shapiro, PhD, professor of physics and Harbert Family Distinguished Chair, Wake Forest University, Winston-Salem, N.C. American Dietetic Association Food & Nutrition Conference & Expo, Sept. 24-27, 2011, San Diego.
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