Special Diets

Beetroot juice has been all the rage lately, particularly after the Auburn University football team announced that beetroot juice was part of its secret nutritional regimen for its players. Scientists have published several studies showing, among other things, that beetroot juice reduces blood pressure and increases oxygen flow to fast-twitch muscle fibers in rats. However, the picture is now complicated by new research that has found that supplementing with beetroot juice does not increase muscular blood flow in humans. Published in the journal Applied Physiology, Nutrition, and Metabolism, the research measured the effects of beetroot juice on the forearm muscles of 12 healthy young men while they performed a handgrip exercise at six different intensity levels. The men received either 140 ml of a nitrate-rich beetroot juice supplement (about half a cup), or a placebo consisting of nitrate-depleted beetroot juice. It’s thought that nitrate is the main active ingredient in beets that contributes to beets’ exercise-enhancing effects. The men consumed the supplement about three hours before performing the exercises. Here’s what the researchers found:

• Nitrate-rich beetroot juice did reduce arterial stiffness in the mens’ forearms, suggesting perhaps that beetroot juice helps to reduce the workload on the heart.
• However, nitrate-rich beetroot juice did not improve the ability of forearm arteries to open up (vascular dilation), and did not increase blood flow in the forearm muscles during exercise.

Nevertheless, researchers stated that the results should be viewed with caution. Because the experiment was carried out in healthy young men performing non-fatiguing exercise, beetroot juice could have a different effect on people in worse health, or in people performing high-intensity workouts.

Source: Applied Physiology, Nutrition, and Metabolism,