Beetroot juice rich in nitrates didn’t enhance muscle blood flow or vascular dilation during exercise, report the researchers. They did find, however, that it “de-stiffened” blood vessels under resting conditions, potentially easing the heart’s workload.
Endurance athletes have been known to drink the bright red supplement based on the belief that it may improve blood and oxygen flow in their muscles during training and competition. Some strength and power athletes consume it in hopes that it can improve their ability to withstand muscle fatigue during repeated bouts of high intensity exercise.
Now, some patients are asking their doctors if they should drink the juice to lower their high blood pressure.
Those potential benefits are what prompted David Proctor, professor of kinesiology and physiology at Penn State, to test the ability of the juice to enhance blood flow to exercising muscles.
Proctor, with other researchers, found that the widely held belief regarding improved muscle blood flow did not hold up to their test.
Proctor and his colleagues gave subjects either a placebo drink containing beetroot juice minus the nitrate or a relatively high dose of nitrate-rich beetroot juice. They found that the latter did not enhance the natural rise in blood flow to the forearm muscles during graded handgrip exercise.
“Beetroot juice also had no effect on the dilation (widening) of the brachial artery in these volunteers,” says lead author and Penn State physiology graduate student Jin-Kwang Kim.
Nitrates and Beet ‘Shots’
Nitrates, found in highest concentrations in leafy green vegetables such as spinach and beetroot, are converted naturally in the body to nitric oxide, a molecule that relaxes and widens blood vessels and affects how efficiently cells use oxygen.
A number of manufacturers have found ways to liquefy beetroots and concentrate the nitrate into beetroot juice “shots.”
“Although several studies have reported indirect evidence of improved muscle oxygenation during exercise after consuming nitrate-rich supplements such as beetroot juice, none of these studies directly measured blood flow to the contracting muscles,” Proctor says. “Our study was the first to directly test this possibility in humans.”
Read more Health News.
Your personality reflects in the heart's electric waves.read more
Love drinking a glass of lemonade? Learn about the possible side effects of excess lime juice before you add too much of it to your diet.read more