Halifax study finds beetroot-based supplements may interfere with workout benefits in women

Runners are seen on a track in this file photo. (Snapwire / Pexels)

A study at Dalhousie University has found beetroot-based workout supplements may interfere with the benefits of exercise on for some females.

The study examined sodium nitrate, which is found in beetroots and in dark-leafy greens like spinach. It’s commonly added to pre-workout products with the idea it will enhance performance, especially in endurance athletes.

While the supplements can often support exercise performance, it was found sodium nitrate in combination with cardio prevented some improvements in females normally associated with exercise, like changes to heart structure, ventricular function and calcium handling in heart cells – which helps with regulating contraction and relaxation.

“We knew that nitrate supplements are taken with the idea that they enhance endurance exercise performance and for potential beneficial effects on the cardiovascular system. We were interested in learning whether this is actually true and whether it would work in both sexes,” said professor Susan Howlett, one of the researchers on the study.

“Very little is known about effects of nitrates in females because most studies in humans and in animals have used only males.”

The study used four treatment groups of mice over 12 weeks: sedentary mice, sedentary mice given nitrates, mice given access to a running wheel, and mice given access to a running wheel and nitrates. The study assessed their cardiovascular function at the beginning and end of the study and looked at how much the mice exercised in that time.

“We did not find any evidence of adverse effects of nitrates. In fact, nitrates increased the distance that female mice ran each day. Despite this increase in voluntary running distance, nitrates reduced the beneficial effects of running on the heart. One good thing we did discover is that the effects were temporary and they ‘washed out’ when we stopped giving the mice nitrates but let them continue to run,” said Howlett.

Researchers say there are important differences between males and females which are often overlooked in research for supplements, and people should do their research on what supplements they’re taking.

“It is important to understand that supplements are biologically active and may have both beneficial and harmful effects. More research in this area is needed, and it is crucial to investigate effects in both sexes,” said Howlett.

Howlett led the study with PhD student Elise Bisset.

For more Nova Scotia news, visit our dedicated provincial page