Study finds betaine increases fat free mass, boosts power output in young women

The new study was published in the Journal of Dietary Supplements​.  It was the work of a team led by Hunter S. Waldman, PhD of Human Performance Research Laboratory at the University of North Alabama.

Betaine is a zwitterionic compound which refers to its property of having both positively and negatively charged groups (‘zwitter’ is a German word meaning ‘hybrid’ or ‘hermaphrodite’). It is commonly isolated from molasses during sugar beet refinement.  

It is present in both plants and animals, being found for example in both wheat bran and shellfish in addition to beets.  It has been marketed as both a weight management ingredient and as sports performance ingredient, though the evidence in favor of its use is not overwhelming.

The researchers noted that betaine intake in the standard American diet is low at less than 350 mg a day.  Studies have found it to be safe and well tolerated at doses of as high as 15 grams a day or even more, though most studies have found effects at 2 grams to 5 grams.

Little know about betaine’s effects in women

Many sports nutrition studies use men for subjects, because without the confounder of menstrual cycles men are easier and cheaper to study.  The researchers noted that for this reason little is known about the effects of betaine supplementation on performance outcomes in women. Only one other recent study has been conducted​​, which found that betaine given at a rate of 2.5g/day to college age women engaged in a resistance training protocol helped them lose fat, but did not boost their absolute strength.

The present study looked at markers of metabolic flexibility, body composition and anaerobic performance. The researchers recruited a cohort of active college age females for their double blind, placebo-controlled trial.  The study design did not include a washout period or a crossover phase both for cost and practicality reasons, as such additional facets often mean not as many subjects complete the full study.

The researchers ended up with 23 subjects for the full study, after six subjects were unable to complete the anaerobic portion of the study during the first visit.  The subjects ceased taking all supplements two weeks prior to the study, and took 2.4 grams of betaine or a placebo for two weeks.  There were three lab visits, one for familiarization with the protocol, one to gather baseline data and another at the end of the supplementation phase.

Experimental group dropped fat, boosted power output

The researchers used a variant of the Wingate anaerobic test done on a cycling ergometer.  Measures of body fat percentage were taken with calipers which gave an indication of relative fat free mass (FFE).  The subjects were also fitted with face masks to measure respiration, and finger prick blood tests were performed to measure lactate levels.  The subjects were also queried on their perceived rate of exertion (PRE) during the Wingate test, which calls for subjects to put out their maximum power for 30 seconds.

“In conclusion, chronic ingestion of 2.4g/day of BET improved FFM, RPE, and mean power output in the latter stages of exercise,”​ the researchers concluded.

The researchers noted that mean power output in the supplemented group increased by 3.2%, while tht group also showed significant increases in FFM.   Taken together, the results suggested collectively “that BET might offer females a dietary supplement which can improve body composition and markers of performance in the latter stages of exercise or competition.”​

Source:​ Journal of Dietary Supplements​
https://doi.org/10.1080/19390211.2021.1973644​
Effects of Betaine Supplementation on Markers of Metabolic Flexibility, Body Composition, and Anaerobic Performance in Active College-Age Females​
Authors: Waldman HS, et al.