Beta alanine trial fails to show effect on swimming performance
The research was published recently in the Journal of the International Society of Sports Nutrition. It was conducted by researchers associated with universities and institutes in São Paulo and Recife.
The researchers were investigating the effects of beta alanine supplementation on swimming performance among a cadre of young competitive swimmers. Thirteen swimmers were recruited for the six-week, double blind, placebo controlled study.
ISSN position paper lays out expected beta alanine benefits
A 2015 position paper put out by ISSN states that in the opinion of the expert panel beta alanine supplementation in sufficient dosages and over a sufficient period of time (4-6 grams a day and 4 weeks) can boost intramuscular carnosine concentrations and can boost performance, especially for short, burst-type actions of four minutes or less. The ingredient may also benefit older consumers by attenuating neuromuscular fatigue.
The researchers recruited 16 young swimmers for their trial. After excluding three, they were left with 13, which they had determined via a statistical analysis was the minimum required to achieve statistical significance. Eight male swimmers and five females were included, all around 20 years of age. The swimmers were all elite class, having recorded a 400 meter freestyle swim trial time that was within about 75% of the current world record time for men and women respectively in a 25-meter pool, regardless of their particular swim specialties.
The swimmers ingested 4.6 grams of beta alanine or placebo every day for six weeks. The dosages were timed at intervals throughout the day, two capsules at a time, to avoid the tingling sensation that can be a side effect of one single big dose of beta alanine, which could have skewed the blinding of the test.
The swimmers trained similarly throughout the period, so it was expected all would improve their times and all would show metabolic changes. But the researchers were expecting a greater gain and more significant metabolic changes in the beta alanine group.
The swimmers performed a 400 meter freestyle swim trial test at the beginning and end of the test period. Multiple blood samples were also drawn after the 400-meter trials to measure the metabolic effects of the beta alanine supplementation. In addition, the swimmers performed a 30-second, tethered maximum effort swim test to measure peak muscular output.
Beta alanine shows no effects
Despite the research backing the ISSN position paper, the Brazilian trial found no effect for the beta alanine supplementation. The supplemented swimmers neither swam faster nor increased their power output over the expected increases with training. Nor did any exhibit any statistically significant metabolic effects.
“Although metabolic, neuromuscular and energy provision parameters changes, no effect from supplementation was found, evidencing that all the alterations found were the result of exposure to training. Thus, it can be concluded that β-alanine supplementation doesn’t changed metabolic contribution and it was ineffective in improving performance during 400-m freestyle,” they concluded.
The researchers noted several limitations of their study, one being that there was no measurement of intramuscular carnosine content. Another was that there was no control of the athlete’s diets, which could affect the results of beta alanine supplementation. Another less significant limitation was that three of the supplemented athletes did experience a tingling sensation, despite the researchers’ attempts to avoid this.
Beta alanine supplier questions paper’s statistical basis
Natural Alternatives International, San Marcos, CA-based manufacturer of CarnoSyn, a branded form of beta alanine, noted the small size of the Brazilian study should be ranged against the large body of science that already supports the use of the ingredient, some of which is referenced in the ISSN position paper.
“We note that 13 subjects were recruited to the study, 5 females and 8 males, but the paper does not disclose as to how many of either gender were supplemented with beta-alanine or placebo. If we assume a distribution of 6 and 7, such extremely low numbers would seldom be expected to show a statistical effect of supplementation even if one were present. But in this case we have the further complication of a different admix of genders and training components. Because the subject numbers were uneven in the two groups, including the gender distribution, one must question if the training response was the same in females and males, adding to the statistical noise obscuring the effects (if any) of beta-alanine supplementation,” said Di Tan, PhD, director of scientific affairs for NAI.
“However, we can say with certainty that supplementation with beta-alanine, in order to augment the modest amounts found naturally in most diets, the exception being in the vegetarian diet, as well as the modest amounts synthesized in the liver, will increase the synthesis and accumulation of carnosine (beta-alanyl histidine) in muscle (Harris et al 2006; Spelnikov & Harris 2019),” she added.
“An increase in the carnosine content in human muscle will certainty lessen the fall in intracellular pH during intense exercise, and will increase performance in different modes of exercise where this is limited by intra-muscle cell pH decline,” Tan concluded.
Source: Journal of the International Society of Sports Nutrition
17, Article number: 40 (2020)
Beta alanine supplementation effects on metabolic contribution and swimming performance
Authors: Silva Norberto M, et al.