It’s no secret that female-targeted research related to sports science and nutrition has failed to mirror the rise in participation and popularity of women’s sports.
As a result, an international team of researchers conducted a standardized audit of the literature supporting evidence-based products on β-alanine, caffeine, creatine, glycerol, nitrate/beetroot juice and sodium bicarbonate.
Study design
The researchers scrutinized the representation of female and male participants in investigations of credible performance pertaining to the quality and quantity of research pertaining to female athletes, particularly high-performance competitors.
How females stack up
Smith, et. al found that within the 1,826 studies totaling 34,889 participants, 23% of participants were women, although 34% of studies included at least one woman. Across the six different supplements, 0–8% of studies investigated women exclusively, while fewer (0–2%) were specifically designed to compare sex-based responses. The annual publication of female-specific studies was ~8 times fewer than those investigating exclusively male cohorts. Interestingly, 15% of the female participants were classified as international/world-class athletes, compared to 7% of men. Most studies investigated performance outcomes but displayed poorer representation of women (16% of participants), whereas health-focussed studies had the greatest proportion of female participants (35%). Just 14% of studies including women attempted to define menstrual status, with only three studies (~0.5%) implementing best practice methodologies to assess menstrual status.
“While it feels like there are more studies, and there are, the percentage of studies on female athletes is still extraordinarily low vs. male athletes. The authors point out that there are more studies being published on female athletes because the total number of sports nutrition studies is increasing, but the gender composition of subjects of those studies has not really changed,” observed Susan Kleiner, PhD, Owner, High Performance Nutrition.
Conclusions
Smith, et. al concludes that even though these supplements are identified by expert groups as evidence-based products that increase athletic performance, specific support for their use by female athletes is lacking in quantity and quality.
“New research should target the efficacy of performance supplements in female athletes, and future sports nutrition recommendations should specifically consider how well female athletes have contributed to the evidence-base,” the authors conclude. “Our audit demonstrates the poor representation of female athletes in the performance supplement literature. This bias is compounded by the inadequate classification and control of menstrual status in 99.5% of studies. Consequently, the current literature fails to provide robust recommendations regarding the efficacy of credible performance supplements in female athletes. Further research among female cohorts, using high-quality methodological approaches, is therefore required, with particular attention to athletes of high athletic caliber as well as robust classification and methodological control of menstrual status according to best practice guidelines. Only then can the effects of performance supplements known to meaningfully enhance performance among male athletes be validated in their female counterparts, providing true confidence in the expert guidelines around the use of these products.”
“The methodology for female athlete research must rise to the level of considering female physiology. Until then, the data are poor,” said Kleiner. “I do hope that we are coming to a time when we will see a change.”
Marketers missing the mark
“The findings by Smith, et. al., support the notion that many of the dietary supplements designed and marketed towards athletes are in fact backed by little evidence demonstrating they work the same in all kinds of athletes,” explained Dawna Salter PhD, RD, Senior Manager of Clinical Research for PLT Health Solutions. “Are we missing an important demographic to which we can design for and market to? I would venture the answer is yes. Garthe, et. al, (2018) writes that ‘Between 40% and 100% of athletes typically use supplements, depending on the type of sport, level of competition, and the definition of supplements,’ and continues on to say that female athletes consistently report a higher usage of dietary supplements than male athletes. That means there are a lot of women who participate in sport, maybe even up to 100% of them, that might believe in and purchase products with meaningful evidence to support they work for their biology.”
Salter added that perhaps, those who are involved in developing and marketing sports supplements for athletes might better take into consideration the potential differences that exist “due to sexual dimorphisms—the biologically expressed differences that can affect physiological processes—processes such as (but not limited to) temperature regulation, metabolism, body anthropometrics and shapes, hydration modulation, and even mental adaptations to physical stress. Just because there exists evidence that an ingredient or product supports performance outcomes in male cohorts, we cannot necessarily assume our product will extrapolate to women in the same way.”
Need states, life stage must be considered
“As a woman who has participated lifelong in sport and recreational athletics, I have often thought the industry might benefit from a more granular breakdown of the demographic represented by the term ‘athlete,’” said Salter.
She went on to say that evidence-based sports nutrition product development might best start with identifying the multiple consumer need states that motivates a woman to be an athlete, such as those top-notch competitive athletes who strive to win and excel in competition, the less-intense recreational athlete, or those who are hope to attain more holistic health outcomes through sport and activity longevity.
“And then, we should not forget to assess the life stages that biological women pass through that greatly affect their nutrition status. Competitive and recreational athletic women can be adolescents, adults, pregnant, breastfeeding, and peri-or post-menopausal. While research on women athletes is sparse, research on women that takes into account their reproductive or menstrual status is virtually absent. Smith, et al. writes, ‘The performance supplement literature does not reflect the menstrual status of the female athlete population. Notably, we failed to find a single study conducted on women confirmed to be eumenorrheic, although five studies claimed to include this cohort.’”
“It is my hope that our industry can begin to better think about needs of women athletes and further, their life stage, as we move into more evidence-based dietary supplements for sports nutrition,” Salter said.
Source: Nutrients
2022, 14(5), 953; doi.org/10.3390/nu14050953
Auditing the Representation of Female Versus Male Athletes in Sports Science and Sports Medicine Research: Evidence-Based Performance Supplements
Authors: E. Smith, et al.