McGregor, who specializes in hormonal health, eating disorders and RED-S, has worked with Olympic, Paralympic and Commonwealth sports teams, and English and Scottish national ballet dancers.
At this year’s NutraIngredients’ Active Nutrition Summit held in Vienna from June 23 to 25, she provided key insights into the unique nutritional needs of the female athlete and the psychological challenges many women encounter across the menstrual cycle.
Should female athletes adjust their nutrition across the menstrual cycle?
A key focus of the discussion centered around the importance of adequately fueling the body to avoid RED-S, the result of insufficient caloric intake and/or excessive energy expenditure.
Research suggests that RED-S can alter a number of physiological systems, including metabolism, menstrual function, bone health, immunity, protein synthesis and cardiovascular and psychological health. McGregor says this particular issue is still one of the ‘biggest challenges’ facing the female athlete.
“The biggest challenge is still the same challenge that it’s always been, which is female athletes not appreciating how much fueling they need in order to support their biological processes but also all the training that they do,” she told NutraIngredients.
“There’s still this belief system that female athletes need to look a certain way to perform a certain way, and I feel unless we start changing that, it’s going to be difficult for female athletes to change their direction of intake.”
RED-S can present particular challenges related to the menstrual cycle. McGregor noted that while there is now a general consensus that women do not need to eat or train differently around their cycle, tracking it can help them better manage any psychological challenges that may arise.
“We have studies that show that when progesterone is dominant in that luteal phase, often we feel less attractive as women,” she said. “If you’re responding to that, you might not fuel your training well.”
This can lead to a pattern of restrictive eating, affecting performance both physically and mentally.
“It’s going to be different for every female and for every cycle as well,” McGregor added. “It’s really important not to underestimate the power of hormones and how they influence how we feel.”
Which specific nutrients do female athletes need?
When it comes to recommending specific nutrients, McGregor said every female athlete will have unique nutritional needs, and a blanket approach to nutrition is unlikely to be effective, with the exception of vitamin D.
“Some female athletes may well need to supplement with iron if they have high menstrual losses,” she added. “Or endurance athletes, we know, have a much higher breakdown of red blood cells, which means their iron levels may be a bit lower.
“If you’ve got someone who is plant-based, then you would probably encourage them to take B12 and maybe omega-3s as well, but it’s very individual and it’s about being able to look at an individual’s blood profile regularly.”
Some women may also struggle to regulate their body temperature during their cycle and may need to adjust their fluid and electrolyte intake when training.
McGregor also suggested that probiotics may be helpful, primarily to support immune health rather than improve performance.
“When I was working towards [the Olympics] in London 2012, we were encouraging athletes to take probiotics 12 weeks out from going to the games because we knew that it reduces their prevalence of upper respiratory tract infections,” she said.
While this immunity link is well-established, research on how gut health impacts performance is still lacking.
“It’s still an emerging area,” McGregor said. “It’s really exciting and really interesting and I think it’s one we can do a lot with as sports dietitians […], but I think we still need a lot more [research].”
Recommending other nutrients, such as creatine, is slightly more challenging, she noted, given the lack of consensus on dosages, timings and use cases.
“More women are becoming interested in [creatine], but I think we have to still be very careful about the application of it,” she said. “There has been a recent position paper talking about the potential benefits of creatine in females, particularly around the menstrual cycle, cognitive function and maintaining muscle mass, […] but I think from an ergogenic point of view, there isn’t really enough evidence.
“The position paper says that it’s looking very, very optimistic, but we still need more studies on the right dose and the right timing. I think we have to be really careful, […] if we don’t have the right information, we could do more damage than good.”