With limited studies on nutritional risks among female athletes, researchers from Rutgers University analyzed a number of rigorously designed studies on the topic that also included recommendations for athletes, coaches, parents, and health professionals.
The review, published in the Journal of Women's Health, evaluated the most recent research using a systematic search of the databases PubMed and Cochrane for published studies (from year 2000 to year 2019) to identify articles that met inclusion criteria.
The criteria included peer-reviewed studies of original research on human subjects 13 years of age or older; a sample size of 19 or more; and studies with a thorough description of sample and methods.
The researchers settled on 11 studies that met their criteria, most of which were cross-sectional in design with few rigorous controls.
Several of the studies in this meta-analysis recommended the importance of monitoring female athletes to avoid the risk of disordered eating and associated medical complications.
The investigation revealed that general nutrition knowledge is lacking among athletes, sports teams, and coaches.
Research showed that energy needs are often unmet in the female athlete due to low energy availability (EA). Athletes in endurance, aesthetic, or weight class-based sports, or sports that promote a lean body type such as ballet, are at an increased risk of the major criteria for Relative energy deficiency in sport (RED-S), the result of insufficient caloric intake and/or excessive energy expenditure. For example, in a recent study of elite ballet dancers, 65% were classified at risk for RED-S.20
Low EA in female athletes may be due to low nutritional knowledge, time management, and food availability, along with greater disordered eating risk, drive for lower body weight for sport, and/or unintended failure to meet energy needs.
The authors point out that “in addition to inadequate macronutrient intake, insufficient micronutrient consumption such as from iron may also occur, leading to stage 1, inadequate iron status. Inadequate dietary intakes, acute inflammation brought on by exercise, sweat, and menstrual losses, especially when heavy, further increase the risk for inadequate iron status and related deficiencies in female athletes. Iron deficiency anemia may be even more common in females participating in intense training, like distance running, due to the potential for additional losses through hemolysis, urine, and gastrointestinal bleeding.”
Exercise-related stress and inadequate dietary intakes may also lead to deficiencies in other micronutrients, especially vitamin D, zinc, calcium, magnesium, and B vitamins. Calcium and vitamin D insufficiency are of particular interest due to related increased stress fracture risk.
The authors note that recent data suggest that about 33%–42% of female athletes are insufficient in vitamin D, with 72%–90% falling short of the Adequate Intake for calcium.
“Dietary supplements, such as vitamins, minerals, amino acids, herbs or botanicals, metabolites, constituents/extracts, energy drinks, calorie replacement products, creatine, vitamin C, or combinations of the above, are common in the sports world because of the held belief that they may compensate for sports performance,” explained the authors.
The report said that while some studies indicate multivitamin supplements may compensate for an inadequate dietary intake, it is suggested that supplementation be limited among young athletes and more cautionary with regard to commercial supplements.
“In general, there is a lack of research on the effect of dietary supplements in female athletes.Therefore, it is highly recommended that supplements be used with caution as their purity, ingredients, and effectiveness are often not well regulated or confirmed,” the report noted, adding that only third-party tested products be considered after companies have shown the safety and effectiveness of their products.
The team also found that strategies to enhance nutrition patterns among female athletes is key in avoiding risks of disordered eating, eating disorders, low energy availability, and symptoms of relative energy deficiency in sports.
The report concluded, “Current research suggests that the nutrition status of female athletes needs to be more closely monitored because of reports of disordered eating risk, low energy availability and its effects on bodily function/performance, and lack of accurate sports nutrition knowledge. These characteristics are common in female athletes and warrant an interdisciplinary team approach in screening, counseling, and treating female athletes. The interdisciplinary team may include physicians, ATs, licensed dietitians, physical therapist, and psychologist or psychiatrist, parents, and coaches.15 Specifically, these teams of coaches, athletes, and health professionals should be educated on the negative health effects of inadequate caloric intake on both performance and long-term health. In addition, early detection of low energy availability and RED-S is essential in preventing further negative consequences.17 Diagnosed stress injuries should be considered a red flag to signal further evaluation, as part of the treatment plan.”
The analysis also provided a list of suggested recommendations:
- Athletes should consider developing individualized nutrition plans with a licensed dietitian who will take into account the specificity and uniqueness of the event, performance goals, practical challenges, food preferences, and responses to various strategies
- Team nutrition education sessions held on various sports nutrition topics with individual sports teams may be beneficial
- Comprehensive educational programs should be developed for coaches, practitioners, parents, and clinicians to facilitate awareness of proper sports nutrition and medical concerns in the female athlete population
- The long-term risks of dietary supplements, and banned substances, should be evaluated by health professionals
- Licensed dietitians, who are also a Certified Specialist in Sports Dietetics (CSSD), should provide nutrition education to athletic teams, individuals, and coaching staff, along with individual nutrition plans and nutrition counseling, in a safe and effective manner
- Screening for disordered eating risk and RED-S should be implemented on a regular basis
- Health professionals may generally inquire about nutrition and eating patterns when meeting with an athlete and make appropriate referrals within the interdisciplinary team when necessary, but the inquiries should be limited because they may not be advantageous for athletes with disordered eating tendencies.
Source: Journal of Women's Health
Vol. 29, No. 5 doi.org/10.1089/jwh.2019.8180
“Nutritional Risks Among Female Athletes”
Authors: M. Gastrich et al.