Nutrition for female athletes - what are the challenges?
The field of sports nutrition is evolving day by day and the abundance of researches about nutrition for optimal performance is incredible. However, sometimes the information available might be not suitable for female athletes. Over the years, the majority of sports nutrition studies focused on men and have been carried out with men. In particular, there has been an interest in male hormones (testosterone) and growth hormones and their impact on performance. This was mainly due to the fact that elite sports were more popular among men. However, with these sports becoming more popular and mainstream among women, sports science and nutrition are starting to explore the effects of female reproductive hormone and menstrual cycle on women’s fuel requirements. In fact, often there is no distinction between women and men despite their body’s physiology and hormone profile being considerably different.
This article is going to explore what kind of nutritional challenges female athletes face and how they can eat well even on the tightest training schedule.
Low Energy Availability (LEA) and Relative Energy Deficiency Syndrome (RED-S)
To fully understand female athletes' challenges when it comes to nutrition, we must explore the concept of LEA and RED-S. First of all, the RED-S, once known as the Female Athlete Triad, is a complex systemic syndrome caused by relative energy deficiency, which includes impared bone health, altered menstrual function, reduced protein synthesis, and impaired physiological functioning. This syndrome can affect both male and female athletes and includes the effects of low energy availability. The term energy availability refers to the amount of dietary energy available to support physiological functions and maintain optimal health after the energy spent during training has been taken into account.
Energy availability = Energy intake - Exercise Energy Expenditure
An athlete is said to be in a Low Energy Availability state when there is a mismatch between the energy intake from food and the energy expended during training, resulting in not enough energy to support physiological functions. The causes of LEA are multiple and may be due to intentional factors (athletes wanting to achieve a lower body weight to perform), unintentional factors ( athletes not being aware of their higher energy requirement and how much food is needed to meet those demands), and, finally, compulsively factors (athletes with disordered eating behaviours).
Sports such as gymnastics, distance running, figure skating, diving, or classical ballet, that emphasize leanness, put great pressure on female athletes’ bodies, and women participating in these sports are more susceptible to having inadequate nutritional intake. In particular, female dancers were found to consume less than 70% of their recommended daily energy requirements. The health risk of under fuelling their body when training at a high intensity can be detrimental.
If female athletes are on a restricted diet for a long period they may not have enough energy to sustain the energy demanded by their physical activity, by their body for daily life activities, and the energy needed for crucial metabolic pathways. This can negatively impact their immune system, their metabolic rate, and bone health. Some of the signs to look out for are:
- Amenorrhoea and/or
- Absence of first menstruation by age 16 and/or
- Disordered eating behaviours
- Poor bone health (low Bone Mineral Density) and/or
- Depression or irritability and/or
- Early fatigue while training
- Lack of improvement in performance
- Impaired protein synthesis
- Frequent illnesses and colds.
To reach optimal performance outcomes and optimise health, it is essential to balance the dietary energy intake and the energy expenditure (energy cost of training and daily life activities). In particular, ensuring an optimal macronutrient intake (protein, carbohydrates, and fats) is essential to success while performing, as the body needs energy and a balance of these 3 macronutrients to move.
Carbohydrates, Protein and Fat
Carbohydrates are needed for exercise performances and to replenish both liver and muscle glycogen stores after training sessions. The recommended daily intake for athletes is between 6-12g carbs/kg body weight. The exact amount will depend on the body size and physical activity level of the female athlete. Fresh or dried fruit, vegetables, brown and white rice, whole grain or white bread, bagels, cereals, rolled oat and potatoes are all good sources of carbohydrates.
Female athletes, and in particular vegan female athletes or those who are dieting to lose weight, are at a higher risk of not consuming enough protein since their protein requirements are greater than the average population. The amount of protein required depends on the type of sports performed. However, the recommendation is to consume between 1.2-2.0 g protein/kg body weight and spread protein-rich meals throughout the day. Consuming around 0.32-0.38g/kg body weight of protein in pre-and post-workout snacks might be beneficial for premenopausal female athletes. Meat, chicken, eggs, cheese, milk, yoghurt, soy products, legumes, and tofu are great sources of proteins.
Fat is the third macronutrient but not less important than protein and carbs. It is essential for female athletes to have an adequate intake of total fat and essential fatty acid. The general recommendation is that fat intake should be between 20-35% of total daily energy intake, as when fat intake is below this value the risk of not meeting the requirements of essential fatty acids is higher. Low-fat diets are not recommended for athletes as the results may be a decreased energy and nutrient intkae, impaired exercise performance, and impairment of the reproductive system (reduced concentration of sex hormones).
What are important micronutrients for female athletes?
The nutrient requirements of female athletes are similar to those of the general populations. However, as female athletes have a higher level of physical activity their energy and fluid requirements will be greater as well as their nutrients and micronutrients needs. These higher needs can be easily met with a well balanced diet, but there are some key nutrients that may need special considerations:
Iron
In general, both male and female athletes are at higher risk of iron deficiency than those less active. Why? Firstly, athletes have a greater iron requirement: their energy production pathways are more active in their cells and they have more red blood cells to carry more oxygen. Secondly, athletes lose more iron through sweat, and in those training at high intensity, red blood cells are broken down more quickly. Female athletes are at a greater risk of becoming iron deficient as blood is lost through menstruation. In particular, endurance female athletes should pay attention to their iron intake to meet their bodies’ needs. Some studies have reported that 15-35% of female athletes were iron deficient and reduced iron stores were found in more than 50% of female athletes.
Currently, the recommended iron intake for healthy women of reproductive age is between 14.3mg and 18mg per day (UK and US). Although there are no guidelines on recommended iron intake for female athletes, many studies have shown that female athletes tend to not meet the above recommendations. Iron deficiency is one of the most common and nutritional deficiency among female athletes. Despite the important role that iron plays in our health, taking iron supplements is not recommended unless prescribed by your doctor.
Calcium
Female athletes who follow a strict diet are at risk of calcium deficiencies. Calcium is important for maintaining optimal bone and teeth health and to promote their growth - around 99% of the calcium in our body is stored in the bones. Therefore, requirements for children, adolescents and pregnant women, and those with higher physical activity levels are increased. For female adolescents, it is recommended a daily intake of 1000-1300mg to sustain their growth, while for those with amenorrea the recommendation is 1300-1500mg/day, due to the detrimental consequences of this on their bone health. The best sources of calcium are dairy products or alternative dairy products fortified with calcium and vitamin D. Other vegan sources of calcium are fortified oat cereals, firm and calcium set tofu, and boiled kale.
Other micronutrients that tend to be low in female athletes are zinc, vitamin B12, and folate. Meat, fish, and poultry are high in iron, zinc and vitamin B12, while folate can be found in whole grains, legumes, dark leafy greens, fortified bread and cereals.
To summarise:
When it comes to nutrition for female athletes the research is still limited, however, there are some important key points to focus on:
- Adequate intake of protein, carbohydrates and fat, based on the athlete’s level of physical activity and age
- Adequate consumption of calcium and iron-rich food.
Following a balanced diet and knowing how much food your body requires to function and perform is essential to avoid any nutrients deficiency.
Francesca is our sports nutritionist who used her sports nutrition expertise while she was a ballet dancer for most of her life. Francesca uses this unique insight to provide clients practical, insightful and lifestyle-driven nutritional advice in both Italian and English. She is a registered associate nutritionist with the AfN. Start your free nutrition assessment to get the best nutritional advice for you.
Further reading
Koutedakis, Y., Jamurtas A. The dancer as a performing athlete: physiological considerations. Sports Med. 2004. 34 (10):651-61.
Doyle-Lucas AF; Davy BM. Development and evaluation of an educational intervention program for pre-professional adolescent ballet dancers: nutrition for optimal performance. J Dance Med Sci. 2011; 15(2):65-75
Hinton PS. Iron and the Endurance Athlete. Appl Physiol Nutr Metab. 2014 May; 39: 1012-1018.
MOUNTJOY M, SUNDGOT-BORGEN J, BURKE L, CARTER S, CONSTANTINI N,LEBRUN C, MEYER N, SHERMAN R, STEFFEN K, BUDGETT R, LJUNGQVIST A.The IOC consensus statement: beyond the Female AthleteTriad—Relative Energy Deficiency in Sport (RED-S). Br J SportsMed. 2014; 48: 491-497. doi:10.1136/bjsports-2014-093502
Briggs C, James C, Kohlhardt S, Pandya T. Relative energy deficiency in sport (RED-S) – a narrative review and perspectives from the UK. Dtsch Z Sportmed. 2020; 71: 243-248. doi:10.5960/dzsm.2020.459
Manore, M., M. (2017). The female athlete: energy and nutrition issues. Sports Science Exchange. Vol. 28, No. 175, 1-5.
Sim, M., Garvican-Lewis, L.A., Cox, G.R., Govus, A., McKay, A.K.A., Stellingwerff, T., and Peeling, P. (2019). Iron considerations for the athlete: a narrative review. European Journal of Applied Physiology, 119, 1463 – 1478
Alaunyte, I., Stojceska, V., and Plunkett, A. (2015). Iron and the female athlete: a review of dietary treatment methods for improving iron status and exercise performance. Journal of the International Society of Sports Nutrition, 12, 38
Comments