SPECIAL NUTRITION CONSIDERATIONS FOR FEMALE ATHLETES
- Annie Bothma, IOPN Sports Performance Nutritionist (EQF Level 7. Masters), Running Coach and Elite Marathon Runner
Nutrition is a crucial aspect of athletic performance for both male and female athletes. However, female athletes may have specific nutritional needs due to differences in physiology, hormonal fluctuations, and potential health considerations. Here are some key nutritional considerations for female athletes.
Female athletes are underrepresented when it comes to research and the vast majority of the sports nutrition research we have we done on male participants. To understand why researchers often shy away from researching female athletes, let's look at some of the big differences between men and women.
One of the most significant distinctions between men and women lies in their reproductive physiology and hormones. After reaching puberty, men typically maintain relatively consistent levels of sex hormones. On the other hand, adult women experience the following:
Cyclical Hormone Changes: Women undergo cyclical shifts in ovarian hormones, which are responsible for the menstrual cycle.
Use of Synthetic Hormones: Many women use synthetic steroid hormones, such as hormonal contraceptives, which affect their hormone levels.
Hormone Fluctuations: Women can experience exceptionally high levels of estrogen and progesterone during pregnancy, followed by a rapid decrease in these hormones during menopause.
These dynamic changes in reproductive hormones are key factors in studies that explore differences between the sexes. They also play a crucial role in examining the impact of factors like menstrual cycle phases, contraceptive use, pregnancy, and menopause on various aspects of nutrition, training, performance, and overall health.
Differences in Metabolism between Males and Females
Females store more fat, despite typically consuming fewer calories than males, even when accounting for fat free mass. Greater storage begins in adolescence and is mostly attributed to differences in sex hormones. It has been postulated that females are more efficient in conserving energy and storing it as fat which is supported by the fact that females must reduce calories by a greater proportion to experience similar weight loss as males.
During exercise, females utilize more fat and less carbohydrate and protein compared to men. However, differences in sex hormones explains only in part, while other mechanisms contributing to the differences remain to be explained. More research is needed to understand exactly how nutritional intake during and around exercise should be adapted to the female athlete’s metabolism.
HOW DOES THE MENSTRUAL CYCLE IMPACT PERFORMANCE?
There are 4 phases of menstruation:
Follicular phase - Low estrogen and progesterone
Ovulation phase - High estrogen and low progesterone
Luteal phase - High estrogen and progesterone
The primary role of these hormones is to support reproduction; however, the fluctuating amounts of estrogen and progesterone also have an impact on the cardiovascular, respiratory, metabolic, and musculoskeletal systems.
Some research has shown improved performance, such as an increase in endurance, insulin sensitivity, and pain tolerance during the follicular phase. Other research shows that the hormonal changes during the menstrual cycle does not impact anaerobic performance. More research is needed to confirm the effects the menstrual cycle has on aerobic and anaerobic performance and if female athletes need to alter their training based on their menstrual cycle.
How a female athlete performs during the phases of her menstrual cycle varies from person to person and should be monitored to track menstrual health for each individual female athlete.
The most common menstrual dysfunction seen in female athletes is amenorrhea. Amenorrhea is generally defined as the absence of menses 3 months or more.
Amenorrhea can be caused by a variety of factors:
Typically, young healthy women have 92% of their total bone mineral content by 18 years old. Female athletes with the Triad may experience compromised bone health, stress fractures, or irreversible osteoporosis at a much younger age. Amenorrheic athletes have lower bone mineral density compared to their eumenorrheic counterparts. While weight bearing exercises generally promote positive bone health, an amenorrheic athlete’s menstrual status may outweigh the benefits of physical activity.
ADEQUATE CALORIE INTAKE
Low-energy availability (LEA) occurs when there is a mismatch between what you’re eating (energy intake) and the energy you expend during exercise, ultimately leaving you with inadequate energy to support the functions required by the body to maintain optimal health and performance.
All athletes should pay attention to their energy intake, since being in a low-energy availability state can significantly negatively impact both health and performance. However, female athletes may be more sensitive to calorie deficits due to the sex hormone differences between males and females.
Female athletes need to get enough energy to meet the demands of sport, daily living, and reproduction. A low energy intakes makes it difficult to get dietary nutrients required for:
Maintenance of bone
Maintenance of blood
Therefore, it is crucial that overall calorie intake is adequate not only to support the demands of training, but also support overall health and longevity. The number of calories needed will vary based on activity level, body composition, and training intensity.
STAY OUT OF THE RED ZONE
A chronic and severely insufficient energy intake causes a state of low-energy availability known as relative energy deficiency in sport (RED-S), which has a host of detrimental long term consequences on both health and performance. Although RED-S is not exclusively seen in female athletes, there is a higher proportion of female athletes suffering from this condition.
By definition, the syndrome of RED-S refers to “impaired physiological functioning caused by relative energy deficiency and includes, but is not limited to, impairments of metabolic rate, menstrual function, bone health, immunity, protein synthesis and cardiovascular health.”
RED-S can be intentional due to a restriction of food intake as result of an eating disorder or unintentional when an athlete is unaware of a mismatch between energy intake vs output. Education, early detection, and support are essential to address these issues.
WEIGHT MANAGEMENT & BODY IMAGE
Female athletes, particularly those involved in sports with aesthetic requirements like gymnastics or dance; or those participating in sports like running, cycling and rock-climbing where power-to-weight-ratio is considered an important factor, may face pressure to maintain a certain body weight or image.
However, it's essential to focus on performance-based and prioritize overall health and well-being over appearance. Athletes shouldn't focus on the scale and instead shift their focus to performance based goals.
"It is not how my body looks, but what my body can do for me!" That is what really matters!
Fuel for the work required. Make sure you don't cut your calories before, during or after your workouts to try lose weight. This will not only compromise your performance, but also your recovery, increase the risk of injuries and negatively impact your overall health.
SURROUNDING YOUR TRAINING WITH GOOD FUELLING PRACTICES
Female athletes should make sure they start their exercise well fueled to facilitate proper adaptations. They should avoid fasted training, since maintaining hormonal balance is crucial, and fasting before training could potentially lead to disruptions in the delicate hormonal interplay. Additionally, as previously mentioned, women may be more sensitive to low-energy availability and may experience a greater negative impact on performance and recovery when training on an empty stomach.
If the training session is over an hour in duration taking on fuel in the form of carbohydrates and fluids to avoid dehydration will allow athletes to get the most out of their training by increasing performance.
Proper post-exercise nutrition is vital for female athletes to replenish glycogen stores, repair muscle damage, and promote recovery. Including carbohydrates and protein in the post-workout meal or snack can be beneficial.
Carbohydrates are a vital macronutrient for female athletes, providing them with the energy needed to fuel their workouts, support recovery, and optimize performance. Here are some of the key benefits of carbohydrates for female athletes:
Energy Source: Carbohydrates are the body's primary source of energy, especially during high-intensity exercise. They are broken down into glucose, which is then used by muscles and other tissues as fuel.
Improved Athletic Performance: Adequate carbohydrate intake can enhance endurance and high-intensity exercise performance. Carbohydrates help maintain glycogen stores in muscles, which are essential for sustained physical activity.
Prevention of Fatigue: Carbohydrates help delay the onset of fatigue during exercise. When glycogen stores are depleted, athletes can experience feelings of exhaustion and decreased performance.
Optimal Recovery: Consuming carbohydrates after exercise helps replenish glycogen stores and kickstarts the recovery process. This is particularly important for female athletes who engage in multiple training sessions or competitions in a single day.
Preservation of Muscle Mass: When the body has insufficient carbohydrate intake, it may turn to protein as an energy source. This can lead to the breakdown of muscle tissue. Consuming enough carbohydrates can help spare protein for its intended role of muscle repair and growth.
Maintenance of Hormonal Balance: Inadequate carbohydrate intake, especially in combination with excessive exercise, can disrupt hormonal balance, leading to irregular menstrual cycles or even amenorrhea (absence of periods). Sufficient carbohydrate intake can help prevent these issues.
Cognitive Function: The brain relies on glucose for optimal functioning. Carbohydrates provide a steady supply of glucose to the brain, supporting cognitive function, focus, and decision-making during training and competition.
Gastrointestinal Health: Carbohydrates are easily digestible and can help prevent gastrointestinal discomfort during exercise. A lack of carbohydrate intake may lead to feelings of "bonking" or "hitting the wall."
Immune System Support: Intense exercise can temporarily suppress the immune system. Carbohydrates play a role in supporting the immune system's function, helping female athletes stay healthier and recover more quickly.
Enhanced Muscle Protein Synthesis: Consuming carbohydrates with protein after a workout can enhance muscle protein synthesis, facilitating muscle repair and growth.
Mood Regulation: Carbohydrates can positively affect mood due to their role in serotonin production. Adequate serotonin levels are important for managing stress and maintaining a positive mindset.
It's essential for female athletes to prioritize carbohydrates in their diet, especially on training days. Opt for complex carbohydrates like whole grains, fruits, vegetables, legumes, and starchy vegetables, as these sources provide sustained energy and important nutrients. Carbohydrate needs can vary based on factors such as training intensity, duration, frequency, and individual metabolic rate.
If an athlete is purposefully restricting their energy intake, consuming enough carbohydrates to fuel performance and recovery can be difficult. Some athletes may consume a low-energy, dense carbohydrates such as whole fruits and vegetables, and then feel more full due to the high fiber content. This may result in consuming fewer calories needed to support an athlete’s energy needs. Some research suggests that this type of diet may be a contributing factor in low-energy availability and menstrual dysfunction seen in some female endurance athletes.
Protein for the Female Athlete
Protein needs for athletes are well established. Protein is crucial for muscle repair and recovery in both male and female athletes. Protein plays numerous roles in supporting their overall health, performance, and recovery. Here are some of the key benefits of protein for female athletes:
Muscle Growth and Repair: Protein is essential for the repair and growth of muscles. Engaging in physical activity, especially resistance training or high-intensity workouts, can cause micro-tears in muscle fibers. Adequate protein intake supports the repair of these muscles, leading to muscle growth and improved strength.
Recovery: Protein consumption after exercise can help speed up recovery by providing the necessary amino acids for repairing damaged tissues and replenishing glycogen stores in muscles.
Enhanced Performance: Protein intake can contribute to improved athletic performance by promoting better muscle function, endurance, and overall strength. Having strong and well-functioning muscles can lead to better movement efficiency during sports and activities.
Appetite Regulation: Protein-rich foods are often more satiating than other types of foods. Including protein in meals and snacks can help female athletes feel fuller for longer periods of time, aiding in appetite regulation and potentially supporting weight management.
Metabolism Support: The thermic effect of food (TEF) is the energy expended during digestion and metabolism of nutrients. Protein has a higher TEF compared to carbohydrates and fats, meaning that consuming protein requires more energy to process, potentially boosting metabolic rate.
Hormonal Balance: Adequate protein intake is important for maintaining hormonal balance in the body. Estrogen may have a positive effect on muscle protein turnover, therefore it is important to avoid low energy deficiency which will negatively impact a female athlete's hormone production. Female athletes who are at most risk of not consuming enough protein are athletes who are restricting energy, dieting for weight loss, and/or vegan athletes. Female athletes who are post-menopausal and women with low amounts of estrogen may not be as sensitive to the anabolic effects of resistance training and dietary practices, resulting in muscle loss. To help counteract this, females are advised to consume frequent protein feedings of 20-40 g at all their meals and snacks and ensure their overall protein intake is sufficient to support their training and health.
Bone Health: Protein is not only important for muscle health but also for maintaining strong bones. Female athletes are at risk of decreased bone density due to factors like intense training, low energy availability, and hormonal changes. Protein, in combination with other nutrients like calcium and vitamin D, contributes to bone health.
Immune System Support: Protein is needed for the production of antibodies and immune system cells, which help defend the body against infections and illnesses. Engaging in regular intense training can sometimes suppress the immune system, and adequate protein intake can support its function.
Prevention of Muscle Loss: Some female athletes may be at risk of muscle loss due to factors like energy restriction, inadequate protein intake, or overtraining. Consuming enough protein can help mitigate the risk of muscle breakdown.
Healthy Hair, Skin, and Nails: Protein is a building block for hair, skin, and nail cells. Ensuring sufficient protein intake can contribute to maintaining healthy hair, skin, and nails.
Blood Sugar Regulation: Protein can help stabilize blood sugar levels by slowing down the absorption of carbohydrates from the digestive tract. This can be particularly beneficial for maintaining consistent energy levels during training and competition.
It's important for female athletes to consume a well-balanced diet that includes an adequate amount of protein to support their training, recovery, and overall health. Sources of protein can include lean meats, poultry, fish, eggs, dairy products, legumes, nuts, seeds, and plant-based protein sources like tofu and tempeh. The specific protein needs of an athlete may vary based on factors such as training intensity, body composition goals, and individual metabolic rates.
Fats for the Female Athlete
Healthy fats play a crucial role in the diet of female and male athletes seeking optimal health and performance. Incorporating the right types of fats into their diet can have several benefits for female athletes:
Energy Source: Fats are a concentrated source of energy, providing more than twice the calories per gram compared to carbohydrates and protein. During prolonged and endurance-based activities, healthy fats can serve as a valuable source of sustained energy, helping female athletes perform at their best.
Hormone Regulation: Healthy fats are essential for the production and regulation of hormones, including sex hormones like estrogen and progesterone. Female athletes often need to maintain a delicate hormonal balance, and consuming adequate healthy fats can support this balance, promoting overall health and normal menstrual function.
Joint and Tissue Health: Omega-3 fatty acids, a type of healthy fat found in fatty fish (like salmon and mackerel) and flaxseeds, have anti-inflammatory properties that can help reduce joint pain and inflammation. This is particularly important for athletes who engage in repetitive or high-impact activities like running. Chronic inflammation can hinder recovery and negatively impact performance.
Vitamin Absorption: Fat-soluble vitamins (A, D, E, and K) require dietary fats for proper absorption. These vitamins are important for bone health, immune function, and overall well-being. Female athletes who are active and often outdoors may benefit from the enhanced absorption of vitamin D, which is essential for bone health.
Cell Membrane Integrity: Omega-3 and omega-6 fatty acids are building blocks of cell membranes, helping to maintain their fluidity and integrity. This is important for overall cell function, especially for athletes whose cells experience increased stress due to physical activity.
Heart Health: Including healthy fats, such as monounsaturated and polyunsaturated fats, in the diet can contribute to heart health by reducing the risk of cardiovascular diseases. These fats can help lower LDL cholesterol levels and improve overall cholesterol profile.
Satiety and Weight Management: Healthy fats can help promote a feeling of fullness and satiety, which can be beneficial for weight management and preventing overeating. Including moderate amounts of healthy fats in meals can contribute to balanced and satisfying nutrition.
Cognitive Function: The brain is composed of a significant amount of fat, and consuming healthy fats can support cognitive function and mental clarity, which are important for both training and competition.
Recovery and Muscle Repair: Some fats, such as those containing omega-3 fatty acids, have been shown to support muscle recovery and repair. This can be particularly valuable for female athletes engaging in intense training regimens with short recovery periods.
Female athletes should focus on including sources of healthy fats such as avocados, nuts, seeds, fatty fish, olive oil, and coconut oil to promote good overall health.
Balance and variety in your diet is important - Don’t excused any macronutrients from your diet. Different macronutrients play different roles for health and performance.
HYDRATION IS KEY
Proper hydration is critical for performance and recovery for all athletes. Proper electrolyte balance is crucial for maintaining hydration and supporting nerve and muscle function.
Fluid needs typically increase during the luteal phase of the menstrual cycle, which occurs after ovulation and lasts until the start of menstruation. This is because progesterone levels rise during this phase, which can lead to water retention and increased fluid requirements.
It's important to stay hydrated throughout the entire menstrual cycle, but paying extra attention to hydration during the luteal phase can be beneficial.
Female athletes should drink water regularly throughout the day and increase their intake during exercise. Individual fluid needs vary based on size, genetics, dietary intake, the environmental conditions and their training load/intensity.
Female athletes are at a higher risk of bone-related issues like osteoporosis and stress fractures. Up to 30% of peak bone mass is acquired during the 3 years of puberty.
Active girls increase their bone mineral content by 17% compared to non-active girls.
Low estrogen levels, seen in post-menopausal women and amenorrheic women results in rapid bone loss. Can result in 3-5% loss of bone mass per year. A diet with sufficient energy intake, levels of Calcium, Vitamin D, as well as carbohydrate and protein intake should be considered for a female athlete’s bone health.
Individuals, especially females who consume diets low in calcium-rich foods, have on average lower bone mass and are at greater risk of stress fractures.
The RDA for calcium is 1000 mg/day and should be consumed in small amounts throughout the day to maximize absorption
Vitamin D Intake
Similar to calcium, Vitamin D is important to a female athlete’s bone health.
Consuming Vitamin D with calcium increases calcium absorption.
Vitamin D plays an important role in Calcium and Phosphorus regulation and athletes who are Vitamin D deficient may have low bone mass and at greater risk of injuries such as stress fractures.
The RDA for adults is 600 IU per day, although sunlight is the best source.
Studies suggest increased protein intake may lead to increased Calcium absorption.
Protein is also an important part of bone structure and protein ingestion increases the production of hormones and growth factors associated in bone formation.
Clear link between continuous and a long-term energy availability deficit and bone health.
Low carbohydrate diets may lead to low-energy availability since carbohydrates are the main energy source for athletes, which negatively affects bone health.
Recent data has shown carbohydrates attenuates the bone reabsorption process during training.
Sufficient calcium, vitamin D, and protein and carbohydrate intake, along with weight-bearing exercises, can support bone health and reduce the risk of injuries.
LOW IRON & ANAEMIA RISK
Iron is particularly important for female athletes because many women are prone to iron deficiency due to menstrual blood loss. Iron is essential for oxygen transport and energy production.
Micronutrient intake for the female athlete can be low if the athlete is restricting energy, follows a restricted diet, or has an eating disorder. In some cases, the RDA for females is higher than males. The recommended intake is for females are 18 mg/day and for males it is 8 mg/day.
An estimated 35% of female athletes suffer from iron deficiency. The primary strategies for iron supplementation are: Increasing dietary iron intake is generally the first method.
Types of iron and absorption:
Heme (comes from animals) and non-heme (does not come from animals).
Sources of heme iron include red-meat, fish, and poultry.
Sources of non-heme iron include fortified cereals, and dark leafy greens, and legumes.
Consuming vitamin C-rich foods alongside iron-rich foods can enhance iron absorption.
LISTEN TO YOUR BODY
Each athlete is unique, and nutritional needs can vary based on factors like age, training intensity, and menstrual cycle phase. It's essential to pay attention to how your body responds to different foods and adjust your diet accordingly.
Remember, it's essential for female athletes to work with a sports nutritionist or healthcare professional who can provide personalized guidance and support. Proper nutrition plays a significant role in optimizing athletic performance and promoting long-term health and well-being.
SOME KEY TAKE AWAYS
How an athlete performs during the menstruation cycle or while taking OCP's is highly variable between athletes.
A pregnant athlete will go through many physiological changes in addition to an increased energy demand.
The Female Athlete Triad is an interrelationship of energy needs, menstrual health, and bone health.
The implications of Low-energy availability and RED-S can cause serious and long-lasting damage.
Female athletes need to consume adequate calories to meet their energy needs and metabolize macronutrients differently than their male counterparts.
Female athletes need to consume adequate micronutrients, especially iron, calcium and vitamin D, to meet their bone health and performance needs.
As more and more women are getting involved in sports around the world, there's growing attention to the fact that there's not enough specific guidance and research on how female athletes should approach their nutrition. This is a concern for those invested in the success of female athletes.
A lot of the current advice is based on studies done on male athletes, which might not fully apply to female athletes due to their unique factors like the menstrual cycle, use of hormonal contraceptives, risks of injuries, and differences in body size and composition.
Despite these challenges, I have tried to provide some of the current knowledge about nutritional strategies for female athletes in this post with the goal to provide some recommendations to help them stay healthy and perform well.
If you would like to work with me one on one to nail down your nutrition as an endurance athlete or you need a running coach to help you prepare for your upcoming race, please click on the link below to learn more about the services I offer.
Contact me at firstname.lastname@example.org to set up a consultation today.
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Gatorade Sports Science Institute, NUTRITIONAL SUPPORT FOR THE UNIQUE PHYSIOLOGY OF A FEMALE ATHLETE, 2021
Elliott-Sale KJ, Minahan CL, de Jonge XAKJ, Ackerman KE, Sipilä S, Constantini NW, Lebrun CM, Hackney AC. Methodological Considerations for Studies in Sport and Exercise Science with Women as Participants: A Working Guide for Standards of Practice for Research on Women. Sports Med. 2021 Mar 16. doi: 10.1007/s40279-021-01435-8. Epub ahead of print.
Asker Jeukendrup, Micheal Gleeson, Sport Nutrition, Third Edition, 2019
Craig Sale, Kirsty Jayne Elliott-Sale, "Nutrition and Athlete Bone Health," Journal of Sports Medicine, 2017, available online at https://pubmed.ncbi.nlm.nih.gov/31696454/
Bryan Holtzman, Kathryn E. Ackerman, PRACTICAL APPROACHES TO NUTRITION FOR FEMALE ATHLETES, Sports Science Exchange (2021)
Abbie E. Smith-Ryan, PhD, CSCS*D,1,2 Hannah E. Cabre, MS, RD,1,2 Sam R. Moore, MS, CSCS1,2, FUNCTIONAL INGREDIENTS TO SUPPORT ACTIVE WOMEN, Sports Science Exchange (2022)