Female Athletes: Hormonal Concerns and Bone Health

By Brenna Thompson, MS, RD, LD
November 4, 2014


Exercise is important for our health, but it can be a double-edged sword. While it has been shown to improve cardiovascular function, sleep, muscle strength, mood, and self-esteem, there is a tipping point. As a runner on the junior and senior high school track and cross-country team, I developed five stress fractures in my tibia bones. Over the course of four years, my doctors fitted me for several different orthotics to use in my running shoes. Their theory was that my flat feet caused the muscles and tendons on my lower legs to pull and stress the tibia bone, leading to the fractures. Around the age of 16, birth control pills were prescribed as a way to increase my estrogen levels, which would help deposit more calcium into my bones and prevent future fractures.

What was never discussed was why my estrogen levels might be low in the first place. The phenomenon of young female athletes experiencing multiple stress fractures and hormone imbalances is more common than you might think. This is often true for adult women as well. Athletic women often look fit and healthy, but underneath their vibrant appearance is a serious condition that is just now beginning to be understood.

FemaleAthlete_UnderEating.jpgFemale athletes often eat too little

Female athletes are often under pressure to maintain a thin physique, especially if they participate in gymnastics, tennis, volleyball, running, dance or swimming. Junior and senior high school are already stressful enough, having to strut around in a bathing suit or skin-tight shorts adds another self-esteem test. Athletics, staying in shape, and being competitive all seem on the surface to be very positive behaviors for young women, but they can be a double-edged sword. To stay lean and potentially gain an edge over the competition, some girls knowingly restrict their food and may develop an eating disorder such as anorexia or bulimia. Other athletes who are perfectly comfortable in their skin may unknowingly under eat based on their exercise demands. This pattern of under eating may start in adolescence, but it can also continue into adulthood, which often leads to hormone imbalances and altered bone density.

Restricted eating and hormone imbalance and the effect on the female athlete

Restricted eating leads the body to shut down non-essential processes. During times of stress and starvation, the last thing a woman needs is the added physical stress of carrying a baby. So the body stops producing estrogen and progesterone in order to prevent a pregnancy. Many young female athletes notice that during the “in-season” time of their sport they lose their menstrual cycle, known as amenorrhea. Many girls think of this as normal, or believe it means they are working harder than their teammates. What they do not realize is that the hormones that normally trigger their menstruation also help their bones absorb calcium, and without those hormones their bones become weak. For many athletes their periods begin again once their sport season has ended. But for teens or women who participate in athletics or workouts year round, or those who actively restrict their diet, their cycles may not return. No matter the scenario, activity levels and calorie intake need to be matched in order for proper hormone cycles to be maintained year round, otherwise they risk developing stress fractures and osteoporosis.

FemaleAthleteTriad_11-5-14.jpgRestoring balance

It is estimated that 78 percent of high school female athletes have one or more components of what is called the Female Athlete Triad, which all starts with under eating for high levels of exercise.

  1. Not eating enough, restricted eating or eating disorder
  2. Amenorrhea (Loss of menstrual cycle)
  3. Low bone density

To help restore menstruation and promote bone health, the underlying calorie deficit needs to be reversed. For some athletes, focusing on eating more through higher calorie meals and snacks is enough. Other athletes will need to decrease their activity level while also increasing their food consumption. If a woman is struggling with an eating disorder, this needs to be addressed before she continues to exercise. Most women find that their periods return within one to three months of increasing their food consumption, but it can depend upon how long the food deficits and hormone imbalance has been going on.

Eating to support exercise, hormones and bones

FemaleAthlete_ProteinShake.jpgTeens can be picky, and their hunger cues can be radically different from adults (although some adults are picky too). Some people are not hungry during the early morning and skip breakfast before school or work, leaving them starving by lunch. For athletes in school, unless they have packed some snacks, the current USDA school lunch menu will not provide enough calories, protein, or fat to support their activity levels.

Athletes and recreational exercisers of all ages need to fuel their bodies properly with real foods. Whipping up a protein shake is a great way for teenagers and adults to bring breakfast to school or work. Studies show that whey protein increases muscle repair, which is just one reason it’s a great addition to an athlete’s smoothie. Finger foods such as deli meat or salami paired with a cut up apple and a small container of peanut butter or cream cheese is another great option that can be eaten on the bus, in the hallway before class, or while doing projects at work. Cereal, bagels, Pop-Tarts®, and donuts are not healthy options since these processed carbs rob the body of important bone-building minerals and do not provide healthy fats and proteins to make hormones.

In schools, class sizes are so large now that students may only have 10-15 minutes to eat once they get their food. The night before class or in the morning before work, parents can help their teen pack a balanced lunch. A high quality thermos will keep leftover chili, chicken wild rice soup, stir-fry, or meatballs warm for hours. Pita pockets stuffed with chicken salad are a delicious way to get young athletes to eat more protein and healthy fat. Serve it with fresh cut veggies and the Lil’ Dipper ranch dressing for a complete meal. Adult athletes can also use these convenient eating tips to make sure they get enough quality food during busy days.

Some athletes will need or want a snack before practice or a workout, great options include:

After sport practice or a workout, be sure to serve up a delicious balanced supper with adequate protein to build muscle, vegetable carbohydrates for vitamins and minerals, and healthy fats to make hormones.

Hungry for more?

For more ideas on how to feed your teen athlete or yourself if you are a regular exerciser, sign up for our Nutrition 4 Peak Performance class.

To learn even more, listen to our podcast: Nutrition to Help Female Athletes Prevent Bone Fractures.

About the author

Brenna loves nutrition and its life-changing effects. With an active lifestyle, she knows firsthand how to use the power of good nutrition to stay energized. She is a registered dietitian and licensed dietitian through the Minnesota Board of Dietetics and Nutrition. She received her B.S. in dietetics from Minnesota State University, Mankato, and completed her dietetic internship at West Virginia University Hospital, Morgantown. Brenna also received a M.S. in applied nutrition, with an emphasis on education, from Northeastern University. She worked as a clinical and wellness dietitian for the Phoebe Putney Memorial Health System in Albany, Georgia.

View all posts by Brenna Thompson, MS, RD, LD

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