Hey Everyone! I attended the annual ACBSP Sports Symposium this past April and listened to this great lecture on the impact of low energy availability on endocrine suppression leading to osteopenia/osteoporosis in young athletes by Michelle Barrack, PhD, RD, CSSD. Michelle did a great job explaining the risks, screening, prevention and treatment for low energy availability and I thought I’d summarize it here for you guys. Hope you enjoy it as much as I did!
The famous “female triad” is known by almost everyone but is usually only recognized when it has reached the extremes: multiple stress fractures, extremely low BMI, loss of menstrual cycle, recurrent injuries, and eating disorders. What if I told you that you do not need to be at the extremes to have the side effects of the female triad? What if I also told you that males could have similar side effects as females but instead of a loss of menstrual cycle, they have a substantial decrease in testosterone levels? All of this can be explained with your body’s energy availability. Energy Availability can be calculated with energy intake minus exercise energy expenditure divided by fat free mass.
Energy Availability = [Energy Intake - Exercise Energy Expenditure]
[Fat Free Mass]
Low energy availability (LEA) can occur with or without an eating disorder, when you have an intentional or unintentional restriction of dietary intake and/or when your energy expenditure is high and intake does not match the expenditure. The majority of the time, athletes do not even know that they are not eating enough food to provide their bodies with enough energy to rebuild itself. If you are experiencing a loss of your menstrual cycle, recurring injury or illnesses, prolonged recovery times, increased fatigue, mental fatigue, lack of focus & concentration or a loss of lean muscle mass, you may be experiencing the effect of LEA. An additional side effect of LEA is having low bone density and an increase risk of osteoporosis in the future. It is important to be able to identify LEA in your athletes if you’re a coach, your patients if you’re a doctor and yourself if you’re an athlete.
This next paragraph will describe the physiological changes that occur in your body with LEA and how it affects you. You may choose to skip this paragraph if it gets too dry. A decrease in energy availability will lead to a decrease in blood glucose levels and insulin throughout your body. This will result in the suppression of leptin secretion. Leptin, which is created by fat cells, is an important hormone for your hypothalamus and helps regulate body weight. Leptin has the ability to cross the blood brain barrier and bind to Ob-Rb receptors in the arcuate nucleus (part of the brain) which activates POMC and inhibits NPY/AgRP neurons. This reaction ultimately leads to appetite suppression and makes you feel "full". The more food you eat, the more leptin is created. With that said, when you have a decrease in Leptin, you’ll most likely experience a decrease in hypothalamic and pituitary function which will result in decreased levels of estradiol, IGF-1, T3, T4, and an increase in cortisol. A decrease in estrogen will often lead to your menstrual dysfunctions. A decrease in IGF-1 will probably lead to a decrease in lean muscle mass. A decrease in thyroid hormone (T3 and T4) will lead to a suppressed metabolism. All of these will lead to the reduction of bone formation and an increase in bone loss. When you have increase bone loss and a reduction of bone formation you’re left with a significantly low level of bone density and this increases the likelihood of the development of bone stress responses and stress fractures.
Now that we got that out of the way, let's talk about how to correct LEA, get your menstrual cycle back, increase your performance, reduce your injuries and become healthier, overall. The best route to take when you identify this in someone is to refer them to a sports dietitian, especially if you are dealing with the extremes. However, you may try increasing your caloric intake in moderation. There are also many meals and snacks that you can eat during your day to add high calorie, nutrient rich foods. A few of these are nuts, nut butters, dried fruits, trail mix, hummus, oil based salad dressings, smoothies and bagels. You want to make sure that you add 1-2 snacks per day and have small, frequent meals instead of large meals. It is also very important to replenish yourself after exercising. The recommended ratio of carbs to proteins in a recovery meal is 1-1.2 g/kg to 0.3 g/kg, respectively. This will include foods rich in calcium and vitamin D: Whole grain cereal with fruit & 2% milk; smoothies (banana, yogurt, nut butter); bagel sandwich with turkey and cheese; oatmeal with yogurt and berries (NOT INSTANT OATMEAL!). These are just some examples of foods that you can incorporate into your diet to maximize your nutrition. If you feel like you or someone you know is dealing with low energy availability, the female triad or an eating disorder, please refer them to a sports nutritionist, primary care provider or psychologist, respectively. This blog is by no means a formula to correct, treat or diagnosis any sort of disorder and should only be used for informational purposes.
If there are any questions that you still have about this topic please leave a comment below and I will get back to you as soon as I can. Thank you and I hope you enjoyed reading about this very important topic that is often overlooked.
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- Andres T. De La Cruz, BS, CSCS
Doctor of Chiropractic Candidate, 2018
Southern California University of Health Sciences