Last week I touched on the negative impact of RED-S on menstrual function (click here). This week I will be discussing bone health. Bones are more than just a static tissue. They are living, growing tissue that are constantly being maintained and remodeled. During childhood and teenage years, new bone is added faster than old bone is removed. Up to 90% of peak bone mass is achieved by 18 years in females and 20 years in males with peak bone mass typically being achieved by the late 20s. After this, bone loss starts to exceed bone formation. This can result in weakened bones or osteoporosis, which increases the risk of fractures.
Weight bearing physical activity such as running or jumping increases bone strength. This is in contrast to non-weight bearing sports such as cycling or swimming that do not offer the same bone strengthening benefits. However, athletes participating in weight-bearing sports still present with weakened bones and stress fractures despite the bone strengthening benefits. This can be the result of undereating.
As I mentioned in my past blogs, under-fuelling can result in missing or irregular periods in females. This in turn, can lead to low levels of estrogen. In males, under-fuelling can lead to low levels of testosterone. These altered level of sex hormones can have negative impacts on bone health. However, under-fuelling, even with normal levels of sex hormones can still negatively impact bone health. This is because under-fuelling alters other hormones that are important for building strong bones. Under-fuelling can also result in compromised bone health because when too few calories are consumed, this often means important bone building nutrients, such as calcium and vitamin D, are missing from the athlete’s diet..
It is easy to focus on short-term outcomes rather than looking at the long-term impact of our nutrition. Insufficient calorie intake can lead to weakened bones and recurring bone injuries in athletes. Sadly, some athletes’ bone health can become so compromised that it results in osteoporosis at a young age. Sufficient calorie intake is a critical component of keeping bones healthy and strong. This will help to ensure training is not missed due to injuries and long-term participation in sport.