Why worry about bone health?
Many people are unaware that bone is a metabolically active tissue. Each day old bone is broken down (bone resorption) and new bone is created (bone formation). Adolescence is a particularly important time for bone health as it is during this period that we accumulate the greatest amount of bone and achieve peak bone mass (PBM). Individuals with a low PBM are at higher risk of fractures and osteoporosis in the future.
Physical activity is generally associated with good bone health as the weight placed on the bone puts the bone under strain sending a signal to form new bone. However, in athletes and individuals where low body weight and aesthetics are important (e.g running, gymnastics) and sports where body weight supported (e.g cycling, rowing, swimming) are more at risk of low BMD. Cross-training with resistance exercise is recommend for athletes in these sports to help maximise bone health.
Energy intake and bone health
Inadequate energy intake during adolescence may result in failure to obtain sufficient PBM. In addition, energy restriction and/or low energy availability can compromise bone health and increased risk of bony injuries (e.g. stress fracture). This is because without sufficient energy, the body prioritises other essential processes (e.g. circulation, breathing etc.) ahead of bone health.
In female athletes the disruption or stopping of the menstrual cycle (amenorrhoea) is also linked to low BMD and its clinical outcomes of osteopenia and osteoporosis. Amenorrhoea and menstrual dysfunction can be caused by insufficient energy intake or low energy availability. This in turn lowers oestrogen concentrations in the body which compromises bone health. In young female athletes, a history of menstrual disruptions can lead to failure to attain PBM.
Calcium and bone health
Calcium is a mineral that helps form our bones and teeth. Our body tightly controls the amount of calcium we have circulating in our blood so if you’re not getting enough calcium in through the diet, the body will start to release calcium from its biggest reservoir – our bones – to stabilise blood levels. It’s important to include calcium rich foods (e.g. dairy or calcium enriched alternatives) each day.
Vitamin D and bone health
Vitamin D is essential for calcium to be absorbed in the gut Vitamin D. Our main source of Vitamin D is sunlight and there are very few foods that contain Vitamin D in adequate amounts. Athletes who predominantly train indoors, compete in cold climates or are covered in long clothing due to uniform regulations may be at risk of low Vitamin D and may require supplementation – a GP can check this. See SDA’s Vitamin D factsheet for more information.
Alcohol and bone health
Alcohol not only negatively impacts muscle repair after training and competition but, in excessive amounts, can also negatively affect bone formation in adolescent and early twenties resulting in a lower PBM.
Protein and bone health
A high protein intake is often reported to be linked with an increase in bone loss, however, there is no evidence that in healthy athletic individuals (without disease or illness) that reported protein intakes negatively affect bone health.
Caffeine and bone health
Caffeine consumption may increases urinary calcium excretion and decreases calcium absorption in the gut. However, research suggests that, at least in healthy individuals who eat enough calcium, these effects are minimal.
An Accredited Sports Dietitian can discuss your dietary calcium requirements and bone health in further detail. For a test for any vitamin or mineral deficiency please consult your GP.
For more information on this or other sports nutrition topics, subscribe to our newsletter or book to see an Accredited Sports Dietitian.