Many factors, including age, activity level, hormonal status and nutrition influence your risk for developing a stress fracture. Although nutritional status is often downplayed, it may play a major role. Specifically, sufficient consumption of healthy monounsaturated and polyunsaturated fats may reduce the risk of stress fractures by increasing absorption of the fat-soluble vitamin D, which helps your bones take up calcium. Furthermore, sufficient dietary fat may help to maintain energy levels during exercise, which may lead to more efficient running form, which may reduce the load on your musculoskeletal system.
Functions of Dietary Fat
Although high dietary fat consumption is commonly linked with excessive weight gain and development of cardiovascular disease, moderate consumption of fat — particularly monounsaturated and polyunsaturated fats — is essential. Fats provide a source of energy, and are important for synthesizing cell membranes and certain hormones. Additionally, vitamins such as vitamin D, vitamin K, and vitamin A are fat soluble, meaning they require fats to bind and absorb them.
Stress Fracture Development
Stress fractures are breaks in your bones that occur as a result of overloading your bones without sufficient recovery. Stress fractures are also linked to poor nutrition in general. A 2001 study published in “American Journal of Clinical Nutrition” showed that young ballet dancers who had sustained stress fractures also had deficient fat and protein intake compared to dancers who had never had a stress fracture. The age, height, weight, and bone density were not different between the two groups of dancers, suggesting that nutritional status plays a strong role in stress fracture development. Furthermore, a 2008 study published in the “Journal of the International Society of Sports Nutrition” showed that fat intake was the best dietary predictor of future stress fracture incidence in female runners.
Dietary Fat and Bone Building
Although the mechanisms by which dietary fat prevents stress fractures are not completely clear, it may enhance absorption of fat-soluble vitamins such as vitamin D and vitamin K, which are instrumental for maintaining bone calcium levels. Vitamin D is stored in your fat tissue, and when bone calcium levels drop below a critical level, your parathyroid glands send a series of signals to release the stored vitamin D, which increases calcium absorption from the intestine and increases calcium recycling in the kidneys, providing more calcium for bone formation. Additionally, vitamin K increases calcium binding to a protein called osteocalcin, which further promotes bone formation.
Fat and Energy Levels During Exercise
A moderate-fat diet may also reduce the risk of stress fractures by providing more energy. This may reduce muscle fatigue during exercise, enabling the muscles to withstand more shock and decrease the impact forces transferred to the bone. Furthermore, a 2000 study published in “Journal of American College of Nutrition” showed that runners who ate a 17 percent fat diet ate fewer total calories per day than those who ate a 33 percent fat diet, and this calorie deficit could contribute to chronic energy deficit and nutrient deficiency if continued long-term.
