Can vitamin D and calcium help reduce your risk of a stress fracture?
Frequency of stress fractures
Stress fractures and musculoskeletal injuries are among the leading causes of medical holdovers that occur during basic military training. As many as 5% of male and 20% of female basic trainees may develop some sort of a stress fracture during military training due to the unaccustomed physical demands and repeated stress to the body, such as marching with body armor and/or a heavy ruck-sack. A less than ideal physical fitness level and/or being overweight or underweight upon entry into the military further compounds the risk for developing a stress fracture.
Long term effects of these injuries
These injuries may not only threaten your ability to continue to serve our country, but they may also jeopardize our overall military readiness. Many trainees get discouraged after a stress fracture because they have to repeat the training once they've healed or they have to separate from the military. In addition, musculoskeletal injuries sustained during basic training or even in day-to-day military operations can contribute to joint or mobility issues (arthritis) later on in your career.
What can you do?
Optimizing your bone health is essential to maintaining your fitness and readiness. Along with proper exercise and training, your dietary intake of vitamin D and calcium may play a role in helping you build and maintain strong bones. Recent studies have linked vitamin D and calcium to bone health and the prevention of stress fractures in military personnel. However, more conclusive evidence is needed to determine whether universal recommendations regarding vitamin D and calcium are warranted in military personnel (especially basic trainees). Currently, the Recommended Dietary Allowance (RDA) for both vitamin D and calcium depends upon your age NOT your profession.
Nutritional biochemists and scientists from the U.S. Army Research Institute of Environmental Medicine (USARIEM) are currently conducting research to determine whether increased vitamin D and calcium intake can improve bone health during military training. Check out more information on this study. 
Tips to Keep Bones and Joints Strong as You Age
Maintain a Healthy Weight
It may sound simple, but staying at a healthy weight is difficult. Our joints are weight-bearing so decreasing the overall wear and tear on the joints helps in the long run. Excess weight also contributes to high blood pressure, diabetes risk, heart problems along with extra strain on our knees, hips, spine, etc.
Eat a Balance Diet
Eating a well-balanced diet is important for maintaining overall health as well as for bone, joint and muscle health. Ensure you are eating plenty of vegetables, fresh fruits, lean proteins and whole grains, and limit your intake of foods that are processed or high in sugar, salt, and fat.
Get the Vitamin D and Calcium Your Body Needs
Eating a wholesome diet that includes adequate amounts of calcium and vitamin D is your first line of defense in meeting your calcium and vitamin D requirements. As we age, our bones are susceptible to osteoporosis the thinning of our bones, which makes them more susceptible to fractures. Calcium in our diet and through vitamins is one of the most important weapons against osteoporosis. Dairy products such as milk, cheese, and yogurt, along with dark leafy greens and broccoli and certain types of fish such as salmon give you the calcium that is critical for bone strength. Look for calcium supplements with vitamin D. For more information on
vitamin D 
or
calcium 
, check out the National Institutes of Health. For more information on calcium, check out the
Keep Moving!
The key is to stay active and continue to move as we age. We boost our bone strength with exercises that “load” or compress them. For more information on
physical activity to protect your joints, look at this article.
Tobacco and Alcohol
Tobacco and excessive alcohol consumption can lead to bone density loss. If you smoke, talk to your provider about quitting. Here are
Quit Tobacco 
resources. Here are resources for
responsible drinking 
.