Doctors out of Israel have recently reported in the Journal of the International Society of Sports Nutrition that low nutritional intake is associated with increased risk of bone leg stress fractures in elite military recruits.
The team of researchers took a variety of measurements in 74 male combat recruits (average age 18 years old) at the beginning of a 4 month training program, after the program, and then again two months later. They measured:
Note that this was not an interventional study. What they wanted to see is if there were any relationships between these measurements and incidence of long bone leg stress fractures. Stress fractures are a major problem in military training.
Throughout the 6 month period, 12 recruits got long leg stress fractures, while 62 did not. The researchers found:
The authors note that in a study in 2008, Lappe et al found a 20% reduction in stress fractures in Navy recruits by supplementing with vitamin D and calcium. But the Israeli authors concluded that vitamin D and calcium supplementation is not worth the 20% reduction.
I disagree. The US Army trains 130,000 soldiers a year and, if the Israel 16% rate were applied to the US Army, over 20,000 would suffer a stress fracture. A 20% reduction would prevent over 4,000 stress fractures per year, a substantial number.
However, it’s important to remember that bone strength is a complex, multi-factorial issue including bone geometry, exercise, over 20 nutrients, height, workload, mileage, footwear and access to medical care. Reducing stress fractures requires a comprehensive approach, not just vitamin D and calcium.
I think a best approach would be to intervene before training. Stress fractures significantly affect military training, both in terms of costs and readiness. Treating fractures is much more costly than preventing them. A few simple measures could include: