Magnesium
Inadequate magnesium is associated with decreased parathyroid hormone. Epidemiologic studies suggest a positive association between increased magnesium intake and BMD. But data from the Women's Health Initiative found that high magnesium intake was not protective of BMD. The bottom line for patients is to eat foods that contain magnesium, including whole grains, vegetables, and nuts. There are no data to support the use of magnesium supplements, Dr. Binkley said.
Caffeine
It's been widely assumed that caffeine is harmful to bone because it leads to increased urinary calcium loss. However, a number of studies have shown that decreased calcium absorption is actually what occurs. “The gist is that for each cup of coffee that we drink, there is a calcium loss of about 5 mg. What does that mean? It means that we need to put about 2 tablespoons of milk in our coffee,” said Dr. Binkley.
The effect of these other caffeinated beverages on calcium absorption is largely negligible. The bigger issue is that soft drinks have replaced milk in the average American's diet.
Protein
One study of elderly patients found that patients getting protein supplements were less likely to have fractures.
In fact, those with higher protein intake and adequate calcium had the best outcomes, suggesting there may be a synergistic effect between protein and calcium. There's no need to restrict protein after hip fractures.