Ever since the 1970s, nutritionists have been arguing over the role of protein in maintaining bone health. Some claim a high-protein diet makes the body excrete more calcium, which in turn could weaken bones. Others assert just the opposite: That dietary protein is essential for maintaining strong bones. Who's right?

Recent research strongly suggests that the protein proponents were right all along. The research shows that a diet high in protein not only keeps your bones healthy; it can significantly slow down the bone loss that leads to osteoporosis.

What all the studies show is that the amount of calcium you excrete depends on more than just how much protein you eat.

The amounts of phosphorus and magnesium in your diet, for instance, play a significant role. But even more importantly, there's simply a lot of normal variation in the amount of calcium individuals absorb from their food-some people just absorb more than others, for reasons researchers still don't understand. In fact, your ability to absorb calcium from your food is probably more important to your bone health than the total amount of calcium you take in.

Results from the long-running Framingham Osteoporosis Study, published in 2000, showed that eating a diet high in protein has a protective effect on your bones as you age.

Among the 615 elderly people in the study, the ones who ate the most protein had the strongest bones, while the ones who ate the least protein had the weakest bones. And over the four-year study period, the people who ate the least protein lost significantly more bone mass than the people who ate the most protein. The connection held up regardless of age, weight, smoking habits, calcium intake and even estrogen use.

In March 2002 an important study showed that the combination of a high protein intake and calcium and vitamin D supplements significantly slows bone loss in older adults. The double-blind study followed nearly 350 sixty-five-year-old men and women over a three-year period. All the participants ate their usual diet, but half were also randomly assigned to take a supplement containing vitamin D and 500 milligrams of calcium, while the others took a dummy pill.

At the end of three years, the researchers found that among the people taking the calcium and vitamin D supplements, the ones who ate the most protein had the strongest bones and absorbed the most calcium.

Cheese and other dairy foods are a great source of calcium. Just one ounce of cheddar cheese, for instance, gives you 204 mg. of calcium. There is a lot of calcium in other low carb foods, including nuts and green leafy vegetables.

The latest research at Tufts University indicates that strength training at any age can actually add bone, not just slow its loss. The study looked at two groups of women aged 50 to 70 for a year. One group exercised 5 minutes on a cycle, stretched for 5 minutes and did resistance exercise on several pieces of strength equipment.

The other group continued their "couch potato" life style. When bone density was compared at the end of the study the strength training group added 1% compared to a loss of 2.5% by the sedentary group. As a bonus the strength training will improve your balance, lower blood sugar and burn calories while you are sleeping.