The latest weight loss fad, the high protein/low carbohydrate diet, has been the source of much criticism from the nutrition community. While many nutritionists agree that the diet may not be nutritionally balanced, one concern, that high protein diets promote calcium losses , may not be warranted.
Recent research by Bess Dawson-Hughes MD and her colleagues at the Bone Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University shows that high protein (and reduced cereal grain) diets do not affect urinary calcium excretion, rather, the protein may decrease bone resorption, a process that make bones stronger.
The study, published in the March issue of The Journal of Clinical Endocrinology & Metabolism, looked at men and women over 50 who were randomized to either a high or low protein intake diet and who were already including the recommended 800 milligrams of calcium in their diet. The researchers found that those who increased their dietary protein by an average of 58 grams of protein a day had 25 percent higher levels of bone growth factor and lower levels of a marker of bone resorption compared with controls. Both these factors indicate healthy bone status.
While this study did not confirm the perception that high protein diets result in calcium loss, Dr. Dawson-Hughes cautions, "this study does not support the high protein, low carbohydrate approach to weight loss. There are many nutrients that contribute to healthy bones and a balanced diet, rich in fruits, vegetables, whole grains and protein is one of the best ways to ensure healthy bones throughout a lifetime."
Dawson-Hughes et al, The Journal of Clinical Endocrinology & Metabolism, 89:1169-1173. "Effect of Dietary Protein Supplements on Calcium Excretion in Healthy Older Adults."
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