Lower sodium diets may be better for bones

New research supports the theory that lower sodium diets may promote stronger bones. In a small study of the effects of sodium intake on bone health in 186 adults, a typical American diet was compared to the non-vegetarian DASH (Dietary Approaches to Stop Hypertension) diet at each of three sodium intakes for 30 days. The DASH diet emphasizes fruits, vegetables, and lowfat dairy products and includes whole grains, poultry, fish, and nuts. This diet is low in fats, red meat, and sugar. Levels of two indicators of bone health improved significantly in those study participants on the DASH diet, while those indicators worsened in those on the typical American diet. More importantly, levels of these indicators generally improved as sodium intake decreased, with the best levels seen at an intake of 1,150 milligrams per day.

Diets high in sodium lead to urine high in sodium, which results in high levels of calcium in urine and contributes to an increased loss of calcium. Some studies have suggested that, for every 2,300 milligrams of sodium in the urine, 40 milligrams of calcium are lost. In theory, this would result in the loss of as much as a third of bone mass in just over 20 years if calcium loss was not otherwise addressed.

The study's authors suggest that calcium, potassium, and magnesium, as well as antioxidants and phytochemicals from fruits and vegetables, along with reduced sodium intake, play a role in supporting bone health.

A diet that emphasizes fruits and vegetables, provides adequate calcium, and is low in sodium has benefits for bone health.

Lin P, Ginty F, Appel LJ, et al. 2003. The DASH diet and sodium reduction improve markers of bone turnover and calcium metabolism in adults. J Nutr 133:3130-36.

Doyle L, Cashman KD. 2004. The DASH diet may have beneficial effects on bone health. Nutr Rev 62:215-20.

* This review of studies examining low-sodium diets was written by Mark Rifkin, MS, Dietetic Intern.

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