Friday, January 30, 2009

Bites: Fruit and Veggies May Prevent Bone Loss

A new study suggests that neutralizing an acid-producing diet may be an important key to reducing bone breakdown, or "turnover," while aging. The study comes on the heels of several other studies questioning the efficacy of consuming more-than-recommended amounts of calcium to protect against bone loss.

The study was led by physician and nutrition specialist Bess Dawson-Hughes at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Mass. ARS is the principal intramural scientific research agency in the U.S. Department of Agriculture.

Fruits and vegetables are metabolized to bicarbonate and thus are alkali-producing. But the typical American diet is rich in protein and cereal grains that are metabolized to acid, and thus are acid-producing. With aging, such diets lead to a mild but slowly increasing metabolic "acidosis."

Researchers led by nutrition specialist Bess Dawson-Hughes at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University conducted a placebo-controlled study involving healthy male and female volunteers aged 50 or older. Key measurements were taken at the beginning and end of the intervention, which lasted three months.

A group of 78 volunteers had been provided either of two bicarbonates--potassium or sodium--along with their usual diet and exercise regimes. Key bone mineral nutrients were controlled to reduce variation in study outcomes. The bicarbonate groups consumed an amount of bicarbonate equivalent to about 9 servings of fruits and vegetables daily. This allowed the researchers to look at possible acid-neutralizing effects from an adequate, not high, alkali load.

The results showed that the volunteers in the bicarbonate groups had significant reductions in biomarkers that are associated with bone loss and fracture.

The authors concluded that increasing the alkali content of the diet, for example by consuming more fruits and vegetables, merits further study as a safe and low-cost approach to improving skeletal health in older men and women.

Source: Agricultural Research Service, USDA

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