Soft-Drinks And Bones

According to new research by experts at Tufts, bone density in women may be reduced by soda consumption.

Boston [09-25-03] More than 10 million Americans, many of whom are women, are affected by osteoporosis, and an additional 34 million have low bone density -- putting them at risk for the disease. Health experts have long suspected that there is a link between reduced bone density and soda consumption – but now Tufts experts have honed in on the problem, with results suggesting that the phosphoric acid in cola drinks may be the culprit.

“Tufts University researcher Katherine Tucker examined the bone mineral density readings of more than 2,500 adult men and women and surveyed their soft-drink consumption patterns,” reported The Los Angeles Times. “She found that women – but not men – who drank more than three, 12-ounce servings of cola per day had 2.3 to 5.1 percent lower bone mineral density in the hip compared with women who consumed less than one serving per day.”

Tucker -- who presented the findings at the annual meeting of the American Society for Bone and Mineral research in Minneapolis -- said that similar results were seen with diet and caffeine-free cola beverages but not with non-cola carbonated beverages.

“This remains a very controversial area,” Tucker – who is the Director of the Nutritional Epidemiology Program at Tufts’ Friedman School of Nutrition Science and Policy -- told the Times. “But it seems that phosphoric acid in cola drinks has a negative effect on bone. When you have phosphoric acid in a cola beverage, the excess phosphoric acid binds to calcium in the gut [which keeps the calcium from being absorbed.]”

The Tufts researcher said that it is also possible that phosphoric acid can adversely affect parathyroid hormone levels in the body, but she noted that more studies are needed to test the theory.

While the new findings bring researchers one step closer to understanding the complex interaction between diet and bone mineral density, there is still much to be explored. For example, the researchers found no link between lower bone density and cola consumption in men.

“Men have different beverage consumption patterns,” Tucker told the Times. “They drink more alcohol, and alcohol can be protective of bone in some ways.”

The Tufts findings ran contrary to a common hypothesis that many people replace milk with soft drinks as they grow older, leading to reduced bone mineral density because of the loss of calcium from milk.

“We did not find that people drinking cola beverages drank less milk than other people,” Tucker told the Times. “Adults don’t drink much milk anyway.”