RESEARCH - Consuming cola may up osteoporosis risk for older women, study suggests

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Source: Tufts University

Date: October 7, 2006

Consuming Cola May Up Osteoporosis Risk For Older Women, Study Suggests

According to the National Osteoporosis Foundation, approximately 55 percent

of Americans, mostly women, are at risk of developing osteoporosis, a

disease of porous and brittle bones that causes higher susceptibility to

bone fractures. Now, Tucker, PhD, director of the Epidemiology and

Dietary Assessment Program at the Mayer USDA Human Nutrition Research

Center on Aging at Tufts University, and colleagues have reported findings

in the American Journal of Clinical Nutrition that cola, a popular beverage

for many Americans, may contribute to lower bone mineral density in older

women, a condition which increases risk for osteoporosis.

Tucker, also a professor at the Friedman School of Nutrition Science and

Policy at Tufts, and colleagues analyzed dietary questionnaires and bone

mineral density measurements at the spine and three different hip sites of

more than 2,500 people in the Framingham Osteoporosis Study whose average

age was just below 60. In women, cola consumption was associated with lower

bone mineral density at all three hip sites, regardless of factors such as

age, menopausal status, total calcium and vitamin D intake, or use of

cigarettes or alcohol.

However, cola consumption was not associated with lower bone mineral density

for men at the hip sites, or the spine for either men or women. The results

were similar for diet cola and, although weaker, for decaffeinated cola as

well.

Men reported drinking an average of six carbonated drinks a week, with five

being cola, and women reported consuming an average of five carbonated

drinks a week, four of which were cola. Serving size was defined as one

bottle, can or glass of cola. " The more cola that women drank, the lower

their bone mineral density was, " says Tucker, who is corresponding author of

the study. " However, we did not see an association with bone mineral density

loss for women who drank carbonated beverages that were not cola. "

" Carbonated soft-drink consumption increased more than three-fold " between

1960 and 1990, cite the authors. They also note that more than 70 percent of

the carbonated beverages consumed by people in the study were colas, all of

which contain phosphoric acid, an ingredient that is not likely to be found

in non-cola carbonated beverages.

While previous studies have suggested that cola contributes to bone mineral

density loss because it replaces milk in the diet, Tucker determined that

women in the study who consumed higher amounts of cola did not have a lower

intake of milk than women who consumed fewer colas. However, the authors did

conclude that calcium intake from all sources, including non-dairy sources

such as dark leafy greens or beans, was lower for women who drank the most

cola. On average, women consumed 1,000 milligrams of calcium per day, and

men consumed 800 milligrams per day, both lower than the daily recommended

1,200 daily milligrams for adults over age 50.

" Physiologically, a diet low in calcium and high in phosphorus may promote

bone loss, tipping the balance of bone remodeling toward calcium loss from

the bone. Although some studies have countered that the amount of phosphoric

acid in cola is negligible compared to other dietary sources such as chicken

or cheese, " Tucker says, " further controlled studies should be conducted to

determine whether habitual cola drinkers may be adversely affecting their

bone health by regularly consuming doses of phosphoric acid that do not

contain calcium or another neutralizing ingredient. "

Tucker stresses that as with any epidemiological study, the results should

be taken with caution. " We are not certain why women who drank more cola

also had lower bone mineral density, " says Tucker. Although adjustment for

fruit juice intake did not change results, women in the study who drank a

considerable amount of cola not only consumed less calcium, but less fruit

juice as well. Previous studies have also shown that low fruit and vegetable

intake may affect bone mineral density.

The message from experts is clear that overall nutritional choices can

affect bone health, but " there is no concrete evidence that an occasional

cola will harm the bones, " says Tucker. " However, women concerned about

osteoporosis may want to steer away from frequent consumption of cola until

further studies are conducted. "

Reference: Tucker, KL, Morita, K, Qiao N, Hannan MT, Cupples A, Kiel DP.

American Journal of Clinical Nutrition. (October) 2006; 84(4). " Colas, but

not other carbonated beverages, are associated with low bone mineral density

in older women: The Framingham Osteoporosis Study. "

http://www.sciencedaily.com/releases/2006/10/061006071856.htm

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