The study, published in the American Journal of Clinical Nutrition, examined 2,500 men and women and found that regardless of age and calcium intake, the women who regularly drank cola experienced loss of bone mineral density. The bone loss was not observed in men or in women who drank non-cola carbonated beverages.
The researchers gave the study participants a questionnaire on their diets, and measured bone density at the spine and in three different locations on the hips. Women who drank four or more colas per week had lower bone mineral density at the three hip locations, but did not experience bone mineral density loss at the spine.
The study disposed of the idea that women who drink cola regularly can offset bone mineral density loss by drinking milk or taking calcium supplements. The researchers found that milk consumption was the same among women who drank cola regularly and those who did not. Only those who drank massive amounts of cola experienced some benefit from milk consumption.
The researchers are uncertain what ingredient in cola affects women's bone health, but they hypothesize that phosphoric acid may turn the blood too acidic, which causes the body to take calcium from the bones to balance out the acidity.
Consumer advocate Mike Adams, author of "The Five Soft Drink Monsters," says drinking diet or regular soda -- not just cola -- directly promotes loss of bone mineral density.
"This is due to both the high phosphoric acid content and the liquid sugar known as high-fructose corn syrup," Adams said. "Both ingredients actually strip bone minerals right out of the body, especially in women."
The study's authors say more research is needed to determine cola's affects on women's bone health, but for now, they say women who regularly drink cola should reduce their consumption.
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