Think drinking “diet” cola is a guilt-free pleasure? Think again when it comes to osteoporosis. Carbonated beverages and colas, including diet sodas, have been linked with increased bone fracture rates in teenage girls. While carbonated beverage consumption was associated with a 300% increased risk of fracture, cola beverages fared worse. They were associated with an almost 500% increased risk of fracture in physically active girls. Another study of 2500 women, whose average age was 60 years old, showed that the more cola consumed, including diet cola, the lower their bone mineral density. No such link was found in men. Unlike the previous study, only cola sodas were linked with lower bone density and not other carbonated drinks.  While some have speculated that soda’s link with osteoporosis  can be explained by a lower milk intake, this study did not show a higher bone density with milk consumption.

Cola drinks, unlike other carbonated drinks, contains phosphoric acid creating an “acid load” on the body that is initially buffered with sodium and potassium. When these stores are depleted, the body utilizes calcium and magnesium from bone as a buffering agent, which is later excreted in the urine. The amount of buffering needed to offset the acid load from one can of coke is equivalent to 4 Tums tablets. This net loss of calcium may help explain the findings of lower bone mineral density among cola drinkers. Animal studies have shown cola consumption leads to loss of calcium in the urine and lower bone mineral density.