Q & A Library

Updated on 4/4/2005

I can give you a number of reasons to avoid drinking colas and other sodas but the carbonation they contain is not one of them. The notion that the carbonation in sodas is bad for bones comes from studies performed in the early 1990s which suggested that drinking carbonated beverages, specifically colas, raises the risk of bone fractures among adolescent girls and older women (former college athletes). No such association was found for non-cola drinks. The researchers also found that a high intake of calcium was protective.

A study published in the American Journal of Clinical Nutrition (September 2001) looked at the question of whether carbonated beverages increase urinary excretion of calcium. If so, this effect might provide a plausible link between consumption of carbonated beverages and an increased risk of fractures.

Researchers from the Osteoporosis Research Center at Creighton University found that excess urinary excretion of calcium occurred only when the carbonated beverages consumed contained caffeine. At least one earlier study had suggested that caffeine consumption can have a deleterious effect on bone health if not counteracted by sufficient calcium. The Creighton researchers found that the caffeine effect they saw was balanced by less excretion of calcium later in the day so that the net result was only a negligible loss of calcium. This led them to conclude that any effect on bone associated with carbonated drinks would stem from lowered calcium intake due to displacement of milk as a beverage. Incidentally, this study was sponsored by the dairy industry, which would have had an interest in the opposite result.

I wouldn't worry about the carbonation in sodas. My concerns about consumption of soft drinks focus more on the unhealthy amounts of sugar, artificial sweeteners and caffeine they contain. The carbonation itself is not a problem, and Perrier and other carbonated mineral waters are perfectly safe.

Andrew Weil, M.D.