Do carbonated drinks damage your bones?

Sugary soft drinks at high intake are associated with lower bone density. A meta-analysis of 26 studies involving more than 124,000 participants found a clear negative relationship, with the strongest effects seen in women and in people under 50. This is an association: whether the soft drink itself is the culprit, or whether it is the fact that soft drinks displace healthier beverages such as milk, has not been established.

Moderate consumption appears to be a different story. In a large study of more than a thousand women between the ages of 44 and 98, moderate soft drink intake was not linked to lower bone density after correcting for age, calcium, exercise and hormones. How much you drink therefore seems to matter.

The type of soft drink also makes a difference. Carbonation itself is probably not the problem. Phosphoric acid, caffeine and sugar are more often cited as possible causes, and even then the displacement of calcium- and vitamin D-rich drinks likely plays a major role. Cola fares worse in this regard than non-cola soft drinks.

In teenagers, and girls in particular, there are indications that drinking large amounts of soft drinks during puberty inhibits the build-up of bone mass. This is a sensitive period: bones grow toward their maximum during those years. A Korean study did find an association, but found that factors such as muscle mass, BMI and calcium intake were the actual predictors. The independent role of soft drinks is therefore difficult to isolate.

Bone health depends on multiple factors simultaneously: calcium, vitamin D, magnesium, protein and exercise all play a part. Soft drinks are one piece of that puzzle, not the sole determining factor. If you drink large amounts of sugary soft drinks and as a result consume less milk, water or other calcium-rich beverages, that is the most concrete reason to limit your intake.