Drinking colas may hurt bone health

Q. Do carbonated drinks leach calcium from bones? Does this increase risk for osteoporosis? Can drinking soda make a diagnosed case of osteoporosis worse?

A. The best answer I can give to your questions is "maybe." A number of studies in recent years have linked carbonated drinks with osteoporosis.

Data from the Framingham Osteoporosis Study (American Journal of Clinical Nutrition, 2006) looked at carbonated drink consumption among more than 1,400 women and 1,100 men. It found that women who drank the most caffeinated cola had the lowest bone density. The biggest effect was seen for those drinking three or more caffeinated cola drinks per day.

The effect was weaker for non-cola and non-caffeinated carbonated drinks. And they saw no link between any of these drinks and bone health in men.

More recent studies came to similar conclusions. One study found a higher rate of bone fractures among teenagers who drank carbonated drinks compared with those who did not.

But no one knows if there is a true cause-and-effect relationship between carbonated drinks and weak bones. Something else about soda drinkers may explain this. Maybe soda drinkers exercise less and smoke more than those who don't drink sodas regularly.

Until we know more, it makes sense for people with osteoporosis to limit carbonated drinks. Cutting back is unlikely to cause harm and might just help. Other steps you can take include:

* Get enough calcium, at least 1,000 to 1,200 mg/day.

* Get enough vitamin D; for people with osteoporosis, 1,000 units per day.

* Get plenty of weight-bearing exercise, such as walking.

* Take medicines to build up bone, such as alendronate (Fosamax) or risedronate (Actonel), as prescribed by your doctor.

* Don't smoke.

* Don't drink too much alcohol.

* Reduce medications (such as corticosteroids) that can decrease bone strength.

* Talk to your doctor about bone health, including changing what you drink.