Many people believe that carbonated beverages are bad for bones because of their high acid content. However, research suggests the carbonation isn't to blame.

A large observational study in over 2,500 people found that cola was the only beverage associated with significantly lower bone mineral density. Carbonated water appeared to have no effect on bone health 

Unlike carbonated water and clear soda, cola drinks contain a lot of phosphorus.

The researchers proposed that the cola drinkers may have been consuming too much phosphorus and insufficient calcium, providing a potential risk factor for bone loss.

In another study, teen girls who consumed carbonated drinks were found to have lower bone mineral density. This was attributed to beverages that replaced milk in their diet, resulting in inadequate calcium intake 

In a controlled study in 18 postmenopausal women, drinking 34 ounces (1 liter) of sodium-rich sparkling water daily for 8 weeks led to better calcium retention than drinking plain mineral water

Additionally, no negative effects on bone health were observed in the sparkling water group.

Animal research suggests carbonated water may even improve bone health.

Supplementing hens’ diets with carbonated water for 6 weeks led to increased leg bone strength compared with tap water 

SUMMARYDrinking carbonated cola drinks may harm bone health, but plain sparkling water appears to have a neutral or positive effect.]