Colas and coffee appear to have some effect on women’s bone density and could lead to osteoporosis. But tea — even the kind with caffeine — and other sodas do not. And men are not affected at all by these beverages.
Confused? You’re not alone.
“Whether there is a causal relationship, and what the exact mechanism of that relationship is, is unclear,” Dr. Rosian says. “Several studies have shown those relationships, but the data overall are not entirely conclusive.”
Another reason could be that the phosphoric acid in cola leaches calcium out of the bone. Supporting this line of thought is that sodas such as lemon-lime drinks or ginger ale, which are not linked to osteoporosis, lack phosphoric acid.
But, Dr. Rosian points out, doctors do not recommend cutting back on other foods with high levels of phosphoric acid, like chicken and certain cheeses.
Lastly, it might be caffeine intake that might lead to lower bone density in women. Supporting this theory is that colas — which contain caffeine — and coffee are linked to osteoporosis, while ginger ale and lemon-lime sodas are not. That, however, could be explained by the non-cola drinks’ lack of phosphoric acid.
Further confounding the caffeine theory is that black tea, which contains caffeine, does not impact bone density, Dr. Rosian says.
Everything in moderation
So while it’s not entirely clear if caffeine consumption lessens bone density, physicians agree in general that consuming excessive amounts of caffeine is not part of a healthy diet, Dr. Rosian says.
“If you drink those beverages in low amounts — less than 400 milligrams — that’s probably OK,” Dr. Rosian says. “That means less than four cups of coffee per day might be fine, and less than two cans of cola a day. But if you can cut these beverages out altogether, that’s even better.”
If you still want to drink carbonated beverages, one alternative could be non-caffeinated beverages, Dr. Rosian says.
A lifetime of weight-bearing exercise and consuming adequate amounts of calcium and vitamin D are the best protection against brittle bones and the health risks associated with osteoporosis, Dr. Rosian says.
“I like to tell my patients to try to get three to four servings of calcium a day,” Dr. Rosian says. “That means some calcium from food at every meal.”
Foods such as non-fat milk, almond milk, yogurt and almonds are naturally high in calcium, as are vegetables such as kale and broccoli. Also, some foods and beverages, such as orange juice and cereal, are enriched with calcium.