Diet cola can hurt bone density

Pamela Egan Practical Practitioner


By: Pamela Egan, FNP-C CDE



Diet cola can hurt bone density



Dear Pam,

My 17-year-old daughter drinks three to six diet cokes a day. Is it true it can deplete the calcium in her bones?

Yes, dark cola consumption among women may be linked to lower bone mineral density compared with clear soda consumption, according to a study of women involved in the Framingham Offspring Cohort.

Results were presented at the 25th annual meeting of the American Society for Bone and Mineral Research.

In other studies, researchers assumed that increased soft drink consumption meant lower intake of dairy and other calcium sources. This study, however, examined total calcium, which was similar across all groups studied.

The researchers studied data on 1,672 women and 1,148 from 1996 to 2001. They took BMD measurements at the spine and three sites at the hip.

They divided participants into two groups: those who drank cola every day and those who drank cola, including clear sodas, once a week or less.

With all dietary sources included, the average daily phosphorus level of cola drinkers was 1,146 milligrams compared with 1,105 milligrams in non-daily cola drinkers. In women, regular cola drinkers had decreased BMD from 2 percent to 5 percent, compared with infrequent drinkers.

Daily cola drinkers had a slightly higher physical activity score and were similar to infrequent drinkers in all other matters.

By process of elimination, the researchers found that the problem may be increased levels of phosphoric acid.

They knew it wasn’t due to lower calcium, caffeine, sugar and they adjusted for calcium and vitamin D and body size.

Soda typically contains 44 milligrams to 62 milligrams of phosphoric acid per 12-ounce serving and 27 milligrams to 39 milligrams in diet cola.

Phosphoric acid is an ingredient in other foods, such as dairy products, but may not have the same effects.

When phosphoric acid comes packaged with other nutrients, it’s absorbed normally and everything is in balance. The problem with cola is that you’re getting those doses of phosphoric acid without any calcium. It’s not balanced, and that extra phosphorus binds with calcium and prevents it from being absorbed.

Eating cheese may be better for preteen girls than taking calcium supplements, according to a study presented at the 25th annual meeting of the American Society of Bone and Mineral Research. It also may be easier to convince kids to eat cheese.

Researchers conducted a study of 149 girls aged 10 to 12 in Finland over a two-year period to compare cheese consumption with calcium tablets in terms of bone accrual.

Participants were randomly divided into three groups: 38 were given measured chunks of cheese, 100 grams per day, 75 were given placebo tablets.

Baseline characteristics were similar; they had an average calcium intake of 600 milligrams per day, which is below the recommended amount.

The cheese patients were given a choice of either mild white cheese (Edam) or cheddar.

Researchers measured bone mass, lean tissue mass and fat at baseline and at 24 months.

Those in the cheese group had a larger increase in total bone mass.

The calcium in cheese seems to be absorbed better, possibly because of the high protein content in cheese.

This article was originally published November 24, 2003 in The St. Tammany News. > Health Articles > Nutrition