Soda and Osteoporosis: Is There a Connection?

From the WebMD Archives

Does this sound like you? While everyone else is at Starbucks getting their morning latte, you're at the vending machine picking up a Diet Coke. And if you're going to a movie, the popcorn just wouldn't be complete without a large soda. But there may be a link between soda and osteoporosis that could be putting your bones at risk.

When Soda Displaces Milk

Experts aren't sure why drinking soda is linked to osteoporosis. It may be simply that the soda is displacing healthier drinks in your diet. If you're guzzling a Pepsi with dinner (or breakfast!) you're probably not drinking the glass of milk or fortified orange juice that nutritionists recommend.

"There is an association between people who have high soda intake and risk of fracture, but that's probably due to the fact that if they have a high soda intake, they have a low milk intake," agrees Robert Heaney, MD, FACP, a professor of medicine at Creighton University in Omaha, Neb., and a nationally recognized expert on osteoporosis.

"Those things have been shown to be linked in various studies. But when you look at the ingredients of the soda and give those to healthy people and measure what it does to their calcium composition, nothing happens at all."

"Individuals who drink a lot of soft drinks aren't going to drink as much nutritious liquid as others," says Bess Dawson-Hughes, M.D., professor of medicine and director of the Bone Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. "We're simply not going to consume beyond a certain volume each day."

So, if you just remember to drink a glass of milk for every can of Diet Coke, you'll be fine, right? Not necessarily.

Soda and Osteoporosis: The Cola Connection

New research indicates that there may be more to the soda and osteoporosis connection than simply replacing the good stuff with the useless stuff.

Researchers at Tufts University, studying several thousand men and women, found that women who regularly drank cola-based sodas -- three or more a day -- had almost 4% lower bone mineral density in the hip, even though researchers controlled for calcium and vitamin D intake. But women who drank non-cola soft drinks, like Sprite or Mountain Dew, didn't appear to have lower bone density.

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Soda and Osteoporosis: Possible Culprits

Phosphoric acid, a major component in most sodas, may be to blame, according to lead study author Katherine Tucker, PhD.

Phosphorus itself is an important bone mineral. But if you're getting a disproportionate amount of phosphorus compared to the amount of calcium you're getting, that could lead to bone loss.

Another possible culprit is caffeine, which experts have long known can interfere with calcium absorption. In the Tufts study, both caffeinated and non-caffeinated colas were associated with lower bone density. But the caffeinated drinks appeared to do more damage.

This study isn't the last word on the subject. Some experts point out that the amount of phosphoric acid in soda is minimal compared to that found in chicken or cheese. And no one's telling women to stop eating chicken.

Smart Steps for Soda Lovers

Whether the apparent soda and osteoporosis link is due to effects of the soda itself or simply because soda drinkers get less of other, healthier beverages, it's clear that you need to be extra-vigilant about your bone health if you're a soda fiend.

"Soda drinkers need to pay extra attention to getting calcium from other sources," says Dawson-Hughes.

A few steps you can take to boost your bone health:

  • Can't give soda up entirely? Cut out one or two cans a day (depending on how much you drink). The Tufts study indicates that it might help to switch to a non-cola soda (like Sprite or Mountain Dew).
  • Better still, for every soda you skip, reach for a glass of milk or fortified orange juice instead. Not only will you be cutting back on any harmful effect from the soda itself, you'll be adding calcium. (If you're a diet soda drinker worried about calories, here's a plus: fat-free milk has even more calcium than higher-calorie whole milk.)
  • Have a breakfast cereal fortified with calcium -- and pour milk on top.
  • Add milk instead of water when you prepare things like pancakes, waffles, and cocoa.
  • Add nonfat powdered dry milk to all kinds of recipes -- puddings, cookies, breads, soups, gravy, and casseroles. One tablespoon adds 52 mg of calcium. You can add three tablespoons per cup of milk in puddings, cocoa and custard; four tablespoons per cup of hot cereal (before cooking); and 2 tablespoons per cup of flour in cakes, cookies and breads.
  • Take a calcium and vitamin D supplement if you aren't getting enough calcium (1000-1300 mg, depending on your age) in your diet.
  • Get plenty of weight-bearing and resistance exercise.
WebMD Feature Reviewed by Charlotte E. Grayson Mathis, MD on February 01, 2007

Sources

Published Feb. 1, 2007.

SOURCES: Bess Dawson-Hughes, MD, professor of medicine and director, Bone Metabolism Laboratory, the Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging, Tufts University, Boston. Robert Heaney, MD, FACP, professor of medicine, Creighton University, Omaha, Neb. Heaney, R., Food and Chemical Toxicology 40 (2002): 1263-70. Heaney, R., Rafferty, K. American Journal of Clinical Nutrition, 74 (2001): 343 - 347. WebMD news article: "Study Links Cola to Bone Loss in Women," Oct. 6, 2006. Sax, L. "The Institute of Medicine's "Dietary Reference Intake" for Phosphorus: A Critical Perspective," Journal of the American College of Nutrition, 2001. Yahoo Health News: "Cola Raises Women's Osteoporosis Risk," Oct. 6, 2006. U.S. Department of Agriculture Dietary Guidelines for Americans 2005, "Food Sources of Selected Nutrients," National Osteoporosis Foundation: "Osteoporosis Prevention: Calcium and Vitamin D Recommendations."

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