Q: I heard that frequent soda consumption leads to weakened bones. Is this true?
– David Karlson, Livermore, Calif.
A: According to a study directed by Dr. Maureen Storey of the Center for Food and Nutrition Policy (CFNP) at Virginia Tech published in the Journal of the American College of Nutrition, “Calcium intake among U.S. adolescents, although inadequate, has remained a constant since the 1970s and does not appear to be linked to soft drink consumption. The data shows that soft drink consumption by teens is actually far less than perceived.”
While CFNP is an independent research and education center, this particular study was funded by an unrestricted grant from the National Soft Drink Association, which (fairly or unfairly) makes the conclusions a bit suspect.
On the opposite side of the argument are doctors of natural medicine and medical doctors who feel that soft drinks are major factors in pulling calcium out of the bones. Author and leading doctor of natural medicine Michael Murray says: “Soft drinks have long been suspected of leading to lower calcium levels and higher phosphate levels in the blood. When phosphate levels are high and calcium levels are low, calcium is pulled out of the bones.”
This opinion is echoed by Drs. James Howenstine, M.D., James Duke, Earl Mindell, (authors and respected professionals in the field of natural health) and T. Dwayne McCay of the Naval Medical Research Institute.
Rebecca Seguin, who is a certified strength conditional specialist and project manager of the Tufts University Center for Physical Activity and Nutrition posted an opinion online in 2003:
“While it is true that calcium metabolism can suffer when you consume considerably more phosphorus than calcium,” Seguin writes, “most sodas have no phosphorus at all and those that do contain modest amounts.”
Seguin further points out that because the Dietary Reference Intake of phosphorus is 700mg per day, and because 8 ounces of Coca Cola, for example, comes in at 41mg of phosporous, it would be necessary to drink six cans of Coke a day just to equal the phosphorus in a serving of All-Bran and skim milk. But, according to the Center for Science in the Public Interest (a nonprofit education and advocacy organization), between 1977 and 2001, milk consumption among teens dropped 40 percent while soda consumption doubled. And sodas no longer are available in 8-ounce cans. A can of soda is 12 ounces and rapidly heading toward 20 ounces.
All health professionals seem to agree on two points. First, many teenagers have replaced milk with sodas and, as a consequence, do not consume enough calcium at a time of rapid physical growth and bone development – when they need it the most. And second, the caffeine found in many sodas can interfere with calcium absorption.
If adolescents and teenagers are substituting sodas for healthier choices like milk (including soy) and fruit juice, then they are not getting the necessary daily calcium.
Linda Buch, ACE certified exercise specialist, will respond to fitness questions only in her weekly column. Send questions to: Body Language, The Denver Post, 1560 Broadway, Denver, CO 80202 or LJBalance@aol.com.
