From the Harvard University Gazette:
By William J. Cromie
Add bone fractures to obesity and tooth decay as another reason that teenage girls should drink less soda pop, particularly colas.
Ninth- and 10-grade girls who drink soda pop have three times the risk of bone fractures compared with those who don’t drink carbonated beverages, according to a new Harvard study. Worse, the most physically active soda slurpers put themselves at five times the risk of abstainers.
“Our findings have implications both for the health of teenagers and for the health of women at later ages,” says Grace Wyshak of the Harvard School of Public Health and Harvard Medical School. She conducted research that examined the relationship between the soda-drinking habits, activity levels, and history of bone fractures of 460 adolescent girls.
Wyshak did two previous studies of soda pop and bone fractures, one on postmenopausal women, the other on teenagers, and reached the same conclusion. In teenagers, she found that two or more cans a day is enough to cause bone weakening.
In a 1994 study, she tested both boys and girls, and found that the same association does not hold true for boys. “I really don’t know why,” she admits. “I suspect it’s related to hormones and the difference in calcium and phosphorus metabolism.”
Colas contain phosphoric acid, which interferes with calcium metabolism and the building of bone mass, a process that apparently affects girls more than boys. The difference becomes especially important as teen drinking of sodas rises steeply while consumption of milk plummets.
“We really don’t know for certain why carbonated drinks, colas in particular, increased the likelihood of bone fractures,” Wyshak notes. “Important questions are yet to be answered. Why is the effect of cola drinks greater for physically active people than for those less active? Is this a foreshadowing of the skeletal health of a population that has gone though adolescence drinking more soda pop than any previous generation?”
One of the major determinants of fracture risk is the amount of bone present, which reaches its maximum during adolescent years. About two years after menopause begins, bone mass begins to decline.
“Adolescence is therefore a crucial time for bone development, and any factors adversely impacting on bone acquisition during this time can potentially have long-standing detrimental effects,” comments pediatrician Neville Golden from Albert Einstein College of Medicine in New York. In an editorial accompanying Wyshak’s report in the June issue of the Archives of Pediatric and Adolescent Medicine, he calls her findings “alarming” and says they warrant further studies that relate the amount and type of carbonated drinks consumed to the amount of calcium in a teen diet.
Wyshak agrees with Golden’s statement that “osteoporosis should no longer be considered only a geriatric disease, but rather a pediatric disease with geriatric consequences.”