OMAHA, Neb.--J. Christopher Gallagher, M.D., and researchers from the Bone Metabolism Unit of Creighton University's School of Medicine discovered that elderly women with high caffeine intakes (300 mg/d) showed significantly higher rates of bone loss at the spine than women with low intakes (less than or equal to 300 mg/d). In particular, researchers noted that bone loss was especially high in the group of women who demonstrated a specific genetic variation of the vitamin D receptor (VDR).
Published in the November issue of The American Journal of Clinical Nutrition (74(5):694-700, 2001) (www.ajcn.org), the study involved 96 women who showed bone loss over a period of three years. Researchers compared the women in terms of VDR polymorphism groups: high variation (BB), no variation (bb) and intermediate variation (Bb).
"We found that [the high variation group] lost more bone," Gallagher said. "Then we started to look at other things that affect the response to bone, like calcium intake, caffeine intake, smoking, etc. The thing that we found to have the most severe effect in conjunction with this VDR change was caffeine intake."
In general, women with a high caffeine intake demonstrated higher bone loss than women with lower caffeine intake. Researchers concluded that consuming more than 300 mg/d of caffeine accelerated bone loss at the spine in elderly postmenopausal women, and women with the BB genetic variant of VDR seem to be at greater risk for bone loss as a result of high caffeine intake.