Sahni S et al. (2008) High vitamin C intake is associated with lower 4-year bone loss in elderly men. J Nutr 138: 1931–1938

Vitamin C can potentially decrease the oxidative stress associated with bone-resorptive processes, and is also essential for collagen formation. This vitamin might, therefore, help to prevent osteoporosis; however, studies of its effects on BMD have provided mixed results. A new study suggests that high vitamin C intakes have a protective effect on bone health in elderly men.

Sahni et al. assessed data from 334 men and 540 women (mean age of whole group 75 years) enrolled in the Framingham Osteoporosis Study. Vitamin C intake (total, dietary, and from supplements) was recorded using a diet questionnaire, and changes in hip, spine and forearm BMD were measured using dual-photon absorptiometry and, at 4 years' follow-up, dual-energy X-ray absorptiometry.

No associations between vitamin C intake and BMD were observed in women. High dietary intakes of vitamin C conferred a protective effect against BMD losses in men, whereas high total intakes of vitamin C only showed this protective effect in men with low calcium or vitamin E intakes. Total vitamin C intake was positively associated with femoral-neck BMD among male nonsmokers. Total and supplemental vitamin C intakes both inversely correlated with trochanter BMD in male current smokers; these findings suggest that such individuals are particularly likely to take vitamin C supplements.

Adjustment for potassium intake attenuated these protective effects of vitamin C, however, which suggests that other factors derived from fruit and vegetable consumption contribute to the observed outcomes.