High intakes of carotenoids may reduce fracture risk

A new study from Australia reports that increased blood concentrations of carotenoids such as beta-carotene may prevent fractures long-term.

The clinical study observed fracture incidents among 998 adult participants who received daily vitamin A
(7.5 mg retinol equivalents) and/or beta-carotene (30 mg) during a mean of eight years (1). The study results showed that participants with increasing concentrations of total carotenoids in blood had a lower risk for any fracture. No association was observed between plasma retinol concentrations and the risk for any or osteoporotic fracture.

The researchers commented that these findings do not support some earlier observational studies which reported an increased fracture risk associated with increased serum retinol levels (2, 3). The new study included a larger number of individuals with higher plasma concentrations of retinol and beta-carotene than previous observational studies, and was able to examine a wider range of concentrations. On the other hand, the new results match earlier reported observations that long-term supplementation with retinol (for up to
17 years) is not associated with the risk for fracture, whereas long-term supplementation with beta-carotene may reduce this risk (4).

1. Ambrosini G. L. et al. Plasma retinol and total carotenes and fracture risk after long-term supplementation with high doses of retinol. Nutrition. 2014; 30(5): 551–556.
   
2. Michaelsson K. et al. Serum retinol levels and the risk of fracture. NEJM. 2003; 348:287–294.
   
3. Opotowsky A. R. and Bilezikian J. P. Serum vitamin A concentration and the risk of hip fracture among women 50 to 74 years old in the United States: A prospective analysis of the NHANES I follow-up study. Am J Med. 2004; 117:169–174.
   
4. Ambrosini G. L. et al. No dose-dependent increase in fracture risk after long-term exposure to high doses of retinol or beta-carotene. Osteoporos Int. 2012; 24:1285–1293.