Wu, A, Huang, C, et al. The Relationship between Vitamin a and Risk of Fracture: Meta-Analysis of Prospective Studies. J Bone Miner Res. 29(9)2032-9.
This was a meta analysis done on studies published in Medline and Embase to determine the relationship between vitamin A intake and the risk of hip fractures. It was found that both high and low blood levels of retinol and vitamin A proposed a risk for fracturing a hip. Because certain vegetables provide the body with carotenoids which develop into retinol and vitamin A as the body needs it, the authors of the study suggest that consumption of vegetables rich in caretonoids (specifically alpha and Beta carotene). These nutrients, which should be converted to retinol in blood, may be better than intake of retinol from meat, which is directly absorbed into blood after intake, resulting in too high levels.