Vitamin A (1944, 1992, 2014) & Cataracts
Researchers noted as early as 1944, after reviewing data from the Nutrition and Eye Disease Study, that moderate levels of Vitamin A in patients' diets were connected to a 40% lower risk of opaque lenses, or cataracts. The researchers adjusted the risk for age, sex, smoking, and heavy drinking and found that for those who were smokers, the cataract risk was reduced by 50%.
Published: Mares-Perelman, J.A., Klein, B.E.K., et al. Relationship Between Lens Opacities and Vitamin and Mineral Supplement Use, Ophthalmology 1944
1992 The Nurses Health Study was a nearly-20-year study which tracked the health of more than 50,000 female registered nurses along with their diet and levels of nutrients. Researchers noted that greater amounts of vitamin A in the diet were tied to 39% less risk of developing cataract.
In the years of follow-up additional women were added to the study as they reached age 45. The women who had the top one-fifth levels of vitamin A were those who had the 39% reduction. Consumption of spinach was most closely tied to lowered risk. In addition, the risk of cataract in women taking vitamin C was lowered by 45%. The researchers did not evaluate consumption of multi-vitamins.
Researchers: S.E. Hankinson, M.J. Stampfer
Published: Nutrient intake and cataract extraction in women: a prospective study, BMJ, August, 1992.
2014 Researchers investigated the effects of vitamin A and beta-carotene (a precursor of vitamin A) on cataract risk by summarizing the evidence from prior studies of both nutrients on cataract risk.
In this meta-analysis (a study of studies) the researchers evaluated information from 22 different studies finding significant connection between vitamin A consumption levels and incidence of cataract.
Researchers: A. Wang, Y. Jiang, D. Zhang
Published: Association of vitamin A and β-carotene with risk for age-related cataract: a meta-analysis, Nutrition, October, 2014.