B vitamins may slow cataract occurrence & development: AREDS data
Vitamins B2 (riboflavin), B3 (niacin), B6 and B12 were all associated with a protective effect against nuclear and cortical lens opacities, according to data from 3115 people aged between 55 and 80 and followed up for an average of 9.6 years.
“The totality of evidence from our study and other studies suggests that B vitamins may have a role in slowing cataract development,” wrote the authors, led by Tanya Glaser, MD, from the National Eye Institute at the National Institutes of Health in Ophthalmology.
“However, additional evidence would be needed to make definitive clinical recommendations. Identification of micronutrients that retard cataract progression would serve as a cost-effective way to reduce the disease burden of age-related cataracts.”
Commenting on the potential mechanism of action, Dr Glaser and her co-authors note that cataract development may be linked to oxidative stress, and that B vitamins may help to maintain eye health by functioning as cofactors in the enzymatic activation of antioxidants.
“It is biologically plausible that their importance may be attributed to their function in the metabolic pathway that eliminates homocysteine, wherein vitamins B12 and B6 act as enzymatic cofactors,” they wrote.
AREDS, AREDS2 & cataracts
“The clinical trial component of the AREDS found that high doses of vitamins C and E, β-carotene, zinc, or a combination thereof had no apparent effect on the development or progression of lens opacities,” explained Dr Glaser and her co-authors. “The AREDS 2, a randomized controlled clinical trial, also found no beneficial or harmful effect of treatment with lutein and zeaxanthin on the occurrence of cataract surgery or progression of lens opacities.
“In this report, cross-sectional and prospective data from the AREDS were used to examine associations between age-related lens opacities and dietary intake of B vitamins and lutein plus zeaxanthin, micronutrients for whom protective associations have been reported. We found that increased dietary intake of riboflavin and vitamin B12 were associated inversely in the cross-sectional baseline comparison for both nuclear and cortical cataracts.”
Key findings
Data from the study cohort indicated that, at baseline, both dietary riboflavin and B12 were inversely associated with lens opacity.
In addition, people with the highest average riboflavin intakes had 22% and 38% lower risks of mild and moderate nuclear cataract, respectively, and a 20% lower risk of mild cortical cataract, compared with people with the lowest average intakes.
People with the highest average B12 intakes also had 22% and 38% lower risks of mild and moderate nuclear cataract, respectively, while the risk of mild cortical cataract was reduced by 23%, compared with people with the lowest average intakes.
The highest average B6 intake was associated with a 33% decreased risk of developing moderate nuclear lens opacity, compared with the lowest average intakes, they added.
No associations were found between lutein plus zeaxanthin intake and any of the cataract measures, added Dr Glaser and her co-workers.
“These findings are consistent with earlier studies suggesting that dietary intake of B vitamins may affect the occurrence of age-related lens opacities,” they concluded.
Source: Ophthalmology
Published online ahead of print, doi: 10.1016/j.ophtha.2015.04.007
“The Association of Dietary Lutein plus Zeaxanthin and B Vitamins with Cataracts in the Age-Related Eye Disease Study”
Authors: T.S. Glaser, L.E. Doss, G. Shih, et al.
