Here is a summary of the recently published (in The British Medical Journal) results of the largest/longest comprehensive survey covering dietary contribution in the prime cause of age-related blindness. The conclusions are persuasive.
Carotenoid rich diet helps cut advanced AMD
09 Oct 15
A higher intake of carotenoids, particularly lutein and zeaxanthin, is associated with a long term reduced risk of developing advanced age related macular degeneration (AMD), two large prospective cohort studies published in JAMA Ophthalmology have shown.1
Carotenoids are fat soluble plant pigments found in red, yellow, orange, and dark green fruits and vegetables. The best sources of lutein and zeaxanthin are green leafy vegetables such as kale, spinach, and broccoli. The pigments are also found in corn, red pepper, and eggs.
The researchers followed 63 443 women from the Nurses’ Health Study and 38 603 men from the Health Professionals Follow-up Study from 1984 to 2010. All participants were aged 50 or over and did not have AMD, diabetes mellitus, cardiovascular disease, or cancer at baseline. The participants were assessed by repeated food frequency questionnaires, which included questions on supplements. The researchers then used predicted plasma carotenoid scores to account for variations in bioavailability across different foods and preparation methods.
They found 1361 confirmed intermediate AMD cases and 1118 advanced AMD cases during the study, which was supported by grants from the US National Institutes of Health. After adjusting for other risk factors the researchers found that a higher intake of bioavailable lutein/zeaxanthin was associated with a 40% lower risk of advanced AMD in women and men (pooled relative risk comparing extreme quintiles = 0.59 (95% confidence interval 0.48 to 0.73); P for trend<0.001).
Other carotenoids, including β-cryptoxanthin, α-carotene, and β-carotene, were associated with a 25-35% lower risk of advanced AMD when comparing participants with the highest intake against those with the lowest. However, intake of carotenoids was not associated with intermediate AMD, suggesting it affects progression rather than initiation of the disease, the researchers said.
They added that lutein and zeaxanthin form macular pigments that may protect against AMD by reducing oxidative stress, absorbing blue light, and stabilising cell membranes. They said that their study lent further support to the causal role of lutein and zeaxanthin in protecting against the development of advanced AMD.
By Jacqui Wise, London
1. Wu J, Cho E, Willett W, et al. Intakes of lutein, zeaxanthin, and other carotenoids and age related macular degeneration during two decades of prospective follow-up. JAMA Ophthalmol Oct 2015; doi: 10.1001/jamaopthalmol.2015.3590.