Dr. Grossman’s Blog

Researchers from Tufts University have found that a diet rich in omega-3 fatty acids and low in starchy carbohydrates can significantly reduce the risk of age-related macular degeneration (AMD).

The study, published in the journal Ophthalmology, is the first to calculate the combined effect of specific dietary nutrients and eating habits on a person’s risk for age-related macular degeneration.

During the study of 4003 participants in the ongoing Age-Related Eye Disease Study (AREDS), each dietary factor was assigned a percentile score; these scores were accumulated to find each participant’s compound score. The compound score was then evaluated for its association with the risk of AMD.

Researchers showed that vitamins C and E, zinc, lutein, zeaxanthin and the omega-3 fatty acids known as D.H.A. and E.P.A. were linked to lower risk for AMD.

The lowest risk of AMD was found in participants who regularly consumed a combination of these nutrients as part of a low-glycemic index diet.

The glycemic index (GI) is a measure of the effects of carbohydrates on blood glucose levels. Carbohydrates that break down rapidly during digestion, such as white bread and pastries, have a higher GI, as they release glucose into the bloodstream rapidly. Foods that break down more slowly, such as vegetables and proteins, have a lower GI value.

Read more about AMD on the Natural Eye Care website

Learn more about food sources for nutrients important for good eye health, including omega-3 fatty acids

SOURCE: “Dietary Compound Score and Risk of Age-Related Macular Degeneration in the Age-Related Eye Disease Study”, Chiu, et al, Ophthalmology, Volume 116, Issue 5, Pages 939-946.

Age-related macular degeneration (AMD) is the most prevalent cause of irreversible blindness in developed countries. Researchers have shown that high dietary intake of beta carotene, vitamins C and E, and zinc may substantially reduce the risk of AMD.

Scientists at the Erasmus Medical Centre in the Netherlands investigated whether regular dietary intake of antioxidants is associated with a lower risk of incident AMD.

Participants in the study included 7983 inhabitants aged 55 years or older in a middle-class suburb of Rotterdam, the Netherlands. A baseline home interview and a series of examinations at the study center were conducted from 1990 until 2004. Food intake was assessed with a food questionnaire, and participants were evaluated for incident AMD (defined as soft distinct drusen with pigment alterations, indistinct or reticular drusen, geographic atrophy, or choroidal neovascularization). Incident AMD occurred in 560 participants after follow-up exams (conducted 8 years later, on average).

Study results showed that participants who consumed vitamin E and zinc were less likely to have AMD.

An above-median consumption of all 4 nutrients studied (beta carotene, vitamin C, vitamin E, and zinc) was associated with a 35% reduced risk of AMD.

Learn more about macular degeneration (AMD)

Find excellent food sources for beta carotene, vitamin C, vitamin E and zinc

SOURCE: Dietary intake of antioxidants and risk of age-related macular degeneration, Leeuwen et al, JAMA, 2005 Dec 28;294 (24):3101-7.

Cataracts are the leading cause of blindness around the world.  Studies suggest that oxidation is responsible for much of the damage to the lens and that antioxidants might protect the lens against formation of cataract.

Scientists at the University of Sydney and the University of Melbourne in Australia have released their investigation of the relationship between antioxidant nutrient intakes and the incidence of age-related cataract.

During 1992–1994, 3654 people aged 49 years or older attended baseline examinations as part of the Blue Mountains Eye Study.  Of these, 2464 (67.4%) of the participants were evaluated again at either 5 years or 10 years.  At each examination, lens photography was performed and food-frequency questionnaires were administered.  Antioxidants, including beta-carotene, zinc, and vitamins A, C, and E, were assessed. Cataract was assessed at each examination from lens photographs with the use of the Wisconsin Cataract Grading System.

Participants whose total intake of vitamin C (diet as well as supplements) was in the top 20% of the group had a reduced risk of nuclear cataract.  An above-median intake of combined antioxidants (vitamins C and E, beta-carotene, and zinc) was also associated with a reduced risk of incident nuclear cataract. 

Study authors concluded that higher intakes of vitamin C or the combined intake of antioxidants had long-term protective associations against development of nuclear cataract in this older population.

Learn more about antioxidants and their importance for good eye health

Read more about cataracts

SOURCE:  Tan, et al, Antioxidant nutrient intake and the long-term incidence of age-related cataract: the Blue Mountains Eye Study,  American Journal of Clinical Nutrition, Vol. 87, No. 6, 1899-1905, June 2008.

A new European study suggests that the combination of low levels of antioxidants and blue light exposure from the sun is associated with certain forms of age-related macular degeneration (AMD).

The EUREYE study, led by Astrid Fletcher, Professor of Epidemiology of Ageing at the London School of Hygiene & Tropical Medicine, is the first to report an adverse association between sunlight exposure and AMD in people with low levels of antioxidants.

It is known that the eye is vulnerable to the damaging effects of sunlight. Ultraviolet radiation is absorbed by the lens, but visible or “blue” light penetrates to the retina, enabling us to see. Protection against the harmful effects of blue light is provided by antioxidant enzymes—including vitamins C and E, the carotenoids (lutein and zeaxanthin) and zinc.

Researchers measured levels of these nutrients in the blood of 4,753 older adults (average age 73.2) who were part of the European Eye Study. Participants were interviewed about their lifetime sunlight exposure and had photographs taken of their retinas to detect AMD.

Participants with the lowest concentrations of antioxidants in the blood were found to be most at risk of AMD due to blue light exposure. In fact, participants with the combination of blue light exposure and low levels of zeaxanthin, alpha tocopherol and Vitamin C were nearly four times more likely to develop AMD. Researchers also noted that blue light exposure in middle age might be more damaging than at younger ages.

Professor Fletcher comments: ‘In the absence of cost-effective screening methods to identify people in the population with early AMD, we suggest that recommendations on protecting the eyes, ensuring that diets contain the right nutrients and antioxidants, are targeted at the general population, and especially middle-aged people’.

Study authors don’t advise people to stay out of the sun altogether — sunlight is important for its role in vitamin D synthesis. However, they do recommend avoiding exposing eyes to too much sunlight by wearing a wide-brimmed hat and sunglasses when outdoors.

In addition, study authors advise consumption of key antioxidants, which can be accomplished by consuming recommended dietary intake levels of vitamin C and zinc and increasing consumption of carotenoid-rich fruits and vegetables.

Learn more about macular degeneration

Read more about antioxidants and nutrient food sources for good eye health

SOURCE: Fletcher AE et al. Sunlight exposure, antioxidants, and age-related macular degeneration. Archives Ophthalmology 2008; 126:1396-1403.