Nutrients and a low glycemic diet protect vision in aging

Researchers at Tufts University in Boston show that several nutrients combined with a low glycemic index diet have a protective effect against age-related macular degeneration. Macular degeneration is a major cause of blindness among older adults in western nations, and is characterized by the accumulation of drusen in the eye’s macula, which can lead to a loss of central vision.

For the current research Chung-Jung Chiu, PhD of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University and colleagues analyzed data from 4,003 participants in the Age-Related Eye Disease Study (AREDS). Dietary questionnaires completed by the subjects were scored for the intake of nutrients tested in AREDS: vitamin C, vitamin E, and zinc, and AREDS2: Lutein/Zeaxanthin, and the fish oil omega-3 fatty acids EPA and DHA. Glycemic index, which measures how fast a particular food raises blood sugar, was calculated for consumed food items. Fundus photographs of the macula of the eye taken upon enrollment were graded for severity of drusen or type of macular degeneration.

Participants whose compound diet scores of both groups of nutrients as well as low glycemic index foods were higher were determined to have the lowest risk of early as well as advanced macular degeneration, compared to the risk experienced by those with lower scores. When single nutrients were analyzed separately, only vitamin E emerged as significantly protective against the disease.

The study is the first to analyze the combination of the two nutrient groups and a low glycemic index diet. “Although the compound score may be a useful new tool for assessing nutrients in relation to AMD, specific dietary recommendations should be made only after our results are confirmed by clinical trials or prospective studies,” Dr. Chiu stated. The study is published in the May, 2009 issue of the journal Ophthalmology.