Dr. Grossman’s Blog

A new study shows why eating a diet rich in antioxidants can help hold off macular degeneration. Macular degeneration causes a gradual loss in sharp central vision, which is needed for reading, recognizing faces, and seeing objects clearly.

Researchers at Brigham Young University and Weill Medical College of Cornell University discovered a link between two processes in the retina that, in combination, contribute to macular degeneration. They found antioxidants in foods such as artichokes, blueberries and pecans disrupt the link and extend the lifetime of photoreceptors and other retinal cells.

“The implication is that people at risk of macular degeneration could help prevent the disease by consuming antioxidants,” said BYU chemist Heidi Vollmer-Snarr.

The new study finds that the buildup of a compound called A2E causes damage to cellular “power plants” called mitochondria. A2E is a natural byproduct of cellular activity that, unlike other compounds, can’t break down or be disposed of by the body.

When A2E encounters oxidative stress created by light exposure it disrupts energy production in mitochondria. Less energy is then available for daily cleaning and maintenance of photoreceptors and other retinal cells, which results in more A2E buildup and the subsequent loss of more cells.

Researchers found that antioxidants disrupt this destructive link and extend the lifetime of irreplaceable photoreceptors and other retinal cells.

This study will be published in the upcoming issue of the Journal of Biological Chemistry.

Read more about macular degeneration

Read more about antioxidants

See other research about macular degeneration

Learn more about natural approaches to preserving vision

Myopia, also called near-sightedness, is a condition in which distant objects appear blurred. Myopia is the leading cause of visual impairment in developed countries, and is present in over 30 million adults in the U.S.
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Researchers in Singapore have found that children who are breastfed are less likely to have myopia. Breast milk is the main source of many micronutrients including docosahexaenoic acid (DHA). DHA is important for photoreceptor and cortical neuronal development, which play a major role in whether children become nearsighted.
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Researchers studied 797 children aged 10 to 12 as part of the Singapore Cohort Study of the Risk Factors of Myopia, including 418 children who had been exclusively breast-fed, and 379 who had not. They performed cycloplegic autorefraction and diagnosed myopia as spherical equivalent refraction of at least -.05 diopters.
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Children who were breastfed had a lower prevalence of myopia (62.0%) than children who were not breastfed (69.1%). This association held even after researchers controlled for factors such as the parents’ nearsightedness, maternal age at delivery and birth weight.
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Read more about myopia, including recommended vitamins and other nutritional products.
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SOURCE: The Journal of the American Medical Association, Vol. 293 No. 24, June 22/29, 2005

Limiting refined carbohydrates in one’s diet may slow the progression of age-related macular degeneration (AMD), according to a recent study by researchers at the Jean Mayer Human Nutrition Research Center On Aging of Tufts University, a research center supported by the U.S. Department of Agriculture.

The study supports findings that suggest men and women over the age of 55 who consume diets of higher-than-average Dietary Glycemic Index foods have an increased risk of AMD.

The Dietary Glycemic Index is an index which indicates the speed at which carbohydrates are broken down into glucose. Foods high on the glycemic index are associated with a faster rise (and subsequent fall) in blood sugar levels than those low on the glycemic index.

In the study, investigators analyzed dietary questionnaires of 4,757 non-diabetic men and women participating in the Age-Related Eye Disease Study (AREDS)—a nationwide eight-year study of men and women from 55 to 80 years of age, experiencing varying stages of AMD.

The study examined participants’ carbohydrate intake over a one year period to calculate the average dietary glycemic index level of foods eaten by the participants.

The researchers concluded that the group of participants who consumed the greatest amount of refined carbohydrates were 17% more likely to develop blinding AMD than the group that consumed the least amount of refined carbohydrates.

Refined carbohydrates refer to foods with their high-fiber components—the bran and the germ—removed. Examples include:

• White rice
• White bread
• Sugary cereals
• Pasta and noodles made from white flour

Unrefined carbohydrates contain the whole grain, including the bran and the germ, and are therefore higher in fiber.
Examples of these include:

• Whole-grain rice
• Whole-meal breads
• Unrefined oatmeal
• Whole-wheat pasta

Based on the study, the researchers conclude that limiting refined carbohydrates in the diets of at-risk elderly people could reduce the number of advanced AMD cases by 8 percent in five years.

The data indicates that it is beneficial for persons at risk of AMD, and especially those with advanced AMD, to consume less refined carbohydrates in their daily diets.

Read what others say about natural products that help macular degeneration.
More about causes, current research, and solutions.

Resources:

SOURCE: Chiu CJ, Milton RC, Klein R, et al. Dietary carbohydrate and the progression of age-related macular degeneration: A prospective study from the Age-Related Eye Disease Study. American Journal of Clinical Nutrition. 2007;86(4):1210-8.

Another great reason to eat fish: a French study has shown that eating fatty fish more than once a month is associated with a 60% reduction in risk for age-related macular degeneration (AMD).

AMD is a medical condition associated with aging in which people gradually lose their sharp central vision. Central vision is needed for reading, recognizing faces, and seeing objects clearly.

A key finding in this study was the positive effect of fatty fish consumption (white fish intake was not significantly associated with AMD). Fatty fish included in this study were both fatty “blue” fish (fresh tuna, canned tuna without oil, mackerel, sardine, salmon) and fatty fish canned in oil (tuna, sardine, anchovy).

This population-based study from southern France reviewed nutritional data from a dietician-administered food-frequency questionnaire to assess the associations of dietary fat with the risk of AMD. AMD was classified from retinal photographs using the international classification and included neovascular age-related macular degeneration, geographic atrophy, soft indistinct drusen, and soft distinct drusen associated with pigmentary abnormalities.

Results of dietary fat analysis showed that high total, saturated, and monounsaturated fat intake were linked to increased risk for AMD, while total polyunsaturated fatty acid was not significantly associated with AMD. Review of fish intake showed that total and white fish intake was not significantly associated with AMD, but intake of fatty fish more than once a month was associated with a 60% reduction in AMD.

Read more about AMD

Learn about other food sources for nutrients important to help fight macular degeneration, including Omega-3 Fish Oil

Source: Dietary fat and the risk of age-related maculopathy: the POLANUT Study.

Eur J Clin Nutr. 2007 Feb 14; Inserm, Research Unit U593 for Epidemiology, Public Health and Development, Bordeaux, France, Universite Victor Segalen Bordeaux 2, Bordeaux, France.