Nutritional supports cannot reverse age-related macular degeneration (AMD) but they may help to retard its progression. AMD is being studied at the Human Nutrition Research Center on Aging at Tufts University. Nutritional biochemist Elizabeth J. Johnson is the lead researcher in a study to determine differences in the body’s ability to absorb and use lutein from eggs, spinach, and lutein supplements for eye health. Lutein is an antioxidant phytochemical concentrated in the eye’s retina. Eggs and cooked spinach are good sources of lutein.
“Designer eggs” from chickens fed marigold petals (high in lutein) were used in the study. Healthy adult men volunteered to consume cooked spinach, the designer eggs, and lutein supplements. The eggs were found to increase the lutein considerably in the volunteers’ blood. The level of lutein was two to three times greater than it was after they are similar amounts of lutein from other sources. It appears that eggs from chickens fed marigold petals can be a bettor source of lutein than either cooked spinach or lutein supplements.
The designer egg in the study had about six times more lutein than the standard egg. Although the lutein was still a modest amount in the designer egg (1.5 milligrams compared to 11 milligrams in a 2-ounce serving of spinach) the egg’s lutein was readily absorbed and went directly into the bloodstream.
Other nutrients may have beneficial effects with AMD. Researchers at the National Eye Institute reported results of a seven-year Age-related Eye Disease Study, and found that people who used a high-dose combination of vitamins C and E plus zinc, for more than six years, lowered their risk of developing AMD by about 25%.
Foods rich in antioxidants may help retard eye cataract progression, but cannot reverse the condition. The same antioxidants are useful to prevent cataract formation.
The normal eye lens contains high vitamin C and E levels, as well as phytochemicals such as lutein and zeaxanthin. All of these substances have antioxidant properties that help maintain healthy cells and tissues in the eyes as well as in other body organs. The antioxidants neutralize oxidative damage from free radicals to the fats, proteins, and other components in the eye lens. Many vegetables and fruits are good sources of these oxidants, and should be part of the daily diet.
In the Nutrition and Vision Project, a section of the Nurses’ Health Study, scientists observed 478 non-diabetic Boston women from 53 to 73 years of age, who previously had not been diagnosed as having cataracts. Eye examinations of the women probed the relationship between newly diagnosed cataracts and the women’s nutrient intake over a period of time. Women who had the highest intakes of vitamins C and E, riboflavin, folato, beta carotene, lutein, and zeaxanthin had a lower prevalence of cataracts than did the women with the lowest intake of those nutrients. Women who had used vitamin C supplements for 10 years or more were 64% less likely to have cataracts than those who never used vitamin C supplements.
Studies conducted elsewhere have yielded similar findings. Women younger than 60 years of age had reduced risk of cataract formation if they had used vitamin C supplements. Also, non-smoking women who consumed foods with high amounts of carotenoids had a lower risk of cataract development. Carotenoids are found in many common vegetables and fruits, such as carrots, yellow squash, cantaloupe, and apricots.
Among the same women, those who used vitamin E regularly had less progression of eye lens damage. The progression over five years of follow-up after the initial examination was 30% lower among women who had used vitamin E supplements for at least 10 years than among those who had never used vitamin E supplements.