Herbs, Nutrition and Cataracts

By Shereen Jegtvig, Certified Nutrition Specialist (CNS);
contributions and review by Brian S. Boxer Wachler, MD

Age-related cataract is a leading cause of blindness in the world today. While the exact cause of cataracts is unknown, scientific investigation is continuing to determine whether consuming herbs, nutritional supplements, and healthy foods can reduce the risk of developing cataracts.

Human studies exploring use of herbs to slow or prevent cataracts appear scarce. But Integrative Medicine reference book cites research using rats in which the herb, turmeric, reduced cataract formation. Remember, however, to never undertake use of any herb as a medicinal remedy without consulting your doctor first.

Turmeric is an antioxidant. And generally eating a healthy diet rich in antioxidants and certain vitamins has been shown in some studies to possibly reduce the risk of cataracts or their progression.

Diet, Oxidative Stress, and Cataracts

Oxidative stress results when we have an imbalance between damaging free radicals and the antioxidants that keep them in check. Free radicals are atoms or groups of atoms (molecules) that are highly reactive with other atoms and molecules because they have unpaired electrons. In the body, a free radical is usually an oxygen molecule that self-stabilizes by taking an electron from another molecule, which in turn tries to take an electron from another molecule, and so on. Free radicals damage the body by stealing electrons from the normally healthy cells of organs and other tissues. This process of stealing electrons from healthy cells is called oxidation.

In the eye, oxidation affects proteins and fats in the lens to the extent that the lens becomes damaged and cloudy, creating what we call cataracts. Preventing free radical damage with healthy foods, particularly those containing antioxidants, may help slow down this process.

Free radicals that damage our eyes and the rest of the body may originate from exposure to pollution or chemicals, smoking, radiation exposure, and eating unhealthy foods. Some free radicals occur from normal daily metabolism, which means even people who don't have those exposures need antioxidants found in the healthy foods we eat.

Antioxidants include some vitamins and phytochemicals that can be found in the foods we eat. Vitamin C, vitamin A, lutein, and vitamin E are some examples of antioxidants that have been shown in studies possibly to reduce the risk of cataracts. These antioxidants, as well as others, are easily obtained from eating a diet containing plentiful amounts of fruits and colorful or dark green vegetables. The compounds that give fruits and vegetables their colors contain the antioxidants that help keep us healthy.

Can a Healthy Diet Prevent Progression of Cataracts?

People who consistently follow a healthy diet that includes fruits, vegetables, and whole grains may show a decreased risk of cataracts. Consumption of fish, which is high in omega-3 essential fatty acids, also has been linked to potentially reduced risk of cataracts or their progression.

While all of the nutrients, antioxidants, and phytochemicals associated with cataract prevention can be found in dietary supplement form, many experts believe these substances should be acquired from a healthy diet rather than as dietary supplements. But some experts advise that, even with a healthy diet, it is prudent to consider adding supplements as well. In particular, laboratory research suggests that supplementation with N-acetyl and L-cysteine may play a role in preventing cataracts or slowing their progression. [See also: Dietary supplements for healthy vision.]

So exactly what is a healthy diet? A healthy diet includes five to nine servings of fruits and vegetables every day, at least three servings of 100 percent whole grains each day, and two servings of fish each week. The total calories consumed should be just enough to keep you at a healthy weight, based on your individual activity level and metabolism. While dark green and colorful fruits and vegetables are not only great sources for antioxidants, their benefits also include folic acid and calcium. Both of these important nutrients also may help reduce the risk of cataracts and should be included in a healthy diet.

To maintain a healthy diet, it is equally important to avoid eating unhealthy foods such as fried foods, processed foods, sugary foods, and foods high in sodium. Note that there is at least some evidence that high salt intake may increase the risk of cataracts, according to research conducted by University of Sydney (Australia) researchers. Some research also suggests that eating large amounts of sugary and starchy foods like white breads, pasta, soft drinks, and pastries also may increase your odds of getting cataracts or having them progress.

Eating healthy foods potentially to reduce your risk of cataracts and other chronic diseases also means giving up those extra soft drinks, desserts, greasy snack foods, and fast foods. But don't worry. Once you get used to eating delicious fruits and vegetables, fresh fish and other healthy foods, you won't miss junk foods. Your reward just might be both a healthy body and healthy vision.

Resources:

Long-term nutrient intake and 5-year change in nuclear lens opacities. Arch Ophthalmol. 2005 Apr; 123(4): 517-26.

Plasma antioxidant vitamins and carotenoids and age-related cataract. Ophthalmology. 2001 Nov; 108(11): 1992-8.

Overall adherence to the dietary guidelines for Americans is associated with reduced prevalence of early age-related nuclear lens opacities in women. J Nutr. 2004 Jul; 134(7): 1812-9.

Health benefits of fruit and vegetables are from additive and synergistic combinations of phytochemicals. Am J Clin Nutr. 2003 Sep; 78(3 Suppl): 517S-520S.

Long-term intake of vitamins and carotenoids and odds of early age-related cortical and posterior subcapsular lens opacities. Am J Clin Nutr. 2002 Mar; 75(3): 540-9.

Food and nutrient intake and risk of cataract. Ann Epidemiol. 1996 Jan; 6(1): 41-6.

[Page updated February 2007]