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Food for Vision

written by Holly M. Gross, M.D.
on Wednesday, 12th June ,2013

According to a report published in February, 2012, Americans spend more than $25 billion a year on dietary supplements. However, as Linda pointed out in her previous blog, what to take and how much to take is unclear, and the evidence often contradictory. Millions of Americans take dietary supplements for eye health, weight loss, joint function, digestive health, clear skin, immune system boosts, and many other reasons, without clear evidence of their efficacy. Some are sold in pharmacies, some at retail stores, and some even at doctor's offices. The allure of taking supplements is multifactorial and understandable; popping a pill is easier than eating a variety of foods; modern medicine cannot cure all diseases and people search for alternative treatments; and many have family members with diseases in which they have an interest in preventing in themselves.

According to the FDA website, the manufacturer of a dietary supplement or dietary ingredients responsible for ensuring that the product is safe before it is marketed, while the FDA's responsibility is to take action against any unsafe dietary supplement product after it reaches the market. There is no requirement to prove that the supplement works for the conditions for which it is marketed, and there is no conformity as to dosages. Therefore, it is very confusing when a patient is told to take "fish oil" or "glucosamine chondroitin", yet the choices on the pharmacy shelf are overwhelming.

The timing of this article happens to coincide with the release of the AREDS 2 study, a large five year study led by the National Eye Institute of the National Institutes of Health. AREDS 2 stands for "Age Related Eye Disease Study" and is a follow up study to the AREDS study which concluded in 2001. In the AREDS study, over 4,500 patients between 55 and 80 years old were treated with a high dose combination of Vitamin C, Vitamin E, beta-carotene, zinc and copper. The treated patients had a 25% less chance of progressing to advanced macular degeneration than those given a placebo. These findings resulted in the marketing and sale of AREDS formula supplements available in pharmacies and doctor's offices, and has been recommended by ophthalmologists since the publication of the results.

Anecdotal evidence and medical practices have also suggested that zeaxanthin and lutein, which are plant derived carotenoids, and omega-3 fatty acids, which are found in oily fishes, nuts, and oils, may also contribute to a decrease in macular degeneration progression. A concern with the AREDS formula was that some studies have shown that beta-carotene supplements in smokers and former smokers may increase the incidence of lung cancer in these individuals, although other studies have disputed this. The AREDS 2 study was conducted to determine if changes to the AREDS formula improved the outcome. The study found that the addition of lutein, zeaxanthine, or omega-3 fatty acids to the original AREDS formula did not contribute to further benefit. The AREDS formula with no beta carotene, and with lower zinc, did not reduce the benefit. The addition of lutein and zeaxanthin may provide a benefit to those who do not consume enough of these vitamins in their diet.

Before the AREDS 2 study came out, several companies came out with products which added various components to the original AREDS study, and we ophthalmologists were uncertain as to what to recommend. Now, we know, thanks to a well constructed, well performed scientific study of lots of people with the condition of interest! For people with intermediate and advanced macular degeneration without vision loss, we recommend the AREDS formula; for smokers or former smokers, the AREDs formula without beta-carotene. This information is important, since two million people in the US have advanced macular degeneration, and eight million more or considered at risk. Macular degeneration is a condition which occurs in people 65 years and older, in which the neural tissue of the eye, the retina, becomes thin and damaged leading to loss of central vision and the inability to read, drive, and recognize faces.

The AREDS studies did not show a benefit for those with early or no macular degeneration, since the incidence of progression over the study period in both groups was so low. Neither study showed a benefit in preventing cataracts, either. Stay tuned for my next article, which will tell you how! We do not recommend high dose vitamins for those with no macular degeneration wishing to prevent the condition, since we don't know the long term effects of high dose vitamins. As mentioned earlier, beta-carotene may increase the risk of lung cancer in smokers. Excess vitamin E has been shown in some studies to increase the risk of hemorrhagic stroke and prostate cancer. As with all medical decisions, the benefit of the treatment must outweight the risks.

For those who do not have macular degeneration, but wish to preserve their eye health, ingestion of foods containing healthy vitamins and minerals is the best way to obtain these nutrients, even better than supplements.

Here is list of common edible sources of nutrients important for eye health.

Vitamin A (important component of the light sensitive cells in the retina; look for deep orange and yellow fruits): cod liver oil, liver, dandelion greens, carrots, broccoli, sweet potatoes, butter, kale, spinach, pumpkin, collard greens, cheddar cheese, cantaloupe, eggs, apricots, papaya, mango, peas, broccoli, milk, tomatoes, peaches, and green peppers.

Vitamin C (anti-oxidant): oranges, grapefruit, strawberries, papaya, green peppers, and tomatoes

Vitamin E (anti-oxidant): vegetable oils (corn and safflower), almonds, pecans, wheat germ, and sunflower seeds

Zinc (trace mineral, supports blood sugar and metabolic rate among other things): beef, pork, lamb, oysters, eggs, shellfish, milk, peanuts, whole grains, and wheat germ

Copper (works with iron to form red blood cells, also important in other body systems): Oysters and other shellfish, whole grains, beans, nuts, potatoes, organ meats , dark leafy greens, dried fruits, cocoa, black pepper, and yeast.

Here is a recipe from Chef Jyl Steinback which is delicious and incorporates many healthy nutrients for the eyes:

GRILLED TUNA WITH PINEAPPLE-ORANGE SALSA (serves 4)

INGREDIENTS: • 1 cup pineapple chunks, drained • ¼ cup orange juice • 1 tbsp. chopped sweet onion (e.g. Vidalia, Walla Walla) • ½ cup chopped red bell pepper • 24 oz. tuna steaks • 2 tsp. garlic powder • 2 tbsp. low-sodium teriyaki sauce

COOKING INSTRUCTIONS: Combine pineapple, orange juice, onion, and red pepper in a medium bowl and mix well; cover and refrigerate until ready to serve. Sprinkle tuna steaks on both sides with garlic powder. Brush generously with teriyaki sauce. Heat broiler or grill to medium-high heat. Cook (grill or broil) tuna 5 minutes; turn tuna, brush with teriyaki sauce, and cook an additional 5 minutes. Serve with pineapple salsa.

SHOPPING LIST: 24 oz. tuna steaks, 8 oz. can pineapple chunks, orange juice, sweet onion, red bell pepper, teriyaki sauce, garlic powder

Finally, for those adventurous cooks wishing to celebrate this summer's emergence of the 17 year cicadas, here is a link to NPR's "Cooking with Cicadas: No Weirder than Eating Cheese" segment from May 29, 2013 http://www.npr.org/blogs/thesalt/2013/05/29/187064786/cooking-with-cicadas-no-weirder-than-eating-cheese

Enjoy!

Holly

Tags: nutritional supplements for eyes, carotenoids, AREDS 2

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