Food Cures (43 page)
Authors: Carol Svec
B VITAMINS
There is strong evidence that two of the B vitamins—riboflavin (vitamin B
2
) and niacin (vitamin B
3
)—may help prevent cataracts, and early research suggests that thiamin (vitamin B
1
) may also contribute to eye health.
Although these vitamins are not antioxidants, they contribute to antioxidant activity by providing some of the building blocks necessary to help the body make antioxidant compounds. So without enough riboflavin and niacin, the risk of cataracts increases. Indeed, several scientific studies have shown that people who eat a diet with plenty of foods rich in riboflavin and niacin can slash their risk of cataracts by about half compared with people who eat a diet with very little of those vitamins.
As with antioxidants, the information about the benefits of B vitamin supplements is less clear. The Blue Mountain Eye Study, the large Australian study with about 2,900 participants, found that those who took riboflavin supplements had a 20 percent lower risk of cataracts compared with people who didn’t take supplements. Niacin supplements lowered risk by 30 percent, and supplements of other B vitamins—thiamin, folate, and vitamin B
12
—also seemed to show some benefit. Combining these vitamins may have an even great effect. A large study conducted by the National Eye Institute in Bethesda, Maryland, showed that people who took a dual supplement containing both riboflavin and niacin reduced their risk of cataracts by 44 percent. Even general multivitamins providing 100% DV for these B vitamins seem to decrease risk by more than 30 percent. As promising as these results sound, the jury is still out on exactly how much of which types of B vitamins is necessary or optimal for cataract prevention. I can only recommend food sources, not pills (with the exception of a multivitamin providing 100% DV for riboflavin and niacin).
BEST FOODS FOR RIBOFLAVIN
:
Liver, lean beef, venison, fortified whole grain cereals, yogurt (fat-free, low-fat), milk (fat-free, 1% reduced-fat), eggs, mushrooms (portobello, white), almonds, coffee
BEST FOODS FOR NIACIN
:
Fortified whole grain cereals, tuna (canned light), chicken breast, lean beef, veal, lean pork, mackerel (not king), turkey breast, wild salmon (fresh, canned), anchovies, kidney beans, peanut butter, peanuts, mushrooms, sunflower seeds
TEA
Tea contains powerful antioxidants, and some research suggests that drinking relatively large amounts of tea—the equivalent of about five cups daily—may help prevent or delay cataract development. But antioxidants may tell only part of the story. While investigating the effects of tea on blood sugar in diabetic laboratory rats, researchers from the University of Scranton discovered that the animals that drank tea had lower blood sugar than those that did not drink tea. But there was also a side benefit—drinking tea reduced the level of glucose in the eye lens,
and
there was a lower incidence of cataracts. In fact, the tea-drinking rats had about half the risk of cataracts as non-tea-drinkers. Both green tea and regular black tea had the same effects, so feel free to choose the type you enjoy most. Or mix it up: green tea has about half as much caffeine, so it makes a soothing drink in the later afternoon or when you want to relax.
WHAT AFFECTS MACULAR DEGENERATION?
The retina is the part of the eye that receives light and images from the world and sends them to the optic nerve to be processed in the brain. The macula is the center, most sensitive part of the retina. It fine-tunes focus at the center of our visual field, the part that allows us to recognize faces, read words on a page, and discern detail in anything we look at. Macular degeneration, then, is a deterioration of the macula, gradually leading to central blindness. Peripheral vision remains clear, so it isn’t a total lack of sight, but the loss of detailed vision. As Nat’s story demonstrated, it’s a life-altering change all the same.
There are two types of macular degeneration: Dry (also called
atrophic
), caused by a gradual breakdown of light receptors; and wet (also called
exudative
), caused by leaks in the blood vessels of the retina, which in turn cause scarring and tissue death. With both types, people usually notice vision distortions first, such as straight lines appearing wavy, along with difficulty reading and recognizing faces. As more and more receptors die, central vision disappears. In its early stages, wet macular degeneration can be treated with laser surgery to seal off the leaking vessels. There is no medical treatment for dry macular degeneration.
Macular degeneration happens most often in people over age 70, primarily women. Although it can run in families, no one knows what causes macular degeneration, or how to stop it once it begins.
HOW FOOD AFFECTS MACULAR DEGENERATION
The Age-Related Eye Disease Study (AREDS), a research project conducted by the National Eye Institute, has given us some clues about how nutrition might help prevent macular degeneration, or at least delay the progression to blindness. AREDS results showed that certain antioxidant vitamins and zinc helped to slow the progression of advanced macular degeneration by about 25 percent over a six-year period. The antioxidants—vitamins C and E, and beta carotene—are thought to prevent damage caused by free radicals, and the mineral zinc is important for the health of all body tissues, but is found in unusually high concentrations in tissues of the retina.
The results of AREDS were so impressive that in the wake of the study’s publication, several supplement manufacturers created special macular degeneration-fighting formulas. However, a 2006 study by researchers from Harvard Medical School linked high levels of vitamin E with
increases
in a measure of inflammation called C-reactive protein (CRP)…and high levels of CRP has been linked to a greater risk of macular degeneration. Could it be that high levels of vitamin E could somehow increase your risk? It is too soon to know. But this conflicting information caused a seismic shift in how eye doctors advised their patients—vitamin supplements can no longer be considered purely beneficial. For this reason, I cannot recommend high doses of vitamin E from supplements, even when they are part of a special macular degeneration formulation. However, I definitely recommend food sources of vitamin E, and/or a multivitamin that
only
provides 100% DV for vitamin E.
BETA CAROTENE, VITAMIN C, VITAMIN E
A study led by researchers from Erasmus Medical Centre in Rotterdam, the Netherlands, followed a group of more than 4,000 people to see how diet affected the risk of developing macular degeneration. After eight years, the scientists compared the diets of people who developed the condition with the diets of those who did not. The results were encouraging: People who ate a diet rich in beta carotene, vitamin C, vitamin E, and zinc had a 35 percent reduced risk of developing macular degeneration compared with people who ate an average diet. And those who ate worse-than-normal diets, with low levels of those nutrients, actually had a 20 percent
increased
risk of disease. I highly recommend that anyone with a family history of macular degeneration follow the food plan for high-antioxidant, high-zinc foods to reduce their risk. For an easy way to get a large dose of all the nutrients, try one of my Smooth-SEE recipes (Chapter 11).
BEST FOODS FOR BETA CAROTENE:
Sweet potatoes, carrots, kale, winter squash (especially butternut), turnip greens, pumpkin, mustard greens, cantaloupe, red bell pepper, apricots, Chinese cabbage, spinach, lettuce (romaine, green leaf, red leaf, butterhead), collard greens, Swiss chard, watercress, grapefruit, watermelon, cherries, mangos, red ripe tomatoes, guava, asparagus, red cabbage
BEST FOODS FOR VITAMIN C:
Guava, bell peppers (red, yellow, green), orange juice, hot chile peppers, grapefruit juice, strawberries, pineapple, kohlrabi, papaya, lemons, broccoli
,
kale, Brussels sprouts, kidney beans, kiwi, cantaloupe, cauliflower, red cabbage, mangos, grapefruit (pink, red), white potatoes (with skin), mustard greens, cherry tomatoes, sugar snap peas, snow peas, clementines, rutabagas, turnip greens, tomatoes, raspberries, Chinese cabbage, blackberries, green tomatoes, cabbage, watermelon, tangerines, lemon juice, okra, lychees, summer squash (all varieties), persimmons
BEST FOODS FOR VITAMIN E:
Wheat germ oil, fortified whole grain cereals, sunflower seeds, almonds, hazelnuts, peanut butter, wheat germ, avocado, pine nuts, tomato paste, flaxseed oil, red bell pepper, canola oil, kiwis, peanuts, olive oil, mangos, turnip greens, Brazil nuts, asparagus, peaches, papaya, radicchio, collard greens, broccoli, Swiss chard, spinach
FAQS
My doctor suggested that I cut down on sugary foods to try to prevent cataracts. I’ve never heard that before—is it good advice?
Cutting back on sugary foods is always a good idea. Whether it will help prevent cataracts is a hot research topic right now. Some scientists from Tufts University analyzed data from AREDS and discovered that eating lots of low-quality carbohydrates increased the risk of cataracts by up to 50 percent. Low-quality carbohydrates are defined as sugary foods, white rice, and anything made with refined white flour, including crackers, breads, rolls, muffins, pasta, and other baked goods. The theory is that these foods quickly raise blood sugars to very high levels and that there’s a cumulative effect. In other words, the more low quality carbs you eat, the more you expose the lens of your eye to potentially dangerous levels of sugar. So if you want another fabulous reason to eat healthier foods—including more fruits, vegetables, and high-quality carbohydrates, such as whole grain food and brown rice—there it is.
ZINC
AREDS and the Rotterdam study confirmed zinc’s role in eye health. Zinc is found in the retina, and helps the functioning of enzymes responsible for eye health. In people with macular degeneration, levels of zinc in the retina can be very low, so eating zinc-rich foods is a logical first step for preventing and treating macular degeneration.
BEST FOODS FOR ZINC:
Oysters, lean beef, crab, ostrich, pork tenderloin, peanut butter, wheat germ, turkey, veal, pumpkin seeds, chicken, chickpeas (garbanzo beans), fat-free yogurt, fortified whole grain cereals, pine nuts, cashews, sunflower seeds, lima beans, lentils, pecans, cheese (fat-free, reduced-fat), fat-free milk, almonds, walnuts, peanuts, black-eyed peas, green peas
LUTEIN AND ZEAXANTHIN
Lutein and zeaxanthin are a matched pair of antioxidants—almost without exception, foods that contain one also contain the other. And they are found in high concentrations in the tissue of the macula. Because they absorb 40 to 90 percent of blue light intensity, these nutrients act like sunscreen for your eyes. Studies have shown that eating foods rich in lutein and zeaxanthin can
increase
the pigment density in the macula—and greater pigment density means better retina protection, and a lower risk of macular degeneration. At least one study has confirmed that eating foods with high amounts of these antioxidants seems to reduce the risk of developing macular degeneration.
BEST FOODS FOR LUTEIN AND ZEAXANTHIN:
Kale, spinach, turnip greens, mustard greens, Swiss chard, radicchio, collard greens, summer squash (all varieties), watercress,
green peas, persimmons, Brussels sprouts, broccoli, pumpkin, corn, lettuce (butterhead, Boston, Bibb, romaine), asparagus, green beans, okra, artichokes, green bell peppers, scallions, carrots
FAQS
Let’s say I try changing my diet to help my macular degeneration, when should I start to see results?
It varies from person to person. Some people might see a dramatic change after just one month, while others may only notice subtle changes, and still others may have to wait for their next ophthalmologist appointment when they are surprised to discover that they do better on the eye exam. But don’t lose faith—all those eye-healthy vitamins and minerals are also helping to keep the rest of you healthy, too!
OMEGA-3 FATTY ACIDS
Retinal pigment cells contain a type of omega-3 called docosahexaenoic acid (DHA), which helps protect light receptor cells in the eye from damage by sunlight and free radicals. In 2006, scientists speculated that fish oil and other sources of omega-3 fatty acids could be natural protection against age-related macular degeneration. If you want to take advantage of this research, I recommend eating two to three servings of fatty fish each week, and strive to incorporate the other omega-rich foods into your daily diet, too.