Macular degeneration is basically a breakdown of the support tissue that maintains the macula. It begins with the accumulation of waste and lipid deposits that clog this support tissue, making it impossible to keep the macula's rods and cone cells clean and supplied with adequate oxygen. Without adequate oxygen, the rods and cones eventually asphyxiate. In wet macular degeneration, abnormal, unstable blood vessels grow through the support tissue, probably in response to this lack of oxygen. Ironically, these vessels are prone to leaks, which flood the rods and cones with blood, asphyxiating them even more quickly. But why does this whole cycle of oxygen deprivation from accumulated waste and lipids begin in the first place? There are two prominent theories that answer this question:
1. Poorly Functioning Blood Vessels
In this scenario, the blood vessels supplying the macula's support tissue do not pick up waste efficiently enough or deliver oxygen consistently enough. As a result, the macula becomes clogged with waste and lacks adequate oxygen. The lack of oxygen kills the support tissue cells and then the rod and cone cells of the macula itself. In the case of wet AMD, new abnormal vessels grow in a kind of misguided effort to supply more oxygen. As we know, these new vessels are weak and prone to leaking, so all they actually wind up doing is wreaking havoc. The question becomes: Why do the original blood vessels become overwhelmed and fail to do their job? The answer may be that the job is too stressful because the waste is too hard to pick up.
2. Abnormal Waste Tips
In this scenario, the real culprit is damaged or abnormal waste. Rod and cone cells have disposable lipid (fatty) tips. When they process light and metabolize oxygen, the tips fall off as waste and new tips grow. Normally these tips are collected from the macula by the retinal pigment epithelium (RPE)--a layer of tissue supporting the macula--and transported on a "conveyor belt" to waiting blood vessels. These vessels flush the waste tips into the bloodstream. But abnormal waste tips lack the handles the RPE uses to identify them and drag them away, so they sit around, taking up space and making it difficult for the RPE to supply fresh oxygen deliveries. The lack of oxygen kills RPE cells and then the rods and cones. Of course, it may also trigger the growth of abnormal leaky blood vessels. The question in this scenario becomes: What is causing the waste tips to be abnormal?
So which scenario is it? We don't know yet; it may even be a combination of both. But either way, free radicals play a role. Understanding that role explains why age, smoking, blue or light-colored eyes, a family history, and our diets are all risk factors--and it tells us what we can do to reduce our risk.
Free radicals are oxygen molecules with an electron missing, which makes them unstable. Left to their own devices, free radicals cause trouble by reacting with other molecules in our bodies, preventing them from doing their jobs or actually destabilizing their structures. You may have heard of free radicals before, since they are now believed to play an important role in the development of certain cancers. Free radicals are a normal part of our system. We produce them as byproducts of oxygen metabolism. We metabolize a lot of oxygen in our maculae, so we produce a lot of free radicals there. Mother Nature has provided our bodies with a natural mechanism for handling free radicals. They are usually picked up and carried off by antioxidants, molecules we get from our food that are designed to pair up electrically with free radicals and neutralize them. So we are actually designed to handle a certain amount of naturally occurring free radicals. If this is true, though, how are free radicals contributing to cancer and AMD?
The problem is that pesticides, car exhaust, cigarette smoke, chemical food additives, household cleaners, and excessive unprotected sun exposure--which we wind up eating, breathing, and soaking up in record amounts--also produce free radicals. These free radicals are toxic to our eyes and to the rest of our bodies. They overwhelm our limited supply of antioxidants, especially if we aren't replenishing antioxidants by eating foods that contain them. When this happens, the free radicals are literally free to react with the cones in our macula, producing abnormal waste tips. These waste tips are called abnormal because they are thought not to have the characteristics of natural waste products produced in the eye. They don't look like waste and they don't act like waste, so they can't be grabbed by cleaner cells from the RPE, the tissue that underlies the macula, and carried away. Instead, they accumulate in permanent deposits that gum up the macula. Eventually, they back up the entire system that keeps the macula alive until it can't process any more waste or deliver any more oxygen. It's essentially the equivalent of putting steel ball bearings in a garbage disposal. Nothing happens to the bearings, but the disposal breaks.
Almost every single one of the risk factors we have for macular degeneration can be linked to free radicals. The older we are, the more exposure we've had to environmental toxins, so aging makes sense as a risk factor. The lighter our eyes, the less protective melanin (or pigment) they have to protect us from free radicals produced by the sun, so blue or light-colored eyes make us more vulnerable than brown ones. Dark green leafy vegetables are rich in the antioxidants that our eyes use to counteract free radicals, so a diet low in these vegetables would leave us more vulnerable. Smoking can be described as the activity of overloading our eyes with free radicals, since the chemicals in cigarettes are full of them. And an imbalance of oils in our body can lead to functional weaknesses and lackluster tissue that is generally ill-prepared to handle the free-radical onslaught of modern living.
YOUR FIVE-STAR PREVENTION PROGRAM
You can do five things to reduce your risk of developing macular degeneration or slow its progress if you already have it.
The First Star: Do Not Smoke
No one should smoke. If you don't smoke, don't start. If you do smoke, stop now. I know that quitting is incredibly difficult and smoking is a great pleasure. But smoking is terrible for your health and for the health of anyone who breathes your smoke. Smoking contributes to cancer, heart disease, emphysema, asthma, and macular degeneration. Smoking adversely affects blood circulation and blood vessel health, making wet macular degeneration more likely. And smoking overloads your eyes with free radicals using up the lutein, zeaxanthin, and vitamins C and E your eyes need to take care of the naturally occurring free radicals produced by oxygen consumption in the macula. Smoking also inhibits vitamins from being processed. I can't say enough bad things about smoking or breathing secondhand smoke, and I can't think of anything good about it, especially not for your eyes.
The Second Star: Wear Sunglasses with Blue Blockers
You are probably already aware of the importance of wearing sunglasses with ultraviolet (UV) light protection. This is important, since UV rays can contribute to cataracts. But extensive laboratory studies of primates provide persuasive evidence that blue light may be more damaging to the macula than UV light. Blue light waves are visible to us; they're what gives the sky or any other object its blue color. Blue light waves are also very short and scatter easily, so a great deal of the glare we experience from sunlight also comes from blue light. Blue blockers are simply a lens tint, usually an amber color, that blocks blue light rays. Unlike other tints, blue blockers don't make the world look darker because they still let in a considerable amount of light while blocking glare. For this reason, blue blockers were very popular a few years ago as sports sunglasses. Many people with macular degeneration find them particularly helpful regardless of their health benefits because they reduce glare indoors and outdoors while keeping the world bright and visible.
Blue light has been shown to cause a photochemical reaction that produces free radicals in the eyes of primates. Researchers believe that these free radicals may interact in human eyes with the high oxygen and lipid content of the rod and cone tips to produce abnormal chunks of metabolized waste. Melanin, the substance that gives eyes their color, protects the macula by capturing the free radicals produced by light and escorting them out before they cause damage to the macula. People with blue or light-colored eyes or fair skin have much less melanin than people with dark eyes. Light-colored eyes transmit up to 100 times as much light to the back of the eye as dark eyes do, and they have less melanin to absorb the light's radiant energy. If you have light eyes, you just weren't designed to take in a lot of sun.
Although the laboratory studies on animals seem nearly unanimous, the real-world studies on people have produced conflicting results. Some studies positively link macular degeneration with any kind of light exposure, while other studies have found a weak correlation. Yet another group of studies has found no correlation at all between macular degeneration and sunlight. One Australian study concluded that the problem may not be how much time you spend in the sun but how sensitive you are to sunlight. It suggested that people who have plenty of melanin and don't tend to burn easily are at less risk for macular degeneration than people who burn easily or are bothered by sun glare, but this study hasn't been replicated. We don't know for sure whether blue light contributes to AMD--but it appears likely. To protect yourself, especially if you have little melanin, wear blue blockers outside.
The Third Star: Eat Plenty of Dark Green Leafy Vegetables
You may have heard that some fruits and vegetables, such as blueberries, broccoli, and tomatoes, are particularly rich in antioxidants. Many cancer-prevention diets recommend broccoli especially. You are unlikely, though, to be eating vegetables that are rich in lutein, an antioxidant important for your macula. These vegetables are less popular and less familiar, particularly outside the South. They are the dark green leafy ones: kale, collard greens, mustard greens, Swiss chard, and spinach. Red peppers and romaine lettuce contain similar amounts of lutein. Johanna Seddon, M.D., and her colleagues at Harvard University first reported the benefits of these vegetables to our eyes in 1994. They found that people who ate at least five servings per week of dark green leafies had a 43 percent lower risk of macular degeneration than those who ate smaller amounts or none at all. While this study did not prove that eating vegetables will prevent AMD, its findings were striking enough to get everyone's attention. I wouldn't be surprised if subsequent studies substantiate Seddon's work in the next decade.
I recommend eating exactly what the folks in Seddon's study ate. To do this, you need to have at least five servings of dark green leafy vegetables per week totaling 15,000 micrograms of lutein per serving. A serving is approximately 3.5 ounces or three cups of greens uncooked. Since tallying thousands of micrograms and estimating ounces is an impossible task (we've tried it), we've found an easier way. On the chart below, 15,000 micrograms is roughly equal to five points. So if you eat any combination of dark green leafies that adds up to 25 points per week, you will get the right amount of nutritional protection and most likely decrease your risk of AMD.
We know that even with the best recipes, there may be times when you aren't able to eat enough dark green leafy vegetables to get all of your lutein for the week. Your local grocery store may not have good-quality produce in stock, or you may be too busy to plan and cook, or perhaps your job or lifestyle requires you to eat what a restaurant menu offers. If this is the case, try eating at least half of your lutein from fresh or frozen vegetables and getting the rest through supplements. There are a number of multivitamins and minerals on the market today that include lutein.
The Fourth Star: Choose the Right Oils and Eat Them in the Right Amounts
Late in 2001, Dr. Seddon and her colleagues at Harvard University reported another startling finding about nutrition and AMD. They found that people whose diets have the right ratio of omega-3 and omega-6 fatty acids have less macular degeneration than those whose diets are skewed. The real bombshell, though, is that most of us are eating skewed diets--very skewed diets. We get five times more omega-6 than we should and hardly any omega-3 at all. Since omega-6 and omega-3 compete with each other in our bodies, what little omega-3 we get hasn't got a prayer of protecting our retinas, which is one of its jobs. It turns out that the rods and cones of our macula need a certain amount of omega-3 to function properly. This may be a major reason that so many of us are winding up with accumulated waste in our maculae and AMD.
Fatty acids are fat molecules found in saturated fats such as butter and in unsaturated fats such as safflower and olive oil. We all know by now that if we eat large quantities of saturated fats, we'll clog our arteries and we'll wind up as candidates for a heart attack. As a result, many people have turned to vegetable oils for a healthier diet. But large quantities of common vegetable oils--like corn, safflower, and soybean oil--may increase our risk of macular degeneration because they are chock-full of omega-6 fatty acids.
You don't have to eat fried food or use lots of vegetable oil in your cooking to be getting too much omega-6, because these oils are key ingredients in just about every commercial food product on the market, especially low-fat foods such as crackers, sports bars, and microwave popcorn. I recently checked every label in a food mart and found that the only products in the whole store that didn't contain omega-6-rich vegetable oils were the ketchup, mustard, and relish. Everything else that came in a box, bag, can, or package contained omega-6 oils, including the Ben & Jerry's ice cream. To reduce your omega-6 consumption, therefore, you need to avoid packaged foods with vegetable oil listed in the ingredients.
Our Heroes: Olive, Canola, Fish, and Flaxseed Oils
The right ratio of omega-6 to omega-3 fatty acids is 3:1, which means that we need to consume approximately three times as much omega-6 as omega-3. So what oils should we use? The answer is monounsaturated oils, such as olive and canola oil for their omega-6 fatty acids, and fish oil and flaxseed oil for their omega-3 fatty acids.
OMEGA-6 FOR COOKING AND BAKING: OLIVE-, CANOLA-, AND OLEIC-RICH OILS
For cooking, use good-quality olive or canola oil. These oils contain high levels of oleic acid, a monounsaturated oil that tolerates heat and light much better than polyunsaturated vegetable oils do, so cooking won't significantly degrade its nutritional content. If you have a recipe that calls for another oil, check with your health-food store. Some of the companies that produce high-quality olive and canola oils also have lines of oleic-rich safflower, sesame, almond, corn, and peanut oils that you can use, especially for baking.
OMEGA-3 FROM THE SEA: FISH OILS
Cold-water fish, such as sardines, herring, and salmon, are good sources of omega-3 fatty acids. If you buy canned fish, choose it in spring water, not soybean oil, which has enough omega-6 in it to drown out the benefits of the omega-3 in the fish. Some health critics caution that ocean-caught cold-water fish carry high levels of industrial toxins in their fatty tissue. Farm-raised fish are safer, but they often have lower levels of fatty acids, so it's a trade-off. Many people prefer to forgo fish oils altogether in favor of flaxseed oil instead.
OMEGA-3 FROM THE LAND: FLAXSEED OIL
Flaxseed oil is one of the world's best sources of omega-3 fatty acids. It has a slightly nutty flavor that makes great salad dressing, especially when it's mixed with your favorite vinegar. Because flaxseed oil is extraordinarily sensitive to light and heat, it comes in a small black opaque bottle with its pressing date and expiration date clearly printed on the label. You can find flaxseed oil in the refrigerated section of a health-food or natural grocery store. Two of the best brands are Spectrum and Barlean's, which also market omega-3-rich Norwegian fish oil capsules. Be sure to store these oils in your refrigerator at home or they will spoil, and discard them after they have expired. To increase your omega-3 fatty acid intake, have a serving of fish or fish oil capsules or a tablespoon of flaxseed oil at least three days a week.
Avoid Junk Oils
No matter what type of oil you buy, avoid the ones in jumbo clear plastic bottles sitting on the grocery store shelves. They're full of off that's been torched within an inch of its life and has little nutritional content remaining. Oil manufacturers want products that never expire so they can sit in warehouses and stores for weeks or months before they're sold, and then they can sit in your kitchen for as long as you'd like. They never go bad. But food that never goes bad isn't food anymore. It's just an industrial invention masquerading as food.
Choose good-quality oils. A good-quality oil is one that hasn't been processed out of its natural state, so that it's still rich in nutrients and not chemically altered. Knowing it when you see it can be tricky. Oils that say "cold-processed" or "expeller-pressed"--processing methods that avoid heat--are better bets, as are oils with some natural color or with expiration dates, but it's sometimes hard to tell what's been heavily processed and what hasn't, regardless of what the label claims. Your best bet is to shop for oils at a health-food store or natural grocery that carries high-quality brands with good reputations in the natural-health community.
The Fifth Star: Take a Balanced Dose of Vitamins and Minerals
In 2001, the National Eye Institute (NEI) announced the results of its groundbreaking ten-year study of vitamins and macular degeneration, the AREDS (Age-Related Eye Disease Study). More than 3,700 people participated from around the country under the direction of the NEI's Division of Epidemiology and Clinical Research. This study proved beyond a doubt that vitamins work if you already have macular degeneration. In fact, they work so well that they can now be considered a treatment, along with laser treatment. The AREDS showed that people with moderate or advanced AMD who took beta carotene, vitamin C, vitamin E, zinc, and copper had a 25 percent lower risk of their macular degeneration progressing than those who took none of these. The AREDS was launched in 1992, before lutein and zeaxanthin were thought to be important nutrients for our eyes, so they were not included in the study, nor was selenium. It is possible that with these additional supplements, the success reported by the AREDS would have been even greater.
If you already have full-blown macular degeneration, it's essential to start taking a good-quality multivitamin and mineral supplement. If you are at high risk for macular degeneration or if you have early signs of it, supplements may help prevent its development or retard its progression, although this hasn't yet been definitely proven. Nevertheless, why wait? Now's a good time to choose a multivitamin and take it regularly.
AT THE VERY LEAST, GET THE BIG SEVEN
If you decide not to follow a nutrition program or plan, you should at least make sure you are regularly eating foods that give you a natural source of the big seven: beta carotene, lutein, vitamins C and E, selenium, zinc, and copper. To help you add these foods to your diet, here's a partial list of sources for these nutrients:
Beta Carotene--red peppers, carrots, avocados, asparagus, squash, sweet potatoes, nectarines, apricots, cantaloupe, mango, papaya, watermelon, kiwi, and dark green leafy vegetables
Lutein--kale, collard greens, mustard greens, spinach, parsley, Swiss chard, and romaine lettuce
Vitamin C--red and green peppers, broccoli, Brussels sprouts, turnips, cabbage, citrus fruits, cantaloupe, kiwi, and dark green leafy vegetables
Vitamin E--seeds, nuts, and whole grains
Selenium--wheat germ, oats and bran, fish, egg yolks, chicken, garlic, and red Swiss chard
Zinc--oysters and fish, pumpkin seeds, ginger root, pecans, and Brazil nuts
Copper--Brazil nuts, almonds, hazelnuts, walnuts, pecans
Wolf berry (Gou Qi Zi): China's Berry for Your Eyes
Wolfberry is a sweet mild fruit that the Chinese have used to ensure healthy eyes for nearly 2,000 years. Mark O.M. Tso, M.D., D.Sc., of the Wilmer Institute of Johns Hopkins University calls it the "Chinese chicken soup for the eye." Sure enough, Dr. Tso discovered that rats that eat these berries (which they love) do not suffer damage to their maculae when they are exposed to strong light, a strong sign of the preservative powers of zeaxanthin. Dr. Tso has launched a clinical study to discover whether wolfberry will also protect the maculae of humans, in hopes of developing a much-needed treatment for dry macular degeneration. Wolfberry may also have beneficial effects on the liver and immune system.
Dried wolfberries are small and sweet, like raisins. To find them, ask a Chinese grocery or certified Chinese medicine practitioner for Gou Qi Zi or contact a Chinese foods and herbs import company such as Rich Nature (www.richnature.com, 425-774-2266).
Bilberry: The RAF Pilots' Secret Weapon
During World War II a group of Royal Air Force (RAF) pilots demonstrated almost supernatural night vision by downing shadowy Luftwaffe fighters during pitch-black raids with devastating accuracy. Legend has it that the secret to their success was bilberry jam. Bilberry, a British cousin of the huckleberry, is said to enhance night vision and, because of its deep pigment and bioflavonoid qualities, may help repair eye conditions associated with cell damage. such as cataracts and macular degeneration. But limited studies conducted in the last ten years have not confirmed these claims. If you'd like to try bilberries, look for bilberry jam at your local specialty food store or natural grocery store and spread it on your toast in the morning.
Choose Any Combination of Lutein-Rich Vegetables That Adds up to 25 Points Per Week *
3 UNCOOKED GIVE YOU THIS CUPS OF MANY LUTEIN POINTS Kale or collard greens 7 Spinach, Swiss chard, or cress 4 Parsley (not dried) or mustard greens 3 Red peppers, romaine lettuce, beet greens, or okra 2 Broccoli (2 cups), peas (1/2 cup), or leaf lettuce 1 * If you eat fewer than 25 points per week, take lutein supplements or a multivitamin with lutein to make up the difference.