Soy for Sight
Soy has some remarkable health promoting properties. It provides protease inhibitors that interfere with the growth of tumors; it contains weak estrogens that not only dull the symptoms of menopause but block breast and prostate cancer; and it provides genistein, an antioxidant that impairs the growth of tumor-causing blood vessels. Genistein also helps prevent retinal disorders and blindness in diabetics.Few people understand what it's like to lose vision except those who have already experienced the problem. Most of the time vision loss is insidiously slow, occurring with advancing age. Two-thirds of adults will experience vision changes due to aging of the lens of the eye during their lifetime. In fact, the focusing lens of the human eye loses about one percent of its clarity for every year of life so that by age 60 only about 35 percent of light reaches the retina. Brighter light is required to read in the adult years and glare begins to become a problem in sunlight. The transparent lens becomes translucent, like a stained-glass window. The lens of the eye may need to be replaced with a clear plastic lens, a cataract lens implant. About 1.5 million of these eye operations are performed annually and are quite successful in restoring clarity to the eye.For others, however, sight loss comes suddenly. Each year up to 6,000 middle to senior-aged adults wake up in the morning to find the vision in one of their eyes is gone, often diminished to the point where objects are just a blur. Even the big E on an eye chart can't be identified. It's a rude awakening that is quite stressful. Doctors call the problem anterior ischemic optic neuropathy, a medical term for mini-stroke of the eyes. Smokers, diabetics, and individuals with high blood pressure are most likely to experience this sudden loss of vision.Recent studies show that blood vessels may temporarily close in the retina, impairing the delivery of oxygen and nutrients to the optic nerve and retina. The resultant eye damage can be permanent. The reason why this eye trouble manifests during sleep is not well understood, but it probably occurs when tiny blood vessels spasm shut while the heart beat is slow and circulation is reduced.How Soy Protects SightResearchers at Johns Hopkins Medical School, the Wilmer Ophthalmological Institute, recently investigated dietary proteins in soy to see if they offered any protection to vulnerable eye tissues should an interruption in blood flow occur. In rodents the blood vessels that supply the eye were intentionally tied shut and then later re-opened and eye tissues were allowed to heal. What researchers found was that the retinas and optic nerves of those animals who were given soy proteins, called isoflavones, exhibited far less damage. Say researchers at Johns Hopkins: "Genistein from soy may be a promising agent for study not only for preventive effects on cancers but also the inhibition of nerve damage in the retina induced by inadequate blood supply."A very small amount of genistein, less than that ingested by Japanese men who frequently consume soy drinks, tofu or miso, is all that is needed to provide protection. Some nutritional supplement manufacturers already offer genistein in soy protein, either encapsulated or as a powder that can be added to foods. Carlson Laboratories of Arlington Heights, Illinois, is the first to include soy isoflavones in an antioxidant eye formula called Eye-Rite.Soy may also have other sight-preserving benefits, notably from its ability to raise "good" hdl cholesterol. A government health panel now suggests minimum hdl cholesterol levels of 35 and preferably above 60. Soy isoflavones raise "good" cholesterol by about nine points and reduce "bad" ldl cholesterol by about 15 points. hdl transports many antioxidant nutrients throughout the body, particularly lutein, a carotenoid pigment recently found to reduce the risk of macular degeneration and cataracts. Lutein is obtained from spinach and kale in the diet and is a yellow pigment that accumulates in the visual center of the eye, called the macula, where it protects photo-receptor cells from sunlight damage. A combination of soy and lutein in the diet would be ideal because more lutein would be transported to the retina and lens of the eye by virtue of soy's ability to increase hdl cholesterol. As estrogen output diminishes, postmenopausal females experience a drop in their hdl cholesterol and they experience a 400-500 percent increased risk for macular degeneration. This is an eye disorder, experienced as a weakening of central vision used for reading, that now affects nearly 12 million senior adults.The Eye/Cancer ConnectionSoy has been studied intensively for its ability to retard the growth of new blood vessels, a process called angiogenesis. New blood vessel growth, which normally occurs during wound healing, may abnormally occur in cases of cancer, diabetic eye disease, and advanced cases of macular degeneration.Solid tumors can't grow beyond 1-2 millimeters in size (about ten million cells) until they connect up to the blood supply via newly-formed capillaries. Once the connection is made, a tumor comes out of dormancy by obtaining nutrients from the blood stream. The tumor thrives and its host begins to lose weight and become starved of nutrients. More than a million Americans are believed to have dormant tumors in their body. Pharmaceutical companies are feverishly searching for the "anti-angiogenesis factor" that could quell tumor growth. Soy, which contains substances called protease inhibitors in addition to the antioxidant genistein, is a natural anti-angiogenic food. Genistein retards the growth of new blood vessels which growing tumors depend upon.Angiogenesis also occurs in diabetic retinopathy, where new blood vessels can grow across the visual center of the eye, the macula, and permanently impair vision. Genistein works in a similar manner to vitamin C and bioflavonoids, like bilberry and grape seed extract, which strengthen blood capillaries walls and retard hemorrhage or new blood vessel formation. In the 1930s Svent-Gyorgi, a Romanian researcher, discovered that vitamin C resolved cases of scurvy where hemorrhaging typically occurred in capillary-rich tissues such as the retina, lung, and kidney. Not all the cases of scurvy resolved until bioflavonoids were combined with vitamin C. Bottom line, soy combined with vitamin C and bioflavonoids puts a triple-whammy on cancer and retinal disorders.While the preventive properties of these antioxidant nutrients have been well-documented, the question arises, can existing tumors and eye problems be reversed? A recent study published in the Journal of Nutrition & Cancer addressed this point. Groups of ten hamsters were given a cancer-causing chemical. Among the group of ten hamsters who did not receive antioxidants, nine developed cancer. In the group that received vitamin C, eight developed tumors. Only half of the hamsters given glutathione, the master antioxidant produced within the body, developed tumors. Vitamin E and beta carotene separately reduced tumors to four in ten. But eight in ten hamsters were tumor-free when all four of these antioxidants were used. The results suggest that an array of antioxidants is more powerful. It also may explain why individual vitamin supplements don't always produce beneficial effects in clinical studies. This bears repeating: soy should be combined with other antioxidants for maximum protection.Glutathione: the king of antioxidantsWhile soy's disease fighting properties are remarkable, the body doesn't totally rely on antioxidants obtained from the diet. It makes some of its own, notably glutathione, which is 2400 times stronger in antioxidant power than superoxide dismutase and 14 times stronger than catalase, the other two prominent antioxidants made within the body. Virtually every life form, from insects to plant life to animals, depends upon glutathione.Glutathione is a master detoxicant with the ability to remove ddt; pcbs; toxic metals such as mercury, lead, and cadmium; and other poisons from the body. It even battles against the toxicity of cancer drugs, which causes a problem cancer doctors call "drug resistance."Glutathione is produced throughout the body but the liver is the only organ that produces a surplus supply of glutathione and, when needed, sends it to other tissues. For instance, low levels of glutathione in the aqueous fluid of the eyes leads to cataracts. Low levels of glutathione in the eye have been correlated with low levels in the liver.The consumption of glutathione in the daily diet ranges from 25-125 mg. Some foods, such as asparagus, grapefruit, avocado, and watermelon, provide about 30 mg. of glutathione per serving. While 50-250 mg. tablets of glutathione can be purchased in health food stores, glutathione itself is difficult for the body to absorb and process and dietary sources are paltry next to what the liver can produce daily--about 14,000 milligrams of this life-preserving antioxidant. The liver requires sulfur to produce glutathione. Sulfur rich foods are eggs, asparagus, garlic, and onions. Garlic also provides selenium which makes an enzyme of glutathione called glutathione peroxidase.Among food supplements, alpha lipoic acid is the ideal way to boost glutathione production in the liver and throughout the body because it is a small molecule that provides sulfur and it can penetrate past the blood-brain and blood-retinal barriers better than N-acetyl cysteine, taurine, or other sulfur-rich amino acids that can be acquired at health stores. In animal studies alpha lipoic acid has already been used to eradicate cataracts and overcome the symptoms of diabetes and is now being used in stroke rehabilitation programs.The body makes fewer antioxidants as we age. Ironically, that's the time when we need more antioxidants than ever to combat disease. Among the most powerful of the antioxidants are genistein from soy, bioflavonoids such as from bilberry and grape seed extract, lutein from marigolds, natural-source vitamin E, and alpha lipoic acid or sulphur to generate glutathione. Soy, spinach, kale, grapes, berries, eggs, garlic, onions, and asparagus head the list of foods that enhance antioxidant protection. These foods and food supplements can help to prolong useful years of vision, even reverse vision problems and help quell tumor growth.Bill Sardi is author of Nutrition & The Eyes, Health Spectrum Publishers, 8851 Central Avenue, G-620, Montclair, California 91763, 800-809-2219.