Glen M. Swartwout, A.B.,B.D., N.D., O.D., F.I.C.A.N.,
F.C.S.O. © 2000, 2001, 2002
AERAI-Publishing: Hilo, HawaiÕi-Kingdom
Cataracts are a loss of clarity in the tissue of the crystalline lens of the eye affecting about 4 million Americans. The average amount of light able to penetrate the lens of the eye at age 80 is only 25% of the level at age 20. Cataracts are the number one cause of vision loss and blindness in the States. 600,000 eye surgeries each year make cataract operations the most common of all the major surgical procedures in Medicare. Eye surgery accounts for about $3.5 billion in costs through Medicare, more than any other surgical specialty. Worldwide, cataracts are the leading cause of blindness, and are projected to blind 40 million people by the year 2025. 15% of people are affected by age 55, and 50% of people are affected by age 75. Also, about 60% of the elderly are forced to avoid night driving due to cataracts.
Most of this appears to be preventable and most cataract patients are in a good position to focus on prevention. Only 3.3% meet the current guideline of 20/50 or worse visual acuity for recommending cataract surgery. A healthy 91.7% even retain vision of 20/25 or better and have the highest likelihood of success with preventive measures. Because doctors themselves lack training in nutrition, most cataract patients are not presented with the existing research in prevention and reversal of cataracts. In fact, only 5% of eye surgeons even believe that it is very likely that anti-cataract compounds could be developed in the future. Impaired visual performance is known to begin at 20/30 or worse acuity in one eye, since there is 3 times the normal rate of falls resulting in hip fracture at this level of visual impairment. This is a risk following cataract surgery as well, due to a sudden change in magnifaction of the entire visual field of one eye. In addition, 8% of patients going through cataract surgery experience complications according to researchers at Harvard Medical School. Beyond all this, the average patient lives only 5 years following cataract surgery. Obviously, surgery does nothing to actually promote health or longevity. Nutritional and other preventive measures, in contrast, produce many side-benefits, including the potential of certain supplements including Vitamin C and Chromium to significantly increase life expectancy.
The tissue changes involved in various types of cataract formation include fibrous metaplasia of the lens epithelium (in posterior synechia following iritis), liquefaction of lens fibers (in cortical spoking and water clefts representing about 75% of cataracts), sclerosis of fibers (in nuclear cataracts, representing about 25% of cataracts), and posterior migration and swelling of epithelial cells (in posterior subcapsular cataracts, or PSC). Brunescent cataracts involve yellowing of the lens due to deposition of fat soluble waste material called lipofuscin related to inability of the liver to break down and eliminate fat soluble toxins.
Among the potentially toxic compounds observed to trigger cataracts include: naphthalene (moth balls), acetone, dinitrophenol (formerly approved for weight loss), cresol and paradichlorobenzol (insecticide) as well as numerous chemicals and solvents. Many drugs can contribute to cataracts, including tranquilizers, radiomimetic drugs, myleran, nitrogen mustard, triethylene melamine (TEM), quinoline, trenimon, endoxan, methotrexate, mevacor, mimosine, corticosteroids (such as prednisolone and cortisone), oral contraceptives, miotics such as pilocarpine, used to treat glaucoma, DFP, phospholine iodide, mintacol, tosmilen, iodoacetic acid, triparanol, dibromomannitol, pantocain, ergot, sulfanilamide, streptozotocine, methoxsalen, accutane. About 25% of cataract patients are on diuretics such as thiazide, which deplete vitamin C and other water soluble antioxidants, while also combining with sunlight to damage and discolor the lens. Among the drugs that have been used to treat or prevent cataracts are: aspirin (not recommended due to side effects; see also herbal section on willow) and catalin (a Japanese eyedrop).
Smoking over a pack of cigarettes a day increases cataract risk by 205% compared to not smoking at all in men and increases the risk by 63% in women. Quitting smoking alone, without detoxification, however, does not appear to completely eliminate the risk. Former smokers still show a 40% elevated risk of posterior subcapsular cataracts in men, and womenÕs risk of cataract doesnÕt decrease even 10 years after quitting. Smoking causes increased lipid peroxidation and depleted antioxidant levels. Low dietary intake of antioxidants further increases the risk posed by smoking. It is estimated that smoking causes about 20% of all cataracts. Herbal programs for smoking cessation have been developed which have proven to be 99% effective for quiting smoking in just one week.
Mercury appears to be a very common trigger. Mercury binds to sulfhydryl groups, including those in the antioxidant enzyme glutathione peroxidase especially needed to protect the lens from free radicals produced by light, since the eye tissue is the only tissue in the body other than the outer layers of the skin which is not protected from the oxidative effects of light by the pigment melanin. A sunglass lens containing melanin has been developed. Another key sulfhydryl group attacked by mercury is found in the enzyme Na,K-ATPase. This enzyme is responsible for pumping fluid out of the lens to maintain a state of relative dehydration necessary for the maintenance of clarity of the lens. When this enzyme is poisoned, the lens swells up with excess water and becomes cloudy. Mercury is retained in the lens longer than any other tissue. Young people with diets low in carotenoids, yet who frequently consume large, long-lived predatory fish which accumulate high levels of methyl mercury, such as tunafish, swordfish, shark, mahi mahi, striped bass and pike show an increased risk of posterior subcapsular cataracts. Methyl mercury can also increase risk of progressive nuclear cataract formation. Other important protective enzymes affected by mercury include SOD, catalase, and G-6-PD.
Other heavy metals are found at increasing levels
in the lens with aging and cataractogenesis, including cadmium, bromine,
cobalt, iridium, and nickel. Cadmium is 2 to 3 times higher in lenses
with cataracts than in clear lenses of the same age. Cadmium displaces
zinc, and like mercury, binds to sulfhydryl groups, thus potentially deactivating
antioxidant functions as well as the Na+, K+ -ATPase pump. Cadmium
can come from cigarette smoke, which has been shown to cause cataracts.
Additional minerals which in certain forms and dosages can become toxic and cause cataracts include: thallium, zinc sulphate, cobalt chloride, sodium selenite, copper, iron, lead, silver and gold.
Oral or intravenous chelation with EDTA or vitamin C may be beneficial to help eliminate heavy metal accumulations.
Lactose, found in dairy products, can contribute
to cataracts, destroying glutathione and vitamin C levels in the lens.
Lactose is a disaccharide comprised of galactose and glucose. Galactose
is known to cause cataracts, as in galactosemia. High galactose diets cause
cataracts in animals. In one population, 22% showed difficulty handling
lactose, but over 50% of those in the same population who also have cataracts
are in this category. About 30% of all cataracts may be affected by this
factor. 47% of people with presenile cataracts have genetic problems
with galactose metabolism. Live culture yogurt, because of its beneficial
bacterial content, is a preventive factor against cataract.
Monosaccharides D-glucose, D-galactose (see above), D-xylose, and L-arabinose are know to be cataractogenic, and should be restricted in the diet. They enter the lens from the aqueous humour and, since they are not efficiently metabolized by the lens with its very low metabolic rate, produce alcohols which do not diffuse easily out of the lens. For example, glucose forms sorbitol, and galactose forms galactitol. These waste products accumulate, osmotically drawing excess fluid into the lens and eventually disrupting the crystalline lattice structure and rupturing lens fibers. Even subtle deficits in sugar regulation can increase the risk of cataract. Impaired glucose tolerance is common among the elderly and can be improved nutritionally.
A similar blockage in the movement of fluids in the eye area can be related to glaucoma, as well as being frequently triggered by focal disturbances of health in the dental area. Injuries in the vertebrae or musculature of the neck can likewise contribute to a drainage ÔbottleneckÕ for the eyes, and thus promote cataracts. Excellent lymph drainage remedies are available, such as Energessence and Lymphomyosot. Stress from any source, and particularly visual stress, also greatly inhibits drainage from the eyes by reducing eye movement and increasing muscle tension in the eyes, face and cervical spine. Body and eye movement along with drinking BEV quality filtered or ionized water are critical to maintaining efficient drainage of toxins and wastes from within the eyes. Exercise also helps improve the body mass index, which reduces cataract risk. Rebounding, which is bouncing on a mini-trampoline, is an excellent form of gentle exercise that stimulates lymphatic drainage of the entire body without stressing the joints or cardiovascular system.
Beneficial foods may include those high in sulfur-bearing amino acids, such as garlic, onions and beans. Foods high in beta-carotene, such as the yellow and orange vegetables are also recommended, as well as foods high in vitamins C and E. Eating more than 3.5 servings a day of fruits or vegetables increases vitamin C intake and reduces the risk for both cortical and subcapsular types of cataract. In one study, spinach was found to be the most significant single food in preventing cataracts, and it provided more beta-carotene than carrots. Another study found lower cataract incidence in elderly beer drinkers, perhaps due to the circulatory benefits of small amounts of alcohol. Larger amounts of alcohol, over 7 drinks a week, increase cataract risk. Other foods that have been suggested include fish, eel, celery, green leafy vegetables, seaweed, citrus, brewerÕs yeast, sprouts, apples, carrot juice and potassium (vegetable) broth, oranges, carrots, tomatoes, cabbage, turnips, green vegetables, (free-ranging) eggs and (raw, unpasteurized) milk. Sardines contain beneficial nutrients such as essential fatty acids, but also contain lipid peroxides, which may increase cataract risk when catalase or vitamin E is low.
It is clearly beneficial to maintain a low calorie diet. Animal studies show that cutting calories 20 to 40% results in 30 to 50% reduction in cataracts, as well as a 30% increase in longevity, increased immune function and decreased risk of cancer. Foods should be whole as much as possible, since the ratio of processed or refined carbohydrates to complex carbohydrates is a risk factor for cataract.
Socioeconomic and educational factors are related
to cataract incidence, perhaps through their effects on diet and health
habits, as well as stress and exposure to toxicity.
Next we will look at research on the role of specific nutritients and remedies in cataract prevention and reversal.