Food for the Prevention Cataracts; Several Studies Recommended
Cataracts are the primary cause of impaired visual acuity in the United States, while macular degeneration is the leading cause of irreversible vision loss, including blindness. Cataract, a clouding of the eyes' clear lenses, occurs when proteins in the lens change their structure due to UV-B light exposure and block light coming into the eye. Cortical cataracts affect the front of the lens. Curing two major eye diseases that cause blindness - macular degeneration and cataracts - may be accomplished by simple diet supplements.
Although no food will directly improve your vision, consuming certain foods regularly promotes optimal vision and can help prevent or slow the progression of some of the leading causes of vision loss. Mounting evidence suggests that many of these operations may be delayed or prevented if people consumed more fruits and vegetables and more of the antioxidant vitamins.
This particular antioxidant is not only found in some common foods, it's also manufactured inside your body. The problem is that when you're young, your body makes enough to meet your needs. As you get older, your body makes less. At the same time, you should need for it increases.
Much attention has been given in recent years to the supplement approach to preventing age-related macular degeneration (AMD), in particular to powerful carotenoid antioxidants lutein, zeaxanthin and astaxanthin.
Lutein and zeaxanthin occur naturally in the macula, where they absorb harmful blue light and protect tissues from the products of lipid oxidation. Astaxanthin, derived from microalgae, is very similar in structure to lutein.
Lycopene seems to protect against cataract development through its antioxidant properties, according to in vitro and animal research at the University of Maryland. They concluded "lycopene protected against experimental cataract through antioxidant properties, making it of potential use in preserving eye health by protecting against cataract formation".
The Harvard researchers, led by Dr William Christen stated that Women in the highest quintile of fruit and vegetable consumption were seen to have a 15 to 20 percent reduced risk of developing cataract, compared with those in the lowest quintile and have a strong biological basis and warrant the continued recommendation to increase total intakes of fruit and vegetables.
Vitamin E is a fat-soluble vitamin and important antioxidant that helps protect cells from everyday damage. For instance, it boosts the immune system and may reduce the risk of cataracts. Foods naturally rich in vitamin E include nuts, such as almonds, vegetable oils, seeds, wheat germ, spinach and other dark, green leafy vegetables.
Orange fruits such as peaches, apricots and Mandarin oranges are a good source of Vitamin A, which has the potential to reduce the risk of cancer; may prevent cardiovascular disease; and may improve vision and reduce cataract formation.
A study from Ohio State University provides the first laboratory evidence that certain antioxidants found in dark leafy green vegetables can indeed help prevent cataracts. Results from laboratory experiments on human lens cells shown that lutein and zeaxanthin, antioxidants found in plants such as kale, spinach and collard greens, helped to protect the cells from exposure to ultraviolet light – a leading cause of cataract formation.
Results from laboratory experiments on human lens cells showed that lutein and zeaxanthin, antioxidants found in plants such as kale, spinach and collard greens, helped to protect the cells from exposure to ultraviolet light – a leading cause of cataract formation. Lutein and zeaxanthin were nearly 10 times more powerful than vitamin E in protecting the cells from UV-induced damage.
Another study published in the journal Ophthalmology suggested that higher intakes of protein, vitamin A, niacin, thiamin, and riboflavin were associated with lower levels of nuclear cataract. Intake of polyunsaturated fats, found in vegetable oils, fish, and fish oils, was associated with reduced levels of cortical cataract. No nutrients were associated with posterior subcapsular cataracts." The only food associated with cataract prevention was spinach - perhaps due to its high content of a nutrient called lutein".
According to clinical researchers from the University of Southampton in England suggested that the risk of nuclear cataract was lowest in people with high plasma concentrations of alpha-carotene or beta-carotene, while those with high plasma concentrations of lycopene demonstrated a reduced risk of cortical cataract. Subjects with the highest lutein levels demonstrated the lowest risk of posterior subcapsular cataract. Researchers concluded that a diet rich in carotenoids may protect against cataract development, although they suggested further research would be needed.
According to a study done by Dr. G. Bhanuprakash Reddy; a senior research officer in national institute of nutrition (nin), India suggested that traditional dietary items can help reduce the problem of cataract in people. He told that spices such as turmeric, cloves, fenugreek, garlic, green leafy vegetables, amla, and bittergourd contain antioxidants have protective effects and if taken as part of one's diet, the incidence of cataract can be reduced.
Researchers led by Allan Taylor of Tufts University in Boston found that women who take vitamin C supplements during their younger and middle-age years may reduce their chances of cataracts later in life. They found that those whose blood samples registered high levels of the antioxidants were less likely to develop cataracts than those who had low levels of the antioxidants.
Lutein is an antioxidant phytochemical concentrated in the eye's retina. Eggs and cooked spinach are good sources of lutein. Spinach's rich stores of beta-carotene, an antioxidant thought to guard the eye's lens from cataract-inducing damage. That also makes carrots, sweet potatoes etc; according to British Medical Journal.
American Chemical Society's Journal of Agricultural and Food Chemistry research in animals suggested that both green and black teas significantly inhibited cataract formation relative to a control group which did not get tea. The researchers found that both teas decreased glucose levels, which in turn affects other biochemical pathways that accelerate diabetic complications such as cataracts.
In the 14-year study by U.S. Department of Agriculture (USDA) conducted on a cohort of 417 women aged 53 to 73 years from the Nurses' Health Study, scientists found subjects whose average carbohydrate intake was between 200 and 268 g/d were 2.5 times more likely to get cortical cataracts than women whose intake was between 101 and 185 g/d. The recommended dietary allowance for daily carbohydrate intake for adults and children is 130 g/d.
People who eat lots of yellow or dark leafy vegetables, as well as foods rich in vitamin E, may be reducing their risk of developing cataracts, according to new research published recently (Jan, 2008) in the Archives of Ophthalmology.
"Although definitive data to guide public health recommendations regarding these and other nutrients in the prevention of cataract will come from randomized trials, a continued recommendation to increase total intake of fruits and vegetables seems warranted," Dr. William G. Christen, from Brigham and Women's Hospital and Harvard Medical School, Boston, told Reuters Health.
Researchers have hypothesized that oxidative damage can lead to cataract formation and that nutrients with antioxidant capabilities, such as vitamin E, lutein and zeaxanthin, can protect against these changes, Christen and colleagues note in their report.
Lutein and zeaxanthin are the only carotenoids detected in the human lens and the oxidation products of lutein and zeaxanthin further support a role for these nutrients in preserving lens clarity, they also note.
Christen and colleagues studied the relationship between carotenoids and vitamin C and E in the diet and the risk of cataracts in 35,551 women who enrolled in the Women's Health Study in 1993 and who were followed for an average of 10 years.
In detailed comparisons of the diets of 2,031 women who developed cataracts with the diets of 33,520 women who did not, the researchers observed "significant inverse trends" in the risk of cataracts and dietary quantities of lutein, zeaxanthin and vitamin E.
Further analysis suggested women with the highest amounts of lutein and zeaxanthin in their diet (about 6,716 micrograms per day) had an 18 percent lower risk of cataract compared with those with the lowest amounts (about 1,177 micrograms per day).
Similarly, women with the highest dietary levels of vitamin E from foods and supplements (about 262.2 milligrams per day) were 14 percent less likely than women with the lowest levels (about 4.4 milligrams per day).
In this study, higher levels of vitamin C were associated with a "weak, and statistically no significant, inverse association with risk of cataract," the investigators also report.
These data, Christen and colleagues note, indicate a decreased risk of cataract with higher dietary levels of lutein, zeaxanthin and vitamin E.
Although reliable data from other studies are accumulating that confirm the value of vitamin E and other antioxidant vitamins, studies in which the subjects are randomly assigned to different levels of lutein and zeaxanthin are lacking, they note.
"Such information will help to clarify the benefits of supplemental use of lutein/ zeaxanthin," they add, "and provide the most reliable evidence on which to base public health recommendations for cataract prevention by vitamin supplementation."
The health publication notes that cataract surgeons no longer recommend waiting for a procedure until a cataract has "hardened" or matured. Instead, cataracts are surgically removed when vision problems caused by the eye's clouded natural lens begin to interfere with daily activities.
However, cautioned nutritional supplements can only delay and to a certain extent prevent cataract but only if given during the initial stage. Do not smoke. Wear a hat or sunglasses when you are in the sun, and avoid sunlamps and tanning booths. Eat healthy foods, and limit alcoholic drinks. Keep diabetes under control.
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