Suffering from cataracts is often considered part of growing old, together with loss of memory, arthritis and all the other ailments of aging.
However, recent evidence has suggested that common prescription drugs may be responsible for a significant amount of cases, rather than the inevitability of old age.
Two studies published a couple of months apart have revealed that taking certain anti-depressants or hormone replacement therapy can dramatically increase the risk of cataracts. In addition, researchers also found that a healthy diet can offer powerful protection against cataracts.
Scientists from the University of Wisconsin’s Department of Ophthalmology and Visual Sciences found that women who ate foods rich in vitamins and minerals were less likely to develop nuclear cataracts (those forming in the centre of the lens), which is the most common form of cataracts.
The study involved over 1,800 women aged between 55 and 86. The daily diets of these women were assessed according to their responses to a food frequency questionnaire (the 1995 Healthy Eating Index, HEI), while the presence of nuclear cataracts was determined four to seven years later.
A high HEI score was the strongest modifiable predictor of a low prevalence of nuclear cataracts. To contribute to the high score, the diet included intakes of the recommended (or higher) levels of vegetables, fruits, grains, beans, fish and other healthy foods. In addition, lower levels of fat, saturated fat, cholesterol and salt.
The high HEI score participants were found to have a 37 per cent lower risk of developing cataracts than those with the lowest HEI scores. The conclusion was that eating foods rich in vitamins and minerals may postpone the onset of cataracts (Arch. Ophthalmol., 2010).
In addition, there is evidence to suggest that specific nutrients might be especially helpful in warding off cataracts. In an earlier study, it was found that women with high dietary intakes of lutein and zeaxanthin, which are found in dark green leafy vegetables, kiwi fruits, grapes, corn and egg yolk, had a 23 per cent reduced prevalence of nuclear cataracts, compared to those who had a low intake of these foods.
Another study carried out in Australia with more than 2,400 older adults found that higher intakes of vitamin C (from both food and supplements) or combined intake of multiple antioxidants (vitamin C, E, beta-carotene and zinc) significantly reduced cataract risk (Am, J. Clin. Nutr., 2008).
Oxidative stress is thought to play a significant role in the formation of cataracts, so it makes sense that antioxidants can be protective as they mop up free radicals which damage proteins and fibre cells in the lens.
Other lifestyle habits also contribute to cataracts. Smokers, for example, are more likely to have cataracts. It is thought that the cadmium in cigarettes accumulates in the lens and causes damage.
Also, cigarette smoke is rich in free radicals, among other things, so it could also be that smoking depletes levels of protective antioxidants (Br. J. Ophthalmol., 1998).
Being overweight appears to have a connection too. Researchers at Harvard University have found that people with a body mass index of 30 kg/m2 or more increased their risk of cataracts by at least a third compared to those with a BMI of 23 kg/m2 or less.
Drinking in moderation is advisable, according to researchers who carried out a 10-year study in Australia. They found that people who drink more than two standard alcoholic drinks per day, or were total abstainers, were significantly more likely to undergo cataract surgery compared to moderate drinkers. In this study, moderate drinking was associated with a 50 per cent lower incidence of cataract surgery (Am. J. Ophthalmol., 2010).
A recent study reported that vigorous exercise can protect against cataracts. The researchers found that men who ran 64 km per week, or more, had a 35 per cent lower risk of developing cataracts compared with men who ran less than 16 km per week.
Using a comparison of fitness, it was also found that the fitter men had only half the cataract risk of those who were least fit. (Invest. Ophthalmol. Vis. Sci., 2009).
Long-term, low-level exposure to toxic metals (lead in particular) results in their accumulation in the lens.
This build-up increases the oxidative burden, thus leading to cataracts (JAMA, 2004).
When Japanese researchers reviewed studies carried out in Japan, Iceland, Australia and Singapore, they found that those exposed to the highest levels of sunlight also had the highest incidences of cataracts.
Some natural treatments everyone can take are bilberries. They have proved to be rich in potent antioxidants with a particular affinity for the eyes.
In a report of 50 patients with senile cataracts, a combination of bilberry and vitamin E for four months stopped the progression of cataracts in 96 per cent of the treated patients compared with 76 per cent of the control group (Altern. Med. Rev., 2001).
Vitamin E was also tested on its own in a randomised controlled trial.
This also showed a significantly smaller increase in the size of the cataracts in the outer rim of the lens in the vitamin E group.
As a result of this research, we can consider that cataracts are not necessarily inevitable and we can change our lifestyle to help our sight.
kathryn@maltanet.net