Eating more antioxidant-rich fruits and vegetables could be the cheapest and most practical means to delay cataract formation, report researchers from the US' Agricultural Research Service.
Several studies have shown that lutein, found in dark green vegetables, can slow the effects of age-related macular degeneration and support for ophthalmologic nutrition and epidemiology is becoming increasingly more established.
But it appears that lutein is not the only nutrient to impact eye nutrition. In a study on almost 500 women, those with the highest intakes of vitamins C and E, riboflavin, folate, beta carotene and lutein/zeaxanthin had a lower prevalence of cataracts than did those with the lowest intakes of the nutrients, according to ARS researchers. And those who used vitamin C supplements for 10 or more years were 64 per cent less likely to have clouded lens than those who never used vitamin C supplements.
The women, aged 53 to 73, had neither previously been diagnosed with cataracts nor diabetes. Food intake was assessed from questionnaires completed over 13 to 15 years.
Cataracts are caused by oxidative damage to proteins and other components inside the lens, causing it to gradually change from transparent to opaque. This obstructs the passage of light and impairs vision.
"As damaged proteins gather, they result in lens opacities," said lead researcher Paul Taylor. "The accumulation of oxidized or modified proteins we've observed is consistent with the failure of protective systems to keep pace with the insults that damage lens proteins."
The proteins in lens cells, called crystallins, act like fiber optics, allowing light to pass through the lens and onto the retina over a lifetime without repair. The lens also contains antioxidants, such as vitamins C and E and the phytonutrients lutein and zeaxanthin, which help maintain healthy cells and tissues in the eye and other organs.
The ARS team said a protective system including protein-digesting enzymes, which may seek out and destroy damaged proteins, as well as antioxidants, which can lessen initial damage and may keep protective enzymes functioning longer could be an effective way to reduce cataract formation.
Worldwide, the costs associated with cataract care, including disability and surgery, are now an estimated $6 billion annually.
Taylor and colleagues have previously shown that vitamin C reduced the risk of cortical cataracts in women younger than 60. The data also indicated that women who consumed higher amounts of carotenoids had a lower risk of cataracts if they had never smoked.
More on the current research is published in the August issue of Agricultural Research magazine.