A new study has verified the link between foods high in antioxidants and a lower risk of age-related cataracts.
Despite some inconsistencies, the findings overwhelmingly support the benefits of eating citrus fruits, capsicum, carrots, tomatoes and dark green vegetables such as spinach, broccoli and kale to delay the onset of these cataracts.
When the normally clear lens inside your eye becomes cloudy, this is known as a cataract. Having a cataract is like looking through a dirty window and it is a leading cause of vision impairment. While most cataracts are found in people aged over 50, cataracts can also occur at younger ages.
University of South Australia Senior Research Fellow Dr Ming Li and colleagues from Xi’an Jiaotong University in China said existing studies suggested that dietary vitamins and carotenoids might be associated with a reduced risk of age-related cataract.
They investigated these associations further by analysing 20 studies from around the world looking at the impact of vitamins and carotenoids (yellow to red pigments found in plants) on cataract risk.
Twelve of the studies were cohort studies, observational studies where certain cohorts or groups of people with something in common are followed over time and outcomes are compared in subsets. Eight of the studies were randomised controlled trials – the most rigorous way of determining if a cause and effect relationship exists.
The researchers concluded that higher consumption of certain vitamins and carotenoids was associated with a significant decreased risk of age-related cataract in cohort studies, but evidence from the randomised trials was less clear.
Their paper was published in the American Journal of Clinical Nutrition ahead of World Optometry Week last week, March 26-30.
“Age-related cataracts are the leading cause of visual impairment among the elderly throughout the world, with unoperated cataracts contributing to 35 per cent of all blindness,” Dr Li says. “Although cataract extraction surgery is an effective method to restore vision, it will have cost society more than $5.7 billion by 2020.”
The study claims this medical bill to restore sight for the estimated 45 million people with cataracts could be slashed in half by a diet rich in colourful fruits and vegetables. Researchers said that with the population ageing and more people needing surgery, urgent action is needed.
“If we could delay the onset of age-related cataract by 10 years it could halve the number of people requiring surgery,” they said.
Current global consumption of antioxidants, however, is well below the recommended level to prevent age-related cataracts.
And in Australia we have a long way to go. The largest ever study in Australia of our fruit and vegie eating habits - a CSIRO study of 145,000 adults over 18 months - found that half aren’t eating the recommended two serves of fruit per day and 66 per cent aren’t eating the recommended five servings of vegies a day.
One tip to improve vegetable consumption is to eat three types of vegies with your evening meal.
More than 700,000 Australians have cataracts and that number is expected to rise substantially with the ageing population, according to the Medibank Better Health Index. Cataract removal is also one of our most common elective surgeries.
Read more about cataracts here.