The study, led by King’s College London, found that higher dietary intake of vitamin C has a potentially preventative effect on cataract progression in the first twin study of cataracts to examine to what degree genetic and environmental factors influence their progression with age.
The research looked at the progression of cataracts in the eyes of 324 pairs of female twins from the Twins UK registry over 10 years by examining photographs of the participant’s lenses that allowed them to analyse the level of opacity of the lens in detail. Participant intake of vitamin C was also measured using a food questionnaire.
They found that those participants who had a higher intake of vitamin C were associated with a 33 per cent risk reduction of cataract progression and had ‘clearer’ lenses after the 10 years than those who had consumed less vitamin C as part of their diet.
The study also found that environmental factors (including diet) influenced cataract more than genetic factors, which only explained a third of the change in lens opacity.
Lead author Chris Hammond said that the findings of this study could have significant impact, particularly for the ageing population globally by suggesting that simple dietary changes such as increased intake of fruit and vegetables as part of a healthier diet could help protect them from cataracts.
First author Kate Yonova-Doing noted, “The human body cannot manufacture vitamin C, so we depend on vitamins in the food we eat. We did not find a significantly reduced risk in people who took vitamin tablets, so it seems that a healthy diet is better than supplements.”
Limitations of the study include that the participants are predominantly of UK-origin and female, reflecting cataract progression between the ages of 60 and 70 years on average, so may not be generalisable.
The study is published in the journal Ophthalmology.