When I was at medical school I learnt that blue eyes are associated with an increased risk of succumbing to the blood disorder pernicious anaemia. For years, I have taken comfort from the belief that having brown eyes afforded me some degree of immunity from disease. This month, however, new research has linked brown eyes with a substantially increased risk of cataract (cloudiness in the lens of the eye). While I and other dark-eyed folk might feel somewhat aggrieved at this fact, it turns out that even those with eyes of lighter hue are at significant risk of developing cataracts: almost everyone over the age of 65 has some degree of cataract formation, and the incidence of this condition is set to treble in the next 50 years. Fortunately, research suggests that upping our intake of certain foods and nutrients has the capacity to dramatically reduce cataract risk. For those of us who are keen to preserve our eyesight as we age, there really does appear to be light at the end of the tunnel.
In health, the lens in the eye is composed of a transparent, jelly-like material that is rich in protein. Over time, the protein in the lens may become damaged, causing it to become cloudy. This process is similar to the change that is plain to see when an egg white is cooked: while a raw egg white is transparent, it becomes opaque when the protein within it is damaged during the cooking process. The damage to the lens that can ultimately lead to cataract formation is wreaked by destructive molecules known as free radicals. Quenching free radicals is believed to be a key to reducing cataract risk.
Free radicals are neutralised in the body by substances known as antioxidants. Some antioxidants are manufactured within the body, but many come directly from the food we eat. Research has found that consuming foods rich in antioxidants known as carotenoids may protect against cataract development. While beta-carotene is perhaps the best-known carotenoid, its less celebrated relatives lutein (pronounced loo-teen) and zeaxanthin (pronounced zee-ah-zanthin) are believed to have a special role to play in terms of combating free radical damage in the eye. One food that is rich in both lutein and zeaxanthin is spinach. In one study, spinach was the food most consistently associated with a reduced cataract risk. Other veggies rich in lutein and zeaxanthin include leeks, peas, and cos lettuce.
While the right diet certainly has a role to play in preserving the health of the eyes, there is also evidence that supplementation with antioxidants such as vitamins C and E can help too. One study published in Archives of Ophthalmology last year showed that individuals taking a multivitamin and mineral containing either or both of these nutrients for 10 years or more enjoyed a 60 per cent reduction in risk of cataract. Another study published in American Journal of Clinical Nutrition found that taking vitamin C supplements for at least a decade reduced the risk of cataract development by a very impressive 70 per cent. The evidence suggests that eating our greens along with additional supplementation with a multivitamin and mineral supplement and 250 ” 500 mg of vitamin C each day can be an effective strategy for keeping our eyes clear of cataracts in the long term.