A good intake of B vitamins can protect your eyesight by preventing cataracts. A cataract is an opacity in the normally crystal-clear eye lens, caused by changes in lens proteins that are similar to those which make a cooked egg white turn cloudy. This opacity results in blurring, sensitivity to sun glare, changes in colour perception, and seeing a halo around lights.
What causes cataracts?
Most people over the age of 65 have some degree of cataract, which progresses with age. The development of cataracts is linked with:
- Exposure to ultraviolet light
- A career working outdoors
- Having light-coloured eyes
- Having laser eye surgery (which thins the cornea)
- Taking certain drugs which increase sensitivity to sunlight (eg tetracyclines, phenothiazines, psoralen, allopurinol),
Previous research has shown that people with the highest dietary intakes of antioxidants such as vitamin C, vitamin E, selenium and carotenoids (eg lutein, zeaxanthin and lycopene) from fruit and vegetables have the lowest risk of cataracts.
Diet and cataracts
Dark green leafy vegetables (eg spinach, kale, watercress), broccoli, carrots and other yellow-orange fruit and vegetables are especially beneficial as they contain carotenoid pigments such as lutein and zeaxanthin. Research involving almost 77,500 female nurses found that, after age, smoking, and other potential cataract risk factors were controlled for, those with the highest intakes of lutein and zeaxanthin were 22% less likely to develop cataracts severe enough to require extraction than those with low intakes.
In another study involving over 50,000 nurses, those who’d taken vitamin C supplements for ten or more years were up to 45 per cent less likely to develop cataracts than those who didn’t taking vitamin C supplements.
A small trial involving 50 people with age-related cataracts found that bilberry extracts plus vitamin E stopped cataracts progressing in 97% of cases due to their antioxidant action.
Researchers have now unexpectedly found that good intakes of B vitamins are also associated with a reduced risk of cataracts.
In the AREDS study, involving 3,115 people aged 55 to 80, who were followed for almost ten years, those with the highest dietary intakes of riboflavin (vitamin B2) were 22% to 38% less likely to develop mild to moderate cataracts than those with the lowest intakes. Similar results were seen for vitamin B12 and vitamin B6.
Why do B vitamins protect against cataracts?
The exact reason why B vitamins protect against cataracts is unknown, as they are not highly oxidant like vitamins C and E. Their protective effect is believed to result from the important role that B vitamins play in energy production, and from the role they play in red blood cell formation.
To reduce light scattering, lens cells lack a nucleus, and the lens does not contain any blood vessels. Lens cells must therefore obtain their supplies of oxygen and nutrients by diffusion from the eye fluids in which the lens is suspended. This leaves the cells particularly vulnerable to nutritional deficiencies such as a lack of the B vitamins needed for energy production.
Vitamin B2 (riboflavin) food sources include yeast extract, whole grains, eggs, dairy products, green leafy vegetables, beans and fortified cereals.
Vitamin B6 is obtained from whole grains, liver, meat, oily fish, soy products, bananas, nuts (especially walnuts), green leafy vegetables, avocado and egg yolk. Yeast extracts and royal jelly are also good sources.
Vitamin B12 is found in liver, kidney, oily fish – especially sardines – red meats, white fish, eggs and dairy products.
Cataract prevention checklist
- Wear sunglasses to protect your eyes from harmful UV rays, especially if you have light coloured eyes and have had previous laser eye surgery. I tick the box on both of these, and wear my sunglasses all year round.
- Only buy sunglasses whose label states: ‘100% UV protection’, ‘Lenses block UVA and UVB rays’, or ‘Full UV400 protection’ (NOT vague claims such as ‘UV absorbing Lenses’ or ‘Blocks most UV light’).
- Wrap-around sunglasses help to prevent reflected light from entering at the sides.
- Kids should always wear sunglasses in bright light, as their crystal clear lenses let in more UV light.
- When working outdoors, wear a wide-brimmed hat or a baseball-cap, even on cloudy summer days.
- Have regular eye tests.
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