A diet rich in green, leafy vegetables such as spinach may help reduce the risk of blindness among the elderly, a major study has concluded.

These vegetables are rich in certain carotenoids which appear to slow the development of AMD (age related macular degeneration), the leading cause of blindness in people over the age of 65.

Researchers believe it is the elements in the vegetables called lutein and zeaxanthin that may help prevent AMD. This would mean that carrots, the most common of the carotenoid family called beta carotene, would not work as a preventative because they are very low in those elements.

If this is true, other vegetables such as kale, mustard greens and turnips would also help fight AMD, although they were not tested by researchers.

They also believe that high intakes of vitamin C, preferably through foods, may also help. A diet rich in the entire antioxidant family of A, C and E may provide protection, but it could be because of another nutrient found in the foods, rather than the antioxidants themselves. This means that supplements would not help.

The study team, known as the Eye Disease Case Control Study, led by Dr Johanna Seddon, discovered that smokers were at the highest risk of developing AMD, although that risk was reduced if the smoker had high intakes of lutein and zeaxanthin.

They examined 356 people with advanced AMD against 520 people with other eye diseases. Those in the group with the highest intakes of carotenoids were 43 per cent less likely to develop AMD than those with a diet low in carotenoids (JAMA, 9 November 1994).

Carotenoids may also reduce the risks of heart disease, especially among nonsmokers. This finding, by a research team from the University of North Carolina, puts carotenoids back on the map after beta carotene had been found by earlier studies not to be a preventative.

But the North Carolina team has discovered that beta carotene accounts for only 25 per cent of the carotenoids found in the blood. They tested the serum of 1,899 men without any known major illnesses, such as heart disease. Men with the highest levels of carotenoids had a risk of just 0.64 per cent of developing a heart condition, and this fell further to 0.28 per cent among those who did not smoke.

!AJAMA, 9 November 1994.