Children have a greater risk of developing asthma if their mothers have too little vitamin E during pregnancy, scientists have found. Researchers in Scotland discovered the link after conducting tests on 1,253 women and their babies over a five-year period.

The women were given blood tests and asked to fill out questionnaires to monitor their food intake at various stages of pregnancy. The researchers then looked at how many of their children went on to be diagnosed with asthma by their GPs.

The scientists divided the women in to five groups according to their vitamin E intake and compared them. They found women with the lowest vitamin E intake - between 3mg and 6mg per day - were five times more likely to have children with asthma than women in the group that had the most vitamin E.

"We know from animal studies that vitamin E influences respiratory development, so we suspect the same might be happening here," said Graham Devereux of Aberdeen University's department of environmental and occupational medicine, who led the study.

The study, published in the American Journal of Respiratory and Critical Care Medicine, cited vegetable oils, margarine, wheat germ, nuts and sunflower seeds as major sources of vitamin E.

Dr Devereux warned pregnant women not to attempt to boost their vitamin E levels during pregnancy by taking supplements because of concerns over high intakes of the vitamin.

"We believe vitamin E probably accounts for around 10% to 15% of the rise in asthma," he added.