But the same researchers have warned that vitamin E supplements do not confer the same effect and could actually make women more susceptible to the effects of cholesterol.

The Michigan Department of Epidemiology's Dr Lori Mosca said: "It's possible that vitamins taken in supplement form may block some of the benefits of vitamins taken from food.

Heart attacks and strokes

"The best scientific evidence we have is that eating a diet rich in fruits and vegetables is protective against heart disease."

Vitamin E occurs naturally in nuts, vegetable oils and a variety of cereals.

The six-day study of 54 women discovered that the vitamin - when aborbed from food - acts as an antioxidant, reducing the effect on blood vessels of a type of cholesterol called low-density lipoprotein (LDL).

Oxidised LDL clogs vessels and can lead to blood clots that cause heart attacks and strokes - both of which can be fatal.

Larger quantities

The research found that the vitamin E supplements taken by women involved in the study were not effective. However, the pills only contained small amounts of vitamin E, leading the scientists to note that pills containing larger quantities could be beneficial.

Food elements that were not found to be useful in reducing the effects of LDL were beta carotene, vitamin C and folic acid.