Beta carotene and vitamin C and E supplements failed in preventing cancer in women, the authors of a new study wrote in the Journal of the National Cancer Institute.

These negative findings came after two other studies that also centered on the supplement forms of the vitamins, and which suggested as well that they weren’t able to prevent the development of cancer.

Many studies have demonstrated that people who eat a healthy diet, rich in fruits and vegetables, are less prone to develop the deadly disease. But this benefit of lowering cancer risk doesn’t apply to supplements, said Dr JoAnn Manson, who led the research for Harvard Medical School in Boston, America.

Over 8,100 women aged 40 or more took part in the study. They were all given one of the supplements, a mixture of the supplements or a placebo. The supplements were 500 milligrams of vitamin C, 50 milligrams of beta carotene and 600 IU (International Units) of vitamin E.

After an average of 9.4 years' follow-up, researchers found that 624 of the participants had developed cancer and 176 died of it. "Simply taking antioxidant supplements is insufficient to prevent cancer development," said Jennifer Lin, PhD, of the division of preventive medicine at Harvard Medical School and Brigham and Women's Hospital in Boston.

On the word of Lin, the justification for the ineffectiveness of the pills could be the fact that all women in the research were well-nourished. The vitamin supplements could be more effective in patients whose diets don’t provide them enough nourishment, she added.