LONDON, Jan. 24 (Xinhua) -- Latest research findings have shown that a high-fiber diet could halve the risk of developing breast cancer for pre-menopausal women.

    Researchers at England's University of Leeds have been tracking the eating habits and health of more than 35,000 women for the past seven years and have found that younger women who eat a high-fiber diet appear to be protected against the disease at least until the menopause, the Independent national newspaper reported on Wednesday.

    The study led by Janet Cade found those with the highest fiber intake of 30 grams a day had a 50 percent lower incidence of breast cancer than those eating 20 grams a day.

    According to the study, the effect was only seen in pre-menopausal women up to the age of around 50. In post-menopausal women a high-fiber diet offered no protection.

    Of the huge group, 257 pre-menopausal women developed breast cancer during the study. These were shown to be women who had a greater percentage of energy derived from protein, and lower intakes of dietary fiber and vitamin C, compared to the cancer-free women, according to the researchers.

    Previous research has not shown a convincing link between increased dietary fiber and a lower risk of breast cancer, and did not draw any distinction between pre- and post-menopausal women.

    "Our study found no protective effect in the older group, but significant evidence of a link in the pre-menopausal women," Janet Cade who led the research was quoted as saying.

    The research suggests several possible reasons for this effect, including that high-fiber foods are rich in vitamins, zinc and other micro-nutrients which have protective anti-oxidant properties; that fiber can smooth out insulin levels in the body, a high amount of which is thought to be a possible cause of cancer; that dietary fiber regulates the levels of the female hormone oestrogen, which is implicated in breast cancer especially relevant to the pre-menopausal group who naturally have far higher levels of the hormone.

    The researchers do not yet know at which point in life dietary habits impact on a woman's susceptibility to breast cancer, suspecting that the relevant exposure may be earlier in life, explaining why the protective effect was not shown in the post-menopausal group.

    The researchers advise a high-fiber diet featuring breakfast cereal, bread, pasta, fruit and vegetables.