Wholemeal bread and wholegrain cereal could be key weapons in the battle against breast cancer.
New research from the University of Leeds has shown how eating more fibre – particularly cereal fibre – reduces the risk of developing breast cancer among pre-menopausal women.
Researchers at the University’s Centre for Epidemiology and Biostatistics have been tracking the eating habits and health of more than 35,000 women for the past seven years, and their latest findings are published in the International Journal of Epidemiology. Their figures suggest that among the pre-menopausal women, those who have the greatest intake of fibre have cut their risk of breast cancer in half.
The research is led by Professor Janet Cade, who explained: “Previous research hasn’t shown a convincing link between increased dietary fibre and a lower risk of breast cancer. But earlier studies didn’t 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.”
Of the huge group, 257pre-menopausal women have 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 fibre and vitamin C, compared to the cancer-free women.
The research, which received initial funding from the World Cancer Research Fund, suggests several possible reasons for this effect:
1. High fibre foods are rich in vitamins, zinc and other micro-nutrients which have protective anti-oxidant properties;
2. Fibre can smooth out the peaks and troughs in insulin levels in the body. High levels of insulin may be one possible cause of cancer;
3. There is a known link between breast cancer and the female hormone oestrogen, and dietary fibre has been demonstrated to regulate oestrogen levels in the body. This effect would be especially relevant to the pre-menopausal group who naturally have far higher levels of the hormone.
Said Professor Cade: “Also, we don’t yet know at which point in life dietary habits impact on a woman’s susceptibility to breast cancer. The relevant exposure may be earlier in life, explaining why the protective effect was not shown in the post-menopausal group.”
Whatever the precise cause, or combination of causes, the study does show a statistically significant effect – and supports the message of eating well to stay healthy. Professor Cade added: “It goes along with the general healthy eating advice to make sure that you are getting plenty of fibre in your diet through breakfast cereals, bread, pasta, fruit and vegetables.”
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Peer reviewed publication and references
International Journal of Epidemiology