Pre-pubescent girls who consume more fibre in their diets can halve the risk of early onset of menstruation, according to scientists at the University of Toronto in Canada.
"The risk of early menarche for girls who consumed more than 25 grams of dietary fibre a day (by eating cereals, whole grains, vegetables and fruit) was approximately half that of girls who had less than 18 grams of fibre a day," said Malcolm Koo, a professor in public health sciences at the University of Toronto.
In a doctoral thesis, Koo studied the role of dietary fibre and its link to the onset of menstruation. The study, which took place from 1992 to 1996, involved 637 pre-menstrual girls in Ontario between the ages of six and 14. Information on dietary intake, physical activity, maternal history and date of menarche was collected. In the study, the age of menstrual onset ranged from 8.5 to 15.6 years with a median age of 13.6.
Oestrogen, a hormone that develops and maintains female characteristics, is known to bind with fibre in the body, Koo noted. Girls with higher fibre diets may be expelling more oestrogen which correlates with later onset of menarche. He also found that girls who consume higher amounts of monounsaturated fats in their diet (such as olive and canola oil) also experience later onset of menarche.
Early menarche (for girls 12 and under) correlates to a 10 to 15 per cent higher risk of breast cancer later in life. Evidence suggests that women who have been menstruating longer have increased breast tissue exposure to oestrogen, which is linked to an increased risk of developing breast cancer.
The study was published in a recent issue of Public Health Nutrition and funded by the National Cancer Institute of Canada.