Lower risk of breast cancer through diet and exercise
Women who lose weight by combining physical exercise and eating less reduce the risk of breast cancer more than women who lose a lot of weight simply by dieting. This is evident from research carried out by Willemijn van Gemert who obtained her PhD on January 22, 2015, at the UMC Utrecht Julius Center in the Netherlands. Her research focused on post-menopausal women.
A total of 243 healthy, overweight women between the ages of 50 and 69 participated in the SHAPE-2 study. Of these women, 97 went on an energy diet for 16 weeks and 98 participated in an intensive four hour per week sports exercise program combined with a less stringent diet. The aim for both groups was to lose five to six kilograms of body weight. The remaining women formed a control group that made no attempt to lose weight. The researchers were particularly interested in the concentration of sex hormones such as estrogen and testosterone, since a high concentration of these hormones is related to a higher risk of developing breast cancer.
The women who dieted lost an average of 4.9 kilos, while those who combined diet and exercise lost 5.5 kilos on average. That amounts to six to seven percent of their starting weight. The weight loss resulted in all women in favorable changes in the concentration of sex hormones. The concentration of several hormones, among which testosterone, among the women who practiced sports dropped more than among the women who only dieted. The amount of body fat also decreased more in the women in the sports group, they maintained their muscle mass and they felt fitter. The favorable effect on sex hormones is mainly due to the greater decrease in the amount of body fat, concludes the researcher. “We advise women who struggle with their weight after menopause to lose weight especially by exercising and in combination with a light diet,” says Van Gemert.
In her thesis, the PhD student also calculated that a quarter of the total number of breast cancer cases among postmenopausal women in the Netherlands is due to lifestyle. Other risk factors for postmenopausal breast cancer besides obesity and too little physical exercise include smoking, alcohol consumption and a low fiber intake.
Source: UMC Utrecht