Everyday ways to prevent breast cancer

But here's another statistic: almost 40 per cent of breast cancer cases can be prevented through lifestyle changes. This estimate comes out of a new report from the American Institute for Cancer Research (AICR) and World Cancer Research Fund (WCRF). The study is an update to the breast cancer chapter in the 2007 report Food, Nutrition, Physical Activity and the Prevention of Cancer: a Global Perspective. The initial project reviewed research from 873 studies about breast cancer prevention, including factors like diet, physical activity and weight. The new report factors in an additional 81 studies published in the last two years.

It's a lot of research to wade through -- that's why there's a panel of experts to make sense of it all. The goal of the project is to look at the data as the whole and pull out the proven strategies that people can use to reduce their risk.

Here are the panel's recommendations:

Maintain a healthy weight. We've heard it many times before: being obese or overweight is a risk factor for many diseases. When it comes to breast cancer, extra weight (particularly around the middle) is a risk for post-menopausal women. Lean is better, provided it isn't taken to the extreme of becoming underweight. (However, for pre-menopausal women, a little extra fat can be a good thing as it lowers risk.)

An excess of body fat affects the circulation of hormones, and makes ideal conditions for carcinogenesis. It can also stimulate the body's inflammatory response (which in turn contributes to cancer progression).

Exercise. Physical activity is important at all ages, but even more so after menopause. Previous research has shown that working out helps the body's immune system and reduces estrogen levels -- a known risk factor for breast cancer.