A new analysis suggests that a diet high in animal products raises the risk of breast cancer, but exposure to sunlight offers protection.

Many studies have suggested a link between a high fat diet, rich in animal products, and breast cancer. Now William Grant, an independent researcher based in Virginia, USA, reveals that dietary differences might explain the geographical variation in breast cancer. Rates are high where the proportion of daily calories from animal products are high. And where vegetable products contribute relatively more to the diet, the rates of cancer tend to be lower.

It may be that high intake of animal products, and fat, cause higher levels of a molecule called insulin-like growth factor, and more of the female sex hormone oestrogen. Both can promote breast cancer.

Another factor important in cancer is exposure to sunlight. Having more UVB radiation, which means higher levels of vitamin D, seems to be protective. For example, mortality rates from breast cancer in the sunny southwest of the US are half those in the northeast. And in Europe, breast cancer rates go up with latitude, if dietary differences are taken into account. For more on how cancer mortality varies throughout the US, visit http://cancer.gov/atlasplus/type.html.

Source

Cancer January 1 2002