Diet and sunlight explain geographical variation in breast cancer

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Diet and sunlight explain geographical variation in breast cancer

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 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