Another link between diet and cancer

First of all, I should share that I am not a vegetarian. However, I also have to admit that I’m not a big fan of beef, although I will eat it. I graduated from a vegetarian university, however, and learned all the science behind why we should limit (or, for some people, avoid) beef from our diet. As I progressed in my practice and became more educated on functional nutrition and the more detailed science behind how the substances in beef react in the human body, I am more discouraged from eating beef. But at least this last study makes me feel ok, because although I do eat it, it is in very limited and small amounts, on a very infrequent basis.

This newest study is part of the Nurses Health Study II, which followed over 90,000 pre-menopausal women for 12 years. Although researchers found no relation between red meat consumption and overall breast cancer risk across time, when they did an analysis of breast cancers fueled by the hormones estrogen and progesterone, they did find a link. After adjusting for established risk factors, they found that the women who reported eating over one and a half servings of red meat per day had almost twice the risk of cancer, compared with women who reported eating three servings or less of red meat per week.

There is still debate over what exactly causes this increase. There are three current theories: First of all, previous studies have suggested that one reason for the increased cancer risk has more to do with the heterocyclic amines (HCAs) that form when red meat is cooked at high temperatures to very well-done status, such as when grilled or fried. In lab studies, HCAs bond to estrogen receptors and create estrogen-like effects. Earlier studies have shown that post-menopausal women who consistently ate hamburger, beef steak and bacon, very well-done, and were getting very high levels of HCAs, they had over four times the breast cancer risk than women who ate these meats rare or medium done. Further research is finding that some people are more susceptible to developing cancer from this exposure than others. This recent study is the first to look at both breast cancers that are and are not sensitive to estrogen, together, which is what may be the most important aspect of this research.

The second theory has to do with the fact that red meat is higher in heme iron than other meats and that heme iron may increase colon cancer risk by damaging the colon lining and increasing the growth of precancerous cells. Several studies have linked this combination and scientists theorize that heme iron may interact with estrogen in enhancing the initial development of breast tumors.

The third theory considers the link between higher fat intake with higher levels of estrogen and another substance that the body can convert to estrogen. Higher saturated fat intake seems to raise levels of insulin, which is a hormone that may promote the development of breast cancer regardless of estrogen sensitivity.

Regardless of HOW increased red meat increases your breast cancer risk, all studies still point to decreasing how much you eat of it. This does not mean you have to cut it out, completely. Really, all foods CAN fit! Just start increasing the amount of fruits, veggies and whole grains and make beef intake less often each week and when you do eat it, make it a complementary dish rather than the main course.

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