For the past several years I have been endlessly asked, “Does soy cause breast cancer?” I have looked through the medical literature and concluded on my own that I see no evidence to substantiate this. Nonetheless, the media fuels this fire,
Irrespective of what the press says based on a few nonhuman “studies” this question remains. However, common sense dictates this makes little if any sense. The incidence of breast cancer in Humans in the 2002 Worldwide IARC CancerBase No. 5 shows that breast cancer incidence in soy consuming countries (China and Japan) is 18.7 and 32.7 per 100,000, respectively; whereas in Western nations (U.S. and U.K.) the breast cancer incidence is 101.1 and 87.2, respectively. Strange anyone would say that soy based isoflavones are to blame for breast cancer, how about the American lifestyle?
To back this thought process up is an excellent review of soy isoflavanoids and breast cancer published in the Nutrition Journal (7:17, 2008) from the Wake Forest School of Medicine. The authors conclude that there is little evidence that dietary isoflavones have a clinically relevant effect on breast tissue either positive or negative
Just this month in the clinical Journal of Nutrition (89: 577-583, 2009) and on Dr. Tanelian’s Medical News is a prospective study from the Vanderbilt University School of Medicine showed that soy food intake was inversely associated with colorectal cancer such that soy foods decreased the relative risk of colorectal cancer risk to 0.67.
Let us review the medical literature before jumping to conclusions on all media fostered sensationalism – some may be valid, but you really want to know the whole story!
Darrell L. Tanelian, M.D., Ph.D.