Soy’s effects on the body are complex and depend on many factors. 

• Its all about estrogen. Some studies have linked excess estrogen to increased breast cancer risk. Soy contains two types of plant estrogens called, isoflavones. These phytoestrogens can interact with estrogen receptors in humans and have either weak estrogenic or anti-estrogenic effects.  

• The amount of phytoestrogens in the average soy-inclusive diet, has not shown an increased cancer risks for humans. 
  • • • Studies that did link soy to increased estrogen were animal studies, where large quantities of soy were consumed. 
      • Studies done in human populations have not linked soy to cancer. 

• Population and ethnicity matters. 
  • • • Soy may be digested and absorbed differently by different ethnic groups. For example, population studies in some Asian countries have shown no increase in cancer risk with soy consumption, and sometimes showed a reduced risk. 

• Age May Matter
  • • • The effects of soy may vary based on your levels of estrogen. Soy may have an anti-estrogenic effect in pre-menopausal women and an estrogenic effect in post-menopausal women. 

• Not all Soy is Created Equal
  • • • One reason so many studies seem to say different things is because they study different types of soy products. Whole-food soy products such as tofu and soybeans may be digested differently than their processed or fermented counterparts.

• Soy Protein Supplement Are More Potent 
  • • Representatives for The American Cancer Society, recommend avoiding soy supplements, such a protein powders, until further research is done. These products contain high concentrations of isoflavones than soy foods. 

More About Soy

Soy is considered a complete protein, which is good news for vegans and vegetarians. Soy also has loads of healthful nutrients such as B vitamins, potassium, fiber, and magnesium.  Soy is more than just its isoflavones and could offer a host of positive health effects. If you are concerned about cancers risks, avoid soy supplements and maintain a balanced diet. In all things, moderation.