A lot of people have been concerned with negative publicity about the health effects of soy products,. First, I want to emphasize that veganism does not mean you eat a soy-based diet, but rather a plant based diet. Get plenty of variety. As Jains with an Indian cultural background, we have many lentils, dals and other sources of protein, for which others may rely on soy. There may be some theoretical concerns with certain types of breast cancer and thyroid disorders, however, most of the health risks have been overblown.
This article provides an overview of many important health issues that have raised in relation to soy intake. One of the takeaway messages is: for thyroid disorders, get enough iodine. Of course each person has to consider what other options they have. Dairy and meat are certainly much worse in terms of cancer risk, heart disease and other health problems.
Another piece of the nutrition puzzle is that processed soy is less healthy than cooked soybeans, tofu or soymilk.