Because the Japanese traditionally eat soy products and have low rates of breast cancer along with generally good health, we think that soy is probably a good thing. Tofu, edamame, and soymilk have all withstood the test of time.
If you like to engage in ‘nutritionism’, evaluating food on the basis of known nutrients (from Michael Pollan), you might base soy’s benefits on it being rich in protein, iron, calcium, zinc, magnesium potassium, B vitamins, and healthy omega-3 fat.
Why have people heard that soy might not be great? Some people are allergic, some are intolerant, some abused it by eating it 6 times a day, but you could say the same of whole wheat. Don’t become obsessive about any one food.
Next time you order a cappuccino, try it with soymilk. Instead of letting milk’s evil saturated fat clog your arteries, you’ll be lowering your cholesterol with soy’s healthy unsaturated fats and plant sterols. Yeah, I know the taste is an acquired one.