|The effects of soy products on health have been hotly debated. An important new study compared consumption of soy protein with or without isoflavones (estrogen-like plant compounds) in men with low testosterone for 3 months. After the protein/isoflavones, there was no difference in testosterone. However, heart and diabetes risk factors improved significantly, whereas thyroid levels were adversely affected. BOTTOM LINE, soy products may have complicated effects on health which could vary based on underlying medical condition.