The same with soy. If phytoestrogenes were bad for health, could vegan bodybuilders build muscles? Unlike milk and also meat full of pure estrogens (although with significantly smaller amounts than phytoestrogens in soy and flax seeds), in normal doses phytoestrogenes actually balance your hormones. Like with everything, if you ate too much of flax seeds or too much of soy, they could harm your hormonal balance.