The Okinawa eat more soy and soya products than anywhere else on Earth! Soya is one of the secrets of their longevity and healthy old age: it's rich in vegetable protein (rather than animal protein) and it contains lots of protective fats and phytoestrogens, which are excellent anti-oxidising hormones (among other things).
It would be difficult to eat as much soya as the Okinawa do, but it's so good for you that we recommend incorporating it into your diet gradually: start by replacing cow's milk with soy milk (it's rich in low-sugar calcium), replacing ordinary yoghurts with soy yoghurts, and replacing cream with tofu or cooking soya. Then introduce tofu and other soya-based products into your diet (soy beans, soy sauce, etc) until you're eating soya at least once a day.