Transcript: How Much Soy Is Too Much?
So we know 7 to 18 servings of soy a day may neutralize some of the beneficial effects of avoiding animal protein; at the same time studies have repeatedly found that women who eat lots of soy appear to have a lower risk of getting breast cancer and a better risk of surviving breast cancer than those who don’t. So is there some magic number of soyfood servings we should shoot for?
So far we know that somewhere between 7 and 18 is bad, so more than 18 definitely gets the axe. This two year study found no effect on IGF levels of adding two servings of soyfoods day, whether they were tofu, soymilk, soy nuts, or the concentrated soy isolate found plant-based meats, protein bars or protein powder, still fine.
Still got a big range here. This study suggested 5-10 servings a day was bad— increased IGF—so nutritional science has slowly but surely been narrowing it down. Same year in Japan, three servings a day cleared the IGF radar. And then, that’s it. That’s all we got so far.
The bottomline is that legumes should be a part of everyone’s daily diet, which means lentils, peas, and/or beans every day, of which soy is an excellent choice, but I recommend that we should probably stick to no more than 3-5 servings a day.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Kerry Skinner.
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