When is soya healthy?
If you are Asian (from Asia) and eating soya, then you are probably eating fermented soya like miso. Population studies indicate that that is healthy for you.
If you are adapted to a western diet, then the soya products you eat are more likely to be processed soya like sausages, schnitzels etc which are made from unfermented soya. Tofu and soya milk are also usually unfermented, but you can make or source fermented products. Unless your soya is fermented according to the old-style recipes where the fermentation has time to properly alter the chemical structure of the soya, it’s probably mostly bad for you.
Fermenting breaks down the phytic acid in the beans which binds with nutrients to stop you absorbing them. In other words, it’s an anti-nutrient.
Soya is a phyto-estrogen, a plant estrogen, so if you eat a lot of it have your doctor regularly check your hormone levels to avoid problems. Some people are more sensitive to the estrogenic effects.
And what if you are eating fermented soya?
Studies show that people on a western diet are better adapted to getting similar health benefits from seeds as traditional Asian-diet populations get from soya, probably because their gut bacteria have adapted. Miso and tempeh are habitually fermented and so are good choices.
How to choose
How does this help me understand all the conflicting information and take the good from it?
It helps you break down the studies:
If something is tested on an Asian population and you are on a western diet, you can’t extrapolate their results to yourself. Asian populations have a low incidence of breast cancer on soya, but western-dieters have a correlation with soya diet and incidence of breast cancer.
Any commercially processed product is less healthy, and processed soya is no different. Check the source of the food in any quoted study to help put the results in context.
2. And it helps you make better choices:
If you want to eat soya, choose fermented options and non-commercially processed ones. Fermenting is also a form of processing, but it breaks down the anti-nutrients in the soya and makes it more digestible. If you’re used to a Western diet and don’t want to ferment your soya, sprout it. Sprouts are jam-packed with goodness.
Don’t make soya a staple dietary choice (never make any food a staple, rather aim for variety).
If you use non-dairy milk options, then try to develop a wide variety of milk sources for your needs, including nuts and oats rather than using a blanket soya-replacement option.