I am not a fan of absolute statements. Through much trial and error, through having to go back on my own words, through being humbled and through life’s experiences absolute statements are not something I indulge in often.
To the best of my ability I do make a solid attempt to qualify what I choose to say or suggest. I like to offer context and both encourage and stress the importance of bio-individuality (what makes each one of you unique), individual preferences, personal sensitivities and each person’s own special make-up. This is achieved through using guidelines and pretext along with both my professional and clinical judgements. Being a human, I know these are not infallible, so I am not as attached to these ideas as I once was. I get it, things change. When we learn more, we can do better, and do better for others.
Such was the story with soy. About a decade ago, it was hailed as the panacea for everything. Great protein, anti-cancer, good for hot flushes, it was touted as the ultimate ‘superfood’. This was mostly due to an enormous push by the agriculture industry, but I think that is a discussion for another day.
Recommendations for soy consumption exploded. I still have people coming in to see me every day, drinking soy milk, eating soy bars and soy sprinkles and tofu, soy burgers, soy ‘chicken’ nuggets, soy hot dogs and a huge variety of soy-based things. This is despite the evidence causing the pendulum swinging the other way on soy.
We have newer or better or more accurate information on soy now. One of the many results of this mega soy push has been an increase in gut and hormone-related symptoms.
Soy is not the health panacea it was cracked up to be. There are a few of the issues with soy:
1. Soy contains protease inhibitors. Protease is the enzyme that breaks down proteins. When you eat soy, you are blunting protein digestion. When protein particles are not fully digested and remain large and unbroken and then they hit the small intestine. What follows are episodes of bloating, immune provocation and gas.
2. Soy contains oligoasccharadies (carbohydrates) that are unrecognizable by the human GI tract. If you are unable recognize them, you are unable to break them down. If you are unable to break something down, and it hits the small intestine, see above. To add to that list, you are giving your microbiome (the colony of beneficial bacteria living in your large intestine) a highly fermentable food to feast on, resulting in even more gas.
3. Compounds in soy slow the conversion of inactive thyroid hormone to active thyroid hormone. So many avid soy eaters present with hypothyroid symptoms, and this is why. Soy, especially consumed at a high rate (1-2 servings/day) can act as a goitrogen - a harmer of and reducer of thyroid function.
4. Soy is a SERM, a Selective Estrogen Receptor Modifier. For some ladies, this means that using targeted soy compounds during hot flashes can help, but more often than not, soy actually exacerbates estrogen-driven dysfunction. Although there are definitely some women who do well on soy (specifically the compound genistein), there are definitely more who flail.
5. Soy is often heavily contaminated with aluminum - terrible for brain health and blood pressure.
6. The majority (close to 98%) of soy in North America is GMO. Say what you will about GMOs, but their safety as a food source has not been adequately vetted, in my opinion, and we are the living, breathing experiments for it at this time.
7. Soy is not-so-great for your little ones, either, speeding up puberty in girls and slowing it in boys.
There is an exception, a tiny silver lining to all this doom and gloom – fermented soy.
Truly fermented soy (not processed pretend-fermented or manufactured products), things like miso, soy sauce and natto, being partially digested through bacterial fermentation, do not have the same reactivity that edamame, tofu and soy sprinkles do.
A question I get all the time is one regarding soy lecithin. It is in everything! I have noticed is that only those who are exquisitely sensitive to soy will not be able to handle it. Most others seem to be just fine. Truth is, you are going to find a lot of this stuff (along with soy oil) in the vast majority of processed/packaged foods, some supplements and things like protein bars and their equivalents.
Soy as a by-product and additive is everywhere, due to the sweeping success of that agriculture campaign I alluded to above.
In general, my recommendation is that soy is a food to be minimized in most (ideally avoided, but I do understand this is not always a possibility in modern life), for the reasons outlined above and because in my experience it is one of those more prone to be allergenic (much like gluten and casein).
As ever, there are nuances: how much, what type and individual sensitivity. For most, a small bowl of edamame or some tofu in soup when you are out to eat at a sushi place once or twice a month are not going to make huge impacts, but for some that certainly will. As always, the responsibility is on you to take control of your own health, your own body and listen to what it tells you.