Tofu makes you dumn?

May 7th, 2011  |  Published in Stumpblog, What to eat  |  29 Comments

I am often asked why I do not recommend soy protein for vegetarians.

On paper, using the logic of “nutrientism” (the idea that we should focus only on isolated nutrients in a food, and that all “nutrients”, e.g. “protein” or “vitamin C”, are equivalent and interchangeable), soy makes sense. It is a plant that appears to be high in the types of amino acids that humans require. It’s relatively easy to grow and is sort of like the universal solvent — you can make damn near anything from it.

In real life, it’s not so simple. “Nutrients” are not whole, complete, discrete foods. Our bodies respond to whole foods, eaten as part of a whole diet, in a context of a whole life and whole environment. We eat food. Not “nutrients”. And, as a food, soy doesn’t offer much benefit compared to its drawbacks.

The aggregate data suggest that whatever benefit soy may offer is vastly outweighed by its many liabilities — especially when it is processed, as it must be in order to be edible. (Really guys — did you honestly think that Tofurkey was healthy?) For a review of the clinical literature and concerns, check out The Whole Soy Story.

One key problem with soy appears to be its effects on brain health with aging.

A study in the JACN followed thousands of subjects following a variety of Japanese and Western-style diets in Hawaii. The study concluded that in subjects ranging from their 70s to their 90s, “poor cognitive test performance, enlargement of ventricles and low brain weight were each significantly and independently associated with higher midlife tofu consumption.” In other words, the more tofu a person consumed earlier in life, the worse their prognosis for healthy brain aging would be.

Of course, this isn’t causative, merely correlative. Other studies have suggested that soy isoflavones may offer a protective effect. Again, the data is mixed.

For instance, one study points out that our conclusions about healthy brain aging depend on the indicators we use to measure it, as well as sex differences. Given soy’s estrogenic actions, what effects does it have on men and women? (In women, for instance, should we assume that more estrogenic activity is always good?)

Another study points out that we have to distinguish between soy’s effects in vitro (i.e. on cell cultures in a petri dish) and in vivo (i.e. in actual people living real lives). “Lab significant” may not be “real world significant”, and/or effects on free-living people may be much different than effects on cells bathed in a medium of isolated substances. As this study comments, “While it has been shown that the soy phytoestrogen genistein inhibits neuroprotective functions in cell cultures, recent in-vivo findings strengthen the case for a possible causal mechanism of soy-induced neurodegeneration.”

Now, the JACN study is ten years old, but another study from 2008 offers similar but somewhat more nuanced results. High tofu consumption was associated with worse memory, while high tempeh consumption (a fermented whole soybean product) was independently related to better memory, particularly in participants over 68 years of age. Another study looking at the same population found that the effects changed when the groups were disaggregated by age and type of memory recall. (BTW, both studies found that fruit consumption was also associated with improved memory across the board.)

What many of these studies indicate to me is that “soy” is not a homogeneous category, just like “meat” can encompass everything from rare Kobe beef to baloney.

Having an ounce or two of traditionally fermented tempeh now and again — importantly, within the context of a traditional East Asian diet, eating patterns, and lifestyle — is not the same thing as drowning in TVP, soyloney, soy milk, and soy cereal  every day within the context of a modern Western diet, eating patterns, and lifestyle.

Ask yourself: How is soy protein powder produced? How do they make soy bacon? Have you read the labels? After considering the actual process by which most mass-produced soy products are created, do you still want to eat them? Do you still consider them “healthy”? What does the rest of your diet look like?

Thus, when we ask “Is soy bad/good for me?” we have to ask:

“Which soy? In what format?”
“For whom?”
“For what purpose?”
“How much are you consuming?”
“What exactly are you assuming that soy will do/not do for you?”
“In whose interests would my soy consumption be?” (In other words, who is telling you soy is good and to eat more?)
“WTF is Tofurkey and why is this offense to Saint Julia Child on my table!?”


  1. inge says:

    May 7th, 2011at 2:37 pm(#)

    I have a deep distrust of food which is not what it pretends to be. If the food is fine, why lie about it? If it’s not, why should I eat it?

  2. Miss Cephalopod says:

    May 8th, 2011at 3:47 pm(#)

    I’d like to point out that soymilk is NOT a highly processed product – it’s ground-up soybeans and water, sometimes with a little sugar and calcium added. Doesn’t sound much unhealthier to me than meat that is pumped full with antibiotics and has to be run through an ammonium and chlorine bath before being sent to the supermarkets; or simple cow’s milk. Ever looked at all the processing that cow’s milk goes through? Not even mentioning it’s not intended for human consumption anyway. (Lions don’t need giraffe’s milk, humans don’t need cow’s milk.)

  3. Sarah says:

    May 9th, 2011at 8:57 am(#)

    Just because most dairy cows are mistreated doesn’t mean milk can’t be a decent food. Provided you have the persistent-lactase genes and a quality source of raw milk, it’s fine – in the same way that a homemade meatloaf from pasture-raised pork and beef is great but a slice of Schneider’s finest balogna, not so much. And commercial soymilk certainly IS highly processed – you can make your own at home and it’s not (although it is still high in phytates, which block mineral absorption – probably why there’s a difference between eating tempeh and eating tofu). But how many people make their own soy milk, and how many grab a carton of Silk or Soy Good on their cruise through the dairy section?

  4. Sharon says:

    May 9th, 2011at 12:28 pm(#)

    To kinda back up Miss Cephalopod, I have to drink soy milk, cow’s milk, sheep’s milk, etc. causes nasty GI issues. Could drinking a cup a day w/ coffee really do tons of harm?

  5. Rachel says:

    May 9th, 2011at 3:51 pm(#)

    Having spent quite a bit of time in East Asia, I assure you tofu is a traditional part of the diet and consumed regularly. Soy milk is also consumed. The study from DGCD (2008) hypothesizes it may be the high folate level of tempeh that’s neuroprotective. Fine. Now what about all those studies that show correlations between high folate and certain cancers (prostate, breast,colon). I’ll let you search through pubmed for the citations.

    The point is, that you will almost always find that some subset of a population will react to a variable; particularly in observational and longitudinal studies that rely on self-reporting (such as food-questionnaires).

    I’d like to know if the incidents of memory decline in the populations studied were more or less than the population as a whole.

    II should point out, a you did, that the JACN study is old. It only used the Pearson coefficient to determine strong correlations. Prolem with Pearson’s is it isn’t very robust, and can only be used to determine linear relations.

  6. M says:

    May 10th, 2011at 7:16 pm(#)

    Google phyto-estrogen and what is does to your body. Tofu is full of it. I started eating tofu when I briefly went vegetarian and it completely knocked my health off balance. My periods became total nightmares and I developed raging fevers each month. This food is essentially plant-based female hormones. Trust me, I have enough hormones already.

  7. Meleah says:

    May 13th, 2011at 4:06 pm(#)

    I don’t drink cow’s milk (lactose intolerant), but there are many non-dairy, non-soy milk beverages on the market. For example, rice milk, almond milk, coconut milk, hazelnut milk, and flax milk. Most of these are readily available at your local megamart. Most taste pretty good, are comparable in price to soy milk, and lack the estrogen-mimicking effects of soy milk. I made the switch :)

  8. Monday 5/16/11 • Derby City CrossFit – Louisville, KY says:

    May 15th, 2011at 6:43 pm(#)

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  9. Linds says:

    May 16th, 2011at 12:40 pm(#)

    I am a semi-vegeterian that avoids most non-fermented soy products like the plague. I eat a large amount of sustainably caught wild fish, hemp, occasional tempeh as setien as well as Quorn to get protein. Yes it can be hard to get protein in my diet but we make do.

    Many people do not know sort of genetic modification is going into soy as well. So many people think it is a wonder plant when in reality, it is full of pesticides and one of the most genetically modified plants out there. Just watch the movie The Future of Food and you will see how this affects farmers and the general population!

    Thus if you are going to be consuming any sort of soy product you should opt for non-GMO fermented tempeh.

    As others have mentioned there are other options to replace dairy that don’t consist of soy. My personal favorite is hemp milk which we get during the winter months when the goats that we get milk from have stopped producing.

  10. Becca says:

    May 16th, 2011at 4:00 pm(#)

    If soy foods are so terrible for cognitive function, then how come asian people are usually the straight-A students who wind up in medical school? And Japanese people (famous for eating lots of soy) have one of the highest expected lifespans of any country, and far lower incidence of breast and prostate cancer than us here in the US. I’ve never heard that asian countries that use the traditional forms of soy (tofu, soymilk, soybeans, miso, soynuts, natto) have any higher rates of alzheimer’s than we do.

  11. Rachel Louise says:

    May 19th, 2011at 4:19 pm(#)

    I take thyroxine as I have no thyroid gland, this has been the situation for 14 years. 4 years ago I dramatically increased my consumption of soy products and this had a disruptive effect on my medication regime, rendering my usual dosage inadequate and causing a return of the hypothyroid symptoms.

    There is a fair amount of evidence that isoflavones in soy can disrupt the transport and uptake of the thyroid hormones, athyrotic individuals dependent on exogenous thyroid hormones cannot just produce more thyroid hormones.

    Untreated hypothyroidism is linked with impaired cognition. Perhaps this is the underlying factor in the correlation between higher tofu consumption and brain ageing.

  12. Friday Link Love | Modern Athena says:

    May 20th, 2011at 4:45 am(#)

    […] Tofu Makes You Dumn – […]

  13. Lieke says:

    May 22nd, 2011at 7:18 am(#)

    Asian people do no eat as much soy as is often implied. Their traditional diet does not depend on it nor are consumed portions large. And what they eat in soy products is not altered too much. Apart from that, academic excellence can unfortunately not be triggered by soy but among others by hard work, ambition etc.
    I stay away from soy products myself: apart from the dubious results concerning soy in some very serious research, most of soy products are extremey well marketed, seriously chemical junkfood, and with a foul aftertaste that no food additives nor loads of sugar and salt can really hide.
    Next time I’m in Canada I’ll have a look at Tofurkey since we don’t have it here (Netherlands) yet: Fascinating! Whoever came up with that???

  14. Mistress Krista says:

    May 23rd, 2011at 12:30 pm(#)

    Re: Asian soy consumption. First, the original comment is fairly problematic in that it lumps all “Asians” together and argues in favour of a timeworn stereotype — that “Asians” are better academic performers. I want to address this because it’s a pervasive myth and erroneous argument.

    Let’s say for a moment that group A is better at academics. Academic performance is typically measured in early childhood, and certainly no later than high school or college. Neurodegeneration does not appear until later in life. Even if we had a region of geniuses, it’s quite conceivable that their cognitive development at 10 is different from their cognitive health at 50 or 80.

    “Asians” is a very broad, heterogeneous group and region with a very diverse cuisine and set of dietary habits. Are we talking about isolated, island-dwelling, coastal populations (e.g. Okinawa)? Inland, grassland-dwelling nomads? Affluent urbanites? Poor rural farmers?

    “Soy consumption” is also a very broad category. Traditionally among “Asian” populations where soy is consumed (which isn’t everyone, BTW), the amounts are (a) very small; and (b) traditionally prepared using fermentation, aging, or some other form of preparation intended to reduce antinutrients and toxins. They are not living on soy bacon and soymilk; they are drinking miso broth with a tiny fraction of fermented soy in it. Additionally, you must understand the entire dietary regime. For instance, many “Asian” cuisines include foods such as seaweed that combat the neurodegenerative or goitrogenic effects of soy.

    To claim that “Asians” eat a lot of soy shows poor understanding of “Asian” cuisine and actual dietary habits as well as regional diversity. It’s like saying that Brie must make you fashionable because the French invented haute couture.

  15. Trishy says:

    May 30th, 2011at 7:18 am(#)

    It is also good to remember that the average American consumes tons of hidden soy already, even if they never drink soy milk or eat tofurkery. Any food product that contains added oil will typically contain soybean oil, and soy lecithin is one of the common preservatives. Pushing soy-based everything as a “healthy” alternative to meat and dairy is probably tipping the scales into the danger zone of soy consumption.

  16. Siobhan says:

    June 5th, 2011at 6:19 am(#)

    Krista: Thanks for this article. I especially appreciated comment #14. You said all of the things I was thinking.

  17. Lieke says:

    June 8th, 2011at 3:30 pm(#)

    Soy is everywhere. Even in baby formula. Since I’ve been alerted to the more dubious properties of soy, I started checking the milk formulas I give my baby. And I’ve only been able to find ONE single type of baby milk formula up to now (where I live) that doesn’t seem to contain soy or soy derivatives. Ironically, it’s the one for babies with cow’s milk allergy and it costs about 5 times as much as the cheapest type.

  18. Mistress Krista says:

    June 9th, 2011at 3:20 am(#)

    @Lieke: I think it’s time to resurrect the wet nurse as a noble profession.

  19. WendiG says:

    June 14th, 2011at 11:59 am(#)

    Although I wish it wasn’t so, the fact is that I find soy in all it’s forms indigestible..perhaps because I was not raised on it, don’t really know.
    Even milk causes problems for me as an adult..have to limit myself to about 1/3 cup a day for coffeee..although anything with a culture base seems okay (yogurt, cheese, etc.)

  20. Amanda says:

    June 14th, 2011at 11:18 pm(#)

    What’s the word on hemp and rice protein powders for those of us that can’t or won’t do whey or egg? I’m using hemp right now, and it tastes great and I can digest it better than anything else, but I wonder if I’m getting all of the amino acids I should be getting?

  21. Mistress Krista says:

    June 15th, 2011at 3:33 am(#)

    @Amanda: I like hemp myself, and have used sprouted brown rice protein in the past. As long as your overall intake isn’t exclusively limited to a few sources (in other words, you don’t live on protein powder), you’re probably fine.

  22. lou says:

    June 21st, 2011at 8:55 am(#)

    personally, i dont believe the hype that soy is either a miracle plant, nor a dangerous food. mostly, i agree with this take on the topic:

  23. Lisa says:

    July 1st, 2011at 7:58 am(#)

    I found this article today about why people like protein and thought you might be interested.

  24. Maureen says:

    July 1st, 2011at 7:11 pm(#)

    Everything in moderation is generally the best policy. There are a slew of articles touting both the positive and negative effects of every food product imaginable.

    I eat a high protein diet where roughly a third of the protein is derived from soy (soymilk, tofu, etc). My Masters degree in Physics (and soon to be PhD!) disagree with the dubious correlation between soy and negative cognitive functioning. =)
    Even if there is a positive correlation (and subsequent causation), the week-to-week difference is probably so small as to be negligible. The cumulative damaging effects could probably be negated with 5 minutes of sudoku daily.

    I wish there were more vegetarian high protein options. I’m sick of the soy-dairy train and the subsequent toxic gas my body produces trying to digest it!

  25. A Guy says:

    July 4th, 2011at 10:22 pm(#)

    Hey guys, (specifically Maureen, comment 24) I’m a 16 year old workout fanatic who also happens to be vegetarian. As a protein substitute, try Quorn, it’s a product that can be found or requested in most health food stores that isn’t soy based, and it is jam packed with proteins. It’s like a Boca stuff but its based from a nutritious mushroom found in Europe. Tastes great, no controversy over it’s contents, and supplements proteins in a vegetarians diet.

    Request “Quorn” at your local health foods store

  26. Mistress Krista says:

    July 5th, 2011at 3:11 am(#)

    I love Quorn! Bummer we can’t get it in Canada.

  27. Ron Dykstra says:

    July 27th, 2011at 6:57 am(#)

    Wow,this “soy thing” really polarizes people. People getting all mad over being told their pet supplement might be bogus is very funny, in my opinion. That kind of response indicates that your beliefs regarding diet have transcended rational discussion, and become dogma.

    Don’t believe Mistress K and her studies? Eat soy till you pop, but don’t get all bent out of shape over it.

    Good will and peace! Eat food, breathe air, drink water, engage in pleasurable exercise. No big deal :)

  28. If it moves, eat it says:

    July 31st, 2011at 10:24 am(#)

    Yeah, I’d leave the quorn alone, mate. It’s not a mushroom. It’s a different type of fungus. Google it.

  29. Lauren says:

    June 8th, 2012at 11:52 pm(#)

    “especially when it is processed, as it must be in order to be edible”

    What? Have you had edamame?

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