Dairy vs. Soy.

The other evening at work, the darling wife got into a discussion about “the evils of soy.” (Cue scary music.) The fellow she was having the discussion with is what could be called anti-anything-that-doesn’t-contain-meat-and-cheese, which is clearly a technical phrase. I believe that a person’s diet is their own choice, and they can consume whatever they see fit, and whatever they enjoy. If you like steak, that’s fine. If you like tempeh, that’s all right. If you like processed food that comes out of a box, can, or wrapper, that’s cool too. Just as long as you recognise that this is your preference, and that not everyone shares this preference.

Since going vegan (remember, it’s only been a week), I don’t believe my wife has ever encountered so much opposition to her dietary choices. Among the arguments against her being vegan that I’ve overheard are:

  • Humans have evolved to eat meat.
  • You’ll never be able to get enough protein without meat.
  • But, meat is delicious!
  • The texture of soy products is just awful. Why would you eat that?
  • Consuming meat is part of the circle of life; it’s natural.

Now, I’m not going to delve into the above because I believe that a lot of people are simply uncomfortable with the idea of being vegan (or heck, just vegetarian) because it’s unfamiliar. So, I have no beef with this (pun partially intended).

However, the discussion about the “evils of soy” made me go a little bit crazy. His argument was that soy has been consumed for far longer in Asia than dairy products, and that the consumption of soy for such a long time directly correlated to the smaller stature of Asian people. And that the reason that those with a European heritage are taller is due to the consumption of dairy.

Wait. What?

He was so vehement about this, that I decided I had to do some research of my own. So, I searched “effect of soy consumption on growth.” Here’s what I found:

  • It is true that soybean-derived agglutinin (or phytohemagglutinin, PHA) can reduce the growth of rats, but, according to the scientist who conducted the research on the growth-inhibiting effects of PHA, the low levels of lectin found in soy products would be very unlikely to cause any risk to human health.” – The University of Illinois
  • “…so far no reports have been published linking adverse effects to isoflavones and it has been clearly demonstrated that normal growth and development are supported by soy formula.” – The University of Illinois
  • “A 1998 report from the American Academy of Pediatrics maintains that “isolated soy protein-based formulas are safe and effective alternatives to provide appropriate nutrition for normal growth and development” in term infants not being fed breast milk or cow’s milk-based formulas.” – The USDA
  • “In studies of several generations of rats fed high levels of soy protein, Badger and his team found they grew and developed normally, except for very minor differences that have not been found in humans. There were no harmful effects, but there were many beneficial health effects.” – The USDA
  • (Based on a direct comparison of milk, breast milk, and soy milk) “Results indicated that growth (weight, length, and head circumference) was normal and comparable among the three groups.” – Joint study between The University of Kansas School of Medicine, University of Utah School of Medicine, and two research groups (abstract only)
  • “The results of at least six clinical trials comparing infants fed soy-based formula with infants fed cow’s milk-based formula indicate that soy-based formula supports normal growth and development in the first year of life.” – Oregon State University
  • “A prospective study evaluating growth and development in children fed breast milk, cow’s milk-based formula, or soy-based formula is currently under way at the Arkansas Children’s Nutrition Center. After five years into the study, adverse effects of soy formula have not been observed, and no differences in growth and development among the various groups have been noted.” – Oregon State University

From what I can see, there has been concern about the impact of isoflavones on growth and development, but it doesn’t look like there’s any evidence to support this. I’m not saying that soy doesn’t have health implications (like possible thyroid concerns if your diet doesn’t include enough iodine), but as far as I can tell, shorter stature is not among them. So, I did the same thing with dairy; I looked up the “effect of dairy consumption on growth.” Here’s what I found for that:

  • “In summary, in our prospective study, we observed a height gain in the children who consumed a high amount of cow milk.” – The American Journal of Clinical Nutrition
  • “Of the foods/nutrients studied, dairy protein had the strongest association with height growth. These findings suggest that a factor in the nonlipid phase of milk, but not protein itself, has growth-promoting action in girls.” – Harvard Medical School
  • “This review shows that individuals who consume cow milk during childhood may experience life history changes, here assessed as accelerated growth in height- for-age, larger adult body size, and possibly earlier sexual maturation for girls.” – University of Oregon
  • “Milk seems thus to have a specific stimulating effect on linear growth… The effects of milk on linear growth and adult height may have both positive and negative long-term implications.” – The University of Copenhagen
  • “We conclude that actual milk intake and the genetic LP trait is positively associated with body height in preadolescents and adolescents. Nevertheless, higher milk consumption in childhood might exert both negative and positive effects, since greater height has been associated with higher risk of some cancers.” – School of Health and Medical Sciences, Örebro University

So, yes, it absolutely seems that consuming dairy results in a generally taller stature, but the long-term implications of this aren’t fully known, and there’s a chance that it could actually be negative.

The last thing I looked up was the assertion that soy has been consumed in Asia for far longer than dairy, which is the main reason that people from there are shorter. It’s actually the complete opposite; the first recorded use of soy for food in Asia was around 3,000 BCE, while the first recorded use of dairy for food in Asia was as early as 9,000 BCE (and yes, I know, Wikipedia is not the perfect source, but it’s what I could find).

Let it be known that I like both soy and dairy products, and am aware that there are pros and cons for both. For example, GMO soy is generally terrible, as is the treatment of cattle on factory farms. But again, I choose to like both, and you may choose whichever you’d prefer (or neither). Just make sure you do your own research to draw your own conclusions.






  1. Agreed 🙂 The only other concern I’ve heard about soy is that consuming in large amounts can alter your levels of estrogen an unhealthy amount.

    If what you’re doing is working for you, then power to you!

    1. Good point! And due to that, women who have breast cancer should limit their soy intake, or avoid it altogether.

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