To soy or not to soy?

An interesting topic that was brought up by my sister-in-law while the family was together for Christmas was the topic of soy products.  She said that there had been some research she had read that suggested a correlation between soy products, which contain hormone-disrupting ingredients, and fertility, and developmental issues in infants and children.  My sister-in-law is a Masters of Science in Genetics and Cell Biology, so she hears of these things and comprehends it much than I will ever hope to.  She did, however send me a few interesting links to websites that have helped me to understand the topic much better.  ***I am by no means an expert on this topic, so anything I write should be taken as any information that is presented to you through any form of media (thank you college for teaching me that): with a grain of salt and as an opinion until you research the evidence for yourself.***  

The general argument of the research I have looked at is that there is evidence that the consumption of soy products, which contain plant compounds that are estrogen mimics, can be harmful to fertility and development when consumed in unfermented forms (not soy sauce, but including Tofu and TVP).  Hormones, such as estrogen, are chemicals released from glands or cells in our body for the purpose of sending messages quickly throughout the body to do or not to do a wide range of functions.  These functions might include telling your body to release insulin, control of the reproductive cycle, or even activation or inhibition of immune system responses.  The interesting quality about hormones that would make them such a health concern is their potency.  Only a very very small amount (imagine a drop of water in a large lake) of a hormone is needed within your body to get the message across for the right response.  So can you think of why eating something with compounds in it that might mimic those hormones that work just fine in small doses might be of concern...?

Common sense would tell us that hormones are a good thing, and in this case, too much of a good thing could be developmentally disastrous.  Lately soy products have been advertised as a health food alternative, "but animal studies suggest that eating large amounts of those estrogenic compounds might reduce fertility in women, trigger premature puberty, and disrupt development of fetuses and children." The specific compound in soy products that acts as estrogen mimics is genistein.  An article explains the research supporting the claims against soy: 

"One study showed that genistein led to reduced fertility and abnormal embryo development in female mice. They were fed one to ten micromoles in their drinking water for four days. The highest doses were associated with fewer eggs that were successfully fertilized and increased cell death in developing embryos. Wen-Hsiung Chan at Chung Yuan Christian University in Taiwan conducted the study, which was published in July in the journal Reproductive Toxicology.
In another study, young female rats were fed high, medium, or low doses of genistein. Those fed the largest quantities from birth to weaning had reproductive effects later, including early puberty and irregular estrous cycles (similar to the menstrual cycle in humans). High doses also led to smaller litters."
While these studies were done on rodents, it could mean important conclusions for the reactions of the same compounds in another type of mammal.... humans.  Just some food for thought... or more thoughts about food choices.  In all reality, I probably won't avoid any and all soy products forever, but what I have read will definitely affect the choices I make at the grocery store.  I encourage you to to click on the links I've provided and read up on the same stuff on this important subject.  If toxicology and hormone mimics interest you more beyond these articles, I would suggest reading "Our Stolen Future" by Theo Colborn, Dianne Dumanoski, and John Peterson Myers.
What are your opinions on soy products?  Does information like this make you start to fear processed foods of all kind?  How do we make the food choices we do when we really don't know the long term effects of consuming them?


  1. Great job on bringing up this topic to get people thinking in a non panic inducing way. The old adage, "Everything in moderation," appears to be more and more true to life. Glad I could lend my scientific knowledge to your blog. :)

  2. Before you go crazy trying to get soy out of your diet, read this: http://www.happyhealthylonglife.com/happy_healthy_long_life/2011/01/soy.html

  3. Thanks for bringing this article to my attention Wendy. Here are my thoughts after reading it:

    Ok, so less-processed forms of soy are favored over other more processed forms.

    This article says that benefits of soy intake associated with reductions in coronary heart disease risk to protection against prostate cancer... is this because the use of soy products is usually as a replacement for meat and dairy products, which are correlated with increased risk of heart disease and cancer in general and not because soy products are the cause of these benefits? This might be the mistake of a correlation and not a causation in summarizing a great deal of research.

    The soy products I would/do eat are usually in the form of soy milk or whole soy beans. I am not particularly a fan of tofu to begin with, and the thought of most cheese and meat fake-outs with soy gross me out. Overall I won't be changing my eating patterns, but I definitely will not be including two servings of soy in my daily diet as the article (http://www.happyhealthylonglife.com/happy_healthy_long_life/2011/01/soy.html) suggested, but I won't avoid soy when I would like it in a latte or only have the option to have a soy burger patty.

    Also within the article it argues: " Bottom Line:  Any harmful effects of soy have only been observed in animals.  No harmful effects have been in observed in humans."
    While this may be true, the reasons for using animals such as rodents instead of human experiments is not merely ethical reasons of not wanting to expose humans to products that may be harmful, but also to see the effects of something over an animal's lifespan and over multiple generations. The nature of hormone-mimics may not have a large effect on the current generation, but could have drastic effects on two or three generations in the future by being passed to the infant through the womb. This is something that we cannot see with humans when soy has only been researched in depth for less than 50 years on its effects on humans.

    In summarization of my thoughts: Processed soy foods that are mass produced should still be approached with skepticism and used in the diet in moderation. While I think they are a better option for a nutritarian than animal meat and dairy products, I suggest that they be eaten in moderation as if they were an occasional treat such as the occasional meat or seafood in the diet. In a time when research comes out constantly telling us certain things are good, the same thing is now bad, then it's ok again; it's really hard to decide what to do and what to eat. The key thing is: everything in moderation. This way you will not be putting all your eggs in one basket, while still getting a variety of foods with a wider range of nutrients than soy products alone can provide.

    I'm looking forward to seeing more research on this subject, and hopefully more outlets that put the scientific information in Layman's terms so everyone can better decide for themselves how to interpret the information in a way that is best for their bodies. -ANK