This was originally published at Keeper of the Home on June 28, 2010.

I know it goes against  everything we hear these days about healthy eating, but I’m here today  to tell you that I don’t eat soy food products, and I don’t really think you should  eat soy food products, either.

There.  I came right out and said it.   Might as well get the controversy right out in the open from the start,  right? (wink)

Honestly, I’m not looking for a fight.  In my real  off-line life, I rarely talk about dietary choices with people  unless they flat-out ask me my opinion.  Diet is a really personal  thing, and people often feel defensive if their choices are questioned.   But the soy issue really concerns me, so I decided to take this  opportunity to talk about  the side of soy we don’t usually hear about.

You’re about to read some big, scientific-sounding words, but don’t let it phase  you. I’ve tried to put everything into plain-Jane language,  for me as  much as for anyone else – I’m definitely no scientist! But I believe  there are at least three good reasons for avoiding soy, and it’s  important to understand them.  Here they are.

1.  Soy Disrupts  Our Sex Hormones

Soy is known as a phyotestrogen.  This  means that it contains natural compounds that mimic estrogen in our  bodies.  This sounds like good news for some people, such as  post-menopausal women.  But what are the effects of phytoestrogens on  babies, little boys and little girls, young women and young men?

Photo by nerissa’s ring

For babies on soy formula, a 1994 study shows that they are consuming the  hormonal equivalent of up to 10 contraceptive pills a day.  Little  systems can’t handle that overload; it puts children at risk for everything from early-onset puberty to permanent endocrine damage. This  might surprise you: the governments of Israel, Switzerland, the UK, and  New Zealand have all issued statements against the use of soy formula  for babies.

Little boys who consume soy may have higher risks of testicular cancer, and little girls may face higher risks of breast  and ovarian cancers, due to longer exposure to sex hormones.  There is also a possible link between soy and lower sperm counts in young men.

Just  100 grams of soy contains the hormonal equivalent of one contraceptive  pill. Considering all the hormonal diseases that are running rampant  today in the West (including infertility), it seems wise to check our  consumption of soy.

2.  Soy Disrupts Our Thyroid

The  thyroid is part of the endocrine system, just as the sex hormones are,  so these two issues are intimately related.  The phytoestrogens in soy  also act upon the thyroid to have a goitrogenic effect, which means they  depress thyroid hormone production, slow down thyroid metabolism, and  potentially cause an increase in the size of the thyroid (known as a  goiter, hence the term goitrogenic).  All of that adds up to one thing:  hypothyroidism.

I have had hypothyroidism since 2001,  possibly earlier.  There are many symptoms of this disease, and it is  often overlooked or misdiagnosed as depression (which at first happened to me). In fact, some experts estimate that there are as many as nine  million undiagnosed cases of hypothyroidism in the United States alone.   If you have any hypothyroid symptoms, try to  eliminate soy from your diet right away.

3.  Soy Contains Anti-Nutrients

Anti-nutrients are chemicals and compounds that prevent nutrients from being properly used by the body.  Here are  two examples of anti-nutrients found in soy:

Protease Inhibitors

Soy  contains protease inhibitors, which frustrate the body’s digestion of  protein.  Studies show that this could cause the pancreas to be  over-worked in the digestion process, and eventually lead to pancreatic  dysfunction.   Protease inhibitors are found in especially high amounts  in raw soy – one reason raw soybeans are considered toxic.  Heating and  processing the soy lessens the amount of protease inhibitors  considerably, but it is never completely eliminated.

Phytic Acid  (or Phytates)

Soy (and many other grains, as well) contains phytic  acid, which acts like a magnet for many important minerals, such as  calcium, magnesium, zinc, and iron, therefore preventing their  absorption into the body. Though phytic acid can also help with ridding  the body of unnecessary and/or unwanted heavy metals such as lead and mercury, this cleansing effect is bad news for those who rely heavily on soy for mineral content in their diet, such as those in developing nations.

What About Soy in Asian Cultures?

Photo by Janet Hudson

Many people are understandably surprised when they discover the negative effects of soy, and often point out that Asian cultures have eaten soy  for thousands of years, with seemingly great health benefits.  There are two important factors to consider here.

1.  Asian cultures have  historically eaten soy primarily in its fermented forms: miso, tempeh,  soy sauce, and tamari are all fermented soy products. The fermenting  process significantly lessens the protease inhibitors and phytates in  soy, almost to the point of elimination.  Tofu is the only non-fermented  form of soy that has been historically common in Asian cultures.

2.   Traditionally, Asian cultures have eaten these soy products in small  amounts, more as sauces and condiments than main dishes.  A typical  starter of soup with three cubes of tofu is very different from a  tofu-based entree where tofu is acting as a meat substitute.  The  average Asian diet in China, Indonesia, Korea, Japan, and Taiwan  includes between nine and 36 grams of soy per day.  Compare that to a cup of tofu (252 grams) or soy milk (240 grams).

In our home, we  do occasionally eat small amounts of fermented soy, such as tamari and miso. But we completely avoid the newer forms of highly  processed soy products such as soy milk, soy protein isolate (common in  protein and energy bars), soy protein powder, and soy cheese. These products are outside the realm of historical understanding and consumption of soy in  Asian cultures.  In addition, some of them, such as soy protein isolate,  contain much higher concentrations of phytoestrogens than  less-processed, more traditional soy forms.

A Few Last  Things To Consider

The soy industry is exactly that – an  industry, with the goal of making money.  They want to convince  us that soy is a miracle health food, and they have invested millions  of dollars in marketing to do just that – quite successfully, I would  add.  For every risk I mentioned above, there is another study that  contradicts that risk and wants to call me crazy.

Soy is not  without its benefits, I admit. But I encourage you all to check out the  facts for yourself. There is just too much evidence of unnecessary  risk for me to consider soy products to be an acceptable food source in  our home.  What about you?

Learn more about soy from these  sources, which I used in writing this article:

Nourishing  Traditions, by Sally Fallon
The Whole Soy Story, by Kaayla  T. Daniel, PhD
Whole Soy
Soy Online
Soy Alert: Health Food or Danger?
Natural  Health News: Be Aware of Soy Risks
Do Soy Foods  Negatively Affect Your Thyroid?
Wikipedia: Soybean

Have you ever heard about these  risks associated with soy?  What do you think?