Friday, November 16, 2007

Soy: hero or culprit?

Since lately several ladies asked me what I think about soy, and especially the phytoestrogens in it, I decided to write an answer here.

You know what, as I noticed, is very characteristic of nutritional research, discoveries and guidelines? Trends. I remember how in studies from 10 or even 5 years ago, they just kept talking on and on about the benefits of soy, how good it is for everyone, how it prevents cancer and heart disease etc. And now it's suddenly the ultimate killer, worse than sugar, salt and MSG, responsible for every kind of cancer you can think of, and for premature sexual development and a variety of other nasty things.

So, while I don't mean to be disrespectful towards any of the experts, my own humble opinion is that the answer must be somewhere in between. I don't think soy is a killer. It has been widely consumed for many centuries in East Asia and I just don't find it credible that such a common crop is lethal.

I'd like to stress that I mean soy as soybean, not soy in processed, pre-packaged and frozen foods which I try to avoid like the plague altogether.

A couple of words about phytoestrogens. I know many people who are nearly hysterical about phytoestrogens and avoid soy in any form – why, phytoestrogens resemble hormones, what sane person would eat hormones with his food, they ask. Maybe the word "phytoestrogens" sounds intimidating and they just don't want to risk it, even if no studies have actually proved that eating soy in reasonable amounts causes harm. Yet these same people don't hesitate to eat meat of animals which have been given hormones to accelerate their growth. What is my point here? Be informed. Do not follow every trend and newspaper guideline and do your own research. Dig up a number of reliable review articles from well-known scientific journals.

Overall, my motto is 'everything in moderation'. If not consumed excessively, I don't see why soy can't have its place in a balanced healthy diet.

(PS: I was going to do a Show and Tell post today, but for some reason blogger won't let me upload pictures. Anyone else struggling with the same problem?)


Gothelittle Rose said...

I was told as a woman with endometriosis to avoid soy and watch out for plant-based estrogens. I don't know if it's true with soy, but I do know that I don't react well to medications with estrogen (like the BCP). It dumps me into a depression that does not lift for a minute until I stop taking it.

I like miso soup (homemade, not the super-salty store stuff), so I indulge once in a while.

What is the story of soy and estrogen for people who should be lowering their intake of the latter?

Anna S said...


If an expert told you to lower your intake of soy-containing products, I won't argue.

However, you must keep in mind that the activity of phytoestrogens isn't like activity of human estrogen. I don't remember exact ratios right now, but the idea is that for the same degree of activity, you'd need 1 unit of human estrogen and MANY units of phytoestrogens. In simple words, they are much weaker than real hormones.

I don't think you'd do yourself harm by a bowl of miso soup now and then, but again, I'm not an expert on endometriosis so you'd better check again.

Michelle said...

I totally agree with you - the answer lies in between. Though I don't mind soy nuts (although I don't really like them) and I use soy sauce in some foods, I kind of avoid it. Esp. soy milk. I will NEVER give soy milk to my boys because (this is just personal theory) I've seen time and time again boys that are total sissies because of the extra estrogen their mom's are giving them through soy milk. Unless they have a milk allergy, I'd use rice milk any day over soy.

Sammybunny said...

As a person with PCOS, I am not allowed to eat dairy for various reasons. I can however have goat milk and goat cheese. I also eat soy in SMALL amounts. I am with Anna, I think anything could probably be bad for you if you consume it like crazy (aka following trends). A common misconception about soy too in East Asia is that they don't eat a WHOLE bunch each day but a small amount whereas we Americans tend to replace a large amount of food with soy instead of eating a tiny bit during the day. I think maybe a lot of our health related issues with soy could be from overeating it during the day instead of a small amount.

Anna S said...


I believe in East Asia they eat smaller amounts of *everything*, while we eat huge portions. That's a major problem. Using smaller plates has worked for me!

tales_from_the_crib said...

picture loader works now!

PhDCow said...

What about babies that were fed soy milk? Both of my children had allergies to both my breast milk and regular milk-based formula, so they were fed soy formula. Any research on this?


pfg blogmatron said...

It might be helpful to google search "genetically modified soy" or "soy Dr. Mercola" while taking in all the information out there to decide.

I had the diagnosis of Stein Leventhal Syndrome(Polycystic Ovaries/PCOS). At the time not much was offered other than repeated surgeries(went through only one nasty experience) ~ nothing was mentioned about diet. Along the journey, after years of hormonal helps in the way of birth control pills or Provera and then even fertility drugs(and then add in years of antibiotics), I had the inclusion of endometriosis and a major issue with dysbiosis. The remedy for the dysbiosis was exactly the opposite of avoiding phytoestrogens. It was eating them in raw form to the extent that a friend joked it being like a cow grazing muchly(salad would be a dough bowl size for me alone). The end result for me was bye bye endometriosis and PCOS and infertility. Phytoestrogens bind the bad estrogen because they are lignans? I've read pros and cons on that, too.

Hope this helps us all dig, dig, dig to find what God has given us to be best toward wellness.

Mrs. Burrows

Terry said...

Anna, as a nutritionist, I'm really interested in your thoughts on drinking soy milk instead of cow's milk. My husband and one of my daughters are lactose intolerant. We turned to soy milk as an alternative. We all drink it with our cereal and my husband and daughter drink soy milk exclusively. Is this possibly an excessive amount of soy? I agree with you on the issue of moderation, but in this case we sort of have no choice. Or do we?

Kathleen said...

Helpful post, Anna! Thanks! I'm definitely turned off all the processed soy foods now :).

magda said...

soymilk does not turn boys into sissies. if you've noticed a connection, it is probably more due to the way that they are raised than the type of milk they drink. many non-white people have trouble digesting dairy.
did you know you can make your own tofu and soymilk from dried soybeans? it's much cheaper this way than buying the readymade products, and this way, you know exactly what's in it! here's an article on how to do it:

Anonymous said...

Anna, while your overall observations about soy in the diet are correct, I have two words of caution about certain groups that should avoid soy.

First, people with thyroid disorders should avoid soy like the plague. It contains goitrogenic substances which interfere with the absoprtion of thyroid meds and with thyroid function in general. Soy sauce is fine, because it is low in isoflavones, but I'm afraid for those of us with Hashimoto's thyoriditis and other forms of hypothyroidism, unfermented soy products are out. It might be okay every once in a while, but a soy-based diet could get a person with a thyroid disorder in serious trouble. I have literally seen my TSH skyrocket during a time period when I was consuming a lot of soy.

Second, I'd advise people who are trying to get pregnant to limit their soy intake. In women, high soy intake lengthens the follicular phase, which may decrease egg quality. A lengthened follicular phase, of course, indicates a lengthened uterine proliferation phase. In other words, women who have a high soy intake are likely to have heavier periods. That's not bad in and of itself, but for women with endometriosis, it can make the condition more painful, and for women with PCOS, it can increase one's risk of endometrial cancer, though probably only slightly.

In men, soy can affect sperm development.

In pregnancy, soy can also increase the risk of miscarriage, acting essentially as an early abortifacient. Even if the risk is theoretical or relatively small, Anna, women such as yourself who are obviously concerned about human life should probably limit their soy intake in early pregnancy to ensure that they don't accidentally abort their babies.

As a matter of fact, sexually active women who are anti-contraceptive should probably avoid soy altogether. Even if the actions of phytoestrogens are weak, they still have some hormonal action, and as such they have the potential to interfere with ovulation, conception, implantation, and pregnancy sustenance.

Studies have demonstrated that 100mg of soy isoflavones (one cup cooked soybeans or 2 cups soy milk) contains the estrogenic equivalent of a birth control pill. I do advise caution. Soy is probably fine to consume, but as in all things, moderation is the best advice I can give.


Coffee Catholic said...

I don't really like soy - except tofu. I'm a weirdo about tofu I LOVE IT!!! And yet, I'm a total meat eather hehe! GOD BLESS!

Kelly said...

Great advice Anna. Portions is really an issue here. We eat such LARGE portions of everything here.

Sara N. Smith said...

I just stopped by your blog for the first time - and I just wanted to let you know what a blessing it is. Your love for the Lord and His truth radiates through what I've read. The "dedicated daughters" post was very good!
May the Lord continue to bless you in amazing ways!

Anna S said...


In general, I'm *very* cautious about soy fed to babies and children, including soy milk and soy-based formula. A question: did soy formula help the allergy?


It's difficult to say for sure, but it does sound like a bit too much. Have you tried rice milk?

PhDCow said...


The soy formula helped immensely. They no longer had diarrhea associated with formula or colic symptoms. They were fed soy formula until they were 12 months and then they spent the next year drinking soy milk. Around 24 months, we transitioned them to whole milk without any problems, suggesting that they probably outgrew their intolerance. Interesting, both my mother and mother-in-law reported having to give us soy formula as babies, so it must be hereditary.


Anonymous said...

For those interested in reading about cautions on soy:

This says aluminum can be in some soy products:


Gombojav Tribe said...

I wonder why everyone worries so much about whole soy foods when they are not the only foods containing phytoestrogens! Here's a little sampling of other foods:

soybeans, cooked, 38.2 mg/ 1/2 cup
onion, 35.8
applesauce, 3.0 mg/1/2 cup
kale, 11.2 mg/1 cup
pinto beans, cooked, 1.9 mg/1/2 cup
garbanzos, cooked, 3.6 mg/1/2 cup
flaxseed, 28.9 mg/ 1 Tbsp
cranberry juice, 44.3 mg / 3/4 cup

We don't hear the hysteria to stop drinking cranberry juice or eating hummus.

If it's phytates that worry you: From Vegetarian Baby and Child:

Charts contained on pages 30-34 of Food Phytates (edited by Rukma Reddy and Shridhar Sathe, CRC Press, ISBN # 1-56676- 867-5) reveal:

The percentage of phytates in soymilk is listed as 0.11%.

Wheat has been called the "Staff of Life."

Durham wheat contains 8 times more phytates than soymilk (0.88%).

Whole wheat bread contains almost 4 times more phytates than soymilk (0.43%).

Wheaties, contain nearly fourteen times more phytates than soymilk (1.52%).

Let's use common logic here. If wheat contains more phytates than soymilk, then wheat should not be eaten either, right? What a silly claim soymilk detractors make. It is without merit.

A typical portion of breakfast cereal consists of two ingredients, cereal & milk. The proportions: three-quarters of a cup of Wheaties weighs 22.5 grams. One-half cup of soymilk weighs 122.5 grams. Ergo, the wheaties contain 342 milligrams of phytates. The soymilk contains 135 milligrams of phytates.

Now, let's get to the point of this. In their introduction and summary of the scientific substantiation to follow, the authors of Food Phytates write:

"Recent investigations have focused on the beneficial effect of food phytates, based upon their strong mineral-chelating property...The beneficial effects include lowering of serum cholesterol and triglycerides and protection against certain diseases such as cardiovascular diseases, renal stone formation, and certain types of cancers."

So you see, phytates are healthy for you. Phytates represent a prime example of using food for medicine.

Of course, if you happen to believe all of the negative soy hype, skip the Wheaties. Skip the soymilk. You can always have a corn muffin, right? Let's go to the phytate chart. What percentage of corn bread is phytates? Oh, no. Corn muffins contain twelve times the percentage of phytates as soymilk, or 1.36%. An extra-large 6-ounce corn muffin (168 grams) contains 228 milligrams of phytates, midway between the (3/4 cup) Wheaties and (1/2 cup) soymilk.

So, take your pick. All of this anti-phytate rhetoric is either A) serious stuff B) ridiculous propaganda. [end quote]

Moderation, eating healthily is all about moderation.

pfg blogmatron said...

In regards to the note on soy being goitrogenic & being an issue for those on synthetic thyroxine, many foods fall into the realm of "goitrogenic foods"(search google for that wording to see). Some sites claim eating raw and in excess is more an issue than eating cooked and in moderation(for chocolate lovers, one site gave that an all clear). I'm sure there are a myriad of pro and con opinion and experiential links on soy while it would be interesting to note which links take into consideration genetically modified/engineered versus organic and allopathic versus naturopathic philosophies/practices.

Very interesting topic ~ thanks for posting, Anna. :-)

Crystal said...

I've posted some links and such on my PCOS blog in regards to this.

I have PCOS so the first I heard about the dangers of soy was as I was learning what to eat and what to avoid to help my symptoms. It was alarming to read about how there are starving nations that refuse to eat soy, they'd rather starve. (The Whole Soy Story).
Also for those concerned about the rainforst they need to watch out about soy as forests are being clear cut to make way for soy crops.
Personally I don't think I've increased my amount of meat simply by taking out soy from my diet, I'm eating more whole food, whole grains, etc, which also are more filling and satisfying anyway.
It's a heated debate I know. And I know my thoughts on the issue. It was interesting to read your response.
There also has been and increased occurance of food allergies recently and soy is amoung some of the highest, right along with peanut and dairy. People are confused why so much of what they eat cause them problems, if they can take out those foods that can't tolerate they end up doing much better.
As for about the animals consumed. Yes it means spending more, but I try often to find local, organic and naturally raised meats. It all comes down to knowing what you are putting in your mouth in my opinion.

Anonymous said...

My mother has endometriosis and I began getting very heavy periods. Worried that I had inherited the same condition, I thought I should get tested. Then one day I learned that soy milk (I drink soy milk daily) has high levels of estrogen. I knew estrogen is somehow involved in the menstrual cycle. However, for some reason unrelated to this, I began to fill my ceral bowls with regular organic milk instead of soy. A couple weeks later I was looking at the calendar, confused, because I usually get very frequent, heavy periods. However, this month my period was on schedule and "normal." At first I couldn't figure out why. Then I realized the only thing that was different lately was the milk I was drinking. I did some research, and I am no expert; however, I truly believe this effect is somehow related to my intake of soy. (Everything else has been the same in my environment...stress, etc.) I am curious to hear your thoughts and hope this personal study is of some help.