A lot has been written about the dangers of soy. In acne forums people strongly advice cutting it out of your diet because of its acne causing effect. But what does the evidence say? Is there a good reason to believe soy causes acne or other health problems?
Leading the charge against soy is Weston A. Price foundation with a cornucopia of soy fear mongering. Chris Kresser continues by labeling soy as toxic food and implying that eating it makes men sterile.
All of that looks scary enough to put most people off soy. While the arguments against soy sound ‘sciency’ they are actually based on really poor evidence. Mostly on preliminary and animal studies and the occasional outlier result. What you don’t hear about are the good quality and informative human studies showing the real picture of soy.
In this post we’ll take a level-headed look at the evidence for and against soy. And in the end try to understand the effect soy has on acne.
Can soy cause acne?
The easiest way to answer whether soy causes acne is to look at relevant studies. Unfortunately we have none. Well, there’s this one study that reported less acne is group that ate more soy, but it’s better relegated to tooth fairy science than taken as real evidence.
Looking at anecdotal evidence (forum posts and other user reports) is a good way to get confused. Some say soy caused their acne. Some say their skin got better when they started eating more soy.
We have really no direct evidence to say either way. So we have to look at what we know about soy and from that infer how it affects acne. Far from perfect, but that’s all we can do at this point.
The possible ways soy could cause acne include:
- Hormonal effects of isoflavones in soy
- The effect of phylates in mineral absorption and balance
- Allergic reactions to soy
Can soy cause acne summary
There’s reasonable evidence to suspect soy can cause hormonal disturbances in women and that could worsen acne for some women. Soy allergies are another potential cause of acne. Soy allergies, however, are fairly rare.
On balance there are many ways soy can help with acne. It stabilizes blood sugar levels and reduces insulin resistance. And its antioxidant potential rivals that of fruits.
Now, let’s look at the above points in more detail.
Hormonal effects of soy
Much has been made of the isoflavones in soy. They are called as plant estrogens because some studies suggest they may have an estrogen-like effect in the body. Some people say these hormonal effects are the reason soy causes acne.
Soy can cause hormonal disturbances in women
In women there’s a delicate balancing act between female and male hormones. Excess of either can cause health problems. Women with acne often have slightly too much male sex hormones (androgens) in relation to female sex hormones (estrogens).
Soy, like all phytoestrogens, can tip the balance towards androgens. It does this in 2 ways. Phytoestrogens bind to the same sites in cells than ‘real’ estrogen does. However, phytoestrogens are thousands of times weaker than real estrogens – they don’t have the same effect on the body. What this means is that phytoestrogens block the effect of real estrogens.
Phytoestrogens can also lower the amount of estrogens the body produces. Estrogens are actually made from androgens. The body uses an enzyme called aromatase to convert androgens into estrogens. Phytoestrogens can block that conversion. This of course leads to situation where you have too much androgens and too little estrogens – the very imbalance that causes hormonal-type acne. Some studies show 20 to 30% reduction in estrogen levels after a month on phytoestrogen-rich diet.
This alone should give a pause to any woman with acne. Such a reduction could easily lead to acne for women prone to hormonal acne. That’s why it’s a good idea to treat phytoestrogens as a potential suspect and see if eliminating them helps your skin.
Soy and male sexual health
Soy won’t make you impotent. The effect of soy on male sexual health has been studies several times. Studies overwhelmingly show no effect on sperm quality, motility, volume, etc.
Similarly the effect of soy on male sex hormones is weak to non-existent. Some studies did show a minor reduction in DHT and free testosterone levels, which would be good for acne. But these results could just show statistical ‘noise’ rather than any real effect.
Soy and hormones conclusion
There’s evidence to show soy can cause hormonal disturbances in women, and these could lead to acne. There’s no evidence to show soy has meaningful hormonal effects in men.
Effect of soy on mineral balance
This is actually one of the legitimate concerns. Soy, like most legumes and grains, contain phytates that bind to minerals in the digestive track and prevents them from being absorbed. Studies often show a dose-dependent relationship, i.e. the more phytate in the mix the less minerals are being absorbed.
I’ll focus on zinc here because it’s the most relevant mineral for acne patients. Also, new studies show that iron and calcium abruption from soy products is similar to that of animal foods.
Zinc
This is a potential concern for acne patients. A few studies have shown positive effects on acne from zinc supplementation. If soy reduces zinc absorption it can potentially affect acne. The situation is made worse by the fact that animal foods are often the richest sources of zinc. So replacing animal protein with soy protein can do double damage: lower overall zinc intake and reduce its absorption.
In a context of otherwise balanced diet this shouldn’t be a problem. One study looked at the effect of 2 to 3 portions of soy foods per day on mineral status in women. The participants were divided to two groups: soy food and animal food. After 10 weeks there was no difference in iron or zinc levels between the groups.
Conclusion
Soy-based minerals may have lower bioavailability than minerals from animal sources. This is partly offset by the fact that soy (and legumes in general) is a rich source of many minerals. There’s no good evidence that even daily consumption of soy would be a problem in the context of otherwise healthy and balanced diet. It may be a problem, if soy and legumes make up a significant portion of your diet and you don’t eat any animal foods.
Soy can be allergic
The most common food allergens in the United States include egg, milk, peanut, tree nuts, wheat, crustacean shellfish, and soy. Best estimates put the prevalence of soy allergy in general population to less than 1%.
Food allergies are known triggers for atopic dermatitis and eczema. It’s possible that allergic reactions to food increase systemic inflammation in the body and possibly even damage the skin barrier function. So we have a reason to believe they can also trigger acne in acne-prone people.
Allergic or sensitive reaction to soy is the most plausible explanation for how soy can cause acne.
Effect of genetic manipulation
The majority of soy is now genetically manipulated, and some people suggest GM soy causes more allergic reactions than non-GM soy. This doesn’t appear to be the case. Studies show that there’s no difference in the type and prevalence of allergic reactions triggered by GM and wild varieties of soy.
Does GM pose other problems? Perhaps. Perhaps not. We have to wait for the evidence, and in case it’s not the subject of this post.
Acne helping effects of soy
Most soy-acne discussions focus on the detrimental effects of soy. Few people ever bother the mention how soy products could be beneficial. Here are a few good reasons to suspect eating soy is good for the skin:
- Good for blood sugar levels. Soy is very low GI and has a high percentage of fat (40% of total calories).
- Reduces insulin resistance. Because of 1) it stabilizes blood sugar levels and 2) studies show that isoflavones in soy can counter insulin resistance.
- Contains omega 3 fatty acids. Soy is one of the few plant-sources of omega 3 fatty acids.
- High quality and digestible protein.
- Antioxidant capacity comparable to fruits.
Other accusations against soy
Weston A. Price Foundation has launched a full-scale gish gallop attack against soy. I’m not going to deal with all the points they raised in this post. Because 1) they are not relevant to acne, and 2) avoid turning this post into full length book. Suffice to say their attack is based more on ideaology than science and evidence. Accusations are based on preliminary and animal studies, and they conveniently ignore better quality human studies that counter their claims.
The Journal of Nutrition published an easy to read and level-headed review of the evidence. Here’s what the author concluded.
Finally, other than allergic reactions, there is almost no credible evidence to suggest traditional soyfoods exert clinically relevant adverse effects in healthy individuals when consumed in amounts consistent with Asian intake.
Insights Gained from 20 Years of Soy Research – The Journal of Nutrition
Conclusion
Soy is accused of many crimes, most of which it is innocent.
There is reasonably good evidence to show soy can worsen hormonal disturbances linked to female adult acne. Studies show that eating foods with phytoestrogens can reduce the amount of estrogens in the body, and this could easily cause or aggravate acne in some women. Women should treat soy as a suspect food.
Soy allergies are fairly common, and food allergies can cause skin problems. Soy allergy/sensitivity is probably the reason it causes acne for some people.
On balance, soy has effects that are good for acne. Because of its nutritional profile, it can stabilize blood sugar levels and reduce insulin resistance. Furthermore soy is strongly antioxidant, its antioxidant capacity comparable to fruits praised for their antioxidant effects.
In the end, soy is just food, and we should treat it like one without ascribing overtly positive or negative qualities to it.
NOTE: Many of my comments below are out of date and incorrect. I learned about phytoestrogens causing female hormonal imbalances about 1.5 years after writing the original post and that part was added later. Most of my comments were written before that.
I am vegetarian almost vegan,and i am since 3 year and yes i am consuming lots of soy and ive been havind acne big problem all of a sudden. My cousin stop using soy because she notice having acne problem. My cousin acne went away ever since.My health food store lady told me there is to much estrogen in soy
Soy has no estrogen, it has compounds that act like estrogen in the body, but they are much weaker than real estrogen. And generally soy consumption has been shown to be good for hormonal issues.
Great information and great site.
Glad to hear you like it!
I like soy, but when I eat it, I get acne flare ups on my shoulders and my back. Nothing on my face. Only when it is : soy milk or yoghurt (no sugar added btw)
Do body creams with soy penetrate through skin raising estrogen?
As far as I know they don’t.
“What we put on our skin is just as important as what we put in our body; both affect the well being of our entire body (skin included!). The next time you slather on that chemical laden lotion or soak in a toxic tub, remember that your skin absorbs a large percentage of what you put on it.”
“the skin is our body’s largest organ, it is also the least vital. As our bodies were intelligently designed, studies show that nutrients absorbed internally are provided first to the most vital organs making our skin the last to receive these vitamins and minerals! These nutrients are necessary for healthy and younger looking skin!”
I’m sorry, but what does this have to do with soy? Not to mention that most of what you quoted is wrong. The skin absolutely does not absorb a large percentage of what’s applied on it. In fact, it’s a very good barrier and a lot of research has gone into developing ways to reliably pass drugs through the skin.
Chemical safety is a real and valid concern, and I fully support efforts to improve it. But these kinds of emotionally-laden, ‘all chemicals are bad’ arguments don’t help anyone. In fact, they make things worse. Because money and effort is spent on debunking silly arguments and developing ways to address ‘manufactured fears’, like parabens. All that time and effort could be invested into real chemical safety.
Hey Seppo, I am totally new to your site and this is one of the first posts I have read. I enjoyed this post on Soy and came across it when looking into how Soy may affect acne as I am eliminating dairy from my diet for a while. I decided on Soy because a Polish woman from my town told me that I should drink a lot of Soy during the second half of my menstrual cycle (I notice I break out in ALOT of tiny spots a week before my period every month) I kin of understand as she believed Soy contains Oestrogen so would therefore help balance the low Oestrogen and high Progesterone levels during this time of my cycle. But after reading your post obviously, since its a chemical acting like Oestrogen, it probably would not have that much of an effect?
Phytoestrogens can have some hormonal effects on the body. As far as I understand, they are quite weak though. That said, based on what Stefani over at PaleoForWomen.com writes, phytoestrogens can be bad for some women. Apparently, they can ‘trick’ the body into sort of ‘counting’ phytoestrogens are real estrogens. The body ‘thinks’ that estrogen levels are sufficient and thus produces less real estrogens. Unfortunately phytoestrogens are much weaker than real estrogens, so they don’t really have the same effect as real estrogens. This may lead to androgen/estrogen imbalances and hyperandrogenic problems, like acne. This is especially a problem for thin women.
Unfortunately, I’ve seen very little actual research on this. So I can’t really say whether Stefani is correct or not, but she says she gets lot of positive feedback from women who drop phytoestrogens from their diet.
Thanks for the speedy reply Seppo. Ah okay, I will check her site out and look more into it. Maybe I will just stay off ALL kinds of milk and stick to normal black and green tea – a cup of milky tea can be so comforting though!
I don’t think that little bit of milk in tea would cause any problems. It’s the dose that makes the poison. But if you want to be on the safe side, you can try almond milk, other nut milks, or rice milk.
Their so- called statement that there is no direct link to soy and acne is ridiculous. Every single person is different. If I consume soy, I’m guaranteed a breakout and I have a ton of proof. Some are fortunate and it doesn’t bother them. I would be happy to prove to these “researchers” that soy is directly linked to my problem.
Unfortunately a single case doesn’t prove anything. I’m sure we can find someone who breaks out after eating carrots. Should we point to that one case and warn everybody that carrots cause acne? Of course not, we have to look at what happens on a larger group of people. Of course we also have to keep in mind that there are individuals that react differently than most people do. That’s a limitation in all current medical science.
When we talk about soy today, we need to take info account whether it’s GMO or not. When it comes to soy milk, we also need to check the processing. i’ve read somewhere that the soy milk available in supermarkets have gone through processes that would cause breakout. So, it’s not just soy, it’s also what soy and how it’s prepared for consumption.
From what I understand there’s no good evidence to show GMOs are anymore dangerous than non-GMO foods. There are plenty of ideologically-motivated groups promoting bad science to further their ideologically-based position than GMOs are dangerous.
Furthermore, it doesn’t help to lump all GMOs. Some varieties may very well turn out to be dangerous, while others are perfectly safe. Safety has to be assed on a case-by-case basis.
So would you pick GMO mucked about with food, over natural grown food?
This statement is silly on many levels. First, you are ‘poisoning the well’ by implying GMOs are dangerous, or, to use the anti-GMO favorite word, ‘frankenfoods’. Also, GMO is a technology for modifying genetic properties of seeds and animals. GMO plants can be grown just as naturally as organic foods.
Would I choose GMO food over ‘natural’ food? Depends on what food we are talking about. If it’s something like Golden Rice over ‘natural’ rice, then absolutely yes. More often than not I just couldn’t care less if the food is GMO or not. By now there’s more than enough scientific evidence to show GMOs cause little to no health problems.
I’m not going to get into a GMO debate here. But if you are interested of a balanced overview of the GMO controversy, I recommend reading this article: https://theness.com/neurologicablog/index.php/the-gmo-controversy/. And here’s a good post that goes over various myths the anti-GMO side perpetuates: https://theness.com/neurologicablog/index.php/persistent-anti-gmo-myths/.
I’m all in favor of thoroughly evaluating safety of GMOs, and I don’t claim they are going to save humanity. At the same time, I have little patience of tired old myths and emotional arguments. If proven safe, we should use all the tools available to figure out how to feed the ever-growing human population in a safe and sustainable manner. GMOs more than likely play some part in that.
i am currently suffering from the effects of eating soya, spots and at times feeling sick/needing to sit down due to lack of energy. i accidentally ate a roll which was made using soya and now my skin has got lots of blemishes, where as before it was totally normal. Its a fact (for me and i don’t need it proven “scientifically) that is causes spots for me and also changes my monthly cycle. Once i stop eating Soya i have no issues with my skin or my monthly cycle. This GMO soya is terrible and shouldn’t be in food.
You might be confused on what science can and cannot ‘prove’. First, science doesn’t prove anything. It’s a process of gathering and evaluating evidence and formulating theories based on evidence. I would never say that science proves soy is 100% safe for everyone. That would be just silly. Take any food and you can probably find some people who get a bad reaction from it.
The point of this post is that there’s no real evidence to show there are any real concerns about soy. Yes, it’s fairly allergenic and that’s a potential problem. Phytoestrogens may also cause problems in some thin women with hormonal issues. But we are still talking about a small number of people and there’s no good reason that other people couldn’t or shouldn’t eat soy.
Furthermore, the problems with soy are unlikely to nothing to do with GMO.
Hi Seppo!
It helped me alot. Im trying to find acne free protein supplement since I go to gym 4 times a week. I’ve tried whey and Egg white so far. I am not going to try soy since i just read your article.lol I was wondering how about Pea Protein? Is there any research or scientific evidence? Thank you for your time!
Scientific evidence regarding what? Acne? Nothing specifically about pea proteins. Some aminoacids, like leucine, affect the mTor pathway, which is sort of a master regulator of acne. High levels of leucine AND insulin in combination can be bad for the skin. Since most proteins also have leucine eating a lot of protein could be bad. But I don’t think it’s a problem unless you also eat a lot of carbs to spike insulin levels.
High intake of soy increases igf-1, which is strongly linked with acne.
True, but I think this has more to do with the fact that they have a lot of protein. I’m pretty sure eating a lot of any food that’s high in protein would have the same effect. And if I’m not mistaken, you probably refer to studies where researchers gave post-menopausal women soy protein supplements in an effort to improve bone health. We have to keep in mind that the participants consumed a lot of soy protein supplements and it would probably be difficult to reach the same level of intake by eating food.
Good article. Is there any scientific research on acne causing effect of EGG? If there is no scientific evidence that egg triggers acne, I would like to try it out since I can’t take whey and soy protein anymore due to acne. I also heard Egg has antioxdant which is good for acne?? I’m considering to get Jay Robb’s Egg white protein..
There’s no specific data on eggs. Some people are allergic to eggs, but if you aren’t, then most likely they have no effect on acne.
On alot of websites, I see that fermented soybean such as Natto and Miso has much lower IGF-1 content than unfermented ones as a result of fermentation process. Do you think 2 serving of natto per day whould increase sebum production?
I have no way to reliably answer this. But my gut feeling is no.
So if you’re not supposed to eat phytoestrogens like Soy, flaxseeds, and sesame seeds, what foods should I eat to increase estrogen that’s not phytoestrogens? Every search for increasings estrogen produces a list of phytoestrogens with these three foods at the top of the list.
There are no foods (that I know of) that will increase your estrogen levels. Phytoestrogens actually don’t increase estrogen levels. They simply block the receptor sites for ‘real’ estrogens but are too weak to have much of an estrogenic effect. Plus they inhibit conversion of androgens to estrogens. There have been a handful of studies that show eating phytoestrogens regularly reduces blood estrogen concentrations.
Hey, I am trying to cut out foods that ‘can’ cause acne, so I came across your article. I have cutten out dairy products out of my diet, but I was wondering I would cut out like soy product too, there is not much left for yoghurt. I am saying this because I want to keep getting my probiotics. Do you maybe know an alternative for dairy- and soy yoghurt that are high in probiotics?
The best way to ‘get’ probiotic bacteria is to eat fiber that feeds the existing bacteria in the gut. Acacia gum is a good option. Probiotics, as supplements, don’t really work. They don’t have much of an impact on the gut bacteria. I don’t know if fermented foods work any better.
Soy tends to be problematic for women with acne. Eating soy regularly can reduce estrogen levels and worsen the androgen/estrogen imbalance.
I did an experiment. I cut all soy out of my diet. To my surprise, my once peaches and cream skin as a teen cleared up. I quit eating soy for about 4 months or so. But after having a Thai fit craving, I had broken down and thought well, let’s just see if this was a coincidence. Sure enough, 3 days later, my chin, jaw and neck broke out. Plus, I felt a bunch of fatigue and just not quite right. So done with the soy. (good bye Thai, I’ll miss you) So later on about 5 months later, my sister was hosting a party and made a dish with marinade with soy . I did not realize this as the chicken was grilled and lost the marinade coloring. You can guess what happened afterwards! Yep! I broke out like crazy. I went back thinking what I had eaten in the last 5 days and was baffled. So I called her up and she told me she had a soy based marinade. Moving along.. same thing happened when I went out to a steak house. NEVER even thought this high end restaurant would use soy as a base for their marinade. Bam! Hello breakout’s and severe fatigue. So this was going on an off for over 2 years. Recently, my family wanted Thai. I couldn’t take it! I sat there drooling, watching my son scoop up that golden slop with his spoon, obviously enjoying every single bit of that savory delicious highly aromatic meal, “Enough!” I gave in and decide: “Heck with it” and took his left overs. Yeah, I’m now paying the price as I look like I have the big dipper on my face. Coincidence? No. This happened during all cycles of them of the month, so hormones are not to play in this. It is soy! It plays havoc on my body!!!! After having so many out breaks after I have eaten soy, it’s clearly obvious, I can’t handle the stuff.
Where can I access the guide you referenced here?:
“To help you cut phytoestrogens out of your diet, I put together a short guide that explains the effect phytoestrogens have in your body in more detail – and we’ll go over the 3 foods you absolutely must remove from your diet. To access the report, just click the download link below and enter your details to the box.”
I can’t see the download link anywhere.
Sorry, that was an old guide and it’s not supposed to be there anymore. In short, foods with highest phytoestrogen content are soy, flax and sesame seeds.
In the summary at the beginning of this article, it states that soy allergies are rare. In the conclusion it states that soy allergies are fairly common. This contradiction is confusing. I like that there was a critical look at the pros and cons of soy, and a lot of references used and cited, but ultimately this seemed more like a college argumentative essay than a well advised article article from a subject matter expert. At least the information contained is helpful and allows one to further research and draw their own conclusions.