Harmful or Harmless: Soy Lecithin | Chris Kresser
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Harmful or Harmless: Soy Lecithin

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soy lecithin, is soy lecithin bad for you
Is soy lecithin bad for you? iStock.com/sergeyryzhov

Soy lecithin is one of the most ubiquitous additives in our food supply. It’s used primarily as an emulsifier, and you can find it in everything from salad dressing to tea bags. Paleo dieters avoid the brunt of it by eliminating most processed foods, but it almost always pops up in chocolate (everyone’s favorite honorary Paleo food) and often appears in supplements.

I recommend avoiding soy as a general rule, but consuming small amounts of soy lecithin as an additive is very different from, say, eating a soy burger  topped with soy cheese or drizzling soybean oil on your salad. This article will probably be more than you ever wanted to know about soy lecithin, but I wanted to do my best to get all the facts out on the table.

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What Is Soy Lecithin?

The term ‘lecithin’ can have different meanings depending on the context, but for our purposes, it refers to a mixture of phospholipids and oil. Phospholipids are a component of the cell membrane in all plants and animals, but lecithin is most often derived from sunflower kernels, rapeseed (canola), milk, soy, and egg yolks. (1)

The specific composition of soy lecithin varies depending on its manufacturer and intended use, but on average, it contains about 35% soybean oil and 16% phosphatidylcholine. (2) Phosphatidylcholine is a type of phospholipid that is abundant in liver and egg yolks, and is the primary form of choline found in foods. (3) The remaining percentage is other phospholipids and glycolipids.

To make soy lecithin, soybean oil is extracted from the raw soybeans using a chemical solvent (usually hexane). (4) Then, the crude soy oil goes through a ‘degumming’ process, wherein water is mixed thoroughly with the soy oil until the lecithin becomes hydrated and separates from the oil. Then, the lecithin is dried and occasionally bleached using hydrogen peroxide.

There are many claims online about soy lecithin being full of nasty chemicals left over from the production process. Not surprisingly, there aren’t many credible sources describing the chemical content of commercial soy lecithin, but I have found some relevant data about the safety of soy lecithin.

Before the ‘degumming’ step where lecithin is removed, the crude oil undergoes a multi-step process to remove the hexane. (5) However, it appears that the FDA doesn’t regulate the amount of hexane residue in food products, and one paper estimated that the residual hexane concentration of soy oil is 500-1000ppm. (6) So, it’s very possible that similar concentrations remain in the soy lecithin. (For comparison’s sake, the concentration limit for hexane in pharmaceuticals is 290ppm.) (7)

According to one analysis, total pesticide residues in crude soy oil are around 400ppb. (8) Since the pesticide concentration of the oil after degumming is similar, it’s pretty likely that some of those pesticides end up in the lecithin as well.

While it’s unfortunate that soy lecithin likely contains pesticides and solvents, I would just encourage you to keep this information in perspective. We’re exposed to hundreds of chemical toxins every day in our air, water, household products, and food, and contaminants in soy lecithin will contribute only slightly to your overall toxic load. After all, we’re talking parts per million and parts per billion, and soy lecithin itself usually makes up no more than 1% of processed foods. (9)

Of course, in an ideal world, we would be able to avoid these things altogether, and I certainly recommend reducing your exposure as much as possible. It’s also a good idea to make sure your detox systems are functioning effectively. But unless you have a severe chemical sensitivity to hexane or pesticides, occasionally consuming small amounts is not worth getting bent out of shape over.

Allergies

Soy allergies are triggered by soy proteins, so whether lecithin triggers an allergic response or not depends on its protein content. One analysis found protein concentrations ranging from 100 to 1,400ppm in six different soy lecithin samples. (10) (For reference, the new FDA gluten-free labeling law requires a gluten concentration of less than 20ppm.) (11) Another analysis of six different lecithin samples found that four had sufficient protein to trigger an IgE-mediated response in people with soy allergies, while two contained no detectable protein at all. (12) However, another study performed similar testing and concluded that even if protein is present in soy lecithin, it’s not a significant allergen for people with soybean allergies. (13)

It’s clear that the source of the soy lecithin is a major determinant in whether or not it will present a problem for those with soy allergies, but if you have a soy allergy, I’d say better safe than sorry. However, because protein is present in such a low concentration, and soy lecithin itself usually makes up no more than 1% of processed foods, it’s probably not a problem for those with minor sensitivities to soy.

GMO

Most of the soy grown in the US is genetically modified, so unless the label says ‘organic soy lecithin,’ it probably came from a genetically modified soybean. You know I’m not a fan of GMOs, due to the presence of potentially transferrable DNA and potentially immunogenic proteins. However, as I discussed in the section on allergies, soy lecithin contains very little soy protein, and lecithin from some sources contains no detectable protein at all. Soy lecithin also contains very little DNA, and the DNA present is usually degraded to the extent that it’s impossible to tell whether the soy is genetically modified or not. (14) Thus, most of the risks associated with consumption of GMOs aren’t relevant for soy lecithin, and shouldn’t be cause for concern.

Phytoestrogens

Soy is the greatest food source of phytoestrogens, and one group of researchers discovered significant estrogenic activity in soy lecithin. (15) Interestingly, none of the soy lecithin they tested contained genistein, which is the predominant phytoestrogen in soy. They concluded that “a so-far unidentified estrogen-like compound” is present in soy lecithin that accounts for its estrogenic activity.

We know how problematic phytoestrogens can be, but again, the dose makes the poison. Remember, soy isn’t the only source of phytoestrogens we’re exposed to. (Did you know that flaxseed is also a significant source of phytoestrogens? In fact, one study showed that supplementation with ground flaxseed altered estrogen metabolism even more than supplementation with soy flour.) It’s definitely best to keep phytoestrogens to a minimum, and individuals dealing with cancer or fertility problems might want to avoid them more strictly. But for most generally healthy people, the small amounts of phytoestrogens from soy lecithin shouldn’t be a problem.

Toxicity

One study that has been used widely as ammunition against soy lecithin is titled “Effects of a Commercial Soy Lecithin Preparation on Development of Sensorimotor Behavior and Brain Biochemistry in the Rat.” Researchers found that soy lecithin in concentrations of 2% and 5% in the diets of pregnant and newborn rats resulted in impaired reflexes and swimming ability, along with other cognitive deficiencies.

It’s important to understand that these effects are due to choline toxicity, not soy lecithin per se. The elevated brain/body weight ratios, plus elevated acetylcholine and choline acetyltransferase levels that resulted from soy lecithin supplementation were caused by the phosphatidylcholine, and would’ve still occurred even if they had used a source of phosphatidylcholine other than soy; even egg yolks.

It would be very difficult to consume as much choline as these rats did, especially from soy lecithin. In fact, most people are deficient in choline! This is just another case of a study being misinterpreted, and you certainly don’t need to worry about soy lecithin causing developmental problems.

Therapeutic Uses

I believe I’ve covered all of the main concerns about soy lecithin, but it’s worth mentioning that soy lecithin is also being recommended and consumed as a dietary supplement. There is a growing body of research supporting its use for improving blood lipids, reducing inflammation, and treating neurological disorders. (16) For instance, one study found that after 2 months of supplementing with 500mg of soy lecithin per day, total cholesterol levels fell by 42% and LDL levels decreased by 56%. (17)

However, most of these studies involve supplementation with a purified form of soy lecithin, which usually contains less soy oil and more phosphatidylcholine than the commercial soy lecithin that shows up in foods. Additionally, isolated phosphatidylcholine is often referred to as ‘lecithin’ in scientific contexts, so some studies supplementing with ‘soy lecithin’ are really just supplementing with phosphatidylcholine.

So once again, it’s not the soy lecithin; it’s the choline. Luckily, you can derive all the benefits of phosphatidylcholine supplementation just by increasing your consumption of choline-rich foods like egg yolks and liver.

So, What to Do?

The only people who need to make a point of avoiding soy lecithin are those with severe soy allergies or chemical sensitivities, and of course, those who notice that they personally react badly to it. And if you don’t have a soy allergy, almost all of the remaining concerns about soy lecithin (pesticides, solvents, and GMOs) can be completely eliminated by purchasing products that contain organic soy lecithin.

But for the vast majority of the population, even conventional soy lecithin isn’t worth worrying about one way or the other. If it’s just as easy for you to avoid it as it is to consume it, then do so. (For example, Enjoy Life is one popular brand of chocolate that is soy-free.) Ultimately, I think most people can just enjoy their occasional chocolate treat without worrying about whether it contains soy lecithin.

374 Comments

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  1. Bumble, I think it’s clear from what Chris has written, that soy lecithin is not something to be concerned about. I assume this would also apply to infant formula.

    Carolyn, from what I can glean, soy lecithin is much higher in phosphatides than sunflower lecithin. I believe the concerns of the soy source are overblown. According to Carlson Wade, author of Lecithin Book, What You Need to Know, published 1980, the best lecithin is pure lecithin granules which contain over 95 percent phosphatides and about 2 percent soybean oil.

    There’s a lot of good info on lecithin at Earth Clinic. http://www.earthclinic.com/Supplements/lecithin.html
    Apparently it’s the only thing that can detox hydrocarbons that build up in the body.

    • You need to read The Whole Soy Story by Kaayla Daniel and The Unhealthy Truth by Robyn O’Brien. Soy formula sets your baby up for thryoid issues, breast cancer and for boys a low sperm count. So, if you don’t want grandchildren feed your baby soy!

  2. All the formulas which is given to newborns as well come with soy lecithin as an emulsifier. Isn’t this dangerous ?

  3. The two latest comments about soy lecithin are interesting but when mentioning sources of lecithin fail to mention sunflower lecithin: perfect choice for those who may have problems with soy lecithin.

  4. I take soy lecithin daily. From day one, I noticed improvement in my short term memory. I am worried a little about the estrogen effect but so far I have no problem.

  5. I took soy lecithin for a month, and when I went for a cholesterol check up i was OFF THE CHART in terms of good to bad ratio. I had so much good cholesterol the doc told me to keep doing whatever the hell I was doing.
    I stopped taking it due to some research suggesting it would mishape blood cells, but im thinking low dose lecethin supplementation could be a good thing?

  6. Question: If eating Paleo is supposed to be so uber-healthy, why aren’t there any caveman running around? I mean, other than the 2 who did those Geico commercials & had a very short lived sitcom on NBC (I think..don’t quote me on the network) about 10 years or so ago?
    I’m just sayin’, lol.

  7. Wish I could find a diet like Nutrisystem that used whey-based products and not soy. I am an estrogen-positive breast cancer survivor and am quite overweight, and due to back issues cannot exercise. I do not cook and so would love to utilize one of those “meals already prepared” diets, but I cannot find any that are not soy based or that aren’t heavy in soy-bean oil.

    If anyone is aware of a meals-delivered diet company that has a good concentration of soy-free products, please let me know! I am desperate to get this weight off because I know my chances for survival are much better if I do.

    • You should take a look at Soylent (contrary to the name it is not a Soy based food). It does contain a small amount of Soy Lecithin, but other than that it is primarily made up of Oats, Brown Rice, and Corn.

      It may not be right for everyone but it’s worth looking into.

    • Lina,

      Where do you live? Google and see if there are any companies near you that make fresh paleo meals weekly – these will not have any soy in them. If you happen to be in DC/MD/VA check out Power Supply or if you are in NC/VA/DC/MD/Greater Philly/Greater NYC/Greater Boston area check out Custom Fit Meals. The company Pre-Made Paleo also makes paleo meals and they ship them all over the US. Hope this helps!

      And please know that all calories are not created equal! Eat whole foods, cut out all the processed junk (to include soda- diet and regular), and get rid of grains and that will help you get rid of the weight!

      Good luck!

  8. Hi all. Like a couple of other posts I am a breastfeeding mother who is having issues with recurrent blocked milk ducts. Lecithin supplements are recommended to prevent clogged ducts but the advised dosage is 3600-4800mg daily. I am right in thinking Chris’ article suggests this is not safe? I really want to crack this problem as blockage after blockage is soul destroying but don’t want to put either my own or my baby’s health at risk. If I can’t resolve the issue I think I will have to give up breastfeeding. Chris – are you still reading / responding to posts? Would you be able to offer any advice?

  9. I tried skimming through all these comments, FIRST, to see if my question was addressed, but I did not see it – so please forgive me if it was discussed already .

    I’d like to know if there are ANY soy products that are ‘safe’ to eat – in quantity – BESIDES organic? The main reason is – I was told – (BEFORE I knew about the ‘dangers’ of soy) that drinking soy milk, using soy flour, taking soy supplements, etc., is very helpful for women in peri and pre-menopause, and those in menopause, etc., to minimize symptoms and help with balance. Once I heard about soy being ‘bad’ for certain people (including those with a Thyroid issue), I stopped using it. What can you, Mr. Kresser tell me about this – and would you please respond to my e-mail? Thank you.

  10. I am very allergic to soy, with a very specific reaction that differs from my other allergies. It has been difficult to find the soy in my diet recently. I do my own cooking and usually eat very plain foods with nothing in them, but I have been using canned milk that doesn’t list soy, as others do. After looking up one of the E ingredients(E322), I found that it is lecithin, and most likely soy. I am certain that this is the source of my recent problems. It angers me to see sources saying that soy lecithin and soy oil do not affect people with soy allergy. They do. It is also frustrating that most milk products are having soy added to them (canned milk and powdered milk). I drink fresh milk, but I like to use stronger milk as a sweetener. I’ve even come across cheese with soy, which I never would have expected. Even makeups are switching ingredients to soy. I all of a sudden have a reaction, and find they have changed their formulae. I have contacted several companies, but unless other people do to, it feels hopeless that things will get safer.

  11. dears.. eating an unprocessed soy bean is NOT the same. i’ve been consuming soy for 54 years and i hate to blow your kite into a tree.. but i’m fine.

    it doesn’t matter.. estrogen is in all things and plus it’s been processed so it makes no difference what it is processed soy, dairy, other packaged nonsense, refined foods are bad for you, period.

    so, don’t blame soy… blame the industry of processing.

    learn something, i grew up in processing and i’ll tell you this much.. there’s a reason why i don’t eat those foods.

    and if you want an estrogen giant.. talk to the USDA about all it’s propaganda and what they’re hiding.

    move along, nothing, as usual to see here.

  12. Chris where are your federal based evidence data in this sory?
    Fact: There is no federal government clinical studies on the health effects of genetically modified/engineered soy and GM soy by products including GM soy lecithin according to the FDA and CDC.

    Fact: The CDC recognizes GM soy and GM soy products as one of 8 major allergens and USDA states over 91 percent of soy and soy products is GM.

    Fact: GM soy and GM soy products in the majority of processed food in the US according to FDA and CDC study 1996-2007 showed 18 percent increase in children food allergies.

    Fact: GM soy and GM soy products are mandated by government food/health agencies in 64 countries to be labelled but not in the US. And China bans direct consumption of GM soy.

    None of these facts should give the consumer confidence in the safety of GM soy lecithin

  13. Although outside the scope of this article, which is health focused, I wanted mention that some people like me avoid soy for policial reasons. There is over production of GMO soy in this country and it is ruining our biodiveristy and putting small farmers (organic and non) out of business. It concerns me that it’s a byproduct of soy processing and I wonder if the industry is just trying to find new places to put it. I don’t understand why it’s in tea (which is what led me here to be begin with).

  14. I don’t know if anyone is still posting/responding, but what about soy lecithin in teas for someone struggling with low T3, normal T4 (or euthyrodism, which Dr. Kresser has written about before)???? It is not an allergy. I was given two boxes of wonderful sounding tea for Christmas…but with soy lecithin…. Do I avoid them to be safe, or can I enjoy them guilt free?

    • Everyone should be aware that if you take Synthroid or its generic equivalent – thyroxine – that soy is CONTRAINDICATED as it reduces the effectiveness of the drug. I found this out after a partial thyroidectomy but the info on the pamphlet enclosed with your prescription isn’t stated until the end – after the chemical diagrams! Anyone with thyroid issues should avoid all soy products.

  15. Hi Chris,
    I don’t understand. You say ” it’s not the soy lecithin; it’s the choline.” If the Soy is the carrier of Choline, then the problem IS the soy lecithin.
    You also say, that products have so little amount in them. If you add all the products we are consuming that have soy lecithin, then that’s a problem, too.
    Plus, if they are spraying it in fruits and vegetables to get them ripe, then we can’t really avoid it, can we?
    Please clarify,
    Thank you

  16. Chris,
    Don’t you think that the overall list of content in soy lecithin (small dose or not) seem quite worrying? Forget about what the studies (so far) are telling us, but in terms of the actual compounds or processes themselves, most of them hold some sort of potential health risk. You say it yourself, soy lecithin appears in all kinds of foods, I know, because I am going out of my way to avoid it, a job which calls for huge determination!
    I think it is important for spokespeople, representing medical science and industry, to keep in mind that not everyman thralls through the ingredient list to look and see if there are potentially contents that calls for further research before consumption. Most people TOTALLY rely on, that some kind of authority is looking out for their best of interest and health.
    If soy lecithin doesn’t cause any thread to good health, then why suggest “.. to keep phytoestrogens to a minimum, and individuals dealing with cancer or fertility problems might want to avoid them more strictly”. ? I am not looking for The Poisonous Dose of soy lecithin, I am far more concerned about slight alterations within the body’s automatic chemical responses, over time potentially leading to DNA mutations (cancer).
    I am not suggesting that soy lecithin, being the isolated little tiny substance that it is, is the only one to carefully reconsider in terms of man’s overall health, there are many others: HFCS, Aspartame, Sodium Sulphite, Potassium Bromate, MSG/E621 as well as a load of others, including various E-numbers.
    -And I am sure that the individual item of food in its wrapping, on the supermarket shelf, only contain a very tiny amount, but have you noticed the size of today’s supermarkets and how many types of products each of them stock?!
    Unless you are Food & Health interested, there is no way that one’s ever going to read, reflect and reconsider which items should regularly be featuring in one’s shopping trolley and which ones (apart from on the odd occasion) should go back on the shelf.
    We really, desperately need some honest guidance from the ‘Experts’, i.e. people like yourself!
    Because people (including myself) read this kind of stuff, in the hope of receiving some kind of ‘truth’ in what to do.

  17. my doctor advised to take 1000 Lecithin and 1000 Arginine daily for neuropathy in hand and feet, most likely due to diabetic.

    After reading all the info I wonder if it is worth the risk since I also have high blood pressure.

  18. MJ I am a BC survivor as well and I was told that soy lecithin is not dangerous. In fact my oncologist is not freaked out about soy at all really. She said in moderation is fine.

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