Harmful or Harmless: Soy Lecithin | Chris Kresser

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. 2 years ago I had breast cancer – estrogen receptive positive – I try so hard to avoid soy because of the estrogenic effect but as you said, it is nearly impossible. Is soy lecithin dangerous for breast cancer survivors? I keep getting mixed information.

    • My cousin is fighting this kind of cancer and the only two studies I was able to find said that there were no measurable phytoestrogens in soy, though Dresser’s article says there are. Now I don’t know what the truth is. My cousin was taking the lipsomal C which is made with non GMO soy lecithin. We talked My Sunflower Oil into making lecithin granules so we could make it at home, but even sunflowers have phytoestrogens. Someone needs to find out the truth about this. No articles or studies out there agree on this issue.

  2. Just want to say that after having severe hives for suddenly for several years I have finally narrowed it down to happening when I eat foods that have soy lecithin. Everything from cheese, chocolate, red vine candy to all kinds of frozen foods….interesting I seem to be able to eat soy products just fine.

  3. I generally avoid soy as much as possible (except for the small amounts of raw fermented organic soy sauce and soy lecithin in some chocolates). However, I do eat about 2-3 tablespoons of whole flax seeds per day. I read somewhere that only ground flax seeds have estrogenic effect on the body and that whole flax seeds are ok to consume. Is this true? And, what about chia seeds? Do they contain phytoestrogens as well?

  4. I am a breastfeeding mama and recently had several clogged ducts. I was told to take a tablespoon of soy lecithin a day because it thins out the milk (without lessening its quality) so that its easier to loosen the plug. I took it because I was doing everything possible to avoid mastitis and having to take antibiotics. Not sure if it made a huge difference but I was able to unclog the ducts and not get an infection. Any idea why it would thin breastmilk?

  5. I do some dietary coaching and have been recommending lecithin to people I can’t get to give up veganism, on the grounds that however good it is or isn’t a choline deficiency is worse. Would you disagree with that? Any thoughts on dosage to get the best risk/benefit ratio?

    • give up NOT eating meat? are you insane?

      i wouldn’t touch animal product if my life (and it does) depend on it.

      i’ve been eating unprocessed soy for decades… now.. when i was ingesting dairy, my life was a nightmare.. since i stopped ingesting what was suppose to be good for me all the issues halted.

      i wonder who is telling the truth? i wonder who is on the USDA side and who IS on the SOY side. ? makes one wonder doesn’t it?

      someone is getting kickbacks. soy is better, overall and sorry all processing is bad.

      do some research, key points: arteriosclerosis.

      • Soy issues are often allergies. It’s like a celiac who continues to eat gluten which will make that person very sick, even in small doses. It is great that you obviously have no allergies to soy.

  6. One good easy homemade chocolate treat is a couple of tablespoons of melted coconut oil (or about 1/2 inch) in a glass custard cup; add powdered chocolate to taste (1 tsp or a little more), and for a good taste, 1/2 tsp or so maca powder ( I use the cooked kind, i.e. not raw, b/c of thyroid issues). If you want more sweetness, add a couple of drops of stevia liquid. Stir of course. Then freeze for about 1/2-1 hour. Easy to remove by pressing a sharp knife down the side. It usually pops up. Sometimes I need to run hot water on the inverted cup for a few seconds; then it pops out. Then eat it like a “bar” of sorts right away, before it melts.

    One of my favorite additions is very finely chopped ginger (Cuisinart).

  7. Chris,

    The article is good but does not provide the meat that I was looking for. If you decide to dig more into it, here are the comments.

    Soy lecithin, apart from additives, I think it can be a very good supplement for brain function, if and ONLY if, the phospholipids in the lecthin piece are untouched and not getting modified in some way in the chemical process.
    Then what amount of phytoestrogens do these lecithin blends contain. Is there any limit? Is there any source to find which supplement (not additive) contain what amount of phytoestrogens?
    When the supplements mention, like phosphatidylcholine or Phosphatidylserine, is sourced from Soy lecithin, 500mg of lecithin contains 100mg of the above stuff, then what is rest 400mg? Is there any way that you can find this information (apart from the manufacturer). Supplement market is not regulated by the FDA (but it should by some body), so they can make all wild claims that they like but they do not suffer from it. The user does.
    What is the difference between Soy lecithin and Sunflower lecithin, for example?
    I think, I will stop for time being.

    Like the way you write your articles though, with scientific proofs but just avoid Life Extension articles style, where they cherry pick their references.

  8. Sorry Aysin but that article did not show why the Japanese live longer than anyone else…… they regularly consume soy….and lots of iodine but that is no answer.

  9. I had never before heard of soy lecithin. I’ll share this information. Thanks for posting! I think the main point here is that the food industry uses too many chemicals and additives in general. We need to eat natural foods like we were meant to!

  10. For all of the people that love chocolate and worry about the ingredients, you should learn how to make your own. It’s easy, 100% healthy and much less expensive than buying it.

        • Here is the recipe I use.

          In a double boiler add and mix 1/2 cup raw cacao nibs, 1/2 cup nuts, 2 cups raw cacao butter, 1 tsp coconut oil, 1/2 cup raw cacao powder, 1/2 cup (or more to suit your taste) xylitol. (if you don’t have a double boiler you can use a large and small ceramic plate)

          Gradually mix in dry ingredients after butter, coconut oil and nibs melt.

          pour in mold or on a plate and refrigerate for 1 hour.

  11. Thanks for this informative, balanced information! I really appreciate your level-headed approach to foods that others in the alternative health community might just blindly condemn. I have found (and I think you would agree based on your “beer-and-pizza-diet” story) that you cannot underestimate the role of happiness in promoting health and wellness. Of course if you react badly to something, you shouldn’t eat it. However, I believe constant, irrational food paranoia is almost certainly a major stressor to the body. I’ve felt much better on Paleo since I have loosened things up a bit and adopted a more light-hearted approach in which pleasure and happiness are factored into my “should I eat this” equation. It is nice to know I needn’t spend too much time fretting over occasional soy lecithin.

  12. I consume flaxseed for its phytoestrogens and avoid soy for its phytoestrogens, because they are different.
    Flaxseed phytoestrogens, lignans, reduce body’s utilization of more estrogenic hormones by making use of themselves, which are so little estrogenic that they make an antiestrogenic effect on the body.
    On the other hand soy phytoestrogens make an estrogenic effect in body.
    I felt like Chris was making a different point about it, maybe someone can explain what was implied more detailed. Please explain if what I do may be bad.

  13. I remember I’ve read something like soy lecithin caused brain shrinkage,probably in rats. I searched for gmo “soy lecithin” brain and one of the first links gave enough information for me to stop and at least forget about not minding consuming gmo soy lecithin. I will also be cautious about gmo soy lecithin being used in anything I consider consuming though gmos in human food is forbidden in the country I live in, luckily I do not buy processed foods.

    http://www.livestrong.com/article/524606-what-are-the-dangers-of-soy-lecithin-ingestion/

  14. While it is true that the amounts of soy lecithin may be small in chocolate, I think we need to apply more pressure to the food industry to eliminate soy additives from our food. And it is more than just about personal health. We need to focus on the larger picture of what soy production is doing to the environment and to the health of those other than ourselves. You might want to view the film available for free online Argentina’s Bad Seeds to see what the soy industry is doing to the populations who have been affected by the expansion of the soy industry in Latin America.

    Also, even in brands of extra-dark chocolate (85% cocoa and above) that do not have soy lecithin, their lighter products such as milk chocolate do have it. I am thinking for example of the one brand of extra-dark choclate that Trader Joe’s still sells that is soy free. Their fair-trade organic line appears to have disappeared.

  15. I read recently that the greater portion of the soy in products here in the United States is grown and processed in China. There are no standards in China to regulate whether they use GMO seeds or the manner with which they process the soybeans. How much of this is true?

  16. Okay for some but not for me. I was eating Aldis 85% chocolate & started getting belly ache. Someone looked at the ingredients and saw it has soy lecithan as an ingredient. I then started to eat 85% Lindt and was fine. No tummy ache.

  17. Thank you for your balanced approach once again to diet and supplements with excellent scientific support. 🙂

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