Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
4 Jun

The Lowdown On Lectins

Little known to the public at large. Little understood by the health community. Omnipresent in our conventional food culture. Proven to be at least mildly detrimental for everyone and downright destructive for the more sensitive (and often unsuspecting) among us. We’re talking lectins today: common natural agents on the one hand, cloaked thugs of the anti-nutrient underworld on the other. Our popular health media, if they’ve heard of lectins, certainly never make mention of them. Famous health gurus never deign to speak of them. In short, lectins thrive in the American diet basically unfettered, unscrutinized. Make no mistake, however. They’re a menacing power to be reckoned with. I’ve addressed them on Mark’s Daily Apple in the past (Why Grains Are Unhealthy) and in my book (The Primal Blueprint), but I still get a fair number of emails and forum questions asking for more info. As I always say, let’s break it down….

What Are They?

Before Monsanto, Mother Nature had her own pesticide strategy. (Humans being among the “pests” to be warded off.) In order to avoid being completely decimated by insects, foraging animals and Groks, plant species evolved assorted anti-nutrients that would make said pests regret their gorges with a variety of mostly digestive related ailments. Low grade toxins, in a sense. A workable balance developed between plants that were able to safeguard their species’ survival and the “pest” patrons that were able to benefit from the plants’ nutrition but learned to partake more sensibly from their supply. Given that our primal forefolk foraged widely and ate a surprisingly diverse diet, the system worked.

Lectins are essentially carb-binding proteins universally present in plants (and animals). Just as they protect plant species from Grok-sized predators, lectins also support other immunological functions within plants and animals (against pathogense, parasites, etc.) They also assist in other functions like protein synthesis and delivery in animals. They’re relatively sticky molecules, which makes them effective in binding with their sought after sugars but undesirable for our digestion, in which their binding powers can lead them to attach to the intestinal lining and wreak havoc. (More on this in a minute…)

Given their omnipresence in nature, a certain amount of lectin consumption has always been inevitable. To the benefit of the plants, lectins are also hard to break down. Regular old digestive enzymes only do about half the job. Human ingenuity evolved across traditional cultures to “predigest” lectins through food preparation practices (fermenting, soaking, etc.). In our contemporary dietary culture, however, we too commonly skip these practices yet rely on the highest lectin-containing foods for our primary food sources.

What Foods Contain Them?

The short answer here is basically all plants and animal products (PDF) to varying degrees. Nonetheless, lectins are concentrated more in some sources than others. Foods with the highest lectin activity include: grains of all kinds (especially wheat), legumes (especially soy), nuts, dairy, and nightshade plants (e.g. eggplant, tomatoes, potatoes, peppers, etc.). Add to this list the oils and other derivative products from these food sources. And yet another, lesser known category: GMO food, since lectins are often spliced into modified varieties in order to enhance “natural” pest and fungal resistance.

What Do They Do To The Body?

Let’s go back to the intestine again. (Some field trip, eh?) Lectins’ stickiness allows them to bind with the lining, particularly the villi, of the small intestine. The result? Intestinal damage (with impaired cellular repair potential), cellular death as well as compromised intestinal villi, which means reduced absorption of other nutrients, including minerals and protein. Add to this altered gut flora, which can allow certain harmful bacterial strains like E. coli to run rampant. Furthermore, because the body is now responding full-time to the needs of the injured gut lining, proteins and other resources are redirected from other basic growth and repair processes. Furthermore, lectins have been associated with leptin resistance, a pre-diabetic condition linked to obesity.

Perhaps the most insidious impacts lectins can leave in their wake is this: leaky gut. Leaky gut is a term for the breach in the intestinal lining created by lectins hand in hand with other antinutrients. Once the intestinal breach exists, lectins and other particles (like partially digested food, toxins, etc) can “leak” into the bloodstream.

Once lectins open the door, so to speak, out of the small intestine, they and other fugitive particles are now free to move about the body and bind to any tissue they come across (anything from the thyroid to the pancreas to the kidneys). Of course, the body reacts to these invaders by directing an attack on these particles and the otherwise perfectly healthy tissue they’re attached to. Enter autoimmune mayhem. That’s why lectins are linked with autoimmune disorders like IBS, Crohn’s, colitis, thyroiditis, fibromyalgia, chronic fatigue syndrome, and arthritis. Specific lectins have been associated with particular ailments (like wheat with rheumatoid arthritis), but more research is needed to trace and confirm these connections. What is clear, however, is the potent autoimmune destruction that can result when the intestinal lining experiences this level of damage.

Primal Advice For Limiting Lectins

As mentioned, lectins are literally everywhere. Although it’s impossible to eliminate them altogether, you can significantly reduce your intake.

  • Purge the worst offenders. That means grains and soy more than anything, but I’d add other legumes to the list as well. Eliminating the foods that contain the highest lectin activity will slash your overall lectin intake – and impact.
  • Cut back on other higher lectin sources. Not everyone wants to nix every dairy or nightshade option. Look at how you can reduce your overall intake of these items while keeping enough to enjoy their flavor and nutrient advantages.
  • Gauge your sensitivity. For those of us who are most sensitive to lectins, more dramatic measures might be needed. If you know or believe that you’ve already suffered some serious intestinal damage, you might do well to steer clear of as many high and moderate lectin level foods as possible. That means perhaps forgoing nightshades, dairy, legumes and even nuts and eggs in addition to all grains and processed foods. Reintroduce desired foods back into your diet by “family” (e.g. dairy, etc.) and be mindful of any physiological effects (however minor) that accompany them.
  • Take up old traditions like soaking, sprouting and using bacterial fermentation techniques for any moderate/high lectin foods like beans you choose to keep in your diet. Fermentation methods are especially effective, virtually eliminating lectins in one study of lentils. All those kitchen rituals you remember from Grandma? They’re adaptive, essentially pre-digestive techniques practiced by traditional cultures around the globe. Going old school on your favorite nut varieties, for example, cuts those lectin levels dramatically.
  • Don’t go wholly raw. Yes, there are legitimate reasons to enjoy raw plants in your diet, but I don’t support the practice as a movement or exclusionary principle for eating. Humans have been cooking for well over a hundred thousand years. Some nutrients are enhanced by heat. Some anti-nutrients (like lectins) are at least partially “disarmed” by it. Cooking methods with a mind toward maximizing overall nutrient value and bioavailability make good Primal sense and can lower your exposure to lectins.
  • Diversify! Restrictive diets make us even more susceptible to the downsides of our foods. (Soy formula fed babies being a dramatic example of this principle.) Make Grok proud and forage more widely for your dinner. Research shows that simply rotating primary foods was enough to limit lectin-related damage in rats that were given rounds of soy feed. A healthy, mostly low lectin diet will offer enough balance and protective nutrition to blunt the impact of the occasional moderate level lectin sources.
  • Avoid GMOs. Hidden lectin is just one more reason to leave GMO products on the shelf.
  • Maintain good overall gut health. Our modern existence sometimes seems like one giant assault against our digestive tracts. Minimize cumulative negative effects and increase positive, protective factors. Eat a healthy diet with Primal doses of probiotics, prebiotics and good fats. Limit stress and the use of medications like aspirin, NSAIDs and antibiotics (as well as secondary exposure through antibiotic-administered livestock). A healthy gut will be better equipped to weather the effects of inevitable but reasonable lectin intake.

Now it’s your turn – for your comments, questions and anecdotes about lectin impact. Let me know your thoughts, and thanks for reading!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Healing or curing digestive difficulties takes a while. One must give the gut a rest, using a famous Indian dish called Kitcharie (mung beans and basmati rice), go through Pancha Karma and/or restorative body therapies for a 3-10 days period of time, taking appropriate herbs to correc the digestive symptoms and then learn about and introduce foods for your Ayurvedic constitution (it IS different for each individual. Stay on a healthy wholesome, non processed, non GMO, organic diet and appropriate herbs and probiotics for the rest of your life and after a few years the gut will heal. You cannot go back to the Standard America Diet. It is the processed foods which are killing us. Ayurveda is an ancient natural medicine that if practiced will produce good health. I am a testimony to this: curing arthritis, IBS, gastritis, and heavy metal poisoning in myself. Seek out a qualified Ayurvedic Clinical Specialist to help you with this.

    Laurie wrote on January 11th, 2013
  2. This is such a great article! Thank you for writing in laymans terms. Kinda difficult to shuffle through the scientific wordage on so many other sites. It would seem as though I am super duper lectin sensitive. Currently on a pretty extreme elimination diet to figure things out after years and years of doctor visits found nothing concrete. I realized this week apples bother me. So I started doing some research and am finding some good links and things are making sense. Although redesigning my entire eating regimen is a bit overwhelming. At any rate…thank you for this information!

    Nikki wrote on January 12th, 2013
  3. I have not read all the comments because they are so many, but this sounds depressing to me. It gives me an awful feeling in my belly to know we live in such a toxic world and everything is toxic. Toxic by nature or toxic by mandkind. Is there anything safe to eat? Everybody talks about “organic, free range, no GMO, etc” but all that is so expensive. Not all of us can afford tu buy “organic” or do we have it available. Any way, I have been asking over and over if somebody has some good info about nixtamalization to make corn “edible”. I have searched every where and CW says nixtamalization eliminates most of the aflotoxins but they do not say anything about lectins. I just want to know if there are studies that can tell me if nixtamalization does make corn at least 99% edible for humans (to much to ask?) lol. Any way, I have eliminated grains and legumes from my diet and honestly, I have not felt any different. Maybe it´s too soon. I started this diet almost a month ago. I eliminated them because of the high carb content, but reading about lectins makes me freak out!! But I still haven´t felt any significant change in my way of feeling by eliminating them from my diet. Thanks for any informative comments.

    Lila wrote on February 12th, 2013
  4. I’ve been sick for the last 2 years. I lost my job a year ago due to my medical issues. I have a hypermobile joints anyway and have recently had surgery on a couple of those to help them out but things have been getting steadily worse.

    Pain. Oh the pain. Now joint swelling (not with my genetic condition). Intestinal issues, trouble walking, muscle pain and now bone pain (scary), rashes and now irritated skin all over that even plain shower water irritates. Foggy brain, forever sleeping or insomina (pick a day/night), I can’t sit or stand for more than 10 minutes. I can’t even do basic food shopping or cooking anymore.

    I have always eaten unprocessed foods. I was vege for 18 years and started eating meat 11 years ago. I have my own chickens (fantastic eggs) and have family raised pork in my freezer, which I eat very little of.

    About a year ago I changed my diet to eliminate gluten and dairy which helped. In the past 4-5 months I have let that slide a bit to “mostly” eliminate. I don’t do soy and have cut out most nuts as they upset my stomach. Actually most things upset my stomach.

    I have been living on chia seed, hemp seed and almond milk smoothies as they sit well on my belly.

    I have some really bad flares every so often and my last one was right around New years which lasted a week. Probably all the crap I ate around that time in retrospect.

    About a week and a half ago I ate 2 sandwiches and some pizza. That put me in bed for a week in agony. Its what the FBI would call a clue.

    So I have been researching lectins. Thus here I am.


    Milk. If I want a cup of tea what do I do? I’m from the Commonwealth and I NEED milk in my tea and I NEED my cup of tea. Rice milk? Lactose free cows milk or almond milk? Which would be better for me?

    I get the soaking of the beans. If I am super sensitive, would that be enough for me?

    What about split peas? Split pea and ham soup out of the question? (My husband wants to make it and I don’t think I can eat it).

    I read somewhere that rice is also bad. True? Bummer as this was going to be my fall back carb.

    I assume the nightshade family is also a no go?

    I read that millet is OK but quinoa is not. True?

    Sorry for the 100 questions but I need to redo my entire diet again and figure out what to feed my kids…..

    Thanks in advance! Glad my hands are working today!

    Raed wrote on February 17th, 2013
  5. Been reading with some interest. Started the 4-hour body diet, close to the Atkins. No wheat/starchy carbs or sugar.

    So were do I get my carbs and fats from? Mostly lean meats/fish/poultry/eggs, beans and lentils. Beans and lentils being an excellent source.

    Now after reading this article, which lets be honest gives massive warnings on lectins/beans and lentils, I feel like I shouldn’t be eating them at all.

    So what should I eat? Someone said Fish/Meat/Fruit.

    So to get this straight, we read an article on beans/lentils, yet there are no figures stating the rate if lectins. We then find little time reducing peoples fears by then giving the amounts left after proper preparation (canned/sprouted) etc, so we have nothing to go on in regards to hard data.

    All the remaining choices fish/meat/fruit have lectins and fruit which is worse has fructose which is very bad for you. Fruit shouldn’t be eaten at all, so that leaves Fish/meat.

    You cannot live off Meat/fish alone (well you probably could but who would?).

    My point is, surely its better to say how much lectins are in beans/lentils and other foods (which is most). How much is left after proper preparation in beans/lentils compared to the safe limits you should digest. That way we can make informed choices, add them as part of our diet, for their benefits which are many and we can all breath a sigh of relief. Or we can say, yep, even after preparation they are still too high (beans/lentils) and then avoid them.
    Sorry mark you have bothered to do none of this, and as such, your article is nothing but pointless gesture, that only scares people and doesn’t really inform them.

    This is either because you are lazy or you lack the real data, which leaves your argument redundant.

    This article is nothing but rubbish, lazy, overblown investigative stabbing at one part of a food source and the negative side of that one part.

    This article is misinformation at it s best.

    Please next time do something better than just scarring people.

    Rich wrote on May 2nd, 2013
  6. I did a search on lectins because i was reading the food list of restrictions on the blood type diet and the foods that are restricted for he specific types are based on specific lectins found in research.

    I knew that plants had defense mechanisms and that fermentation is a positive thing but I had not placed a name on those defence mechanisms yet so thank you for that.

    Good luck to all of us trying to make our way through this food jungle to find the path that is the healthiest! 😉

    Jenaya wrote on May 2nd, 2013
  7. Its come to my attention, after reading all night about lectins and managing to speak to one of the Uk’s front runners in lectin research (all in 8 hours lucky huh?)

    There is a pattern with lectins and one that is not really discussed here, due to marks poor scientific background and essentially data copied and re-woreded from the internet.

    Lectins are highest in seeds. be that beans, lentils tomato seeds etc.
    After speaking to a leading scientist, many of the items listed can be drastically reduced of lectin count by simply removing the seeds, like a tomato.

    So you will see things like cucumber, garlic, tomatoes, listed, because they contain seeds. Remove the seeds, and in theory you will remove the lectins or so the logic goes.

    To deseed your tomatoes, aubergines, etc dont eat seeds, if you have a problem nuts etc, and if you can eat fermented products, as this seems to be the only reliable way to reduce the lectin count (I say ‘seems’)

    Garlic is a seed but why is leek on the list? Leek, is from the onion family but it is the flower you are eating, and not the seed.

    NOtice how all the plants that aren’t listed, broccoli, cauliflower etc aren’t the seed bearing part.

    So instead of thinking, I cant eat anything, simply removing seeds could be a great way to enjoy those foods gain.

    Of course im not a scientist, but have had some good information, and the logic of my idea stands up due to the high lectin content of (seeds) and the low content of suggested plant foods that are seedless

    Hope this helps, but dont take my word for it.

    Also think of this. Japanese people have the longest and best health, along with scandinavians. Yeh the eat lectin rich foods, or do they?

    They ferment soy which removes the lectins and anti nutrients (as far as I can ascertain) and the eat sea food and sea weed (see weed apparently blocks the effects of lectins through binding.

    So yes you can eat all the foods you are now scarred of, but just check the process.

    If you really cant eat pulses/grains, thats fine, plenty more food out there, stop winging and get on.

    Today for breakfast, I had 3 eggs free range organic, korean style with some fermented soy bean (soy sauce) with a turkey breast. Yum.

    Lunch cod fillet with a de-seeded tomato and deseeded pickled cucumber salsa, with virgin olive oil. Fresh steam broccoli al with a simple balsamic dressing.

    So ive had almost no lectin intake apart from the eggs. Is that going to cause me any issue? hell no. My diet is too varied, too balanced (if there is such a thing which I dont think there is) and I feel great.


    Rich wrote on May 3rd, 2013
  8. oxalates, lectins, peptides, flouride, arsenic..and on and on… good luck!

    joey wrote on May 12th, 2013
  9. If soy and beans are so bad why lots of peoples who consume a variety of legumes are on the list of the longest lived nations in the world?

    Think Sardegna in Italy, Ikaria in Greece and finally Japan..something doesnt add up here. These are ancient traditions, people living long and healthy lives for many generations..but not so far away from us like paleo people..

    Sara wrote on May 17th, 2013
  10. Can’t believe the difference giving up grains has made in a couple of weeks ! Followed the advice and now I just feel not hungry after eating. Not full, not bloated. My abdomen is right down plus I’m losing a couple of lbs a day in weight. I added back a few things to test it out and the problem came back to a MUCH lesser degree. Superb advice so thank you.

    Yve wrote on September 10th, 2013
  11. Good article. People can complain and say this is extreme eating, however unless they have had inflammatory bowel problems and actually understand how this way of “elimination” may be required for some people, then they need not mock the lifestyle. It’s a real issue and if you don’t suffer from it then kudos to you. As for me, soy, legumes and pasta destroy my gut. Thanks Mark!

    Julie C. wrote on December 30th, 2013
  12. Good information from the blogger.
    I am struggling to overcome food addictions and was looking for info that would let me continue to eat the way that I am use to with some modifications. Instead I see good reason to change and to make every effort to eliminate some foods and severely limit others. Thank you to those who shared there experiences and their knowledge, especially that on GMO’s.
    I had wondered why GMO’s were so bad – I thought that there had to be some specific reason(s) for banning them in Europe (or is it parts of) and trying to get the use listed on labels. Now I know that lectins are spliced into the genome(?correct me if I am wrong), meaning that there is a higher level of lectin in GMO crops. I had been so busy with other activities that I had not done research on this.

    LK wrote on February 28th, 2014
  13. I agree with the critics. This article mis-represents the lectin danger. I don’t know anyone who eats unsoaked beans other than edamame which, interestingly, is not mentioned. So when you say beans are a danger because they are one of the foods that contain high lectin activity, people think canned or soaked beans.
    The other thing that is mentioned which is also touched upon by Rob Wolf is the whole plant defense thing. Sorry but if this is a plant defense mechanism, it doesn’t work. There was no way for humans for the majority of the time we ate beans to connect beans with any digestive ailment they were having. And the damage it was supposedly doing was not nearly enough to cause people to stop eating beans.
    Thirdly, I don’t see any references to studies or evidence of any kind about what lectins do in your digestive system. Thing that bothered me most was that nuts were on your list. Sorry, but I’m not aware of any nut-soaking or nut fermenting practices that any cultures have engaged in. Nuts are goof for you. Someone reading your article is now going to cut back or eliminate nuts which are a very healthy food.

    Eric Nastav wrote on March 8th, 2014
  14. It sucks that Soy contain lectins. Its one of the most overlooked, worst offenders for weight gain in the Blood type O group.

    Hyip wrote on September 15th, 2014
  15. At 74 a Vegan following mostly the philosophy/ way of eating of Natural Hygiene all my adult life and in excellent health I am sure the way food is produced is so important, just consider the amount of milk a cow produced when I was a child and the enormous quantities demanded of the poor animal today by a dairy industry that in the UK is in spite of this massive increase in quantity economicaly unviable at present. Clearly if you feed cows on soy rather than grass a much different milk will result,and meat. Eggs fed on grain and what they can forage for will be significantly different from cheaper concentrate fed birds. Follow the money,if the bottom line is all food producers are driven to consider its a poor lookout for all of us whatever way of eating we chose.

    Tony Edwards wrote on February 5th, 2015
  16. I had a client walk into my office today asking if I knew of lectin blockers. I told her I did not. After several hours of research and reading I came away with a new appreciation of lectins. I found a few products, very expensive products, that will bind to specific lectins. What I wanted to find is a universal binder that will inhibit most if not all lectins. I found two universal lectin inhibitors. The first is alcohol. The second is vinegar.
    After reading you article everything makes sense. Fermentation creates alcohol which inhibits lectin. The stomach of a cow or goat creates acetic acid, vinegar, which also inhibits lectin.
    After proper cooking techniques which eliminate most lectins, a glass of red wine or a good vinegar dressing will also breakdown lectins.
    If you do not like liquid vinegar, there are vinegar tablets available at most health food stores.

    Larry Johnson wrote on June 16th, 2015
  17. I can tell you all one thing….lectins have destroyed my intestines….grains have, legumes and phytates….I recently went through the low-carb detox and flu. It was brutal but I feel like a million dollars now……I will spend the rest of my life avoiding these foods as much as possible.

    Josh wrote on August 4th, 2015

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