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. I am really impressed with your writing skills as well as with the layout on your weblog. Is this a paid theme or did you modify it yourself? Anyway keep up the excellent quality writing, it’s rare to see a great blog like this one today..

    weight loss wrote on June 15th, 2011
  2. Re: “secondary exposure through antibiotic-administered livestock).” I’ve heard that when you’re on anti-biotics that you should stop taking probiotics because these renders antibiotics innefective. If that is the case, could it be that taking probiotics daily also means it’s (relatively) safe to eat meat from animals that have been raised on antibiotics – i.e., taking probiotics means your body will also be able to handle the antibiotics in the meat?

    Mariana wrote on June 27th, 2011
  3. My mother has diabetes and fibromyalgia. It’s tough to see her struggle and I try to learn as much as I can from great blogs like this one to avoid going down the same path. In spite of eating healthy (chicken, brown rice, sprouted flourless bread, veggies, etc), last year I got relentless IBS-like symptoms literally overnight and spent 8 mos. with a doctor who wanted to prescribe me pills for severe cramps but I refused. I wanted to know the cause and kept asking for test after test that only showed I was healthy as a horse. Yet, I had persistant abdominal pain all throughout my abdomen. My doctor did not suggest any dietary changes, but I cut out caffeine and beer and the pain subsided but not the fatigue and brain fog. Finally, I went to a naturopath and he put me on L-glutamine powder and an insulin-resistant diet that I tailored to be grain-free as well. This healed my gut tremendously. Magnesium glycinate helped with the constipation. Within 4 weeks I was able to eat whatever I wanted again, but I was so impressed with the dietary changes, I’ve since learned to soak and ferment rice and buckwheat and rely more on sweet potatoes.

    Colleen wrote on June 30th, 2011
  4. It is a short put up to state, very merely, thanks a ton. I’ve had an opportunity to atone for this post and the comments as we speak and I’m really grateful for knowing the content of this blog

    technical training wrote on July 2nd, 2011
  5. Wow – this is the post I’ve been searching for.

    After dealing with bizarre RA-like, debilitating joint pain that neither orthopedist nor rheumatologist could identify, but were happy to treat with pharmaceuticals, I casual mention by my chiro – “You know you shouldn’t be eating wheat, right?” got me looking into this whole primal thing.

    I can’t say unequivocally that cutting the grains (though corn and rice still manage to sneak in now and then) has fixed the issue, because I had a full pregnancy-related remission and haven’t had troubles since. I only got serious about cutting grains after I started feeling twinges in those same joints and panicked about needing to go back on injectable TNF blockers.

    I have found a lot of advice – don’t eat gluten, don’t eat sugar, don’t eat grains, etc, but until now I was missing the underlying, big fat scientific WHY. I feel like I have my answer now. I never knew exactly why grains were so awful, other than that “humans were never supposed to eat them.”

    I read this with big, wide open eyes wanting to jump up and scream, “YES YES YES!” Light bulbs turned on, sirens went off. Thank you thank you thank you.

    Susie wrote on July 17th, 2011
  6. Really if you are going to eat lectin foods, cook them well and at high temps. Also soak when you can. This raw food idea is way off. There is a reason why people cook things.

    Dinkle wrote on July 22nd, 2011
    • Thank you for your post, Dinkle! I find it interesting that the original article mentions soaking and fermenting but not cooking, and that out of a million responses, almost nobody mentions this. I guess it would turn this whole conversation into a non-issue, since everybody cooks beans, anyway.

      Liz wrote on February 19th, 2012
  7. Hmm…The only thing I eat for my evening meal is boiled egg and peas. I love it. And now it’s bad? :(

    Miss Kimbers wrote on July 23rd, 2011
    • Peas nor eggs have harmful lectins for any Blood Type. Ultimately no food is inherently “bad.” It just depends on how susceptible you are to it. This is dependent on several other factors including overall gut health, level of consciousness, belief systems…etc…

      Steve Beisheim wrote on September 2nd, 2011
  8. It appears that you’ve got put loads of effort and exhausting work into your submit and I require way more of these on the web in current times. I sincerely received a kick out of your post. I don’t really have considerably to say responding, I solely wished to remark to answer very good work.

    how to get new friends wrote on August 2nd, 2011
  9. Here is an excellent write-up on lectins:

    Given all the blood-type bashing going on above, I probly shouldn’t say it, but there is a lot of info to be learned from it — especially about lectins. For Susie above, diving into the sequence of blood-type books will enlighten you a lot about why gluten is bad, etc. For Pam above, with all your frustration and lack of solution still… give the blood type diet a look. You may be surprised (as I was) to find it solve some of your issues.

    I admit some of the blood type info “seems” non-scientific and unjustified (I don’t know if it is or isn’t)… But most of what I learned from it has proven itself true to me, my friends, my family, and my patients (I’m a dentist). I don’t want to perpetuate a debate, but based on my experience, I’d definitely recommend reading into it. Take it all with a grain of salt if you must. It may not be always correct and it may not apply to everyone equally or at all. But it sure works miracles for many.

    I’ve learned things about myself and other genetic issues such as what it means to be a non-secretor and why non-secretors are so much more health-sensitive to foods. The blood type theories have been the most helpful discoveries I’ve ever made for my own health issues. I’m sure it will help others too.

    And to Luke above who argues against the blood type diet so fiercely, you keep stating that the blood type diet works on type O’s because it happens to match primal. What about the converse? Maybe the primal diet works for O’s because it happens to match the O diet? I don’t know anything about the primal diet (I’m new here), so am not making any claims or discrediting it. I just thought it was funny how one-sided your argument is 😛

    Chris wrote on September 1st, 2011
    • Hey Chris,

      Thanks for your comment man. It’s good that you are a critical thinker and make an effort to understand both sides to any argument. All of my clients benefit when they avoid harmful lectins, you can even see the research just by using Google. Did you know that the HIV Virus is bound and inhibited by the Banana Lectin? Nature rocks….

      Steve Beisheim wrote on September 2nd, 2011
    • Hey Chris,

      Welcome – and I hope you actually take the time to read and learn about the Primal diet.

      If you read my posts I explain why it can’t be the other way around… I don’t have the time to repeat it all, but the reason essentially boils down to the fact that:

      1) The author contradicts himself between books and his two diets… it cannot be science based if the rules are not consistent… you cannot say cherries are super food, and THEN in the same book say they are toxic, and in another diet say that they are BENEFICIAL to the people you said they were toxic for before.

      2) Regarding the primal O’s etc… this is based on the fact that as I have repeatedly stated… I am an AB, and I was told that meat etc was bad for me and I should consume soy… and this FAILED… however when I eat Primal (NO soy and definitely meat), I get results… if you look at the people that are positive to the Blood diet they are O’s.. so this is why it isn’t the other way around… if only the O’s (that get essentially a “primal diet”) do well, but the A’s, B’s and AB’s tend to fail, then this shows that the blood type diet isn’t working (otherwise why would all the A’s, B’s and AB’s FAIL), but it is because it is all the O’s on a primal diet!!!

      If it was the other way around… ALL the types, O’s, A’s, B’s and AB’s would WORK, and as a result, if these people went on a primal diet, then ONLY the O’s would do well… but this is NOT what happens…

      It is the first case… when O’s switch to primal (not much change, as they essentially are cutting out wheat etc and eating meat), then they still do well, but all the A’s, B’s and AB’s that FAIL on the blood type, switch to primal and do WELL.

      I trust as a dentist you can understand this?!?! If only ONE subset of a diet works, then it is clearly FALSE.

      And if the people that FAIL on the parts of the diet (blood type A’s, B’s and AB’s) that are wrong, switch to another diet (primal) and it WORKS AND the people that were essentially following the other diet (i.e. primal) on the first diet (blood type O’s) switch to primal and it STILL works, then it is the PRIMAL part that is true and the blood type that is WRONG.

      That is WHY I repeat my observation – it is almost ALWAYS O’s that praise the blood type diet and defend it. And I see this is the case here – ALL the people that defend the diet are O’s (i.e. eating more primal) and all the people who hate it (like me) tend to be A’s, B’s and AB’s… this is EMPIRICAL evidence that the diet ONLY works for O’s because they are essentially eating primal, and primal is the actual reason, cause all the A’s, B’s and AB’s that hate the blood type diet cause it is rubbish, find that primal (i.e. eating like an O) world for them… and that is why it isn’t the other way around, if A’s, B’s and AB’s start eating primal which is eating an diet for O’s (which they are TOLD emphatically by the blood type diet they SHOULD NOT – as it is toxic for them) and it works for them then it is the blood type diet that is FALSE. SURELY as a dentist, you understand this?!

      Sorry, I cannot explain this any more.. this is LOGIC and deduction… I don’t say that to imply you can’t understand logic and deduction, I simply say this is the process… and there are only so many ways you can explain it.

      In the end, I OBJECT to the blood type diet, because as I have stated before, if you release a diet with certain rules, that are in fact FALSE and cause health damage, and then release a NEW diet book that CONTRADICTS the first, yet STILL sell the first, you are ethical bankrupt.

      If you do keep reading here you will see that Mark gives all the information you need away for free on this blog… you can buy his books, but they are just a way to quickly get the essential information without spending time reading all the posts here. He is not pushing a diet that only works for SOME… it is based on genetics and evolution and as a result, it will work for all.

      I wasted a lot of money on the blood type books and as you can see from all the people that dislike it here (again all the A’s, B’s and AB’s) they feel the same way too.

      If Steve and you can tell me you are NOT O’s, then that would be a start to proving me wrong.

      It isn’t critical thinking just because you agree with each other… critical thinking involves differentiating between correlation and causation.

      There is a correlation between type O diet and primal diet, but the causation of the results that Type O’s get is due to the primal nature of it, and this is evidenced by the effects a primal diet (i.e. a O diet) has on people that according to blood type dieting should suffer due to their blood type.

      Anyway – I have added all I can here, I KNOW I am repeating myself, and in the end, my posts are not for people that wish to admit they know nothing about a subject, but still challenge it… I can ONLY implore yo to keep reading, and you will see what I saw when I discovered Mark’s Daily Apple whilst being miserable on an AB blood type diet.

      Steve has a business based on this stuff, so he also won’t budge… that is fine.

      I have NO business or profit motive… my only motive is to HOPEFULLY explain to the people that are reading all this to not buy into the blood type hype and rubbish, and present a point of view I have (and yes it is emphatic and fierce – because when people’s health is at stake, and you have looked at the evidence as I have and have the conclusion I have it is reprehensible NOT to be emphatic and try as many ways as possible to persuade). I may be wrong, I am willing to admit that… but I’m admitting the blood type diet works for O’s, I am just reaching out to the A’s, B’s and AB’s like me to save themselves the pain, and the money.

      And if one A, B or AB read all this and realises they would be better off eating primal (or more like an O), then like the many that have posted here as well, they will be better off. I make no money from it, but I do feel good knowing someone isn’t putting themselves through the hell I went through when I was also conned by all the “endorsements” by O’s raving on about a diet that only works because it is primal.

      Regarding lectins… I agree with this… but you don’t have to adhere to the blood type diet to avoid lectins…. it is the blood type fan brigade that have hijacked this post about that… the impact of lectins was raised well before the author of the blood type diet… he jumped onto that bandwagon (again I feel like I am repeating myself).

      And here endeth the rant… because if you still want to follow the blood type diet after all that I AND may others smarter than me have written here (and elsewhere) about it, then all I can say is I pray you are an O and all the very best of luck to you. To those that reconsider and avoid this rubbish as a result of my rants… even if it is just one of you, then it was worth the time and effort.



      LukeinOz wrote on October 19th, 2011
      • Hi Luke, thanks for your detailed explanation. Of course the logic and deduction you present is plain. IF the blood type diet works only for type O’s, then I would agree with everything you said. However, my implied question was: “Why do you think the blood type diet fails for A’s, B’s, and AB’s?”

        Your personal experience is one thing, but where is the statistically significant data that confirms it? I don’t have any data that proves it works. But you claim to have data that proves it doesn’t. Why do you claim that?

        I have anecdotal evidence that makes me believe it is accurate. I have met at least 20 type A’s, who know nothing about the blood type diet, but all claim to thrive on what they describe as the blood type A diet. I.e., every single type A I’ve interviewed (20-ish) claim that eating red meat makes them feel lethargic.

        I have met at least 40 type O’s, who confirm their diet matches the O diet or the primal diet.

        It’s the B’s that throw me… they all love chicken and tomatoes, the 2 worst foods for them. However, they all do very well with dairy (the only blood type that does well on dairy). This “confirms” one more aspect of the blood type diet.

        The ABs are a crazy group. I haven’t found any correlations between their reported diets / lifestyles and the blood type AB diet. I’m not surprised the AB diet didn’t work for you. It’s a difficult one. Did you discover your secretor status btw? That will alter the diet quite a bit.

        Chris wrote on December 27th, 2011
  10. If you can’t afford to go “primal”, then soaking grains and legumes overnight does work. My autistic son can handle these things so much better when I soak them.
    Also, make sure you have probiotic foods like cultured veggies or kefir. I can’t tell you how much that has helped our digestion.

    RM wrote on October 18th, 2011
  11. Regarding pork, you should avoid it because it’s not a very clean animal in regards to digestion, and tends to hold more parasites like worms.
    Just ask the jewish people this. That’s why they don’t eat pork or shellfish (which are the bottom feeders of the ocean and consume the ocean’s crap). They are not clean food sources.

    RM wrote on October 18th, 2011
  12. Helena,
    You might want to check and see if you have a thyroid disorder. I started reacting like crazy to all sorts of foods that never bothered me before, and found out I have Hashimoto’s disease. Once I started on Armour Thyroid, my crazy food allergies calmed down quite a bit.
    I think this is due to an overreacting immune system, and metabolic issues. I also had chronic yeast infections as well.
    I’m sorry for your situation. It can be hard.

    I am so sorry to

    RM wrote on October 18th, 2011
  13. Not to stir the debate back up yet again on the blood type diet pros/cons but I’m an A+ that ate lots of meat,cheeses, and drank lots of milk throughout my youth and even more so in my 20’s as I was into weightlifting. Bottom line is I felt like crap more and more as I went through my 20’s. So much so that after picking up a copy of the blood type diet, juice fasting for a month, then eating a veggie diet that evolved back to a modified Mediterranean diet w/ a fair amount of fish, I can say I feel a world better at 40 than when I was in my 20’s. I’ve since read D’Adamo’s new book on genotypes and am very impressed w/the emerging field of epigenetics. The study of how our genes are in fact not static at conception but constantly interacting w/our environment (even and especially in utero)modifying them to a surprising degree.

    Just wanted to chime in as an A blood type due to someone earlier saying that they thought no one other than O’s rave about D’Adamo’s stuff. I know plenty of A’s and B’s that subscribe to his work to some degree. I being one of them.

    The Buddhist Cowboy wrote on November 12th, 2011
  14. Hi everyone! First time commenting, but my husband and I have been reading MDA on and off for a while now.

    I’m a 26 yr. old epileptic with FMS and anxiety. I make a conscious effort to listen and be in tune with my body, and it’s telling me that I need meat, green veggies, and fruit. I have a natural aversion to pork, shellfish and catfish , white potatoes, oats and other grains, and sometimes tomatoes. I don’t seem to have an issue with rice or beans, though, and I’m glad to know that soaking/sprouting/fermenting does well to reduce/eliminate lectins. I have a serious problem with sugar and bread, and it’s a constant battle to cut those things out of my diet, which I know I should do (there are obvious side effects for me.) Luckily, I don’t drink sodas, coffee, or add sugar to my tea! Reading this article confirms some things for me, which is pretty exciting, but pretty overwhelming, since I’ve had to do so much independent research to get the nutritional info I need. I second a more specific article in the future – one with examples of recipes, etc., to help us who are still struggling. If anyone has tips on weaning off sugars, let me know. (I love fruit, but will eat more fruit than veggies if I’m not careful.)

    One thing I find interesting about the nightshades is reflected in someone’s comment that “anyone that eats a raw potato will tell you how toxic they are,” which my husband would tell you just isn’t true. He’s eaten more than one raw potato and has had no noticeable issues. Of course, he has a stomach of steel! When I mentioned it to him, he said that he’s never eaten a raw potato that’s sprouted, so he must be safe. Not trying to start an argument, just commenting that there is something to be said for catering to the individual’s needs when it comes to nutrition. Unfortunately, there’s some grey area, which makes things complicated.

    Thanks again!

    ChelseaKeebs wrote on January 7th, 2012

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