The Low-down on Lectins

The Low-down on Lectins

We all know beans make us fart, but why? Lectins! But is that all they do?

Lectins are a type of protein that can bind to cell membranes, they offer a way for molecules to stick together without getting the immune system involved, which can influence cell-cell interaction. Sounds ok so far right?

So what is the purpose of lectins? They are a plants  defence against microorganisms, pests, and insects. They may also have evolved as a way for seeds to remain intact as they passed through animals’ digestive systems, for later dispersal. This also means they are resistant to human digestion and they enter the blood unchanged. So are they important? Yes. 

Lectins are thought to play a role in immune function, cell growth, cell death,  body fat regulation, immune response and toxicity. They happen to be found in a abundance in raw legumes, grains, dairy products and certain vegetables. 

Because we don’t digest lectins, we often produce antibodies to them. Almost everyone has antibodies to some dietary lectins in their body. This means our responses vary. Certain foods can even become intolerable to someone after an immune system change or the gut is injured from another source. Intestinal permeability (leaky gut) plays a huge roll in the effects of lectins and how our body reacts to them. 

There are some lectins that no one should consume. Ever wonder why you don’t see sprouted red kidney beans? It’s due to a specific lectin type which can lead to red kidney bean poisoning usually caused by the ingestion of raw, soaked kidney beans. As few as four or five raw beans can trigger symptoms.

Raw kidney beans contain from 20,000 to 70,000 lectin units, while fully cooked beans usually contain between 200 and 400 units.

Beneficial lectins (yes there is such a thing)

For the most part people tend to react negatively to lectins, however there are also health promoting lectins that can decrease incidence of certain diseases. The more regularly you consume them there ability the body has to build a tolerance to them thus reducing many of the “unsightly” symptoms. The body uses lectins to achieve many basic functions, including cell to cell adherence, inflammatory modulation and programmed cell death.

So yes the body needs lectins, perhaps in controlled moderation. We all know that consumption of lectins can lead to gas, bloating and in some cases nausea and diaper. Did you know that researchers have stated that many forms of food poisoning may have actually been lectin poisoning

“Leaky Gut"

Lectins can damage the intestinal wall lining, leading to intestinal permeability also known as leaky gut. 

 As food passes through the gut, it causes very minor damage to the lining of the GI tract. Normally the cells repair this damage fairly quickly. The whole point of the gut lining is to let the “good" stuff past and keep the “bad" stuff contained. This means it is important for the cellular repair system to be running at full efficiency. 

 However  lectins can slow this fast reconstruction process. Our cells can’t regenerate as fast as they need to in order to keep the intestinal lining secure. This means our natural gut defences are compromised after the damage occurs and the gut can become “leaky,” allowing the stuff we don’t want  to pass back and forth through the gut wall. 

 Another issue with this is how it affects the absorption, or rather lack of with regards to important vitamins and minerals.

Immune response on lectins

When lectins affect the gut lining it can cause other symptoms to show up as an immune response. Skin rashes, joint pain, inflammation, chronic disorders such as autism in children, MS and various other autoimmune diseases. 

When someone is suffering from Crohn’s disease, IBS (irritable bowl syndrome) or any IBD (irritable bowl disease the gut lining seems to be more sensitive to food lectins. This is something to consider when planning your dietary needs.

Good news is that for the most part the effects of lectins only lasts for as long as they are in the body, more good news is that we can negate the effects of at the very least reduce them significantly by eating a variety of fruits and vegetables which have antihistamine or low histamine properties. Variety is key rather than sticking to one type. Adding in foods with beneficial bacteria (e.g., fermented foods) will also help in this regard.

What about grains? 

As you have heard me say repeatedly, stick to the unprocessed, unrefined versions for best results. They are not only more nutrient dense but also contain more lectins and other possible anti- nutrients so consuming sparingly may be something to consider. Yes I know your grandmother and her mothers mother were all able to consume these grains with not a care in the world, the problem is that to only have these grains been altered but also the fact that they were once a seasonal crop and not abused as we do now.

The average North American diet is highly grain-based: bread, pasta, rice, cereals, etc. are everywhere, especially in processed foods.

We over indulge in grains and the body simply cannot process it fast enough. 

We have also lost the older arts which our ancestors used in daily practice. Fermenting, sprouting, soaking etc to avoid the issues coming from lectins. 

Did you know that the amount of lectins vary from crop to crop and season to season? 

Grain, cereal, dairy, and legume (especially peanut and soybean) lectins are most commonly found to be the cause of digestive complaints. Legumes and seafood are the most abundant sources of lectins in most diets. With regards to soybeans I would avoid them unless organic (they are one of the most genetically modified crops out there) and also fermented and again only in moderation. 

How can we reduce or neutralize lectins?


Sprouting seeds, grains or beans decreases the lectin content. I even soak and sprout my nuts - do you soak your nuts?

As a general rule, the longer you soak and sprout the more lectins are reduced. In some cases the lectin activity is enhanced by sprouting (like alfalfa sprouts). The lectins in some grains and beans are in the seed coat. As it germinates, the coat is metabolized – eliminating lectins.

Soaking and cooking

Even wonder why grandma bothered with the long soak, rinse and boil session when preparing beans and grains? Lectin reduction. This is probably the most classic method of preparing beans and grains.

This seems like a lot of work but it doesn’t have to be. Soak while you sleep! Soak beans and legumes overnight, and change the water often if you can. Be sure to drain and rinse before cooking and even take it one step further by adding baking soda to the water to help neutralize the lectins even further. 

What about fermenting?

Why not let your bacteria do the work for you? Fermentation allows beneficial bacteria to digest and convert many of the harmful substances. We need this. Some of the healthiest populations stick to fermented foods such as fermented soy products like miso, tempeh, nori and tamari. Some vegetables such as cabbage may also have fewer ant-inutrients when fermented, this is why I add unpasteurized sauerkraut to each meal. Talk about a digestive aid!

Unfortunately not all lectins are destroyed by these methods, and some particularly stubborn lectins in beans remain no matter how long you soak or ferment. A little reduction is still better than none in my opinion though. 


As an honourable mention some seaweeds and mucilaginous vegetables have the ability to bind lectins in a way that makes them unavailable to the cells of the gut.

Some experts hypothesize that it’s no coincidence the top 8 allergens also contain some of the highest amounts of lectins (including: dairy, egg, wheat, soy, peanuts, tree nuts, fish, shellfish).

Some experts also elude  that lectins cause urinary tract infections. I’ve seen in my own practice how dairy can contribute to ear infections in those of certain decent more than others. Of course there are many determining factors in this regard.  Other experts also believe that the reason anemia is higher in developing countries is due to excessive levels of lectin consumption.

Should you avoid lectin foods or not then? Bottom line I say you should listen to your body, heal your gut so you can tolerate them better and eating them regularly will help your body adapt better. Don't forget to soak, this is key. 


Soaking and sprouting chart 

Lectin food chart

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