Perhaps, at some point, you’ve considered a diet that’s gluten-free, or paleo, or keto, or vegetarian, or dairy-free… But, have you considered a lectin-free diet?

Ever feel like there’s a nutritional buzz word you just keep hearing, but you can’t quite connect what that word means? Lectins seem to be one of those buzz words. It’s out there in the blogosphere, but what exactly are lectins and how are they affecting your overall health? I wish I had a simple answer for you, but like so many current nutrition topics, more research is needed to definitively say if a lectin-free diet is a healthy choice.

There has been an increased interest in just what exactly these proteins do in our bodies. Research has shown that lectins can have both positive and negative effects on our health, but no studies have proven without a doubt that they can cause or cure any medical conditions. Like many hot nutrition topics, the jury is still out on whether the good outweighs the bad and if a lectin-free diet is actually effective. So let’s take a look what science has discovered about lectins so far, so you can make a more educated decision about what feels right for your body.


What are lectins?


Lectins are proteins in plant-based foods. They are attracted to and bind to carbohydrates. They are found in most plants but are most abundant in food items like legumes, whole grains, and some vegetables such as potatoes and tomatoes.

For a plant, lectins are a source of protection as they grow. Lectins allow plants to thrive, protecting them against predators. Because of its resistance to digestion, a seed may even be able to pass through a predators digestive tract and come out the other side unscathed, allowing it to thrive even after being eaten by a predator.


Activity of lectins


Lectins have the ability to bind to carbohydrates on cell membranes in the digestive tract. This can promote cell to cell interaction. In fact, these proteins can travel far from the gut. They can pass through unhealthy gut walls and end up in distant organs, like your thyroid or pancreas (R).


Lectin sensitivity


Our bodies are not able to fully break down lectins, so they pass through our digestive tract intact. Sometimes, our bodies can recognize them as invaders and develop antibodies against them. While this happens to most everyone, the degree to which this affects us is as individual as each person. Occasionally, this immune system response can build and lead to complications. This is what is referred to as “lectin sensitivity.”

Some experts have concluded that this sensitivity is due to a less than optimal balance of gut flora, meaning there isn’t the right balance of bacteria living in our digestive tract. They argue that sensitivity to lectin can be triggered by infection and autoimmunity (R). This means that people suffering from autoimmune disorders such as Celiac disease or Crohn’s disease will most likely suffer from some not-so-nice side effects after eating foods high in lectins.


Digestion and lectins


New research regarding the digestion of lectins is being conducted as we speak. To date, researchers have uncovered some interesting links between lectins and digestive issues. As we said, animal studies have shown lectins ability to strip the mucosal membrane from the small intestine. This leads to increased inflammation and a bacterial imbalance, a prime breeding ground for peptic ulcers. Peptic ulcers are sores that develop in the lining of the gut. They are also furthered by histamine discharge from gastric mass cells caused by lectis. This stimulates acid secretion, which further compounds the risk of peptic ulcers (R).

Lectins can strip the mucosal lining of the small intestine, leading to overgrowth of unfriendly bacteria, as demonstrated in animal studies (R). Ever heard of small intestinal bacterial overgrowth (SIBO) or leaky gut syndrome? There’s definitely a tie there! The alteration of the gut bacteria may lead to autoimmune disease, as your body may start to produce antibodies against lectin (R).

This altered gut status lends support to the “caveman diet” approach in which most starchy foods are avoided. The argument being that this type of diet can support a healthy amount of mucus linings through the body, protecting from things like peptic ulcers and upper respiratory infections (R).

Because of their binding ability and effect on gut health, lectins are suspected to cause nutrient deficiencies.


Who may be at a higher risk of suffering from or developing a lectin sensitivity?


Almost everyone is eating lectins multiple times a day, so why aren’t we all suffering from autoimmune diseases and peptic ulcers? The reason is still being researched, but one strong hypothesis is the role genetics plays in how our bodies react to dietary lectins. We all have lines of defense to protect our cells, which are determined both by nature and nurture.

Viruses are also thought to have a strong effect on how lectins affect us. Viruses can strip away our defensive coatings that protect our cells, causing our cells to be more vulnerable to lectins preset in our bloodstream.

Those suffering from the following may be at a higher risk of suffering from or developing a lectin sensitivity:

  • Celiac’s disease
  • Crohn’s disease
  • Irritable bowel syndrome
  • Severe vitamin D deficiencies
  • Any other autoimmune condition
  • Severe acute stress or chronic stress
  • Severe acute or chronic infections
  • Infections requiring antibiotics, which disturb your gut flora

    What happens if you suffer from lectin sensitivity?


    When enough lectins are consumed, it can signal our bodies to evacuate contents from our digestive tracts. This means vomiting, cramping and diarrhea. It’s similar to consuming large amounts of alcohol, which can damage the lining of our digestive tracts and cause some pretty yucky problems in the bathroom the next morning.

    Aside from causing digestive system symptoms such as vomiting, cramping, and diarrhea, lectins may also cause a broader immune system response as the body’s defenses move in to attack the invaders. Symptoms can include skin rashes, joint pain, and general inflammation. Other chronic disorders may be correlated with leaky gut — for example, researchers have even noted that children with autism have very high rates of leaky gut and similar inflammatory digestive tract diseases.


    Cooking with lectins


    Was the body ever equipped to deal with eating foods containing lectin? Eating grains, for example, is something relatively new in the span of humankind. Before modern agriculture, grains were not a big part of our diets. A theory surrounding the introduction of the Paleo diet suggested that evolution just couldn’t keep up with the sudden shift to eating grains and our bodies reacted poorly. Luckily, our ancestors grasped the concept of “survival of the fittest,” and found a solution to the problem of lectins. Soaking, fermenting, sprouting and cooking will decrease lectins and free up the good nutrients.

    When cooked, lectins break down. This lowers the availability of lectins in the food and therefore the risk or benefit that may arise from eating them. Pressure cooking and soaking may break down the lectins even further. This has led to recommendations to soak and/or pressure cook beans if you find you have trouble digesting them.

    Fermentation allows beneficial bacteria to digest and convert many of the harmful substances, including lectins. This might be why the healthiest populations stick with fermented soy products like miso, tempeh, tamari and natto.

    Here’s some added bonuses: Certain seaweeds and mucilaginous vegetables have the ability to bind lectins in a way that makes them unavailable to the cells of the gut. Also, lectins are resistant to dry heat, so using raw legume flours in baked goods should be done with caution.


    Lectin-free diets


    The average North American diet is highly grain-based: bread, pasta, rice, cereals, etc. are everywhere, especially in processed foods. The list of foods to avoid on a lectin-free diet is a hefty one. It is not a diet change to be taken lightly, as it eliminates many otherwise healthful foods. These foods include:

  • Nightshade vegetables, such as tomatoes, potatoes, peppers, and eggplant.
  • All legumes, including bean and peanut products.
  • All grains and dairy are out.
    The best course of action before embarking on a lectin-free journey is to consult your healthcare provider or a Registered Dietitian.


    The upside: Cancer-fighting properties


    Digestive system cancers are often underdiagnosed or diagnosed late, causing them to have a high mortality rate. Digestive system cancers include cancers of the esophagus, stomach, small intestine, colon, liver, and pancreas. Lectins are being studied for the role they may play in the treatment of these types of cancers. Because they bind to carbohydrates in the digestive tract, they may hold the answer to cancer treatments (R).




    While I know you may have landed on this article looking for a definitive answer to the health of dietary lectins, research has not been able to give us that answer yet. If you’re searching for a dietary answer to your gut or autoimmune problems, you may be on the right track considering restricting or reducing your dietary lectins. Be sure to consult a healthcare professional to be sure that you are still maintaining proper nutrition while finding the root cause of your issues.

    Love and Health,



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