Episode 78 – Lectins

What are lectins? 

  • Lectins are a type of protein found in a range of foods.  
  • Lectins are grouped together based on the fact they are all proteins that bind to carbohydrates. This feature protects plants in nature.  
  • Although it may actually cause issues with digestion as it makes lectins stable in an acidic environment. 
  • The human stomach is acidic to facilitate the breaking down of foods. Lectins are resistant to being broken down in the gut due to being unaffected by this acidity.  
  • There are many different kinds of lectins that all have different effects on the human body. 
  • Ricin, for example, found in castor bean seeds is known to be toxic to humans when consumed, however, not all lectins need to be approached with the same amount of caution.  
  • Some lectins are completely harmless and may even provide health benefits.  

What foods contain lectins? 

  • Lectins are found in legumes, soy food, grains, vegetables (particularly nightshades), some nuts including cashews and peanuts, seeds, and some fruits.  
  • Gluten found in wheat products is actually considered a lectin amongst many others found in a wide range of foods.  
  • Lectins are even found in some dairy products (A1 protein is a lectin-like protein), eggs, and meat from animals that have been fed corn and soy.  

What are the proposed benefits of avoiding Lectins?  


1. Some lectins are actually poisonous  

One of the most well-known and clear reactions in people eating lectins is red kidney bean poisoning. Even small amounts of raw or undercooked kidney beans can cause nausea, vomiting, stomach upset, and diarrhea. Milder effects include bloating and gas. 

2. One of the most cited reasons for removing lectins from someone’s diet is that you “can’t digest them”.  

That in itself is true. As previously mentioned, lectins are somewhat immune to the acidic environment of our stomachs that are made to break down foods.  

But this doesn’t necessarily make something bad for you – for example, some types of fibre are resistant to digestion and we know that fibre is not bad for you  

For those experiencing gas, bloating and other digestive issues after consuming lectin-rich food there may be merit in reducing their intake. But not by cutting out foods. It could be recommended that they soak their nuts, seeds, and legumes and cook all other foods well to reduce lectin content.  

3. Lectins Reduce Nutrient Absorption  

Active lectins found in foods like grain, nuts, and legumes can interfere with the absorption of some nutrients including iron, zinc, and calcium. 

BUT a lot of plant-based foods contain an array of what we call anti-nutrients. For example, phytates and oxalates are also found in vegetables, grains, and legumes, and tannins in tea and coffee.  

All of these nutrients are known to hinder the absorption of other helpful nutrients. But that doesn’t make the foods that contain these ‘anti-nutrients’ harmful to our health.  

From a nutrient absorption perspective, there is some merit in increasing daily intakes of some nutrients affected by these anti-nutrients. Especially if plant-based foods are your main source of things like iron, zinc, and calcium. 

Weight loss and lectin-free diet? 

According to DR Gundry, lectins can cause weight gain, gastrointestinal disorders, autoimmune disorders, and allergies.  

A large majority of the evidence he cites tends to be the anecdotal results of his patients and followers such as Kelly Clarkson. 

When it comes to actual scientific evidence, research into lectins is pretty slim pickings.  

Are there any benefits to lectins? 

  • Lectins potentially have a number of health benefits.  
  • Some lectins act as antioxidants that protect the body’s cells from damage.  
  • They also slow the digestion and absorption of carbohydrates which can help you stay fuller for longer and prevent sharp increases in blood glucose levels.  
  • There is some research into lectins as anti-cancer treatments but research here is still in its early days.  
  • Furthermore, there is a wide array of research showing that lectin-containing foods such as legumes, whole grains, nuts, and seeds are associated with lower rates of type 2 diabetes, cardiovascular disease and are helpful for maintaining a healthy weight. 
  • These foods are also great sources of many nutrients such as healthy fats, fibre, vitamins, and minerals.  

Summary / how much should people care about lectins? 

  • If you have trouble digesting lectin-containing foods, extra sprouting, cooking, and soaking could be beneficial
  • The general person doesn’t need to worry about them 
  • Include lectin-containing foods in your everyday diet

Relevant Links/ Resources

Studies Mentioned:

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