Food Freedom Friday Edition 337 - Lectins

Lectins are one of the numerous antinutrients found in plant foods. They are defined as proteins that bind to carbohydrates and form a part of a plant’s defense mechanisms, protecting them from being eaten by pests. When looking at the foods that modern humans choose to eat, lectins are found primarily in legumes and grains. 

You may or may not have heard about plant toxins and antinutrients but you have most probably heard of gluten which is a prevalent and problematic lectin consumed in abundance as part of the standard modern/Western diet. 

It is important to understand all lectins, the possible effects on they may have on your health, and how to avoid them, if necessary. 

What Are Lectins

As previously mentioned, lectins are proteins that bind to carbohydrates. They are found in virtually every class of organism including plants, microbes, animals, and humans. 

When it comes to lectins in the diet, the main focus is on lectins in plant foods. Lectins are part of a plant’s chemical defense system against pests. When these chemical defenses are eaten by humans , they can cause digestive issues and inhibit the body’s ability to absorb various nutrients including zinc, iron, and calcium.

Impact Of Lectins

Though research into the effects of consuming lectins is still emerging and more needs to be done, studies have raised the question whether lectins are harmful. 

For people with IBS, IBD, Crohn’s, autoimmune diseases, and food sensitivities, a lectin free diet has been found to be beneficial.

Some ways lectins can impact human health include:

Malnutrition

Lectins have been shown to inhibit the absorption of calcium, phosphorus, iron, and zinc. Since lectins are found in the same legumes and grains that contain these minerals, the nutrient value of these foods may be much lower than stated on nutrition labels.

Some experts consider the polyunsaturated fats (PUFAs) in many plant and seed foods as antinutrients. When combined with lectins, PUFAs can inhibit trypsin and other digestive enzymes, leading to greater reductions in nutrient absorption. 

Inflammation

Lectins may be the active compound in many inflammatory plant foods.  In studies, lectins have been shown to exacerbate inflammation associated with IBS and autoimmune conditions like rheumatoid arthritis and psoriasis.

People with IBS and leaky gut are also more susceptible to the negative effects of lectins, and their effects can be felt immediately. 

Aging 

Lectins are also sticky proteins and can bind to glucose and AGE molecules in joints, between nerve junctions, and within myelin sheathes, contributing to glycation and aging, along with inflammatory conditions like diabetes and arthritis.

Disrupt Intestinal Flora and Hormone Signaling

When the lectin proteins bind to cells lining the digestive tract, they can disrupt intestinal flora growth and hormone signaling.

Promote Leaky Gut 

Lectin binding in the gut has also been associated with damage to the tight junctions among intestinal cells, leading to leaky gut. This is turn has been linked to autoimmune disorders.

It has been estimated that up to 90% of patients with autoimmune disorders have shown significant improvement after eliminating sources of lectins from their diets. 

Digestive Problems & Lectin Poisoning

When consumed, lectins in their active state can cause negative side effects. In addition to disrupting intestinal flora, hormone signaling, and contributing to intestinal permeability, some lectins like phytohemagglutinin (a type of lectin that can cause red blood cells to clump together) are so acutely poisonous to the intestines that they can cause stomach pain, nausea, vomiting, and diarrhea. The most publicized accounts report severe reactions in people eating even small amounts of raw or undercooked kidney beans.

Certain lectins are more poisonous than others. Castor beans and several other plants contain a poisonous lectin called ricin. Ricin is a potent toxin that has gained attention in recent years because it could be used as an agent of biological warfare or as a weapon of mass destruction. Even a tiny dose of ricin can prove to be fatal.

Lectins in GMOs

The lectin proheviein occurs naturally in rubber and has been synthesized in various genetically modified foods for its anti-fungal properties. 

The inclusion of lectins from non-food plants has led some experts to forecast allergy outbreaks, especially in people with latex sensitivities. 

In 1998, it was revealed that lab rats fed GMO potatoes with an insecticidal lectin gene incurred major damage to their immune systems, and vital organs including kidneys, spleens, and brains. 

Though these researchers had been a highly respected for over 30 years, and though these findings were supported by over twenty scientists, this information has sadly been ridiculed by many experts, especially those receiving funding from pharmaceutical and agricultural corporations.

Foods High in Lectins

The foods with the highest lectin content are: 

·       Beans and legumes

·       Grains

·       Nightshade vegetables (tomato, potato, eggplant, peppers, tomatillo)

·       Dairy products

Lectins In Beans & Legumes

Most beans are high in lectins. Commonly consumed legumes that contain high levels of lectins include: 

·       Lentils

·       Peas

·       Kidney Beans

·       Black Beans

·       Lima Beans

·       Soybeans

·       Peanuts 

Lectins levels in raw kidney beans are so high that eating only a few raw or undercooked beans can cause symptoms of toxicity including vomiting and diarrhea. 

Once cooked kidney beans still contain 200–400 hau per serving, which is not enough to cause toxic symptoms in most people, but may exacerbate IBS and intestinal issues in vulnerable people. 

The lectins in peanuts may be particularly resistant to degradation from heat. A study revealed the presence of lectins in the bloodstream of groups of people who ate raw and roasted peanuts.

Lectins In Grains

Gluten is the most infamous lectins found in grains, but it’s only one of many. Grains that high contain lectins include:

·       Wheat

·       Wheat germ

·       Barley

·       Rye

·       Quinoa

·       Rice

To put these lectin levels in context, these grains contain around 3000 mcg of lectins per 100-gram serving. But with proper preparation you can dramatically reduce lectins and other antinutrients. 

Nightshades

Popular nightshade vegetables containing lectins include: 

·       Potatoes

·       Tomatoes

·       Eggplant

·       Peppers (bell, cayenne, paprika)

It’s worth noting that many studies have not shown lectins present in tomatoes to negatively affect human health. 

Can Lectins be Beneficial?

Within the field of nutrition, there is some disagreement regarding whether lectins portray benefits or drawbacks to human health. Some researchers even correctly point out that lectins may have antioxidant properties. 

However, when you reduce oxidizing foods like the PUFAs obtained from many vegetable oils, the need to consume more antioxidants to offset them is almost eliminated. 

Some lectins have been shown to reduce inflammation, suggesting that more research needs to be done to better understand the link between inflammation on some lectins and not others.

There is also a belief among many mainstream nutritionists that because many lectin-containing foods also provide B vitamins, protein, fiber, and minerals, the nutritional benefits outweigh any potential drawbacks. However, this view seems short-sighted when considering that people can obtain a significantly greater abundance of more highly bioavailable nutrients from animal products like meat, eggs and seafood, without exposure to plant toxins. 

If you are looking to avoid lectins stick with low lectin foods and reduce lectin concentrations with appropriate preparation methods.

Animal products are generally lower in lectins than any other types of foods. Low-sugar fruits and low-carb vegetable are also viable options. 

Since lectins attach to carbs, and fat doesn’t usually come with carbs, most fats have low, to no lectins. Healthy low lectin fats include: 

·       Ghee

·       Tallow

·       Lard 

·       Coconut Oil

·       Olive Oil 

Reducing Lectins In Your Diet

If you opt to continue eating lectin-containing foods there are methods you can use to protect yourself. 

Peeling and deseeding plant foods as well as using high cooking temperatures can remove the majority of lectins from most legumes. 

One study showed that boiling red and white kidney beans can completely remove all lectin content and fermenting lentils for more than 72 hours can eliminate the majority of lectins.

Preparation and Cooking Tips to Reduce Lectin Content

• Research demonstrates that sprouting, fermenting, soaking overnight and cooking high lectin foods does dramatically reduce the lectin content, making them safer for most people. In addition to removing seeds and peel, using traditional preparation methods can support lowering lectin concentrations:

• If you choose to eat beans, be sure to prepare and cook them properly, and NEVER eat raw or undercooked. Be sure to soak beans in water for at least 12 hours before cooking, changing the water frequently. Rinse the beans well, discarding the water used for soaking. Cook for at least 15 minutes on HIGH heat, ideally using a pressure cooker.

• If consuming grains, keep in mind that the only way to make bread safe is to buy organic whet AND raise the bread using traditional methods of yeast or sourdough, which breaks down the gluten and other harmful lectins.  You would be hard pressed to find this in our grocery stores. You will need to make it yourself or purchase it from a traditional artisan bakery.

• Many beans, seeds and grains can be sprouted to deactivate lectins. There are some exceptions, such as alfalfa, where sprouting increases lectins.

• Plant lectins are most effectively neutralized when cooked under pressure relatively quickly. This method is ideal for beans, legumes, quinoa and rice, for example.  Avoid slow cookers for plant foods, as they will increase lectin content because of the low temperature used.

There are some safe lectins in many foods. The lowest lectin content options are asparagus, garlic, celery, mushrooms and onions. Cooked root vegetables like sweet potatoes, yucca and taro, along with leafy greens, cruciferous vegetables, avocados, olives and olive oil are all examples of healthy foods that do contain very low amounts of lectins.  They can often be eaten without restrictions.

The Takeaway

Lectins are antinutrients found in plants. These sticky proteins can bind to glucose in your body, and could potentially cause many downstream negative health consequences. Research shows that lectins can contribute to various health issues.

The highest levels of lectins are found in legumes and grains. Reducing lectins in your diet may offer various health benefits including improved digestion, reduced inflammation and gut permeability, and greater nutrient absorption. It may, however, not be possible to eliminate all lectins from your diet.

 The key is to identify the worst culprits, cut those out, and make sure you are preparing food in ways that minimize or reduce lectin content.  How strict you need to be will be determined by your health status, genetics and willingness to explore the possibility that lectins are standing in your way of better health.