Protein Priorities: Are Lectins the New Gluten?

In the simplest terms, lectins are carbohydrate-binding proteins that you can find in most plant-based foods, including potatoes, beans/legumes, wheat, tomatoes, eggs, dairy, and peanuts.

In nature

Plants produce toxic lectins to survive in nature, as they protect the plant against insects, fungi, molds, and diseases.

In our bodies

Lectins allow molecules to stick together, which can influence cell-to-cell interaction. When they enter our body unbound, they can’t be digested (similar to fibre), allowing them to cross into our bloodstream. In small amounts, lectins are important to our bodies, as they’re involved in our immune functioning, cell growth, cell death, and much more. However, large amounts can create some problems.

Research has suggested that lectins that haven’t been hydrolyzed by cooking can cause acute gastrointestinal distress, which can lead to gut-related issues such as bloating, abnormal stool passing, and stomach pain. When consumed, uncooked, in excess by someone with dysfunctional digestive enzymes, there can be intestinal damage (leaky gut), which ultimately can lead to a variety of autoimmune diseases.

The autoimmune effects depend on the interaction between lectins in our diets and our gut microbiota, which determines bacterial growth and toxin release. If the lectins enter our circulation, they have the potential to create autoimmune responses in our bodies, inducing inflammation and potentially disease, such as rheumatoid arthritis, diabetes, gut disorders, and celiac disease.

Preliminary research suggests that eliminating foods containing lectins can potentially diminish disease symptoms in some patients with existing autoimmune disorders.

Eating large amounts of foods in which lectins haven’t been hydrolyzed by cooking can create toxic reactions in the body, but we eat most lectin-containing foods only after they’ve been cooked, meaning the lectins have been inactivated. So, for most people, eating whole grains, legumes, and other vegetables such as potatoes will not create adverse health effects.

Cooking, soaking, sprouting, and fermentation have all been linked to the reduction and elimination of lectins from the foods we eat.

Kidney beans and soybeans contain very high amounts of lectins, which, if eaten without soaking and cooking first, can cause toxicity in the body, leading to nausea, vomiting, and diarrhea. However, when cooked, the amount of lectin is significantly reduced, allowing for safe consumption levels. In addition, fermentation of soybeans (tempeh and miso) can reduce lectin content by 95 percent.

Wheat products, when eaten raw, have high lectin content. However, when cooked, lectin content is almost completely eliminated. For example, research studies have found almost no lectin activity in pasta likely due to the cooking process involved. Ensure you’re consuming wheat that has been cooked (pretty much any type of bread you find) or sprouted.

Lectins are found in some of the foods we eat, but not all of them. Some of the foods containing lectins are excellent plant-based sources of nutrients.

Legumes and wheat provide our body with complex carbohydrates, fibre, antioxidants, protein, and other nutrients important to our health and well-being. Eliminating these foods can also lead to the elimination of several important nutrients from our diet.

Lectin content is often reduced or eliminated through various cooking processes. Most of the lectin-containing foods are consumed after they’ve been cooked, not eaten as raw foods (see Soaking and Cooking Tips). This means that the majority of people should be able to consume lectins without adverse health effects.

There isn’t enough human-based research to suggest we should completely avoid foods containing lectins; however, some individuals with specific autoimmune conditions may benefit from eliminating lectins from their diet.

Cooking foods that contain lectin usually reduces or eliminates most of the lectin activity, making them safe to eat.

Most healthy individuals can consume lectin-containing foods without causing harm.

Lectin-containing foods are high in fibre and other important vitamins and minerals, so including them in your diet has many health benefits.

If you purchase dried beans and legumes, they must be soaked and cooked before consuming to avoid the problems associated with excess lectin consumption. Canned beans and legumes are already cooked, but they should be rinsed first to remove some of the salt added during processing.

Soaking

First, dried beans and legumes, with the exceptions of black-eyed peas and lentils, should be rinsed well and then soaked in room-temperature water to rehydrate them for quicker, more even cooking.

To slow soak, cover 1 lb (450 g) dried beans with 10 cups (2.5 L) water and refrigerate, covered, for at least 4 hours or overnight. To quick soak, leave the covered pot at room temperature for 1 to 4 hours.

Cooking

After soaking, drain and rinse the beans and add to a stockpot, then cover them with three times their volume of fresh water, and bring to a boil. Reduce the heat and simmer gently, uncovered, stirring occasionally until tender, for at least 45 minutes, depending on the type of bean. Add more water to keep the beans from becoming dry.