The reason that lectins are a recent concern, is because it has been discovered that the human does and cannot digest them.   An additional problem with lectins is that they can attach to the single cell membranes in the intestines and then enter the blood stream.  This cannot be a a good thing as lectins may go through the bloodstream and attach to other tissues, membranes and cells.   Lectins in the blood have been shown to cause blood cells to cluster together.  In the blood stream vessels this could be a severe problem.   They can also prevent the absorption of nutrients by cells and thus they are called antinutrients.   They can cause a person to have an upset stomach when plants with lectins are eaten without being cooked.   It is the reason that some people get sick when they eat undercooked foods.   In some studies, conducted by the FDA, the lectin in just four red kidney beans can cause severe nausea, vomiting, and diarrhea.  From these and other studies, it has been established that some foods with lectins can make people quite sick.   These same studies have shown that cooking with moisture, such as using steam, can help to reduce lectins in our foods.  Cooking can also break down the starches into simpler carbohydrates.   When lectins are cooked, they are also more likely to attach to carbohydrates and then pass through the body without causing any negative effects.  On the other hand, slow cookers, such as low heat crock pots are not recommended for preparing kidney beans because they do not have high enough heat to break down the lectins.  The main ways to break down lectins and make them harmless includes:

• boiling
• fermentation
• sprouting
• peeling
• deseeding
• pressure cooking

Positive Effects of Lectins

While lectins have some undesirable effects, they also have some positive ones. Small amounts of lectins may help the good bacteria that live in human digestive systems.  They can help attach to unneeded food particles that are not needed and then they can pass through without damage to the body.  

Research has been conducted that demonstrates that lectins can be used to help diagnose cancer cells.   Because lectins can attach to cancer cells and then block the absorption of nutrients, they can help to slow the growth of cancer cells.    In much the same way, they can prevent cancer cells from multiplying.   Researchers are even looking at lectins as potential treatments for illnesses caused by bacteria, fungi, and viruses.

A Lectin Free Diet

Would it be wise to consider a lectin-free diet?   Dr. Gundry popularized the lectin-free diet. He is a former heart surgeon who switched his focus to food and supplement-based medicine to prevent the need for heart surgery and other body decadence.

Dr. Gundry describes lectins as the main danger found in the American diet. In response, he has written a book that provides information on how to avoid lectins while suggesting alternative food choices and lectin free recipes.  According to his book, Dr. Gundry’s plan is to help people improve their health and reduce their weight through a lectin free diet.  The plan includes supplements Dr. Gundry has developed and that are sold under the GundryMD brand.

Alongside many other foods, Dr Gundry recommends eating sweet potatoes to limit the intake of lectins.

In addition to Dr. Gundry, other scientists also believe lectins are harmful and that they cause inflammation.   One study links lectin to autoimmune diseases, including celiac disease, diabetes, and rheumatoid arthritis.    The concept is that these lectins can break through the digestive membranes and enter the blood stream.  Then they travel throughout the body attaching themselves to cartilage, bone, organs cellular systems such as blood and hormones.   This leaking of lectins into the blood stream happens when the lectins cause fissures and ulcerations in the intestines and which cause irritable bowel syndrome.  When the lectins travel throughout the body, they can cause the buildup of undigested lectin proteins in the bone joints causing variations of arthritis.  Then can cause lectin protein buildup in the cardio and vascular systems which can cause heart problems and high blood pressure.   However, many other surgeons believe that it is not lectins but man-made granulated sugar that causing these problems.   The studies have not been conducted long enough nor thorough enough to be conclusive.

One article discusses the research associated with wheat germ lectin. It has been determined that wheat germ lectins can impact the immune system and thereby reduce the body’s defenses against inflammation.  Long-term inflammation has been linked to serious medical conditions, including heart disease, cancer, and depression.   It could then be assumed that following a lectin-free diet could be a way to lower inflammation in the body. However, more research in humans is needed before the effect can be confirmed.

Disadvantages of lectin free diets

Eliminating grains, beans, certain vegetables and some fruits also eliminates some of the healthiest foods available.   This is the reason that it is so difficult for some people to follow such a diet for a long-term period.   For example, research has shown that consuming whole grains can help reduce heart disease, diabetes, and cancer, which might be more important than any of the damage caused by wheat lectins.  Fruits and vegetables also have many associated health benefits. Eating more fruits and vegetables can reduce multiple conditions, including heart and lung diseases. They may also impact cancer risk and help people avoid gaining weight.   A lectin-free diet would be difficult for vegetarians or vegans to follow, since legumes, nuts, seeds, and whole grains provide plant-based proteins, which is the only alternative to meats.   A final consideration is that lectins are required to help reduce constipation, because they are part of the fiber of most plant food.   Finally, following a lectin free diet is expensive because it requires specialty milks, pasture-raised meats and other items grown under special situations.  

Foods to eat

Let’s consider the foods that a person could eat for a lectin free diet.  According to Dr. Gundry, the following foods are low in lectins and they are very healthy:

• pasture-raised meats
• A2 milk
• cooked sweet potatoes
• leafy, green vegetables
• cruciferous vegetables, such as broccoli and Brussels sprouts
• asparagus
• garlic and onions
• celery
• mushrooms
• avocado
• olives or extra virgin olive oil

According to Dr. Gundry, people should limit (not totally avoid) the following foods when trying to avoid lectins:

• legumes, such as beans, peas, lentils, and raw peanuts
• squash
• nightshade vegetables, such as eggplant, peppers, potatoes, and tomatoes
• fruit eaten out of season, which is still allowed in moderation
• grains

Dr. Gundry recommends completely avoiding the following foods:

• corn (especially GMO corn, which includes almost all corn)
• meat from corn-fed animals
• A1 milk

Conclusions

Lectins may be harmful, but other research does exist which demonstrates that when food is cooked well, particularly when it is prepared with high temperatures, the lectins are reduced to almost nil.   Therefore, even though lectins can be harmful, a person only needs to prepare their food simply through cooking.  For example, eat roasted peanuts not raw peanuts.   Don’t eat potatoes daily but rather, eat in moderation.   While lectins may cause some damage, there is strong research to support the benefits of eating plant foods.   Many plants are high in lectins, but lectin levels can differ significantly between plant types and in the way that they are cooked. There are also many kinds of lectins, and some seem to be beneficial.  It is also important to remember that much of the research involving lectins has been via animals or test-tube studies.  Furthermore, many studies have looked at single lectins rather than how they act while in the foods that contain them.

Therefore, our recommendation is to be aware of lectins, but aside from that, it might not be right to totally avoid foods with lectins.   The available research does show lectins can be harmful, but remember, that is only for foods that are raw or not properly prepared.    It seems that caution and care are all that is needed here.   A ggod recommendation might be to suggest to everyone to strive to avoid processed foods as much as possible.   Seek to eat other foods in moderation and finally eat foods that are well cooked.  That is what most of us do anyway.