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Have you wondered whether you should be avoiding lectins? Some consumer health sites caution about the potential negative effects of these natural food compounds, but (as often is the case) there is more to understand. In this article, you’ll learn about 5 potential benefits of lectins and how to decide whether you should be including or avoiding these compounds in your diet.
But first, let’s review what they are…
What are dietary lectins?
Lectins are a large group of proteins found in plants, animals, and microorganisms. They have the ability to bind to carbohydrate components on cells, which allows them to take on active roles in the body such as cell development and host defense.
There’s no such thing as a lectin-free diet since lectins are so pervasive. However, some foods are higher in lectins than others, such as legumes, whole grains, peanuts, and nightshade plants such as tomatoes, peppers, and potatoes.
Can lectins be harmful? “My Instagram feed says so…”
There are concentrated amounts of lectins in raw legumes that are known to be harmful. This is well known and documented as a reason for food poisoning after consuming raw kidney beans, for instance. Animal studies also suggest that raw legume consumption may harm the gut lining and have knock-on effects that compromise nutrient absorption and immune function. However, these risks can be eliminated by proper preparation – cooking at an appropriate temperature and for an appropriate length of time. Soaking, germinating, and fermenting beans also reduces lectins and is part of many traditional legume preparation practices.
As yet, no human studies have demonstrated harm from lectins when food is properly prepared. However, anecdotal reports suggest that some individuals do genuinely feel better when they reduce high-lectin foods. One possible explanation may be some form of dysbiosis (such as small intestinal bacterial overgrowth, or SIBO) that is aggravated by the high prebiotic fiber content of lectin-rich foods (high lectin foods are also typically very high in fiber). Dysbiosis can cause localized symptoms in the digestive tract and/or symptoms in other parts of the body such as joint pain or brain fog since bacterial compounds (such as pro-inflammatory lipopolysaccharides) from the digestive tract can be absorbed and travel through the bloodstream. If this is occurring, addressing the dysbiotic gut bacteria may resolve the supposed lectin intolerance. One other rarer possibility is that some individuals with autoimmune diseases may generate antibodies to lectins. These antibodies then cross-react with cells in their body that are structurally similar to the lectins causing the antibodies to attack the body’s own cells. This process is known as molecular mimicry and may be the only true reason to avoid or minimize certain lectins.
Overwhelmingly, however, the evidence points to the beneficial health effects of high lectin foods since they are predominantly plant foods and high in fiber, vitamins, minerals, and phytonutrients. Traditional diets that are known to be healthy on average, such as the Mediterranean and Okinawan diets, are rich in lectin-containing foods.
Not only that, lectins may actually provide some benefits in their own right…
5 surprising potential benefits of lectins
Scientific papers have reported on these potential benefits of lectins:
Lectins can be antimicrobial
In fact, plants use lectins primarily in their defense mechanisms against insects, molds, fungi, and other diseases. Lectins work against pathogens by binding to carbohydrates on the surface of the microbes. This influences their biological activity and how well they can bind to your cells. It can also weaken the integrity of the bacterial or fungal cell wall. These mechanisms may play a role in keeping the gut microbiota optimized and in check.
Lectins can boost immune activity
Plant lectins have also been observed to increase host immune responses. They can increase the activity of phagocytic cells (specialized immune cells that can “gobble up” pathogens and clear up debris after a microbe is defeated). They have also been shown (in animal studies) to increase the production of immune signaling molecules that improves defense against active infections. These properties have also made lectins a target vaccine adjuvant to improve the effectiveness of chemotherapeutic and other vaccines.
Lectins may improve blood sugar regulation
Some plant lectins have been shown to help improve blood sugar regulation. So far this has only been demonstrated in cell and animal studies, but this is intriguing nonetheless.
Lectins can stimulate digestive function
Plant lectins are known to stimulate cholecystokinin production in the digestive tract, which in turn promotes pancreatic enzyme and bile secretion and – essential digestive products that allow us to break down and extract nutrients from food. Cholecystokinin also stimulates mid-gut motility which helps move foods along the digestive tract and prevents stagnation (which could lead to dysbiosis).
Lectins may have anti-tumor activity
Several plant lectin types have been demonstrated as having anti-tumor activity in various cancer types including leukemia, sarcoma, hepatoma, and breast cancer. Lectins may be able to target malignant cells through the specific carbohydrate structures found on their surface.
Final thoughts
Although science hasn’t fully explored how these potentially beneficial actions translate into human health, it is likely that lectins don’t deserve to be blanket-labeled as harmful. And even if their mechanism of action involves exerting some form of mild stress on the body (triggering immune activity, and gut motility could, for instance, be interpreted as a mild danger response), we shouldn’t discount the potential for beneficial hormesis in most individuals – that a little bit of stress can be helpful.
For further reading, I recommend the following:
- Deanna Minich’s journal article on antinutrients in foods
- More about hormesis in health
- Vojdani’s work on lectin immune reactivity that may be relevant to some individuals with autoimmune disease
Do you eat or avoid higher lectin foods? Let us know in the comments below…
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Yes, I eat lectin containing foods but have adjusted to soaking and/or sprouting them before cooking. Always cooking thoroughly, and avoid use of floured lectin products – ie, garbanzo, lentil and split pea flour – because these are made from raw legumes and may not be thoroughly cooked when used in ‘quick’ baking recipes. It is best to slow cook the proteins for better digestion and nutritional availability.
Thank you for this information. I LOVE beans of all kinds and eat a good amount of potatoes, both sweet and white. I had cut back on eating beans for awhile because of the concerns about eating lectins. Then I heard Dan Buettner speak about his Blue Zones research. He recommended eating about a half cup of cooked beans daily, so I now enjoy eating beans again.
So are lectins dangerous? i’m afraid to eat
Hello apoel,
We don’t think that lectins should be considered dangerous as a whole. There are traditional food preparation practices that reduce lectin content in foods – such as soaking, sprouting, and fermenting and these are beneficial for increasing nutrient bioavailability from food. There are only a few instances where we see lectins may be problematic but certainly not for most of the population.
So is Dr. Gundry wrong?
We do think there is more to the lectins story. Thanks for your comment, Susan!
– Team DrKF
I listened to both sides of the story about lectins; but I found the warnings about lectins exaggerated, and compared the warnings to a modern day version of blood letting. At least the ads seemed like marketing fear mongering with images of spiked lectins passing through the gut like sword play. I had to think on my own, and I also found evidence that people with a variety of diets lived longest for reasons I can not quite comprehend except that they lived in communities with highly active lifestyles – in Japan, Hawaii, Indonesia, South America, and even Italy & Africa… So, that includes just about everyone who eats fish, tomatoes, rice, and beans. As a result I decided to research lectins more widely, and came across your article here, which I found really refreshing to read. I decided I will continue to enjoy my spaghetti and meatball meals as well as my favorite chile recipes made in the crockpot. You would have to be a little one track minded to say that exercise doesn’t affect your weight. I remained at my high school weight (165 lbs) well past 50 years old, mainly because I continued the same activities I enjoyed the most, like basketball and long jogs. The activity always helped regulate my food intake, and I still have a decent appetite. I mostly drank a lot of water.