A current trend in the health-sphere is eliminating foods that contain lectin. Celebrities like Kelly Clarkson claim that by eliminating them she was able to miraculously drop thirty-seven pounds off of her frame, and even medical authorities such as Dr. Steven Gundry, MD have written books about their alleged dangers. [1] But what is a lectin? Why don’t most people hear about them? Are the claims legit science or just a bunch of junk? And is the lectin-free trend going to wind up like the gluten-free craze that only in the past few years has seemed to calm down? Let’s explore all of this in today’s post about lectins so that YOU can make an informed decision about your diet. Are you ready? Then let’s get started!

Lectin 101

So… what are lectins again? Ask anyone on the street and they’ll mostly scratch their head in confusion. Let’s identify what they are in this section. To put it simply, lectins are a naturally occurring type of protein that can found in a number of plant-based foods. Similar to how gluten is a kind of protein, so too are lectins. Lectins exist to protect the plant as it grows. And like with gluten, they may cause problems in certain individuals. They can also become problematic when eaten in excess, particularly when the food is consumed raw. [2]

You can find lectins in the following foods:

• Potatoes
• Eggplants
• Wheat
• Rice
• Most grains
• Legumes
• Peanuts
• Peas
• Tomatoes
• Squash
• Corn
• Peppers
• Berries
• Pomegranates

Before you panic about the lectin content in foods, keep in mind that most, if not all, lectin can be eliminated through a variety of cooking and prepping methods. Boiling, baking, sautéing, and pressure cooking is one of the best ways to achieve this, in addition to fermenting, sprouting, peeling, and de-seeding. [3]

Good… or Bad?

Let’s weigh in the good and bad aspects of lectins. Starting with the bad.

The current research on the negative effects of lectin consumption is a bit complicated. Some of the symptoms include upset stomach, bloating and gas, gut irritation and damage, vomiting, and impaired nutrient absorption (which leads to deficiencies). [4] One of the more severe side effects of lectins is the triggering of an autoimmune response, therefore worsening inflammation and conditions like arthritis. [5] A cautionary tale that anti-lectin proponents often employ is the danger of consuming raw kidney beans. They contain a type of toxic lectin known as phytohemagglutinin, which can cause severe bouts of vomiting, diarrhea, and even hospitalizations; all it takes is to consume four to five improperly cooked beans, according to the USDA. [6] Overall, people who swear by going lectin-free take a further step and claim that all lectins are downright dangerous and that everyone should avoid them. Which brings me to mention a couple of errors with this line of thinking.

Firstly, there’s no denying that we’re all uniquely different and therefore can react either negatively or positively to lectins. So, if cutting out lectins is making a massive difference in your quality of life, then who am I to judge or tell you otherwise?

Secondly, a common thing that people overlook with lectins is the way that they’re prepared. I don’t know about you, but I would never go about eating a raw potato or an uncooked cup of beans. It’s pretty safe to say that most people are not going to be eating these foods uncooked. Let’s also remember that many other lectin-containing foods can still be eaten provided you remove the seeds. Thus, it’s perfectly safe to eat a tomato as long as it’s de-seeded.

Third, and perhaps most significantly, is the lectin-free diet itself. For the most part, it seems as though you’re encouraged to eat a whole foods diet based on plenty of plant-based and animal foods. The people who experience weight loss or any dramatic sort of change are probably feeling good not because they removed lectins per se but rather that they cleaned up and improved the overall quality of their diets. Meaning, they most likely transitioned from a modern diet of processed, fast food and junk. Anything that gets you to eat real foods is going to have some kind of beneficial effect. Which begs the question- did removing lectins really help you, or did eating better food?

I want to bring up a few of the criticisms against the lectin-free diet. The first comes from Harvard University stating, “These theories have fueled the profitable anti-lectin movement, spawning bestselling books and enzyme supplements to prevent lectin activity in the body. However, there is very limited research in humans on the amount of active lectins consumed in the diet and their long-term health effects. Anti-nutrients including lectins are most often studied in the diets of developing countries where malnutrition is prevalent, or where food variety is very limited and whole grains and legumes are important daily staples.” [7]

Cleveland Clinic dietitian nutritionist Ariana Cucuzza echoes these sentiments, elaborating that, “It’s kind of controversial. There are some studies on lectins since the 1970s, but they are very inconsistent, and a lot of them are in very isolated environments like in test tubes or animals. So, translating [the results of those studies] to humans can be very confusing, and people don’t really know how it affects us.” [8]
The criticism towards the anti-lectin trend is further carried on by Dr. Robert Eckel, a past president of the American Heart Association and current professor of medicine at the University of Colorado, “This is against every dietary recommendation represented by the American Cancer Society, American Heart Association, American Diabetes Association and so on. But scientific presentations that are not yet peer-reviewed and published are inadequate evidence.
I’m not saying this is definitely wrong. I’m saying, at this point, there’s not adequate research to make any conclusions. At the same time, it opens up the door to do controlled studies that may lead to finding something novel and applicable.” [8]
In fact, on the contrary, there are actual benefits to consuming lectins. They ironically can act as an antioxidant and protect our cells from free radical damage, thus exerting an anti-aging effect. [9] In fact, there’s emerging research showing that in low, non-toxic amounts they can cause cancer cell death. [10] [11] Lectins are also being studied for their ability to aid in the growth of healthy gut cells, particularly in patients that struggle to enough food (i.e., chemotherapy). [10]
Also, just because a food contains lectins does not mean it is inherently bad for you. Tomatoes, for instance, contain lycopene, an antioxidant known for its potential protective effects against sun damage and prostate cancer in men. [12] [13] Cooked legumes (beans, peas, lentils) are also high in fiber, which feeds the good bacteria down in our gut. (It should also go without saying that fiber helps to regulate bowel movements!)

Closing Thoughts

By cutting out a laundry list of foods using inconclusive, faulty research as justification is a recipe for disaster. Unless there’s a legitimate medical reason you need to exclude them, you shouldn’t be afraid to have some fresh pomegranate seeds or a baked potato. You’ll only be missing out on the nutrients and potentially creating an unhealthy obsession with food. As it stands, the research remains inconclusive. The vast majority of people who claim a lectin-free diet is working for them either are dealing with very serious, complicated health issues or have never actually eaten a healthy diet to begin with. Otherwise, only resort to an lectin-free diet under the supervision of a doctor or dietitian. He or she can help you to customize a meal plan that ensures you’re still getting enough nutrients.

Sources:

[1] https://www.healthline.com/health-news/kelly-clarkson-diet
[2] https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-q-and-a-what-are-dietary-lectins-and-should-you-avoid-eating-them/
[3] https://www.medicalnewstoday.com/articles/319593.php
[4] https://www.healthline.com/nutrition/foods-high-in-lectins
[5] Vasconcelos IM, Oliveira JT. Antinutritional properties of plant lectins. Toxicon. 2004 Sep 15;44(4):385-403.
[6] https://u.osu.edu/chowline/tag/phytohaemagglutinin/
[7] https://www.hsph.harvard.edu/nutritionsource/anti-nutrients/lectins/
[8] https://www.livescience.com/62914-what-are-lectins-plant-paradox.html
[9] https://innspub.net/ijb/study-lectin-antioxidant-cytotoxicity-anticancer-properties-punica-granatum-fruit-juice-eac-cells-swiss-albino-mice/
[10] Liu Z, Luo Y, Zhou TT, Zhang WZ. Could plant lectins become promising anti-tumour drugs for causing autophagic cell death? Cell Prolif. 2013 Oct;46(5):509-15.
[11] Singh RS, Kaur HP, Kanwar JR. Mushroom lectins as promising anticancer substances. Curr Protein Pept Sci. 2016;17(8):797-807
[12] https://www.sciencenews.org/blog/food-thought/dietary-protection-against-sunburn-recipe
[13] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4616444/