Are Lectins Bad For You? The Truth About Lectin in Beans

Beautiful beans! These little legumes really don’t get the credit they deserve. They’re affordable, packed with cruelty-free protein, rich in fiber, easy to prepare, versatile and delicious! Need I say more?

Turns out, I do.

See, I’ve been hearing some nasty rumors about beans lately. Some people say they’re making us gain weight. Others claim that they’re interfering with our blood sugar. Some even say we should avoid legumes because they contain “anti-nutrients.” What?!

I know there’s a lot of information out there when it comes to what to eat for optimal health, which can be confusing. We’re constantly bombarded with messages about which foods cause disease and which prevent it, what we can (and can’t) eat if we want to lose weight and what’s safe to feed our families.

Don’t get me wrong, many of these messages about food are not only valid but also incredibly important. But when the facts are cherry-picked, how can we possibly decide what to listen to?

The truth is out there! And when it comes to the bean debate, I’m gonna help you find it. That’s why I asked our super-knowledgeable Nutrition Director, Jen Reilly, to weigh in. Wait ‘til you hear what she has to say—it’s gonna restore your love for beans!

Take it away, Jen!

What Are Lectins?

Before we dive into the health benefits of beans, let’s dissect why they often get a bad rap. Lectins in beans have been labeled as “anti-nutrients” that cause IBS, inflammation, obesity, and some autoimmune diseases.

So what are they? Lectins are a protein—more specifically hemagglutinin—that bind to carbohydrates. When they bind to carbohydrates, it makes them harder to digest. Hemagglutinin can also make red blood cells clump together.

Lectins are found in a third of the foods we eat and the lectin content is especially high in raw legumes, grains and seeds. Lectin-containing foods are the latest in a string of enemies named by fad diets. So what makes lectins harmful?

Some lectins—especially raw red kidney beans—may be harmful and may be responsible for damaging the intestinal wall leading to nausea, diarrhea and vomiting. It’s also possible that people with certain health conditions such as Crohn’s disease and Irritable Bowel Syndrome (IBS) are more sensitive to the damaging potential of dietary lectins and/or cannot digest lectins. And if you have Rheumatoid Arthritis, you may benefit from reducing or avoiding most lectins (study).

But proper cooking eliminates harmful active lectins almost completely (more on how to make sure you’re properly cooking your beans below). Truthfully, many lectin-containing foods in a healthy diet are served cooked, anyway.

Plant Foods High in Lectins

What foods are high in lectins?

Beans

Kidney beans are among the highest in lectins, but properly soaking and cooking dried beans denatures harmful lectins. Canned beans are already cooked, so while they aren’t the preferred option, they’ll be low in lectins.

Peanuts

Did you know that peanuts are a form of legume? Peanuts are commonly consumed raw and peanut lectins can also be found in the blood when consumed in large amounts.

Whole Grains

Raw wheat—such as raw wheat germ—can be a great source of fiber but contain high amounts of wheat lectins. Raw whole grains are a no-no if you’re trying to reduce or avoid lectins.

Soybeans

Uncooked raw soybeans are high in lectin. Because most soybean products aren’t boiled, if you’re sensitive to lectin, you may want to avoid them.

Potatoes

Potatoes are in the nightshade family and are high in lectin. While most people don’t eat raw potatoes, their skins contain high amounts of this protein.

Why Beans Are Good For You

Before we dive into some of the sneaky rumors surrounding beans, let’s review why they’ve built up such a great reputation over the years. Countless studies sing the praises of legumes (split peas, beans and lentils) of all shapes, sizes and colors. Here are just a few of the many wonderful things to love about them:

• Beans are among the cheapest sources of protein on the planet and produce the lowest level of greenhouse gases per gram of protein (World Resources Institute report on Sustainable Diets).
• They may be responsible for keeping your heart healthy by preventing coronary heart disease (study)—meaning they lower or prevent high blood pressure and help ward off strokes.
• They’re chock full of antioxidants, which prevent inflammation, aging and may reduce the risk of cancer.
• Because of their hard-to-find soluble fiber, eating 3-½ or more servings a week (about 1-¾ cups cooked beans or lentils total over the course of a week) will lower your type 2 diabetes risk by 35%. Plus, their resistant starch can also improve gut health.

However, despite all of the support from the medical community, beans have started getting a bad rap. The criticism mostly stems from the latest pseudoscience-based diet fad that tells us we should avoid foods that contain lectins. Plus, we’re hearing buzzwords like “phytates” and used in misleading ways to criticize beans. This negativity is also riding on the coattails of the anti-carb craze. Because yes, some people are still trying to convince us to be afraid of carbs, even the healthy, complex ones from the plant kingdom.

But, beans are not the enemy. In fact, any diet that suggests you eliminate a global dietary staple with a near-perfect nutrition profile (low in saturated fat, rich in fiber, iron, copper, magnesium and antioxidants) has nourished the planet since 6000 B.C. raises red flags for nutrition experts. So, let’s explore four of the most destructive bean critiques and what the research really says:

Myth #1: The Lectins in Beans are “Anti-Nutrients”

Back in 1988, lectins started giving beans a bad name when several hospital workers got sick from eating undercooked kidney beans (study). Unfortunately, beans’ image took another hit in 2006 when a Japanese TV broadcast introduced a new weight loss strategy that called for sprinkling powdered, toasted white kidney beans onto staple foods. Those beans weren’t cooked properly, either (beans should be boiled for at least 60 minutes after soaking and these were toasted for just 3!). As a result, over a thousand viewers suffered from intestinal problems and 100 people were hospitalized (aka “the white kidney bean incident in Japan”).

No conclusive research has been done in humans to support claims that properly cooked beans are responsible for causing IBS, inflammation, obesity, etc. In fact, there’s a large body of research on the health benefits of lectins! Studies indicate that they may improve gut health, prevent tumor growth, slow down cancer cell growth and prevent obesity.

Here’s another thing to keep in mind: Most healthy plants contain lectins. Ya know what else they contain? Fiber! Fiber is essential for a healthy metabolism and digestion, as well as a strong immune system. It also helps prevent cardiovascular disease and diabetes. Avoiding lectins means avoiding plants, and avoiding plant-based foods means avoiding fiber. You catch my drift?

Myth #2: Beans Slow Mineral Absorption

The phytates in beans may indeed slow or reduce the absorption of certain minerals. But, beans also happen to be quite rich in those very minerals! The confusion may come from the fact that some foods (such as whole grains) are rich in phytates but not as high in minerals as legumes, meaning that it may be harder to absorb enough minerals from those foods alone.

But unless your diet is very high in high-phytate grains with very little legume variety, this shouldn’t be an issue. And if you want to play it extra safe, load up on garlic and onions in your bean dishes—they’re pros at increasing mineral absorption. Score!

Here’s something else that the critics often don’t take into account: Phytates actually have a handful of positive traits. They may stop the growth of cancer cells (research article) and prevent osteoporosis (study). So, as long as you’re getting plenty of mineral-rich foods (which is exactly what you’ll get if you eat a variety of plant foods) in your daily routine, you may actually benefit from the phytates in beans. Go figure!

Myth #3: Beans Cause Blood Sugar Spikes

This criticism is misleading and simply not true. And it really makes my beans boil because I have two kids with type 1 (insulin-dependent) diabetes. They eat beans nearly every day and I’m able to watch their blood sugars on continuous glucose monitors every 5 minutes.

The digestion of carbs in beans is so slow that we often see a welcome, slow and subtle rise in their sugar levels several hours after eating beans. Nothing even close to a “spike” occurs. In fact, I attribute their steady blood sugars (few spikes and few crashes) to their bean-heavy diets.

And the research backs up my at-home experience. Studies suggest that because of their low glycemic index (due to high fiber content), the digestion of carbohydrates in beans is slower, doesn’t cause sugar spikes and results in better long-term blood sugar control as indicated by lower hemoglobin A1C (HgbA1C) blood test results.

Some argue that the fiber in beans is the real reason that people who eat a lot of them have better sugar control. But one study dispelled this myth by comparing two different diets for type 2 diabetics. One diet contained 1 cup of legumes per day and the other contained no legumes, but included an increased amount of insoluble fiber. The group consuming the legumes had better long-term blood sugar control than those consuming a diet high in fiber but devoid of legumes (study).

Myth #4: The Protein in Beans is Insufficient

It’s argued that animal protein is higher-quality than the protein in beans and the protein in beans isn’t sufficient for building and maintaining muscle mass, especially as we age.

Animal protein is “complete,” meaning that it contains all nine essential amino acids, which are building blocks for our bodies. Animal protein also has more protein per ounce than legumes.

Some folks suggest that these tidbits mean that animal protein is better quality than plant protein. This argument would only hold up if it were difficult to meet our basic protein needs with plants—and that’s simply not the case.

Legumes contain eight of the nine essential amino acids needed to build protein (and soybeans actually contain all nine!). But, the ninth amino acid (methionine) is easily found in whole grains. Most adults can meet their methionine needs by eating four servings a day of whole wheat grains (for example: one bowl of oatmeal, two pieces of whole-grain bread and a serving of quinoa).

Now, as for building and maintaining muscle, getting enough high-quality protein (which can come from beans and a variety of other plant sources) is just one piece of the puzzle. In fact, there is such a thing as too much!

Research shows that eating more protein than your body really needs in a day (multiply your weight in pounds by 0.36 or your weight in kilograms by 0.8 to get your daily requirement in grams) has no benefit and can actually be harmful to kidney function and bone health.

You can build and maintain muscle mass by getting the right amount of protein, practicing regular strength and resistance training and eating plenty of complex carbohydrates. This does take more maintenance and dedication as we age (because estrogen and testosterone levels decline) but it’s far from impossible. Moreover, no validated research indicates that animal protein is an essential piece of the puzzle.

How to Reduce Plant Lectins in Beans

While it’s not advised to eat raw beans, properly cooking lectin-containing foods like beans is how you reduce lectins and avoid lectin poisoning. Here are some simple tips:

• Dried beans must be soaked overnight before you cook them. This makes them easier to digest and starts the process of eliminating the harmful active lectins we talked about.
• Learn how long to cook your favorite beans. Raw kidney beans require the longest cooking time, so boil them for a full hour to neutralize the plant lectins. Other beans only need to be boiled for 20-30 minutes (actual time depends on size—smaller beans need less time) as long as they’ve been soaked. Using a pressure cooker is also a great way to ensure beans are fully cooked in less time.
• If you’re using a slow cooker: Raw beans simmered on low heat or cooked in a slow cooker will reduce lectin activity—but not completely remove all the lectins. Consider boiling the beans before adding them to your favorite recipe.

How to Ease the Impact of Beans on Your Digestive Tract

If beans lead to uncomfortable digestive issues, here are a few tips to add them into your diet without an upset stomach:

• Ease legumes into your diet if you’re not already regularly eating them. Start with smaller varieties like lentils and black-eyed peas.
• Consider cooking them with kombu seaweed, which contains enzymes that break down gas-causing compounds. This should make them easier to digest.
• Consider adding probiotics and digestive enzymes to your routine to ease digestion.
• Look for BPA-free cans or BPA-free tetra paks when you’re buying canned beans. Also be sure to rinse them well to remove excess sodium.

The Bottom Line: Beans Are NOT The Enemy

There are many types of lectins, and not all are harmful. In fact, most lectins pass through your digestive system unchanged by digestive enzymes.

Beans an important part of a healthy plant-based diet. As long as you’re properly cooking beans, you shouldn’t need to avoid them unless you have an allergy or particular digestive challenges like Crohn’s or Irritable Bowel Syndrome. If you do have Crohn’s or irritable bowel, some of the tips above may help if you want to eat beans—consult with your doctor when in doubt.

I hope this information eases any concerns you might have about beans. If you have any remaining questions, ask them in the comments below. I’ll be answering as many as possible!

Thank you, Jen! That was fascinating and so helpful. And beans—thank you, too!

Here’s something I want you to remember: When it comes to food, many people and organizations have a lot on the line. They may have your best interest in mind, or they may have other motivations clouding their vision. You are wise and intuitive, and you know better than anyone else what’s good for you. Let your voice be the loudest.

Your turn: What are your burning bean questions? I’d love to hear what’s on your mind in the comments below!

Peace and bountiful beans,