We’re all familiar with that schoolyard rhyme: “beans, beans, they’re good for your heart…” As adults, we roll our eyes, but have you wondered where the rest of that rhyme came from, or why foods like legumes are so troublesome to digest?
Most of our foods contain particular compounds that, by nature, strain our digestive systems. While that doesn’t mean we can’t tolerate them, research is discovering why some foods are so tough to digest, and the implications of consuming them anyways. And in the case of beans and legumes (to name but a few), the leading culprit we’ve found is lectins.
What are lectins and what they do
Lectins are a protein found in various plant and animal-based foods. In fact, almost all plant and animal substances contain them in small quantities.
We know that proteins are the building blocks of muscles and are critical to our health, so the question for most of us is: if lectins are just proteins, how could they be bad for us?
Simply put, lectins bind cells together. Specifically: sugars. They’re also in a category known as “antinutrients” because of their ability to impair the body’s ability to absorb nutrients properly. Because we can’t digest lectins, they tend to pass unnoticed through our systems.
For most people, this means that antinutrients like lectins pose no problems. In small amounts, lectins have numerous health. They’ve been shown to have an essential role in immune function, cell growth, and may even be helpful in cancer therapy.
This does not mean we should include them in every meal. A diet rich in lectins can demolish your gut lining and tight junctions (tight junctions are the areas where the membranes of two adjacent cells join together to form a barrier). This is especially true for those who suffer from GI disorders or immune dysfunctions.
How lectins are harmful
Nature never intended for us to digest lectins, they were meant for the protection of their host organism. They act as a natural insecticide, protecting plants, grains, and legumes from natural predators. When predatory insects come in contact with them, the lectins disrupt insect metabolism entirely, preventing invasions and attacks on the plants.
So, let’s revisit our childhood and rewrite that schoolyard rhyme: the more lectins you consume, the more discomfort, nausea, vomiting, diarrhea, flatulence, and most importantly, malabsorption of nutrients you might experience.
If these symptoms sound familiar, it’s because foods with high lectin content are everyday staples in our diet. Foods such as dairy, nightshades (tomatoes and peppers), whole grains, seeds, GMO’s, and yes, legumes are in the top 30% of lectin-containing foods concerning content per portion.
Some experts may suggest that removing lectins from your diet altogether can nourish the gut back from antinutrient-caused distress, making the change critical to GI and immunity disorders treatments. However, we would caution against removing entire categories of foods from your diet unless it is absolutely necessary. Especially because high-lectin foods do have some benefits, like fibre and minerals.
How to prepare foods that contain lectins
An alternative to eliminating lectins from your diet is to prepare them properly. There are techniques from around the globe that weaken and eliminate lectin proteins, making these staple foods much more comfortable to digest and enjoy.
Below are our four favourite ways of preparing legumes, grains, and seeds so you can keep them in your diet without worrying about the adverse effects of lectin protein:
Beans (canned or dried) in particular benefit from soaking, as do many harder grains and pseudo-grains like oats, rye, barley, wheat, and quinoa. Soaking and rinsing legumes and grains removes starches, acids, and proteins, making minerals more bioavailable and the grain easier to digest. Put yours in a deep bowl and cover with water by about 2 inches. Allow them to soak for a few hours up to overnight. Drain, rinse and repeat until the water runs clear. We like to add a 1″ piece of kombu or dulse seaweed to the water when soaking beans to break the lectin down further.
For most beans and seeds, sprouting deactivates lectins completely. Why? Because you’re no longer eating them in their contained form. Instead, since they’ve begun the initial stages of germination, they’ve evolved from that seed state. The nutrients are even more available when you sprout, and it’s a lot of fun for the family when you have a hand in ‘growing’ your own food. This works for almost all legumes except for alfalfa in which, interestingly enough, lectins increase when sprouted!
3. Boil or Pressure Cook
It seems evident that you would boil or pressure cook legumes and grains. Still, these techniques have many benefits, one of which is ridding beans of lectins. Studies show that boiling soybeans, red beans, and many others at 212°F/100°C for a minimum of 10 minutes reduces lectin content to negligible amounts.
Fermentation is the process of allowing good bacteria to grow in food. The bacteria break down possibly harmful proteins, including lectins. Fermentation is a universal approach that’s been used across many cultures to prepare and consume foods that are otherwise difficult to digest. In fact, fermented foods are fantastic for your health. That good bacteria we mentioned is also known as probiotics – an essential part of your gut health. Just think tofu, tempeh, miso, kefir, and natto as examples of fermented foods that would contain high levels of lectins before fermentation, and you’ll see why the technique is so far-reaching in time and space.
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Rhodes, Jonathan M. Genetically modified foods and the Pusztai affair. BMJ. 1999 May 8; 318(7193): 1284.
Miyake K, Tanaka T, McNeil PL, 2007 Lectin-Based Food Poisoning: A New Mechanism of Protein Toxicity. PLoS ONE 2(8): e687. doi:10.1371/journal.pone.0000687
DeMarco, Vincent G., et al. Glutamine and Barrier Function in Cultured Caco-2 Epithelial Cell Monolayers. J. Nutr. July 1, 2003 vol. 133 no. 7 2176-2179.