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Diet & Nutrition

Beans: Nutritional Friend or Foe?

Beans are a no-go on Keto and Paleo diets, but why? We weigh the health benefits of eating beans with the potential drawbacks. You decide which route is best for you.

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Health Benefits of Beans

  • Beans contain a multitude of nutrients. 
  • They’re low in fat, high in protein (15–20 grams per cup), and rich in magnesium, folate, zinc, copper, iron, phosphorous, and other vitamins and minerals. 
  • Dark-colored varieties such as red, black, and kidney beans are loaded with cancer-protective antioxidants.
  • Fiber is where beans really shine. One cup of navy beans, for example, contains 20 grams of fiber, which is about 70 percent of the recommended daily value. 
  • Beans also contain resistant starch, which encourages the growth of beneficial bacteria, lowers blood sugar, improves insulin sensitivity, reduces cholesterol and triglycerides, and may protect against colon cancer.

Preparing Beans to Counteract Compounds that Irritate the Gut

On the other hand, beans also contain compounds that can interfere with nutrient absorption, irritate the gut, and cause digestive issues. Below is a look at each of these compounds, and ways to keep them from interfering with your continued enjoyment of beans.

1. Phytates

Beans and other legumes, grains, nuts, and seeds store phosphorous as phytic acid—called phytate when it’s bound to a mineral in the seed. Phytates are an energy source for the sprouting seeds, and also prevent them from sprouting prematurely. But phytates can interfere with the body’s absorption of minerals, including zinc, iron, manganese, and, to a small degree, calcium. They can also make proteins, fats, and starches harder to digest.

Use your bean: To deactivate most of the phytic acid in beans, combine them in a large bowl or pot with water to cover by 2 inches, then soak for 8–12 hours. Drain, rinse well, and cook as usual (soaking reduces cooking time). And the upside: phytic acid seems to have some powerful health benefits. It’s an antioxidant, and may bind cadmium, lead, and other heavy metals, preventing their absorption. Foods with high phytic acid content also seem to reduce the risk of breast, prostate, and colon cancer, and may protect against hardening of the arteries.

2. Lectins

Found in high levels in beans and legumes, grains, nuts, and nightshade vegetables such as eggplant and potatoes, are proteins that bind to cell membranes. They act as natural pesticides, protecting plants from insects, fungi, and harmful microorganisms. The problem is, lectins can bind to the intestinal wall, making it more permeable and triggering a condition called leaky gut syndrome, in which partially digested protein and toxins “leak” through the intestinal walls and enter the bloodstream, causing systemic inflammation and other problems. Some even say that lectins are linked with Crohn’s disease, colitis, IBS, fibromyalgia, and other autoimmune conditions.

Use your bean: Thoroughly cooking beans dramatically decreases their lectin content, and also breaks down some of their complex starch into simple carbs, which then bind with the lectins and remove them from the body. Don’t use a slow cooker; the temperature’s not high enough to deactivate lectins. Instead, use a pressure cooker, or boil beans on the stovetop. Fermenting and sprouting can also reduce lectins. But don’t sprout kidney beans; they contain a lectin called phytohaemagglutinin, which can cause severe gastrointestinal symptoms including nausea, vomiting, and diarrhea even in very small doses. Kidney beans should always be thoroughly cooked.

3. Protease Inhibitors

Found mainly in beans, grains, nuts, and seeds, are compounds that block protease, the body’s protein-digesting enzyme, thus interfering with the body’s absorption of protein. Over time, this causes levels of enzymes, especially one called trypsin, to increase in the intestines, and can lead to leaky gut. Soy is especially high in these compounds, and the protease inhibitors in soybeans appear to be more resistant to cooking and processing.

Use your bean: Soaking and cooking deactivates the majority of protease inhibitors in most beans. Fermentation has been shown in some studies to completely remove protease inhibitors, especially in soy—so stick with tempeh, miso, and other fermented soy products. On the flip side, some studies suggest that the protease inhibitors in soy may contribute to their anticancer effects.


An acronym that stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, are carbohydrates that are poorly absorbed by some people, especially those who have IBS or other digestive problems. Because they’re easily fermented by gut bacteria, they can cause significant bloating, gas, stomach pain, diarrhea, constipation, and other digestive symptoms in some people.

Use your bean: While most beans are high in FODMAPs, chickpeas, lentils, and peas are allowed on most FODMAP diets. Canned beans are lower in FODMAPs than regular beans and, not surprisingly, soaking before cooking can reduce FODMAPs too.

5. Saponins

Found in beans, peanuts, legumes, and other plant sources, are thought to damage the membrane lining of cells, especially in the intestines. When the intestines become more permeable, as in leaky gut, toxins can enter the bloodstream and cause systemic inflammation and other issues. In extremely high quantities, saponins can destroy red blood cells if they enter the bloodstream.

Use your bean: Cooking beans doesn’t reduce the saponin content, but soaking and fermenting do. And, like other so-called antinutrients, saponins have some health benefits. Studies suggest that they decrease blood lipids, normalize blood glucose response, and reduce the risk of cancer.

Bean Alternatives

If beans don’t agree with you, or you just can’t or won’t eat them, be sure you’re including these important supplements in your diet:

  • Digestive enzymes. Look for a digestive supplement formulated specifically for beans, or one that contains alpha-galactosidase, an enzyme that helps break down the complex sugars in beans.
  • Fiber. Beans are extremely high in both soluble and insoluble fiber. Choose a fiber supplement that contains both, and if you’re avoiding beans because of digestive issues, check with your doctor first.
  • B-complex vitamins. Beans are packed with Bs, so if you’re not a legume lover and don’t eat a varied diet, consider supplementing. Sublingual forms are great if you suffer from digestive problems.
  • Mineral complex. Beans are an excellent source of magnesium, copper, phosphorous, iron, potassium, and manganese. If you also avoid nuts and seeds, look for a full-spectrum, multi-mineral supplement. Liquid forms tend to be better absorbed, especially if you have digestive issues.
  • Protein. Most of us get plenty of protein, but if you’re a vegan and don’t eat beans, you may need to supplement. Look for protein powders made from sprouted rice, sprouted quinoa, hemp seeds, chia seeds, or artichoke protein.

What’s the Difference Between Beans and Legumes?

Beans and Legumes: What’s the Difference?Legumes are a broad category of seeds that grow in pods. They include beans, peas, and lentils. So beans are always legumes, but legumes aren’t always beans.

Legumes are a broad category of seeds that grow in pods. They include beans, peas, and lentils. So beans are always legumes, but legumes aren’t always beans. For varieties where you eat both the seed and the pod—such as snow peas or green beans—the legume is considered a vegetable. And while we call peanuts “nuts,” they’re different from tree nuts like almonds and pecans. Because they’re seeds that grow in pods, they’re technically legumes—but they don’t have the same nutritional profile.

Try our Farmers’ Market Green Lentil Salad recipe.