You Don’t Know Beans
The truth about legumes
If you’re a fan of the Paleo diet, you may have heard that beans are second only to grains in their abilit y to damage your gut, increase your weight, and generally harm your health. But most studies agree that people who eat beans have a lower risk of heart disease, cancer, and overall mortality. So are beans friend or foe? Here’s what you need to know.
If you’re a fan or a follower of the Paleo diet, you’ve probably heard that beans are second only to grains in their ability to damage your gut, increase your weight, and generally harm your health. But most studies agree that people who eat beans have a lower risk of heart disease, cancer, and overall mortality. So are beans friend or foe? As with most things, the truth lies somewhere in the middle.
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. And dark- colored varieties such as red, black, and kidney beans are loaded with cancer- protective antioxidants.
But 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.
On the other hand, beans also contain compounds that can interfere with nutrient absorption, irritate the gut, and cause digestive issues. Turn the page for 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.
4 FODMAPS, 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.