Though high in fiber, protein and vitamins, beans always seem to get a bad rap. High amounts of a sugar substance called oligosaccharide occur in the skins of beans and other legumes. These oligosaccharides generate gas in the bowel when they break down, which can lead to flatulence. However, some beans are more gassy than others. For example, dried beans, such as lima beans, tend to trigger more gas than processed canned beans.
General Bean Types
In general, canned beans trigger less intestinal gas than dried beans. Canning removes some of the gas-causing sugars and coating. You need to rinse the canned beans a few times to remove the salty liquid. The liquid itself contains some of the oligosaccharides. All undercooked beans tend to cause more gas than well cooked, softened beans. Baked beans may cause less gas than other types of beans, but it depends on the ingredients. For example, beans mixed with fermented beer plus lots of sugar and salt can cause gas.
Dried lima and navy beans cause the most intestinal gas, according to the cooking science website Exploratorium.edu. Any dried beans, including kidney beans and borlotti beans, cause excess gas unless they are thoroughly soaked. All of these forms of dried beans require soaking before cooking so that they're soft and the toxins they contain are removed. Fresh beans such as broad beans and French beans have a softer shell and cause less gas than their harder-shelled cousins.
Soaking any dried beans makes them more easily digestible by breaking down their starches, according to the University of Illinois Extension. The easiest way to soak beans is to leave them submerged in a bowl of cold fresh water overnight. Use 6 cups of water per pound of beans. As with canned beans, rinse the liquid once the beans have soaked, as the soaking water has a lot of starch and gas-causing substances.
If you experience real discomfort or pain from intestinal gas after eating beans, some over-the-counter digestive aids can help. For example, Beano contains an enzyme that breaks down the oligosaccharides in the body, according to the National Digestive Diseases Information Clearinghouse. You can take the aid as a tablet or as a liquid treatment in five small droplets every time you eat beans. This helps reduce the flatulence and gas buildup.
- Exploratorium; Getting a Bang Out of Beans; Anne Gardiner, et al.
- Centers for Disease Control and Prevention: Vegetable of the Month -- Beans
- National Digestive Diseases Information Clearinghouse; Gas in the Digestive Tract; January 2008
- University of Illinois Extension: Dry and Canned Beans -- Teacher Guide;