Beans and Flatulence: Fact or Fiction?
Dry beans and other pulses like chickpeas and lentils, have tremendous nutritional benefits like fibre, protein, folate and iron and also promote good health. Some people experience bloating and gas as a result of eating beans and this is often said to be a reason why people do not consume beans more often.
However, recent evidence suggests that people may develop a tolerance to flatulence produced or gastrointestinal symptoms associated with consumption of pulses. A study published in the Food Research International journal in 2010 reported the results of a study that looked at whether flatulence, abdominal comfort, bowel movements, and overall GI function improved over time as pulses were consumed every day for a one month period. Healthy adult males between the ages of 18 and 40 were given soups made from either chickpeas, lentils or dry peas versus a potato control every day for a period of 28 days. They were asked about their GI symptoms at different times throughout the study using a questionnaire. Pulse consumption was not associated with significant changes in participants’ perception of the occurrence or severity of flatulence. There were also no significant differences in abdominal discomfort reported over time or between any of the treatments.
Similar findings were reported by researchers from the University of Colorado. Healthy adults between the ages of 26 and 57 ate 1⁄2 cup pinto beans, baked beans, black eye peas, or controls (canned green beans, canned carrots, or chicken soups) every day for 8 to 12 weeks. Less than half of the participants reported increased flatulence during the first week of the study diets. By the second or third week of bean consumption, 70% or more of the participants felt that any increase in flatulence had dissipated. Interestingly, 3-11% of the participants reported increased flatulence even when eating the control foods that did not contain any known flatulence–producing compounds. The study was published in the Nutrition Journal.
The primary flatulence-producing compounds in pulses are the oligosaccharides including raffinose and stachyose which are carbohydrate compounds that are not readily digested by humans because of their chemical structure. Soaking and rinsing dry beans before cooking, as well as rinsing of canned beans, can reduce the levels of these hard to digest sugars. It is also important to note that gas production is a normal physiological process that to some extent, aids in digestion by softening and helping to move stools through the colon.