Several chemical compounds of legumes are responsible for an uncomfortable, rather embarrassing consequence of eating some beans; the generation of gas in the digestive system.
Some of the most popular legumes include chickpeas, soybeans, lentils, broad beans, kidney beans, azuki beans, lima beans and mung beans. Within this group most patients report lentils, soybeans and chickpeas being the most problematic in a flatulent sense!
There are certainly measures we can take to de-gas these delicious legumes, which I’ll refer to shortly. But let’s look at the cause of this windy problem.
Everybody produces a mixture of gases from their intestine, about half a kilo per day, thanks to the growth and metabolism of our resident bacteria. Many legumes cause a sudden increase in bacterial activity and gas production a few hours after they are consumed. This is because they contain large amounts of carbohydrates that human digestive enzymes can’t convert into absorbable sugars. These carbohydrates therefore leave the small intestine unchanged and enter the large intestine, where our resident bacteria does the job we are unable to do. The cell wall cement (that is the layer of the cell wall of these plants that binds two cells together) generates carbon dioxide and hydrogen, and the legume itself also contains a troublesome sugar complex, an oligosaccharide which also produces gas. A rather explosive threesome!
Overnight soaking and long cooking helps somewhat. Soak your chosen legume overnight, discard the soaking water and
start cooking with fresh water. Boil them briefly, then let stand for an hour. Again discard the water after and start cooking again. Prolonged cooking also helps to break down much of the oligosaccharide and cell wall cements into digestible simple sugars.
Bay leaves and seaweed
A method I can personally vouch for is adding a large bunch of fresh bay leaves to the cooking water or a small amount of seaweed, such as kombu, wakame or nori. Beware of adding too much seaweed however, I have had the rather unpleasant experience of finding a seething mass of seaweed arising out of the saucepan, strewn inelegantly across my cooktop!
So given the above, let’s re-embrace those legumes we love but avoid due to gas production. But also remember to chew well, don’t gulp, as there is an enzyme in our saliva which helps break down carbohydrates, a shame to miss this important step in sound digestion!