Beans and Why They are Indigestible: Beans and Flatulence i.e. Intestinal Gas

The other day, my stomach was acting up. At the time, I thought it was beans. Later, I suspected food from an over-priced restaurant.

Everyone know beans are hard to digest, and that anaerobic bacteria in the intestines degrade these into methane and carbohydrates that the bacteria ingest. Methane (CH4) and sulfur dioxide (SO2) as well are released to the atmosphere with a characteristic odor.

Beans have multiple gas-causing ingredients, but one that gets lots of attention is undigestible sugars. There are several of these such as alpha-galactosides, raffinose, stachyose and verbascose in the case of beans.

Products like Beano, designed to reduce gas production, break down the sugar before it can reach eager intestinal bacteria. Beano is alpha galactosidase, and no less than Benjamin Franklin in 1790 suggested taking medicine to ease digestion.

It has been found that the levels of flatulence-causing stachyose and raffinose were reduced by 92 and 80 per cent, respectively, by germinating the soybeans under in the presence of the food grade R. oligosporus fungus, according to findings published in the Journal of Agricultural and Food Chemistry. Traditional soy foods like miso, tempeh and natto cause little gas because of the extended fermentation.

Others say that soaking the beans will help. There are two effects, one is that soaking (and discarding the liquid) will extract the soluable, but non-digestible sugars. In addition, bacteria and fungus may take root in the water, and begin to digest the sugars -- much like the fermentation techniques above. The enzymes may even remain in the pot to aid digestion.

The bean hull is an important problem source as well that is not degraded by the alpha-galactosidase.

Beans with relatively less fiberous skin will produce less gas. Beans lilke garbanzo beans or bean paste will induce gas less because they have thinner skins.