Bean fossils have been found in Egyptian tombs, American caves, and Asian prehistoric sites. The beans used for human food are separated into two broad agronomical categories, green and dry. All beans are annuals. The plants produce pods which contain the seeds. While beans are inexpensive, easy to prepare, tasty, and loaded with protein and carbohydrates, many humans avoid them because of the problem of intestinal gas.
Gas is caused by the body's inability to digest the complex carbohydrates found in beans.
Before any carbohydrate can be absorbed from the intestines into the bloodstream, it must be broken down into a single sugar. If it can't be broken down, it can't be absorbed, and will pass whole into the lower intestinal tract where bacteria ferment it, causing gas. Beans contain a triple sugar, stachyose, a quadruple sugar, raffinose, and a five sugar, verbascose, and, since most humans can't digest these sugars, the bacteria go to work on them and create fumes through a fermentation process. Reasearchers have found that the enzyme alpha-galactosidase will help break down these complex sugars. A product, marketed under the name Beano, to reduce intestinal gas formation uses this enzyme to help reducethe formation of intestinal gas.