The common bean (Phaseolus vulgaris) is a leguminous plant with a huge number of varieties which, in dietary terms, can be placed in two categories: shell beans and snap beans, in other words those harvested when completely ripe and the seeds eaten, and those harvested when the pod is small and tender, eaten whole (French beans or cornette).
There are two types of plant: climbers, which can reach a considerable height (hence the legend of the magic beanstalk) and dwarf varieties.
Beans originated in the Americas and were imported to Europe in the 16th century.
Eating raw beans can be poisonous, especially in children, due to a toxic protein, phasin, which is completely eliminated by long cooking.
When cooked, however, beans are full of beneficial properties: they can control glycemia and cholesterol, and help prevent heart disease and arteriosclerosis.