Eating four or five raw red kidney beans can induce severe stomachache, vomiting, and diarrhea due to the toxin phytohaemagglutinin. This flavorless lectin requires thorough cooking to be neutralized and poses a significant risk even in small quantities. Under-cooked beans can be more toxic than raw ones if slow cooking methods fail to reach a rolling boil.
The oldest known domesticated beans were discovered in Guitarrero Cave in Peru, dating back to the second millennium BCE. These seeds predate the arrival of beans in Europe by thousands of years and were grown in Thailand from the early seventh millennium BCE. The common bean Phaseolus vulgaris originated in Mesoamerica and spread southward to the Atlantic seaboard.
Native Americans developed the Three Sisters system by interplanting beans with maize and squash to maximize yield and soil health. The tall stalks of the corn provided a natural trellis for the bean vines to climb while the broad leaves of the squash shaded the ground to retain moisture. This companion planting method fixed nitrogen in the soil and was used across Chile in Pre-Hispanic times.
Beans have traditionally been viewed as a food of the poor because they create a class-based antagonism where the wealthy consumed meat while farmers ate grains and vegetables. This perception was reinforced by flatulence caused by oligosaccharides like raffinose and stachyose that the human digestive tract cannot break down. Despite their high protein content ranging from 21 to 25 percent by weight in dry beans, they were often relegated to the lower rungs of the social food hierarchy.
India stands as the world leader in the production of dry beans followed by Myanmar and Brazil. Tanzania is the most important producer in Africa and the global production of legumes has increased from 40.78 million metric tons in 1961 to 81.80 million metric tons in 2016. As of 2023 the Norwegian Svalbard Global Seed Vault holds more than 40,000 accessions of Phaseolus bean species.
The Mexican jumping bean is not a bean but a segment of a seed pod occupied by the larva of the moth Cydia saltitans. These pods start to jump when warmed in the palm of the hand because the larva moves within the pod. Scientists suggest this behavior may help the larva find shade and survive on hot days.