 For
more than 300 million of the world’s people, an inexpensive bowl of common beans (Phaseolus
vulgaris) is the centerpiece of the daily diet. This staple is the world’s most
important food legume, far outdistancing chick-peas, faba beans, lentils, and cowpeas. The
global bean harvest of 18 million tons annually has an estimated value of US$11 billion.
Nutritionists characterize the common bean as a nearly perfect food
because of its high protein content and generous amounts of fiber, complex carbohydrates,
and other dietary necessities. A single serving (1 cup) of beans provides at least half
the US Department of Agriculture's recommended daily allowance of folic acid—a B
vitamin that is especially important for pregnant women. It also supplies 25 to 30 percent
of the recommended levels of iron and meets 25 percent of the daily requirement of
magnesium and copper as well as 15 percent of the potassium and zinc.
The common bean was domesticated more than 7000 years ago in two centers
of origin—Mesoamerica (Mexico and Central America) and the Andean region. Scientists
believe dry beans, along with maize, squash, and amaranth, probably began as weeds in
fields planted to cassava and sweet potatoes in Central America. Over the millennia,
farmers grew complex mixtures of bean types as a hedge against drought, disease, and pest
attacks. This process has produced an almost limitless genetic array of beans with a wide
variety of colors, textures, and sizes to meet the growing conditions and taste
preferences of many different regions.
Beans are grown from sea level to more than 3000 meters, chiefly by small
farmers with average landholdings of less than 1 hectare, without irrigation, and using
little or no fertilizers or pesticides. Much of the bean production in Latin America and
sub-Saharan Africa, where three-quarters of the crop is grown, takes place on steep,
erosion-prone slopes with low soil fertility.
In recent years the common bean has found an important market niche in
burgeoning Latin America cities, where millions of rural poor have migrated, seeking jobs
to support their families. With about 70 percent of Latin America’s population now
concentrated in urban centers, bean farmers are finding new sources of cash income.
Latin America is the most important bean producing region, its 8 million
hectares accounting for nearly half of global output. Beans are the fourth most important
source of protein in tropical America and surpass two popular regional root
crops—potato and cassava—as a source of calories. Throughout the region the
common bean is known as the "poor man's meat." Because there is no cheaper
source of protein, per capita consumption of beans is high in very poor countries, such as
Nicaragua (with 22.5 kilograms per capita per year), and in poorer regions of higher
income countries, such as Northeast Brazil (with 18.5 kilograms per year).
Dry beans were introduced in sub-Saharan Africa several
centuries ago by Portuguese traders. Today, the crop is a
vital staple on this continent, providing the main source
of dietary protein for more than 70 million people. Dry beans
are grown mostly by women for subsistence and the market on
more than 3.5 million hectares, accounting for a quarter of
global output. Production is concentrated in densely populated
eastern Africa, the lakes region, and the highlands of southern
Africa.
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