Peanut, Arachis hypogaea, is not a nut but a legume. However, as it is so universally used as a nut, and as most people refer to it as a “nut,” I’ve included it here. Native to Mexico, Central and South America, the peanut’s shell is, botanically, the fruit, and the peanut itself is a seed. It appears that it was initially domesticated in Argentina or Bolivia and there is evidence that in prehistoric times it was domesticated in Peru. It made its way to Mesoamerica well before the invasion of the Spanish. It was taken around the world and is now grown or used everywhere.
Peanuts grow best in light, sandy soil, and need five months of heat and significant rainfall. There are now thousands of cultivars. The most known, include the Spanish group, the Virginia group, the Valencia group, the Runner group and the Tennessee Red and Tennessee White groups. In the U.S., most peanuts are grown in the South, primarily Alabama. China is the largest producer worldwide, but not the largest exporter, as they use peanuts for both the seed and for oil. Peanuts are susceptible to Aspergillus mold, which releases a known carcinogin, aflatoxin. The elderly, small children and those with compromised immune systems are at greatest risk of illness from aflatoxins.
Peanuts are eaten salted, boiled, in candies and baked goods, in many of the world’s cuisines where they are ground and made into pastes and sauces, made into peanut butter, and much more. The oil is used in cooking because it has a mild flavor and high heat point.
Peanuts have a number of industrial uses and are also a valuable crop as nitrogen-fixers, as are other legumous crops.
Peanuts are very nutritious as well. In addition to a high protein content, they contain monounsaturated fat, lysine, niacin, and antioxident polyphenols, as well as resveratrol. In fact, they contain as much as 30 times more resveratrol than grapes.
Unfortunately, some people are allergic to peanuts. The allergies can vary from mild to life-threatening. There are a variety of theories about the allergies, but recent research has found that by giving children who are severely allergic to peanuts extremely minute amounts, doctors can minimize the allergic response over time. This is new, however, and anyone who is concerned about peanuts and allergies would be wise to talk with a specialist about treatment.