Peanut butter is a food paste made primarily from ground roasted peanuts, with or without added oil. It is popular throughout the world and is also manufactured in some emerging markets. Its primary use is as a sandwich spread.

In some types of gourmet peanut butter, chocolate or other ingredients may be added. Various nut butters are also made from other nuts.

History

Evidence of modern peanut butter comes from US patent #306727 issued to Marcellus Gilmore Edson of Montreal, Quebec, in 1884, for a process of milling roasted peanuts between heated surfaces until the peanuts reached "a fluid or semi-fluid state." As the product cooled, it set into what Edson described as "a consistency like that of butter, lard, or ointment."

J.H. Kellogg, of cereal fame, secured US patent #580787 in 1897 for his "Process of Preparing Nutmeal," which produced a "pasty adhesive substance" that Kellogg called "nut-butter."

Health benefits

Peanut butter may protect against a high risk of cardiovascular disease due to high levels of monounsaturated fats and resveratrol; butter prepared with the skin of the peanuts has a greater level of resveratrol and other health-aiding agents. Peanut butter (and peanuts) provide protein, vitamins B3 and E, magnesium, folate, dietary fiber, arginine, and high levels of the antioxidant p-coumaric acid.

Plumpy'nut is a peanut butter based food used to fight malnutrition in famine stricken countries. A single pack contains 500 calories, can be stored unrefrigerated for 2 years, and requires no cooking or preparation.

In the novel Make Room! Make Room! by Harry Harrison, and the film Soylent Green, based on the novel, an impoverished and malnourished world is portrayed; the government supplies a peanut butter ration to prevent "the kwash" (kwashiorkor, associated with protein deficiency) in children.

Health concerns

For people with a peanut allergy, peanut butter can cause reactions including anaphylactic shock which has led to its banning in some schools.

The peanut plant is susceptible to the mold Aspergillus flavus which produces a carcinogenic substance called aflatoxin. Since it is impossible to completely remove every instance of aflatoxins, contamination of peanuts and peanut butter is monitored in many countries to ensure safe levels of this carcinogen. Average American peanut butter contains about 13 parts per billion of aflatoxins, a thousand times below the maximum recommended safe level.Fact: date=December 2007

Some brands of peanut butter may contain a small amount of added partially hydrogenated vegetable oils, which are high in trans fatty acids, thought to be a cause of atherosclerosis, coronary heart disease, and stroke; these oils are added to make the butter easier to spread. Natural peanut butter, and peanuts, do not contain partially hydrogenated oils. A USDA survey of commercial peanut butters in the US did not show the presence of trans fat.