Peanuts have come full circle. From their origins in central South America, peanuts were taken by European seafaring explorers to Europe and around the world to Africa and Asia before heading back to the Americas in colonial Virginia. Along the way, the peanut became one of the foods that changed the world.

How did that happen? How did a little ground nut — which isn't a nut at all but a humble legume in the same plant family as peas and beans — become one of the most important foods the world has ever known?

"Peanuts are unique because they are perfectly suited to treat both malnutrition and over-nutrition" says Pat Kearney, MEd, R.D., program director for The Peanut Institute, a nonprofit organization that supports nutrition research and educational programs that promote healthful lifestyles. "They contain a powerhouse of nutrients, including shelf-stable protein, healthy fats, micronutrients and antioxidants, and have been linked to longer life with less disease. But peanuts are also affordable, which means they're accessible to those who need to incorporate them into their diet consistently, including those who are severely malnourished and those who are overweight and obese."

Something else worked in the peanut's favor to help it gain global popularity. Europeans, who were introduced to them in Brazil, found them easy to transport back to Europe and from there around the world. "Since peanuts are protected by a hard outer shell, they could be easily stored, survive for months with minimum spoilage and were an ideal food for mariners," said Andrew F Smith, author of the book "Peanuts: The Illustrious History of the Goober Pea" and a professor of culinary history in the Food Studies Department at the New School University in New York.

A brief history of the peanut

A large pile of peanuts spread on a thin rugEuropean explorers carried peanuts around the globe, and other cultures found plenty of culinary uses for the legume. (Photo: Thamizhpparithi Maari/Wikimedia Commons)

The earliest-known wild strains of peanuts date to about 7,600 years ago in Peru. Wild strains still grow in Paraguay and Bolivia, which is where the peanut may have been first domesticated. In pre-Columbian times — before the arrival of European explorers — peanuts were depicted in the art of some cultures and were widely disseminated in South and Central America and around the Caribbean region.

By the time Europeans came across peanuts in Brazil, cultivation had spread as far north as Mexico City where Spanish conquistadors found them in the marketplace. The conquistadors took peanuts back to Spain and from there explorers and traders spread peanuts worldwide. "The Portuguese introduced peanuts into their African enclaves, where they quickly spread throughout tropical Africa because peanuts are 50 percent oil and there was virtually no oil plant in Sub-Saharan Africa," said Smith.

Peanuts came to North America in the 1700s, arriving in the British colonies on slave ships from West Africa. The slave traders likely used peanuts as food for the slaves during the voyage, Smith said. The colonists considered the plants difficult to grow and harvest and regarded the nuts as food for livestock and the poor.

By the 1790s, roasted peanuts were sold on the streets of New York and at fairs. Peanut production grew steadily in the 19th century, and the popularity of peanuts increased during the Civil War when their high protein helped sustain both armies.

Curiously, it was PT Barnum's post-war circus and the vendors who hawked "hot roasted peanuts" to the crowds that helped spread the popularity of peanuts across America. Later they became popular at baseball games, but poor quality and primitive harvesting methods continued to hold down demand. As the 19th century gave way to the 20th century, several interconnected factors would forever change the role of peanuts as a commercial crop and undergird what Smith called "the peanut’s rise to stardom."

The modern peanut

Workers bag peanuts from a harvester in Queensland, Australia in 1927Workers bag peanuts from a harvester in Queensland, Australia in 1927. (Photo: Queensland Agriculture And Stock Department, Publicity Branch/Wikimedia Commons)

Beginning around 1890, mechanical aids to plant, grow and harvest peanuts were invented. Cultivation went from hand-picked and hand-processed to totally mechanized in a very short period of time. By 1920, various types of mechanical planters, cultivators, diggers and pickers were in use. A similar revolution occurred in peanut processing that led to processing plants growing into large factories. As the supply of peanuts increased, quality improved, prices dropped and peanuts became accessible to virtually everyone.

Something else happened to another Southern farming staple about this time. The boll weevil was destroying cotton crops. George Washington Carver, a former slave who became director of the Agriculture Department at Tuskegee Normal and Industrial School in Tuskegee, Alabama, helped African-American farmers convert cotton fields into peanut fields. Peanuts were a crop the farmers could at least eat if they couldn't sell, Smith said.

Peanut harvesting is now so quick and efficient that transforming peanuts from raw legumes into a roasted, salted snack in an airtight package takes less than a day. A tractor with a "digger-shaker" attachment ensures that nothing is wasted. The peanuts are collected in a hopper and the plants are dropped back onto the ground, where they can be baled for cattle feed or mulched into the soil, Smith said.

Biggest producers

World peanut production is about 29 million metric tons per year, with the United States being the world's third largest producer, after China and India, according to the American Peanut Council. The United States, however, is the world's largest peanut exporter. That's because most of the peanuts grown in China and India are consumed domestically as peanut oil, according to the Council. In fact, more than 50 percent of the global peanut crop is crushed and converted to culinary oil, Smith said.

Georgia is the leading peanut-producing state, followed by Texas and Alabama. About half of all U.S. peanuts are grown within a 100 mile radius of Dothan, Alabama. Dothan is home to the National Peanut Festival, which is held each fall to honor peanut growers and celebrate the harvest.

Peanut allergies

About 0.6 percent of Americans are allergic to peanuts, according to the National Institute of Allergy and Infectious Diseases. If you're one of those who suffer from peanut allergens you can take heart in knowing that the National Peanut Board (NPR) has invested more than $12 million in food allergy research, outreach and education in the hopes of one day making peanut allergies a thing of the past. In the meantime, the board offers resources, including a website about peanut allergy facts, and assistance to parents, schools, health professionals and foodservice professionals to safely manage food allergens while still serving peanut products.

At the same time the board is working to expand the presence of peanuts in America's menus and at retail outlets, according to MenuMonitor, an online resource that tracks and analyzes the food and foodservice industry. Powdered peanut butter, for example, has exploded on the market, with major brands like Jif entering the category, said Lauren Highfill Williams, NPR marketing and communications manager.

Nuts about peanuts

A girl buys nuts from a peanut vendor in New York City in 1949A girl buys nuts from a peanut vendor in New York City in 1949. (Photo: John Craven/Fox Photos/Getty Images)

Peanuts are by far the most popular nut in the United States, according to Williams. Total U.S. peanut consumption for 2013 to 2014 was 1.5 billion pounds. During the same period, the total U.S. almond consumption was less than half that at 636.3 million pounds.

In 2012, according to the USDA, Americans consumed 1.2 million pounds of peanut butter, 390 million pounds of peanut snacks, 372 million pounds of peanut candy and used 656 million pounds of peanut oil.

Many products containing peanuts that we enjoy today originated in the early 20th century. They include Cracker Jack (1893), Planters peanuts (1906), Oh Henry! candy bars (1920), Baby Ruth candy bars (1920), Butterfinger candy bars (1923), Mr. Goodbar candy bars (1925), Reese's Peanut Butter Cup (1925), Peter Pan (peanut butter) (1928) and Snickers candy bars (1930), the world’s best-selling candy bar based on 2012 sales. In 1954, Mars added the peanut M&M to its popular M&M candy line.

Peanut butter, Smith pointed out, is a quintessentially American use of peanuts. People in other parts of the world eat peanut butter, he said, but nowhere is it devoured with the same gusto as it is in the United States. Peanut butter is in an estimated 85 percent of U.S. home kitchens.

That's quite a legacy for the "goober pea," as Southern soldiers called peanuts when they were cut off rail lines and farms during the last years of the Civil War and had little to eat other than boiled peanuts. Various artists such as Burl Ives, Tennessee Ernie Ford and The Kingston Trio popularized a song by the same name:

Sitting by the roadside on a summer's day

Chatting with my mess-mates, passing time away

Lying in the shadows underneath the trees

Goodness, how delicious, eating goober peas.

Peas, peas, peas, peas

Eating goober peas

Goodness, how delicious,

Eating goober peas.