Scientists from the University of Florida have found that peanuts often rival fruits in their levels of antioxidant.
"When it comes to antioxidant content, peanuts are right up there with strawberries," said Steve Talcott, an assistant professor of food science and human nutrition at UF's Institute of Food and Agricultural Sciences. "We expected a fairly high antioxidant content in peanuts, but we were a bit shocked to find that they're as rich in antioxidants as many kinds of fruit."
Antioxidants are chemicals that block the aging effects of free radicals - unstable molecules naturally occurring in the human body that damage living cells. The damage caused by free radicals has been linked to heart disease, stroke, certain cancers and macular degeneration of the eye.
The Florida researchers found that peanuts contain high concentrations of polyphenols - particularly p-coumaric acid - and that roasting can increase the level of the compund, boosting overall antioxidant content by as much as 22 percent.
"If you compare peanuts to other foods people think of as rich in antioxidants - mostly fruits and berries - peanuts come out somewhere in the middle," said Talcott. "They're no match for the foods at the top of the scale, such as pomegranate, but they do rival other foods."
He said roasted peanuts are about as rich in antioxidants as blackberries or strawberries, and richer in the chemicals than fruits such as apples, carrots or beets.
The researchers' findings were part of a broader study designed to measure the nutritional differences between traditional peanut breeds and the growing number of high oleic ("good" fat) peanuts now available to peanut growers. However, the tests showed no significant differences in antioxidant content between high-oleic and traditional peanuts.
Agronomy professor Dan Gorbet, heads of the University of Florida's peanut-breeding program, said it should be possible to breed the nuts with the purpose of creating high antioxidant levels.
"The big question is not whether it can be done - the question is whether the demand is there. So far, people haven't been seeking out peanuts for their antioxidant content, but maybe in the future they will be," said Gorbet.
Last month, a study from Pennsylvania State University suggested that one serving of peanuts or peanut butter a day could help children and adults meet requirements for nutrients often lacking in American diets.
Kristen Ciuba, a spokesperson for the The Peanut Institute that part funded the research, told FoodNavigatorUSA.com that although past studies had shown that peanuts are high in nutrients, this was the first time, to their knowledge, a study had shown that just one portion a day could provide enough nutrients.
Moroever, peanut butter and peanut eaters had increased levels of vitamin A, vitamin E, folate, calcium, magnesium, zinc, iron and dietary fiber in their diets.
The researchers also concluded that their study "helps to dispel the myth that higher-fat foods automatically lead to weight gain", noting that the peanut eaters had leaner bodies compared to the non-peanut eaters, as measured by body mass index (BMI), an indicator of body fatness. Peanut eaters also had lower intakes of "bad" saturated fat and cholesterol, and higher intakes of "good" monounsaturated fat and polyunsaturated fat.
"Peanuts are higher in fats than other foods, but most of these fats are unsaturated," said Ciuba.