Peanuts, often derided as unhealthy party food, contain the same amount of beneficial chemicals as strawberries, researchers have found.
Peanuts may help fight disease
A University of Florida team says peanuts are rich in antioxidants which protect cells from damage linked to heart disease and cancer.
Peanuts also contain high levels of protein and "good" monounsaturated fat.
But a spokeswoman for the British Dietetic Association said people should steer clear of salted peanuts.
The US researchers tested the antioxidant content of a dozen different varieties of peanuts.
ANTIOXIDANT LEVELS - HOW PEANUTS COMPARE
Top - Pomegranate
Bottom - Apples
Antioxidants are the naturally occurring substances in plants that protect the body from free radicals - 'volatile' chemicals in the blood.
Although free radicals do play an important role in the immune system, they also alter cholesterol in a process known as oxidation, which is thought to speed up the hardening of the arteries.
Red and orange fruits and vegetables are already known to be particularly high in antioxidants.
But the US researchers found peanuts were also high in the beneficial chemicals.
They found peanuts contain high levels of polyphenols, a family of chemicals commonly found in foods, which have strong antioxidant properties.
The nuts contain a high level of one particular polyphenol called p-coumaric acid.
The researchers discovered that roasting peanuts can increase the level of the acid in nuts, thereby increasing their overall antioxidant content by up to 22%.
The study will be published in the journal Food Chemistry later this year.
Steve Talcott of the University of Florida, who led the research, said: "When it comes to antioxidant content, peanuts are right up there with strawberries.
"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."
He added: "Compared to foods long-considered rich in antioxidants, mostly fruits and berries, peanuts come out somewhere in the middle.
"They're no match for the foods at the top of the scale, such as pomegranate, but they do rival other foods that people eat just for their antioxidant content."
The team are now looking at the possibility of specifically breeding peanuts high in antioxidants.
Dr Frankie Phillips of the British Dietetic Association, told the BBC News Website: "Peanuts do contain high levels of chemicals known to act as antioxidants."
But she said there were several reasons why people should not replace their five fruit and vegetables a day with peanuts.
"Peanuts are high in monounsaturated or 'good' fats. But, regardless of the type of fat, that means they are high in calories.
"So if you're trying to be careful about your weight, having handfuls of peanuts isn't the best way of losing weight."
Dr Phillips, a registered dietician, added: "In addition, in this country we tend to eat salted peanuts, and it's not good for you to have high levels of salt.
"Probably the best way to eat them is when they are combined with mixed fruits so they aren't covered in salt, and you're also getting the health benefits of the fruit."