The researchers looked at data from a United States Department of Agriculture national survey showing what people eat. From this they concluded that peanut butter and peanut eaters had higher intakes of several hard-to-get nutrients compared to those who do not consume peanuts.
Kristen Ciuba, a spokesperson for the The Peanut Institute that part funded the research, told FoodNavigatorUSA.com that although past studies have shown that peanuts are high in nutrients, this is the first time, to their knowledge that a study has shown that just one portion a day can provide enough nutrients.
The 2005 dietary guidelines shows that a typical American diet is lacking in vitamin A, vitamin E, vitamin C, calcium, magnesium, potassium and fiber.
The researchers noted that eating a daily serving of peanuts or peanut butter can help children and adults meet nutrient needs, adding that peanut butter and peanut eaters had increased levels of vitamin A, vitamin E, folate, calcium, magnesium, zinc, iron and dietary fiber in their diets.
"Including peanuts and peanut butter daily in a calorie-balanced diet can help consumers achieve important nutrient goals set by the US government," said Penny Kris-Etherton, the author of the study and distinguished professor of nutrition and the Pennsylvania State University.
One serving of peanut butter or peanuts, for example, contains 18 and 16 percent respectively, of the daily value for vitamin E and almost 10 percent of the recommended daily allowance for folate.
Likewise, a one-ounce serving of peanuts or a two-tablespoon serving of peanut butter contains about 2 grams of fiber, hence as much as a slice of whole-wheat bread, while a one-ounce serving of peanuts or a two-tablespoon serving of peanut butter contains 13 and 14 percent, respectively, of the daily value for magnesium.
The researchers also conluded 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 .
She did not think that any food companies had yet expressed an interest in using this research for marketing purposes, but she thought that this study would fuel more research, which in turn could increase peanut consumption levels.
The finding of this paper will be published in detail in the December issue of the Journal of the American College of Nutrition.