Peanuts are the most frequently consumed “nut” in the U.S., even though technically they are not nuts. Unlike tree nuts (almonds, cashews, pecans, pistachios, walnuts, among others), peanuts grow on the ground and belong to the legume family, which includes beans, lentils and peas. They are typically grouped with tree nuts because they have many physical and nutritional attributes in common. In some ways, peanuts are even better for you than true nuts.
What’s in a peanut? Plenty of good things for your heart, including B vitamins (notably folate), vitamin E, magnesium, iron, copper, potassium and fiber, along with an array of phytochemicals, such as arginine (which helps relax blood vessels and lower blood pressure), phytosterols (which lower cholesterol) and phenols (antioxidants). Peanuts also have more protein than any tree nut—ounce for ounce, as much as poultry, fish or meat. It’s true they’re high in fat and thus calories, at 160 per ounce, but as with all nuts, most of the fat is heart-healthy unsaturated fat.
Studies have shown that all kinds of nuts have beneficial effects on blood fats, inflammation, blood vessel function and overall heart disease risk. Few have looked at peanuts alone, but a 2003 study published in the Journal of the American College of Nutrition found lower triglyceride levels in people eating peanuts. And in an earlier study, in the journal Lipids, women had lower cholesterol when they consumed one to two ounces of peanuts a day for six months in place of other fats and some meat. Moreover, peanuts have been linked with reduced oxidation of LDL cholesterol (oxidation makes this “bad” cholesterol even more damaging to arteries) and lower insulin levels.
People who regularly eat nuts, including peanuts, tend to be healthier, in general. And they tend to weigh less—or at least don’t weigh more—than people who don’t eat them. Like all nuts, peanuts are filling because of their protein and fiber.
Smooth or crunchy?
Peanut butter has the same nutritional benefits as peanuts. In the Nurses’ Health Study, women who reported eating a tablespoon of peanut butter at least five times a week had a lower risk of cardiovascular disease, compared to those not eating it.
But check the ingredients: most peanut butters have added salt and sugar. And some contain added partially hydrogenated oil, a source of unhealthful trans fat, though the amounts are very small. Natural peanut butters tend to be nothing but ground peanuts.
Bottom line: Unless you are allergic, there’s good reason to enjoy a handful (an ounce or two) of nuts most days, with peanuts as one variety. Eat them in place of other foods, particularly snacks that are high in calories and low in nutrients.