Pistachios are a cholesterol-free food as well as a plant-based source of protein and fiber. They are naturally low in sodium. Pistachios are a good source of several nutrients including copper, Vitamin B6 and manganese. Most of pistachios' calories come from fat. However, the fat is mostly comprised of the "good" unsaturated fats. Pistachios are also a source of thiamine, a B-complex vitamin that helps with muscle and nervous system function, as well as antioxidants. There are more antioxidants in pistachios than in any other nuts that humans consume. They also provide smaller amounts of iron, magnesium, phosphorus and potassium.