Health Benefits of Roasted Pistachios: 

A one-ounce serving of roasted pistachios equals 49 nuts — more nuts per serving than any other nut and contains more than 10% of the Daily Value for dietary fiber, vitamin B-6, thiamin, phosphorus and copper.
Pistachios are especially rich in phytosterols, which are directly associated with lowering cholesterol levels and may offer protection from certain types of cancer.
Pistachios are a very high-quality plant source of protein, providing adequate and balanced amounts of essential amino acids. In addition, pistachios are relatively high in a nonessential amino acid, arginine, which may play a potential role in prevention or reduction of cardiovascular disease. While pistachios contain fat, the fat is predominantly monounsaturated, similar to that found in olive oil.