A pistachio is the small, green, edible seed of the Pistacia vera tree, which is characterized by a hard, splitting shell. Grown in warm climates, the nuts are consumed roasted and salted, or used as a flavor and coloring in desserts, confections, and other dishes. Rich in protein, healthy fats, fiber, and vitamin B6, pistachios are also known for their antioxidant properties and potential health benefits. They may help lower LDL cholesterol, improve blood vessel function, support gut health, and assist with weight and blood sugar control.