Peanuts are rich in proteins, amino acids, mono-unsaturated fatty acids, and minerals, notably iron, making them a good, if limited, substitutes for animal protein sources. They're a high energy food, containing a potent average of 567 calories per 100 grams. They contain appreciable sources of many B-complex vitamins like niacin, thiamine, vitamin E and folates, with 100 grams of peanuts containing over 50 percent the recommended daily allowance. They are not sources of Vitamin A, C, B-12, D or K.
According to Nutrition-And-You.com, peanuts are also a good source of antioxidants, notably p-coumaric acid and resveratrol, which some studies indicate may help in reducing cancer risk, heart disease and damage to the nervous system. The MAYO clinic recommends eating peanuts for their unsaturated fats, fiber, vitamin E and plant steroles, all of which contribute to lower cholesterol and general heart health. The Peanut Institute reports that peanuts contain one of the highest natural sources of arginine, which studies have shown to reduce blood pressure.
The United States Department of Agriculture maintains a database of specific nutritional information for raw peanuts, both generally and for specific breeds of peanuts on its National Nutritional Database, available on its website. The Peanut Institute offers additional nutritional information as well as details for other peanut products, such as roasted peanuts, peanut butter and peanut oil.