Sunflower seeds are an excellent source of Vitamin E and a good source of B1, manganese, magnesium, copper, selenium, phosphorus, and folate. Sunflower seeds are high in Vitamin E, which have antioxidants that help neutralize free radicals that could otherwise damage cells. Studies found that sunflower seeds were one of several seeds and nuts that contained phytosterol. Phytosterols are believed to reduce blood levels of cholesterol, enhance the immune system, and decrease the risk of cancer. Sunflower seeds are also a good source of magnesium, which is necessary for bone health and energy production.