Pumpkin-Sunflower Seed Smoothie. Pumpkin seeds are one of nature's almost perfect foods. They are a natural source of beneficial carbohydrates, amino acids and unsaturated fatty acids. They contain most of the B vitamins, along with C, D, E, and K. They also have the minerals calcium, potassium, niacin, and phosphorous. They are very high in potassium, and have good amounts of beta carotene and vitamin C.