Miso soup is a traditional Japanese soup made from a fermented soybean paste called miso. The main ingredients of miso soup are tofu, udo, and enoki mushrooms. Tofu is a soft, cheese-like food made from soybeans that is high in protein and low in fat. Udo is a type of edible seaweed that is often used in Japanese cuisine. Enoki mushrooms are long, thin mushrooms with a mild flavor that are often used in soups and salads. All three of these ingredients are commonly used to make miso soup.