Natto is in the category of soyfoods, much like tofu, soy sauce, tempeh, and miso. It is not a supplement; it is a traditional Japanese staple food with records dating back to at least 1000 years. Rhapsody's natto is made by fermenting cooked soybeans using Bacillus subtillis culture. The soybeans turn sticky and develop a very distinct flavor that can be likened to strong aged cheese. - Richest food source of vitamin K2 (About 5-10 mcg per 1 gram on average). - Natto has the fibrinolytic enzyme nattokinase. - Pyrroloquinoline Quinone (PQQ), new research has shown natto to be a uniquely high source of PQQ. - Probiotic, for a healthy digestive system. Natto is fermented by the Bacillus subtilis bacteria. Additionally, Natto has 10 grams of High-Quality Vegetable Protein per 2 oz serving. Dietary changes and the industrialization of food production have lead to deficiencies unimaginable 50 years ago. Fermented foods such as natto, tempeh, miso, sauerkraut, pickles, and so on, play an important part in regaining the health we once took for granted. Rhapsody Natto comes in a 3.5 oz container to minimize waste and is 100% compostable.