Tatsoi is a superfood high in vitamins A and C, fiber, calcium and folate, the latter of which is needed to make red and white cells in our bone marrow and to produce both DNA and RNA. Tatsoi also contains phytonutrients, which provide antioxidant and anti-inflammatory benefits. Its glossy, green, spoon-shaped leaves are edible along with their stems and provide a bright, earthy-sweet flavor with mustard notes.