Spinach

Spinach (Spinacia oleracea) is an annual or biennial leafy plant of the amaranth family. It is thought to have originated in Persia and to have reached Korea by way of China. Older Sino-Korean names include jeokgeunchae, "red-root vegetable," after the rosy base of its stems, and pachae.

Spinach appears in Korean writing in Hunmongjahoe, a sixteenth-century character primer compiled by Choe Se-jin, which suggests it was already being grown in the early Joseon period. Growers distinguish two seed types: prickly-seeded strains with narrow leaves, suited to autumn sowing, and smooth-seeded strains with broad, wavy leaves, preferred in spring; hybrids of the two are common.

In Korea spinach is sown in spring, in summer (only in cool highland areas) and in autumn, when the crop is harvested from October through March. Winter spinach grown outdoors in coastal areas is especially prized. Two well-known examples are seomcho, the broad, thick-leaved island spinach of Sinan in South Jeolla, and Pohangcho, a short, fragrant variety with plump roots from Pohang in North Gyeongsang. Cold and sea wind make these winter greens noticeably sweet.

In the kitchen spinach is usually blanched briefly and seasoned as namul, the role it plays in sigeumchi-namul, or added to soups made with doenjang.

• Vitamins: Spinach is rich in vitamin K and is a source of vitamin A, folate and vitamin C.
• Minerals: It provides magnesium, potassium and iron, although the iron in plant foods is absorbed less readily than iron from animal foods.
• Vitamin K and warfarin: People taking warfarin (Coumadin) are advised to keep their intake of vitamin K–rich foods such as leafy greens consistent from week to week and to talk with their doctor before changing their diet.
• Oxalates: Spinach is high in oxalate. People who have had calcium oxalate kidney stones may be advised to limit it; a healthcare professional can give individual guidance.