Spinach has been providing humans with bountiful nutrition for more than 2,000 years. By the time this cool-season annual reached western Europe in the 11th - 15th centuries, it was already an established crop and widely cultivated in the Middle East and Asia. It has long been considered the “Captain of Leafy Greens,” which is an apt title for this vitamin- and mineral-packed veggie. However, raw spinach contains oxalic acid which, when eaten in large quantities over time, can actually interfere with the absorption of some of the nutrients like calcium and iron for which spinach is famous. Also, because ...