green healthy leavesDark leafy greens are perhaps the most concentrated sources of nutrients. They provide minerals,  like iron, calcium, potassium, and magnesium and vitamins, including vitamins K, C, E, and many of the B vitamins. They also provide a variety of phytonutrients ,  including beta-carotene, lutein, and zeaxanthin.

However, when most Americans hear “leafy greens” they automatically think “spinach.” Spinach is one of the least nutrient-rich green leafy vegetables. According to the USDA National Nutrient Database, one cup of raw spinach contains only 1 mg of iron.  Spinach also contains oxalic acid, which binds with iron, hence inhibiting its absorption.  Raw kale, for example, contains 1.1 mg of iron per cup, but the iron in kale is a lot more likely to be absorbed by the body, because kale is very low in oxalic acid.  And as far other minerals and vitamins, kale, dandelion greens, collard greens, arugula, watercress, mustard greens, and turnip greens all appear to be more nutritious salad choices than spinach. Plain old lettuce, while still healthy, is not as nutrient-dense as are darker leaf vegetables.
To make your next salad more nutritious, try decreasing the amount of spinach to about 50%, substituting the other half with a new leafy green.