Kale, a headless, leafy green of the cabbage family, is low in saturated fat and rich in antioxidants. A 67-gram, 1 cup serving of kale provides 206 percent of the recommended daily allowance of vitamin A, a nutrient which benefits mucus membranes, skin and vision. A 67-gram serving also contains 684 percent of the recommended daily allowance of vitamin K, which is critical for blood clotting and strong bones, and 137 percent of the recommended daily intake of vitamin C.
Of the 6 grams of carbohydrates found in a cup of kale, two are fiber. Kale has 33 calories per cup and also contains 3 grams of protein. It is a source of B-complex vitamins and several minerals, such as copper, calcium, potassium, manganese and magnesium.
Among the phytochemicals in kale, sulforaphane and indole-3-carbinol protect against prostate and colon cancers, and diindolylmethane, produced when indole-3-carabinol is metabolized, is known for its effectiveness in fighting infections. Beta-carotene, the source of kale's vitamin A, and lutein and zeaxanthin, also found in kale, contain cancer-fighting and antioxidant properties. Zeaxanthin is a carotenoid that is absorbed into the eyes' retinal macula lutea. Having antioxidant and light-filtering properties, zeaxanthin is known to help prevent retinal detachment and may offset risks of macular degeneration. Studies of the flavonoids, quercetin and kaempferol contained in kale note they support heart health and tend to lower blood pressure.