Like other members of the cabbage family, cabbage contains a powerful phytonutrient, sulforaphane, that boosts the body's detoxification enzymes, and may reduce the risk of some forms of cancer. Cabbage is especially high in beta-carotene, vitamin C, vitamin K and fiber. Be careful to cook cabbage as briefly as possible and in stainless steel pans to avoid too much of the smelly sulfur compounds that overheating may release. Note that the same amount of raw cabbage contains about half the calories and carbohydrates as cooked cabbage, but some of the other nutrients are reduced with prolonged cooking.
Red cabbage is higher in fiber than green, with 4 ounces of it boiled and drained offering 2.7 grams. It's higher in vitamin C, offering 25.8 grams for 4 ounces cooked. Red cabbage is also higher in calcium, iron, and potassium than its green cousin.
Savoy and napa cabbage contain 20% of the RDA for vitamin A, while red and green cabbages contain considerably less. Bok choy contains the most vitamin A, supplying 60% of the RDA, although it is equal to red and green cabbage in other nutrients.