Both bok choy and napa cabbage are greens often used in Asian stir-fries and soups. While both cabbages make a healthy addition to your diet, knowing the nutritional similarities and differences between the two can help you understand the benefits of both.
Similar Calories and Macronutrients
If you're counting calories, bok choy and napa cabbage are interchangeable, and both make a low-calorie, filling choice. A 100-gram serving, approximately 1 cup, of either cabbage cooked contains 12 calories.
Carb and fat content are also similar. A 100-gram serving of either bok choy or napa cabbage contains 2 grams of carbs, and both are fat free.
There is a slight difference in protein and fiber content, however. Bok choy contains 2 grams of protein and 1 gram of fiber per cup, while the same serving of napa cabbage contains 1 gram of protein and no fiber.
Similarities in Vitamins and Minerals
Although their nutritional makeup is not exactly the same, each cabbage contains a small amount of a number of B vitamins and similar mineral content.
You need to consume B vitamins daily because they're water-soluble and not stored by the body. Each cabbage contains less than 10 percent of the daily value of riboflavin, niacin and vitamin B-6 in a 100-gram serving. Bok choy also contains a small amount of thiamine and pantothenic acid.
Both cabbages are good sources of folate, meeting 10 percent of the daily value in a serving of bok choy and 11 percent in a serving of napa cabbage. Folate helps make red blood cells, and women of childbearing age need adequate intakes to prevent neural tube defects in their children.
Each cabbage meets less than 10 percent of the daily value of iron, magnesium, phosphorus, zinc and selenium.
Vitamin A and C Differences
One of the significant differences between bok choy and napa cabbage is their vitamin A and C content. Bok choy is a much better source of both vitamins, meeting 85 percent of the daily value for vitamin A in a 100-gram serving and 43 percent of the daily value for vitamin C. By comparison, the same serving of napa cabbage meets only 5 percent of the daily value for both vitamins.
Both vitamins A and C are essential nutrients. You need an adequate intake of vitamin A to keep your skin and bones healthy. It's also needed for vision, especially at night. Vitamin C also supports bone health and is needed to help your body fight off infection, heal wounds and absorb iron.
Calcium and Potassium Differences
Although the differences aren't as great as they are for vitamins A and C, there are some slight differences in calcium and potassium content between the two cabbages.
A 100-gram serving of cooked bok choy meets 9 percent of the daily value for calcium, while the same serving of napa cabbage meets 3 percent of the daily value. Greens are often recommended as an alternative source of calcium for people who do not consume dairy products. While both greens contain calcium, bok choy is the better source for those who need to up their intake.
Bok choy is also a better source of potassium, meeting 11 percent of the daily value per 100-gram serving versus 2 percent in the same serving of napa cabbage. Adequate intake of potassium helps regulate blood pressure and assists with the transportation of nutrients in and waste out of cells.