“Health from Eating” Series | There are many kinds of dark vegetables, how to eat them more healthily?

Leafy vegetables are the main source of calcium, iron, carotene, riboflavin and cellulose in our diet, and are almost a must-have for everyone at every meal. Especially dark-colored vegetables play a big role in our daily diet.

What are Dark Vegetables?

Dark vegetables refer to dark green, red, orange, and purple vegetables. Their leaves or fruits are often darker in color.

Common dark green vegetables include: spinach, rapeseed, celery leaves, water spinach, mustard greens, chrysanthemum cabbage, leeks, bean sprouts, broccoli, radish tops, shepherd's purse, etc.

Common red and orange vegetables include tomatoes, carrots, pumpkins, red peppers, etc.

Common purple vegetables include: red amaranth, purple cabbage, purple sweet potato, purple clam, perilla, purple asparagus, purslane, etc.

Generally speaking, the darker the color of leafy vegetables, the more calcium, iron, carotene, vitamin B2 and vitamin C they contain. Dark-colored leaves generally contain 1 to 2 times or even 10 times more calcium and iron than light-colored leaves, and 5 to 10 times or more carotene, vitamin B2 and vitamin C. Light-colored and crispy vegetables can be eaten raw, but dark-colored vegetables need to be cooked.

What are the benefits of cooked dark vegetables?

1. It can improve the utilization rate of vitamin K and carotenoids in green leafy vegetables and orange-yellow vegetables. This is because these two substances are only soluble in oil, and hot cooking can soften the cell wall, promote the dissolution of carotene and lycopene, and improve the absorption rate.

2. It helps to remove oxalic acid. During cooking, blanching and frying can help remove most of the oxalic acid in vegetables.

3. Cooking can soften the fiber, which can effectively relieve symptoms for patients with weak stomach, indigestion, gastrointestinal bloating, chronic diarrhea, etc.

4. Heating vegetables can kill bacteria and insect eggs. Some anti-nutritional factors and oxidases that destroy vitamins can also be inactivated during the heating process.

This article was scientifically reviewed by Xin Xiaowei, nutritionist and deputy director of the Nutrition Department of the Cancer Hospital, Chinese Academy of Medical Sciences.