To maintain normal immunity, eat foods rich in vitamins, dietary fiber, and protein. 1. Vitamins: Vitamins are important nutrients for the human body and help maintain the body’s metabolism, thus maintaining normal immunity. Foods rich in vitamins include fruits such as apples and kiwis, and various vegetables such as bok choy and spinach. 2. Dietary fiber: dietary fiber can promote gastrointestinal peristalsis, which is conducive to improving the body’s gastrointestinal tract digestive function, and helps to promote the body’s metabolism, to maintain the body’s normal immunity. Foods rich in dietary fiber include a variety of coarse grains, such as sweet potatoes, corn and so on. 3. Protein: Protein is essential for the composition of the body, but also the basis for the formation of immune substances. Therefore, maintaining an adequate intake of protein is conducive to maintaining the normal immunity of the body. Protein-rich foods are fish, shrimp, soy products, milk, eggs and so on. To maintain normal immunity, in addition to attention to balanced nutrition, but also need to do more exercise, and pay attention to rest, avoid smoking and alcohol.