Old people with poor constitution often catch a cold and want to improve their immunity? You can add some protein powder or the usual one. Eat more fish and shrimp and so on. You should also eat more fruits and vegetables. To supplement the body's vitamins. If you want to be in good health, you must be in a good mood and do more appropriate exercise. Usually, you should go out more and get in touch with people. Improve people's spirit. You can also go out for a walk, or walk slowly. Both will do. But stick to it for a long time, and don't fish for three days and dry the net for two days. That won't do. Old people should eat less cold things, especially things that have just been taken out of the refrigerator. It is easy to hurt the spleen and stomach of the weak. You can also do moxibustion. Improve people's oxygen, that is, immunity will be improved. You can try.