Serve protein at every meal
The older you are, the less likely you are to get enough protein, says Lisa Hark, Ph.D., R.D., a family nutritionist and the author of Nutrition for Life. The main reason: Foods high in protein, like lean meats, poultry, fish, and beans, can be time-consuming to prepare—and who wants to bother when you’re cooking for two (or one)? But eating protein-rich foods helps your body make antibodies that fight colds.
Another reason to consume lean meats, beans, or poultry at every meal: All these foods are rich in zinc, which plays a role in white blood-cell production. One easy way to sneak in some extra protein: Snack on nuts, suggests Hark. They also contain magnesium, another mineral with immune-boosting properties.