6. Vitamin C
There’s evidence this classic cold fighter can help boost immune function, but taking massive doses once you have a cold won’t hasten your recovery.
Vitamin C is important for a properly functioning immune system, and not getting enough vitamin C may be putting you at risk, says Patel. One 2013 meta-analysis of 30 studies and more than 11,000 people showed that those living with episodes of high stress, like marathon runners, were 50% less likely to catch colds if they took a daily supplement of 200mg of vitamin C.
Use it: Find C naturally in pills or foods like sweet peppers, berries, and oranges; or take up to 250mg a day in supplements (RDA is 75mg daily for women over age 19).