6 Foods That Prevent Sickness

Fresh Clementines

Despite all the controversy surrounding vitamin C's effect on colds, recent research shows that while this powerhouse antioxidant can't prevent them, it can help cut down on the duration and severity of colds. Clementines are a great source of vitamin C -- two fulfill 100 percent of your RDA. What's more, clementines are easy to pack and eat (no sticky fingers, since their skins peel off effortlessly).

Recommended serving size: 2 clementines

Calories: 138