I've always heard that taking Vitamin C will help prevent colds and flu. Is that true?

Vitamin C may help reduce the severity and symptoms of your cold, however there is no conclusive evidence that vitamin C prevents colds. Too much vitamin C--500 milligrams or more--may cause stomach upset and diarrhea. Better to get your vitamin C from food sources: citrus juices and fruits are the richest source, but other fruits and vegetables contribute a healthy dose as well, such as strawberries, cantaloupe, green peppers, cabbage, broccoli, and potatoes. Food sources will help contribute to your fluid intake, and staying well hydrated is critical for helping you feel better when you are ill, and helping prevent colds and flu in the first place. By drinking plenty of fluids, we help keep our mucus membranes moist. Our mucous membranes are our number one defense against invading viruses that can make us sick.

Melinda Hemmelgarn, M.S., R.D., Former Nutritional Sciences Specialist, University of Missouri-Columbia