In the wake of the cold season, many of you may be tempted to stock up on Emergen-C or Airborne. Both of these supplements contain a megadose of vitamin C and zinc and are popularly known to prevent the common cold. Additionally, they are in the form of dissolvable tablets that can be easily mixed into drinks, making them more portable and somewhat tastier.

Before I go into the effectiveness of these two products, let me give a brief overview of both vitamin C and zinc. Vitamin C is an essential nutrient that improves the body's absorption of iron, assists in the metabolization of proteins, regenerates antioxidants, and helps the body's immune system. However, symptoms such as diarrhea, nausea and kidney stones can be the effect of consuming too much vitamin C. Like vitamin C, zinc is important to the body's immune system but can also cause nasty side effects when the body receives too much.

The Institute of Medicine suggests adult men consume at least 90 milligrams of vitamin C a day and adult women consume at least 70 milligrams of vitamin C a day. The IMO says that consuming an upwards of 2,000 milligrams of vitamin C per day is safe. Unfortunately, dietary supplements do not have to pass safety and efficiency research before hitting the shelves. One serving of Emergen-C contains 1,000 milligrams per serving, with each packet containing two servings.

With that information in your noggin, ask yourself, "Am I a marathon runner?" If so, more power to you and buy all the Emergen-C and Airborne your heart desires. According to a 2007 Cochrane review of 30 placebo trials containing over 11,000 participants, marathon runners were able to reduce their risks of getting a cold by 50 percent when consuming between 250 to 1,000 milligrams per day of vitamin C. For the rest of the participants, it only reduced the length of a cold, but did not prevent actually getting one. Additionally, if the participant started taking the supplement after the start of the cold, the nutrient did not have any impact on the length or symptoms of the cold.

For all you Emergen-C and Airborne users, fear not! Sesso recommends that a food-based approach is the way to go anyways. Vitamin C is naturally abundant in citrus fruits, tomatoes, leafy greens and broccoli. Zinc can be found is commonly found in red meats, whole grains, poultry and beans. In addition to eating vitamin-rich foods, exercising regularly and taking a daily multivitamin are two more ways to boost the immune system. Lastly, it never hurts to wash your hands frequently, have a clean living space and distance yourself from your sickly friends.