Also known as ascorbic acid, vitamin C is a compound found in high amounts in many citrus fruits, like grapefruit and oranges. Vitamin C was first associated with helping reduce the common cold when Linus Pauling, a Nobel-prize winning chemist, published a book in 1970 linking increased intake of the vitamin with reducing symptoms like sniffling, sneezing, headache and runny nose. While vitamin C's definitive benefits may be mixed, determining the proper dosage for you may help to reduce your cold.
Cochrane Study
Researchers at the Cochrane Database of Systematic Reviews evaluated numerous studies on vitamin C and how taking it affects colds, according to "Newsweek" magazine. After reviewing data on 11,000 patients who took 200 mg of vitamin C or more, the researchers found vitamin C did not reduce colds in the general population. However, Health.com notes the study has been criticized because the dosage of vitamin C typically reviewed -- about 500 mg per day -- was too low. This indicates that you may need to take higher dosages of vitamin C to have beneficial effects.
Compromised Immune Systems
The Cochrane study did find, however, that those with compromised immune systems or who were under intense physical stress experienced a reduction in experiencing a cold through vitamin C supplementation. Examples of those who benefited from taking vitamin C include marathon runners and soldiers working in the subarctic. These groups were found to be 50 percent less likely to experience a cold.
Vitamin C Daily Dose
Vitamin C is a water-soluble vitamin, which means your body can only absorb so much of the vitamin at one time and that your body does not make vitamin C. Excess amounts of vitamin C will be released via your urine. The U.S. daily recommended allowance by the U.S. Food and Nutrition Board of the institute of Medicine for adults ages 18 and over is 90 mg for men and 75 mg for women. This is the amount sufficient to build collagen, an elastic fiber in your body and the neurotransmitter norepinephrine.
Cold Prevention Dosage Recommendations
Although vitamin C has not been definitively proven to reduce the incidence of a cold, Dr. Mary Hardy, the medical director of the Simms/Mann-University of California, Los Angeles interviewed at Health.com recommends taking 500 mg of vitamin C twice per day. When you experience the first signs of your cold -- sneezing, sniffling, headache, etc. -- start taking this vitamin C dosage. Continue to take this dosage for five to seven days after beginning.
While vitamin C may not relieve cold symptoms in all people, it likely cannot hurt because vitamin C is a powerful antioxidant and can help to fight off inflammation in your body. However, you should not exceed the tolerable upper intake level for vitamin C dosage, which is 2,000 mg for adults older than age 19. If you have concerns or specific health issues, always speak to your physician as supplements are not regulated by the Food and Drug Administration.
