& Joannie Dobbs Saturday, December 15, 2007
Vitamin C can halve cold risk during strain
Few if any nutrients have caused more scientific controversy than vitamin C, also known as ascorbic acid. What caused this uproar? Linus Pauling, Nobel Prize winner for both chemistry and peace, proposed that a high vitamin C intake could prevent the common cold.
Pauling's studies led him to believe that the optimal intake of vitamin C was many times greater than standard recommendations. His views stimulated nutrition scientists to think more about the role of nutrients in promoting long-term health in addition to preventing obvious dietary deficiencies.
Question: Does vitamin C prevent the common cold?
Answer: After many studies and millions of dollars spent on research, vitamin C did not turn out to be the preventive cold cure that researchers hoped it would be. However, vitamin C supplementation has been shown to cut the risk of catching a cold in half for people exposed to an extreme physical stress like running a marathon.
Q: What is the function of vitamin C in the body?
A: Vitamin C is essential for maintaining the structure of blood vessels, joints, tendons and bones. Also, certain nerve functions depend on vitamin C.
In addition, this vitamin doubles as an antioxidant that protects many cell components from oxidative damage. Even the use of fat for energy requires vitamin C.
Q: What happens if you do not consume enough vitamin C?
A: Early studies found that clear signs of vitamin C deficiency appeared in healthy volunteers after about five months of an extremely low vitamin C diet. Less obvious effects might appear more quickly. The first symptom noticed was rough skin that was soon followed by tiny blood spots appearing on the skin.
As vitamin C deficiency progressed, gums became red and swollen and tended to bleed easily. This was soon accompanied by back and joint pains.
Q: How much vitamin C is recommended?
A: The Institute of Medicine recommends a daily intake of 75 milligrams (mg) for women and 90 for men. If a food or supplement label indicates 100 percent of the Daily Value for C, it contains 60 mg. The Linus Pauling Institute at Oregon State University recommends at least 400 mg per day, and the Institute of Medicine proposes that 2,000 mg is the maximum safe daily intake for adults.
Q: Does vitamin C in skin products provide any benefit?
A: A number of studies indicate that topical vitamin C use can help to protect the skin from sun damage and aging. Skin researchers are actively seeking the most effective forms of vitamin C to include in new skin products called cosmeceuticals.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
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