Overview

Almost solely on its reputation to fight colds, Vitamin C has become the most widely used supplement. Yet, it's what many don't know about C that may help most—from fighting free radicals to promoting healthy joints. It's clear this nutrient is more than just a cold fighter.

The Full Story

Usage

Amount: The amounts recommended vary more for Vitamin C than for any other nutrient, but many sports nutrition experts agree that between two and four grams per day may be beneficial for active individuals.

Linus Pauling, a world-renowned scientist, humanitarian, educator, and health proponent, suggested optimal daily intakes are between two and nine grams. (Dr. Pauling was also the only recipient of two unshared Nobel Prizes. In 1970, he wrote what became the national best-selling book Vitamin C and the Common Cold, which is what originally brought public attention and increasing demand for this vitamin. Later, he published two other popular books and a stack of scientific and popular papers on nutrition.)

Sports nutrition expert Dr. Michael Colgan recommends up to 12 grams per day for athletes, depending on bodyweight, activity levels, and other factors.

Timing: Because Vitamin C is rapidly absorbed by the body and used within about two hours, it may be best to take it in divided amounts throughout the day at about four-hour intervals with food.

Intense physical exercise is great for your health, right? Well, of course. But what many people who exercise don't realize is that the stress we place our bodies under is just that: stress. And not unlike the physical stress of illness, intense exercise can wreak havoc on the immune system, leading to an increase in infections.

That's where Vitamin C steps in: it's often used by athletes as part of a vitamin/mineral formula to counteract this stress—to help them remain optimally healthy, so they can stay active.

Questions and Answers

Q.	What does the research on Vitamin C show?
A.	So much research has shown Vitamin C's effectiveness for so many benefits that it's difficult to list even a fraction of it! To mention just a few... clinical research has supported Vitamin C's ability to help reduce the length and severity of the common cold. C also decreases the production of histamine, which leads to watery eyes and a runny nose, so it's helpful for relieving cold and allergy symptoms. Plus, it's been shown to help relieve exercise-induced asthma. Research also shows C is essential for healthy bones and joints and may reduce muscle and joint inflammation as well as pain and stiffness. It's even been shown to help prevent sunburn. And this is just the short list!
Q.	Could any other supplements make Vitamin C even more effective?
A.	Actually, it's more of the opposite. Vitamin C has been shown to make many other supplements more effective. For example, Vitamin C regenerates oxidized Vitamins A and E and some of the other antioxidants in the body, helping support their effects—giving the body an extra advantage when fighting off free radicals. C also improves the absorption rate of iron. Some experts do suggest using a natural source of Vitamin C, such as rose hips, which contain certain bioflavonoids and other enzymes that may help the body assimilate Vitamin C. And hesperidin, a bioflavonoid, may increase Vitamin C's free-radical-scavenging abilities.
Q.	What's the most common amount of Vitamin C used to achieve optimal results?
A.	The amounts recommended vary more for Vitamin C than for any other nutrient, but many sports nutrition experts agree that between two and four grams per day may be beneficial for active individuals. Sports nutrition expert Dr. Michael Colgan recommends up to 12 grams per day for athletes, depending on body mass, activity levels, and other factors. Linus Pauling, a world-renowned scientist and health proponent, suggested optimal daily intakes are between two and nine grams. In 1970, Dr. Pauling wrote what became the national best-selling book Vitamin C and the Common Cold, which is what originally brought public attention and increasing demand for this vitamin.
Q.	Can too much Vitamin C cause any side effects—is it safe?
A.	While not likely, diarrhea and stomach upset may occur when large amounts (over 5,000 mg) are taken at one time. Think of it as nature's way of letting you know you've had enough. If you are pregnant, no more than 5,000 mg per day is recommended.
Q.	Can I get the same effects of Vitamin C by eating regular C-containing whole foods?
A.	Although Vitamin C is abundant in citrus fruits, such as oranges, lemons, limes, tangerines, and grapefruits, as well as in vegetables like red and green peppers, broccoli, tomatoes, asparagus, and dark leafy greens, it's also one of the least stable vitamins. In fact, it's easily destroyed by cooking and processing, and because it's used up more rapidly during times of both physical and emotional stress, it's important to ensure enough is being consumed. So while it's a good idea to eat C-containing foods, it's also a good idea to supplement with a quality source of C (such as a multivitamin) each day.

Safety Information

Safety:
Diarrhea and stomach upset may occur when large amounts (over 5,000 mg) of the ascorbic acid form are taken at one time. This is called "bowel tolerance" and indicates your body has had enough.

If you are pregnant, no more than 5,000 mg per day is recommended.

Toxicity:
None known.

Bans and Restrictions:
None reported.

References

Cohen, H.A., et al., "Blocking Effect of Vitamin C in Exercised-Induced Asthma," Arch Pediatr Adolesc Med 151.4 (1997) : 367-70.

Hemila, H., "Does Vitamin C Alleviate the Symptoms of the Common Cold? A Review of Current Evidence," Scand J Infect Dis 26.1 (1994) : 1-6.

Hemila, H., "Vitamin C Supplementation and Common Cold Symptoms: Factors Affecting the Magnitude of the Benefit," Med Hypotheses 52.2 (1999) : 171-8.

Levine, M., et al., "Criteria and Recommendations for Vitamin C Intake," JAMA 281.15 (1999) : 1415-23.

Ness, A.R., et al., "Vitamin C Status and Respiratory Function," Eur J Clin Nutr 50.9 (1996) : 573-9.

Simon, J.A., "Ascorbic Acid and Cholesterol Gallstones," Med Hypotheses 40.2 (1993) : 81-4.

Tauler, P., et al., "Diet Supplementation with Vitamin E, Vitamin C, and Beta-Carotene Cocktail Enhances Basal Neutrophil Antioxidant Enzymes in Athletes," Pflgers Archiv: European Journal Of Physiology 443.5-6 (2002) : 791-7.

Thompson, D., et al., "Prolonged Vitamin C Supplementation and Recovery from Demanding Exercise," Int J Sport Nutr Exerc Metab," 11.4 (2001) :466-81.