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Vitamin C
Supplement Review

By Dr. John M Berardi, Ph.D.
First published at www.johnberardi.com, Nov 17 2003.

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Nutrient:

Vitamin C

What is it?

Vitamin C is a water-soluble vitamin (dissolves in water) and is therefore associated with both intracellular fluids (cytoplasm) and extracellular fluids (blood). Since vitamin C is water soluble, it is difficult to achieve toxic concentrations of this vitamin.

What does it do?

Vitamin C supplementation does not produce a dramatic effect (unless you are starting with a rare vitamin C deficiency) however, it does act as an effective antioxidant, both in quenching free radicals and reactive oxygen species as well as regenerating vitamin E in the intracellular fluid. In acute exercise, free radical production is likely and potential DNA damage is a result. Vitamin C removes most free radicals and reactive oxygen species.

In addition to its antioxidant effects, vitamin C can reduce muscle soreness, improve recovery from muscle damage, and normalize stress hormone concentrations.

Where does it come from?

Vitamin C is found in many fruits (especially citrus fruits) and vegetables (especially the green leafy ones). It can also be found in tablet form.

How do I use it?

Any active person would benefit from 250mg of vitamin C taken 2x per day unless they already have a very high fruit and vegetable intake. Taking more than 250mg of supplemental C at a given time is not advisable as it increases the risk of pro-oxidant effects (vitamin C can oxidize, making it a mild reactive species itself) and oxidative damage.

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Scientific References:

1) Ashton, T., et al. (1998). Electron spin resonance spectroscopy, exercise, and oxidative stress: an ascorbic acid intervention study. J Appl Physiol. 87(6): 2032-6.

2) Alessio, H.M., et al. (1997). Exercise induced oxidative stress before and after vitamin C supplementation. International Journal of Sports Nutrition. 7(1): 1-9.

3) Bland, J. (1998). The pro-oxidant effects of vitamin C. Altern Med Rev. 3: 170, 1998.

4) Jakemen, P. and Maxwell, S. (1993). Effect of antioxidant vitamin supplementation on muscle function after eccentric exercise. Eur J Appl Physiol 67:426-30.

5) Kaminski M, et al., (1992). An effect of ascorbic acid on delayed-onset muscle soreness. Pain. 50(3): 317-21.

6) Levine, M., et al. (1998). Does vitamin C have a pro-oxidant effect? Nature. 395: 231-232.

7) Podmore, I. et al. (1998). Vitamin C exhibits pro-oxidant properties. Nature. 392: 559.

8) Vansankari, T., et al. (1998). Effects of ascorbic acid and carbohydrate ingestion on exercise induced oxidative stress. Journal of sports medicine and physical fitness. 38(4): 281-285.