Majid Koozehchian, M.S.
Vitamin C is a water soluble vitamin, and thus our body does not retain it in large amounts. It is a strong antioxidant that has a key role in protecting against oxidative damage and tissue trauma. Vitamin C can neutralize potentially harmful reactions in the watery parts of our body, such as blood and the fluid inside and surrounding cells. It is one of the vitamins that many athletes consume in rather substantial amounts; therefore they are more familiar with it than with other vitamins.
Recommended Daily Allowance (RDA) for vitamin C
The current RDA for vitamin C is 90mg/d for males (+19yrs) and 75mg/d for females (+19yrs). Active individuals need more vitamin C due to the increased stress associated with exercise. Highly active athletes may require at least 100mg/d of vitamin C to keep normal vitamin C status and protect their body from the oxidative stressors of exercise. People can get this amount from a normal diet (1).
Vitamin C supplementation and different types of exercise
Some studies indicate that vitamin C supplementation does not improve physical performance in well-nourished athletes. However, others suggest that supplementation (600mg/d) for 21 days before a race enhances resistance to the post-race upper respiratory tract infections that occur commonly in ultramarathoners and may reduce the severity of such infections in sedentary people.
High-dose vitamin C supplementation (1000mg/d) for 21-days in marathoners and cross-country skiers reduced the risk of colds by 50%. Vitamin C supplements also attenuated the increase in concentrations of plasma interleukin-6, -8, and -10 in runners ingesting 1500_mg/d for 1_week prior to the race and on race day. Interleukins are a family of proteins produced by macrophages and T-lymphocytes that involved in inflammation and immunity. They control some aspects of the immune response by conveying signals between white blood cells.
Some weight trainers, especially bodybuilders, believe that benefits from vitamin C include antioxidant properties, limiting cortisol production, helping the growth of steroid hormones, helping with iron absorption, reducing muscle soreness, and boosting the immune system. It is believed that vitamin C for bodybuilding should be consumed in daily dosages of about 500-1500mg/d, spread out over 2-3_doses.
According to Jakeman’s study, vitamin C supplementation (400_mg/d) for 21 days before and 7 days after performing 60 min of box-stepping exercise had a protective effect against eccentric exercise-induced muscle damage in young healthy men (2).
Vitamin C was also reported to reduce soreness after bouts of sit-ups. A 12 hour delay in the beginning of muscle stiffness with participants taking vitamin C was also noted. Vitamin C (400mg/d) for a 2 week period before an intermittent shuttle run showed a modest decrease in soreness with both interleukin-6 and malondialdehyde increases compared to placebo.
Food Sources
Fresh fruits and vegetables are the best sources of vitamin C. Among the excellent sources of vitamin C are peppers, strawberries, oranges, lemon juice, papayas, cauliflower, kale, mustard greens, and Brussels sprouts (3).
In sum, the results of vitamin C studies are inconsistent. Some show that vitamin C supplementation improves physical performance in those who are vitamin C deficient. Other studies suggest that vitamin C supplementation does not boost the performance capacity in those who are not deficient. With respect to the available evidence, we can conclude that vitamin C supplementation may help to improve physical performance in athletes who have a vitamin C deficiency (4).
Blood levels of vitamin C remain steady at nearly 200 mg per day. Although vitamin C can be well tolerated at doses well above the RDA recommendations, adverse effects can occur at doses above 3 grams per day, although overload is unlikely. The common 'threshold' side effect of megadoses is diarrhea. Other possible adverse effects include increased oxalate excretion and kidney stones, increased uric acid excretion, preoxidant effects, iron overload, reduced absorption of vitamin B12 and copper, increased oxygen demand and acid erosion of the teeth (5).
References & Further related information related to vitamin C:
- Petersen EW, Ostrowski K, Ibfelt T, Richelle M, Offord E, Halkjaer-Kristensen J, et al. Effect of vitamin supplementation on cytokine response and on muscle damage after strenuous exercise Am J Physiol Cell Physiol 2001 Jun;280(6):C1570-5. http://ajpcell.physiology.org/content/ajpcell/280/6/C1570.full.pdf
- Jakeman P, Maxwell S. Effect of antioxidant vitamin supplementation on muscle function after eccentric exercise Eur J Appl Physiol Occup Physiol 1993;67(5):426-430. http://www.ncbi.nlm.nih.gov/pubmed/8299614
- Nieman DC. Exercise immunology: nutritional countermeasures Can J Appl Physiol 2001;26 Suppl:S45-55. http://www.ncbi.nlm.nih.gov/pubmed/11897882
- Ilhan N, Kamanli A, Ozmerdivenli R, Ilhan N. Variable effects of exercise intensity on reduced glutathione, thiobarbituric acid reactive substance levels, and glucose concentration. Arch Med Res 2004 Jul-Aug;35(4):294-300. http://ac.els-cdn.com/S0188440904000578/1-s2.0-S0188440904000578-main.pdf?_tid=4599804a-f71a-11e3-a0cc-00000aacb362&acdnat=1403117976_9405f8ecf7bbe7dae5f411850c1efa1c
- Powers SK, DeRuisseau KC, Quindry J, Hamilton KL. Dietary antioxidants and exercise J Sports Sci 2004 Jan;22(1):81-94. http://www.tandfonline.com/doi/pdf/10.1080/0264041031000140563