MICROgenics^® Chewable C 500mg

Vitamin C functions

As an electron donor, vitamin C acts as a cofactor for enzymes involved in collagen, carnitine and noradrenaline formation, and the metabolism of tyrosine and peptide hormones.¹ Vitamin C is also a powerful water-soluble antioxidant that protects low-density lipoproteins from oxidation, reduces harmful oxidants in the stomach, and promotes iron absorption.

Vitamin C deficiency

Humans are one of the few mammal species that cannot synthesise vitamin C and there is no significant body storage. Vitamin C deficiency appears after about one month on a vitamin C-free diet. The earliest effects of a vitamin C deficiency are weakness, depression and lethargy. Collagen formation becomes defective, leading to weakened blood vessels walls and capillary fragility, which may appear as spots of bleeding under the skin, swollen or bleeding gums, nose bleeds, painful joints, and easy bruising. Lowered immunity and anaemia are commonly associated with vitamin C deficiency.

Vitamin C boosts immunity

Vitamin C supplementation can boost immune cell activity, lymphocyte proliferation, chemotaxis, and delayed-type hypersensitivity, and protects white blood cells and tissues from reactive oxygen species generated by immune and inflammatory responses.²

A meta-analysis of 29 controlled trials that used a minimum of 200 mg of vitamin C daily for colds found that it did not affect the incidence but did cause a small reduction in the duration and severity of colds.³ However, in a subgroup of six studies in which subjects were under intense physical stress from exercise training in cold weather, subjects taking vitamin C had a 50% reduction in incidence of colds.⁴

Some of the vitamin C studies that showed little or no effect used only 200 mg a day, a dose that vitamin C advocates consider to be too low to be effective.⁵ They claim that vitamin C is used up rapidly in infections and large, divided doses of vitamin C maintained over several days are more effective. In the meta-analysis of 29 trials reported above, one trial using a one-off dose of 8 g of vitamin C at the onset of symptoms was more effective for symptom relief than trials using lower doses. In a two-year controlled trial, subjects who developed colds or flu were given 1 g of vitamin C every hour for the first six hours and then 1 g three times a day until symptoms improved.⁶ Vitamin C used in this way decreased cold and flu symptoms by 85% compared to the control group.

Vitamin provides antioxidant protection

Vitamin C is a powerful water-soluble antioxidant that works to trap damaging free radicals produced during metabolic activities before they can initiate lipid peroxidation. Vitamin C helps detoxify potentially harmful substances and can regenerate vitamin E, the body’s main fat-soluble antioxidant, and the antioxidant betacarotene from their radical forms.

Vitamin C helps make strong connective tissue and heals wounds

Vitamin C is needed for hydroxylation of proline and lysine for strong collagen formation and for cross-linking in connective tissue.⁸ It maintains the integrity of collagen in the skin, blood vessel walls, heart valves, cartilage, tendons, spinal discs, gums, bones, teeth, and the cornea and lens of the eyes. It is also needed for the synthesis of the glycosaminoglycans chondroitin sulfate, keratan sulfate and hyaluronic acid that are part of connective tissue in cartilage, gums, and skin. Vitamin C helps form new connective tissue in the skin to heal wounds and is especially important after surgery.

References

1. Levine M, Rumsey SC, Daruwala R, Park JB, Wang Y. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23
2. Wintergerst ES, Maggini S, Hornig DH. Immune-enhancing role of vitamin C and zinc and effect on clinical conditions. Ann Nutr Metab 2006;50(2):85-94.
3. Douglas RM, Hemila H. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev 2004;4.
4. Hemila H. Vitamin C supplementation and respiratory infections: a systematic review. Mil Med 2004;169:920-925.
5. Vitamin C Foundation. Vitamin C as a cold cure. Available at: http://www.vitamincfoundation.org/
6. Gorton HC, Jarvis K. The effectiveness of vitamin C in preventing and relieving the symptoms of virus-induced respiratory infections. J Manipulative Physiol Ther 1999;22:530-533.
7. Carr AC, Frei B. Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans. Am J Clin Nutr. 1999 Jun;69(6):1086-107.
8. Fain O. Musculoskeletal manifestations of scurvy. Joint Bone Spine. 2005 Mar;72(2):124-8.