Vitamin C is one of the best known and most common household supplements. Parents, workers and children have been ‘popping’ vitamin C for immune support and antioxidant benefits for many many years, possibly since it was discovered for its powerful scurvy benefits.
Now is NOT a time to forget vitamin C.
I am currently aware of two clinical trials investigating the benefits of high dose intravenous vitamin C and its effects on those with COVID-19 – a Canadian trial, and a Chinese trial. Both trials are expecting to be completed later this year. It is far too early to suggest that vitamin C can do anything for COVID-19, however we can hope.
Vitamin C is an essential micronutrient with potent antioxidant abilities and widely supportive roles in the immune system. It contributes in both the innate and adaptive immune systems, as well as supporting the epithelial barrier function of the skin. Its gene regulating benefits are hypothesised to be responsible for its beneficial effects on B- and T-cell proliferation and differentiation, and its ability to scavenge and protect the body’s tissues and cells from damage are examples of the numerous ways this essential vitamin functions within the body.
Put simply, a 2002 study found that taking two 500mg tablets of vitamin C daily resulted in significantly fewer colds and a significantly shorter duration of severe symptoms, when compared to taking none. A 2006 study found that 500mg of vitamin C daily significantly reduced the frequency of the common cold. A 1976 study found that 1000mg of vitamin C daily resulted in less chest colds, and a 1973 study found that 500mg of vitamin C significantly reduced the severity and total intensity of colds. This 1973 study investigated further and found that vitamin C helps by altering the frequency of toxic and catarrhal complexes (catarrh produces phlegm). I suspect that by now we have discovered quite a few more mechanisms of action.
Moving away from the immune system, a 2018 study has found 500mg of vitamin C taken twice daily to be beneficial for both blood sugar, and blood pressure levels in those with type 2 diabetes. A 2017 study identified that adults with a history of smoking, prediabetes or type 2 diabetes, and/or obesity, have greater vitamin C requirements. And a 2019 study found that 500mg of vitamin C, taken twice daily, improved post-operative pain, analgesia requirements and functional outcome in those who underwent foot or ankle surgery. A 2018 study also found vitamin C to be helpful in postoperative healing after tooth surgery.
Vitamin C is an essential vitamin; our bodies cannot make it, so it must be obtained from our diet via food or supplementation. It is believed to be involved in heart health, immune health, eye health, skin health, bone and ligament health, gene health, teeth health and more. Its antioxidant properties make it a valuable vitamin for health overall.
Fresh fruit and vegetables are great sources of vitamin C. Supplementation is another option.
 Carr, A. C. and S. Maggini (2017). “Vitamin C and Immune Function.” Nutrients 9(11).
 Carr, A. C. (2020). “A new clinical trial to test high-dose vitamin C in patients with COVID-19.” Crit Care 24(1): 133.
 Van Straten, M. and P. Josling (2002). “Preventing the common cold with a vitamin C supplement: a double-blind, placebo-controlled survey.” Adv Ther 19(3): 151-159.
 Sasazuki, S., et al. (2006). “Effect of vitamin C on common cold: randomized controlled trial.” Eur J Clin Nutr 60(1): 9-17.
 Elwood, P. C., et al. (1976). “A randomized controlled trial of vitamin C in the prevention and amelioration of the common cold.” Br J Prev Soc Med 30(3): 193-196.
 Wilson, C. W. and H. S. Loh (1973). “Common cold and vitamin C.” Lancet 1(7804): 638-641.
 Wilson, R., et al. (2017). “Inadequate Vitamin C Status in Prediabetes and Type 2 Diabetes Mellitus: Associations with Glycaemic Control, Obesity, and Smoking.” Nutrients 9(9).
 Jain, S. K., et al. (2019). “Role of anti-oxidant (vitamin-C) in post-operative pain relief in foot and ankle trauma surgery: A prospective randomized trial.” Foot Ankle Surg 25(4): 542-545.
 Li, X., et al. (2018). “Role of vitamin C in wound healing after dental implant surgery in patients treated with bone grafts and patients with chronic periodontitis.” Clin Implant Dent Relat Res 20(5): 793-798.