Vitamin C
Vitamin C: the immune system’s rapid-response powerhouse.
Vitamin C is often the first nutrient people reach for when they feel a sniffle coming on—and for good reason. This water-soluble vitamin plays an active, hands-on role in immune defense, working at nearly every stage of the immune response. If vitamin D is the strategist, vitamin C is the first responder—rushing to the site of infection, supporting immune cell function, and helping control oxidative stress created during the battle.
Here’s why we love vitamin C for immune health:
Vitamin C accumulates in immune cells—especially neutrophils—where it supports chemotaxis, phagocytosis, and microbial killing.
It strengthens epithelial barriers (skin, respiratory tract, and gut lining), helping prevent pathogens from entering the body in the first place.
Vitamin C supports both innate and adaptive immunity, enhancing the function of lymphocytes while protecting immune cells from oxidative damage.
It is a powerful antioxidant, neutralizing free radicals generated during infection and inflammation—reducing collateral tissue damage.
Vitamin C supports healthy cytokine signaling, helping the immune system mount an effective response without tipping into excessive inflammation.
Adequate vitamin C levels are associated with shorter illness duration and reduced symptom severity during respiratory infections.
During infection or physiological stress, vitamin C levels drop rapidly, increasing the body’s demand exactly when immune support is needed most.
According to evidence-based research:
Vitamin C supplementation reduces the duration and severity of common cold symptoms, particularly under conditions of physical stress or deficiency.
Vitamin C improves neutrophil function and enhances microbial clearance.
Deficiency is associated with impaired immunity and increased susceptibility to infections.
Vitamin C contributes to maintenance of the epithelial barrier against pathogens.
Higher vitamin C status is linked to improved immune resilience and recovery.
Supporting Medical Research & References:
Carr AC, Maggini S. Vitamin C and immune function. Nutrients. 2017;9(11):1211.
Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013;(1):CD000980.
Wintergerst ES, Maggini S, Hornig DH. Contribution of selected vitamins and trace elements to immune function. Ann Nutr Metab. 2007;51(4):301–323.
Maggini S, Beveridge S, Suter M. A combination of micronutrients supports immune function and helps to prevent infections. Nutrients. 2012;4(9):1342–1360.
Padayatty SJ, Levine M. Vitamin C: the known and the unknown and Goldilocks. Oral Dis. 2016;22(6):463–493.
