Vitamin C and Immune Function: A Review
Carr AC, Maggini S
Nutrients • November 2017
Plain Language Summary
This review explains how vitamin C helps your immune system fight infections. It supports the skin and gut barriers that keep germs out, helps immune cells work better, and is used up faster during infections. Taking vitamin C supplements can reduce how long colds last and how severe they are. During illness, the body needs more vitamin C (1-2 grams daily), while 200mg daily is typically enough for prevention in healthy adults.
Key Findings
- 1Vitamin C supports epithelial barrier function against pathogens
- 2Accumulates in phagocytic cells to enhance microbial killing
- 3Supports lymphocyte proliferation and function
- 4Supplementation reduces duration and severity of common cold
- 5Higher doses (1-2g/day) needed during active infection
Abstract
This comprehensive review examined the role of vitamin C in supporting immune function. It covered vitamin C’s contributions to innate and adaptive immunity, its accumulation in immune cells, and effects on common respiratory infections.
Study Limitations
- Review focused on mechanistic studies
- Some evidence from cell/animal studies
- Optimal dosing still debated
- Benefits vary by individual baseline status