Ultraviolet (UV) radiation, whether from natural sunlight or artificial sources like tanning machines (sunbeds), has complex effects on human immunity. While moderate UV exposure supports vitamin D synthesis—which is beneficial for immune function—excessive exposure, particularly from tanning devices, can suppress immunity and increase health risks.
What effect does UV light have on the immune system?
1. UV Radiation and Immune Modulation
A. Immunosuppressive Effects
Local Immune Suppression:
UVB (280–315 nm) and UVA (315–400 nm) rays penetrate the skin, damaging DNA in keratinocytes and immune cells.
This triggers the release of immunosuppressive cytokines (e.g., IL-10, TNF-α), reducing the skin’s ability to fight infections and cancers.
Langerhans cells (key immune sentinels in the skin) are depleted, weakening antigen presentation.
Systemic Immune Suppression:
Chronic UV exposure (especially UVA in tanning beds) can suppress T-cell function, reducing the body’s defense against infections and vaccines.
Studies link excessive tanning bed use to increased susceptibility to viral infections (e.g., herpes simplex, HPV) and bacterial skin infections.
B. Vitamin D and Immune Benefits
UVB-induced vitamin D enhances innate immunity by promoting antimicrobial peptide (e.g., cathelicidin) production.
However, tanning machines emit mostly UVA, which does not efficiently produce vitamin D, negating this benefit.
How can the impact of ultraviolet rays on immunity be dealt with scientifically?
1. Reduce frequency and control duration.
Tanning sessions should not exceed 10 minutes and should be no more than twice a week to avoid long-term cumulative exposure.
2. Strengthen care before and after surgery.
Moisturising and using antioxidant (vitamin C and E) and restorative skincare products can reduce the damage caused by ultraviolet rays.
3. Pay attention to changes in the body.
Seek medical attention promptly if you experience repeated infections, abnormal skin itching, or erythema, and stop using tanning products.