Aging decreases the capacity of human skin to produce vitamin D3.
Level 5 - mechanism / opinion, no new human data
Ex vivo laboratory bench research using surgically obtained human skin tissue.
PubMed 2997282 · doi:10.1172/JCI112134
What was done
Surgically obtained human skin samples from donors aged 8 to 92 years were evaluated to measure epidermal concentrations of provitamin D3 (7-dehydrocholesterol). A subset of skin samples was exposed to ultraviolet radiation in vitro to quantify and compare previtamin D3 generation in the epidermis and dermis between young (8- and 18-year-old) and older (77- and 82-year-old) donors.
What was found
Epidermal concentrations of provitamin D3 declined in an age-dependent manner. The epidermis was the primary site of previtamin D3 formation in both age groups, accounting for >80% of total cutaneous production. Comparison between young (8 and 18 years) and older (77 and 82 years) donors revealed a >2-fold decrease in the skin's capacity to generate previtamin D3 following ultraviolet radiation.
Why it matters
This study provides a physiological mechanism for the higher risk of vitamin D deficiency in older adults, showing that cutaneous synthesis capacity declines intrinsically with age.
Limits
The study evaluated ex vivo tissue samples irradiated in a laboratory setting rather than in vivo systemic vitamin D production. The total sample size is not reported in the abstract, and the direct UV production comparison is based on only four specific donor ages. Potential confounders like anatomical skin site, pigmentation, and baseline donor sun exposure are not described.
Cited by
- supports Cutaneous production rate of vitamin D decreases as humans get older.