[Vitamin D: evidence and controversies]

Area of Science:

• Endocrinology
• Dermatology
• Public Health

Background:

• Vitamin D is essential for musculoskeletal health and mortality reduction in at-risk groups.
• Emerging evidence links vitamin D to cancer, cardiovascular disease, autoimmune disorders, and infections.
• Widespread vitamin D insufficiency has been reported globally, prompting public health concerns.

Purpose of the Study:

• To review the evidence on vitamin D status, its role in various health conditions, and the impact of ultraviolet radiation.
• To evaluate the adequacy of current recommendations for vitamin D serum levels.
• To discuss the balance between sun exposure for vitamin D synthesis and its carcinogenic effects.

Main Methods:

• Review of existing epidemiological studies and scientific literature on vitamin D.
• Analysis of recommendations from health organizations regarding vitamin D sufficiency.
• Examination of the role of ultraviolet radiation in vitamin D synthesis and skin cancer risk.

Main Results:

• Epidemiological studies indicate widespread vitamin D deficits across global populations.
• Current recommendations suggest serum levels of 20 ng/mL (50 nmol/L) are adequate, potentially indicating an overestimation of deficiency prevalence.
• Ultraviolet radiation is a source of vitamin D but is also a known skin carcinogen.

Conclusions:

• Sun exposure should not be the sole source of vitamin D due to skin cancer risks.
• A balanced approach involving moderate sun exposure, dietary intake, and supplementation is recommended.
• Further research is needed to clarify optimal vitamin D levels and safe sun exposure guidelines.