Evidence check: Vitamin D Test in the context of Langlebigkeit

The evidence for a vitamin D test in the context of longevity is weak. While vitamin D is essential for bone health, immune function, and possibly inflammation modulation, a direct causal link between vitamin D testing (either blood levels or genetic variants) and extended lifespan is not supported by robust human studies. The provided context only mentions the VDR FokI polymorphism (rs2228570), whose connection to insulin resistance is rated as 'unclear'. Large RCTs (e.g., VITAL) show no significant reduction in all-cause mortality from vitamin D supplementation in healthy adults. Genetic testing for VDR variants does not provide clinically actionable information for longevity. Therefore, the evidence grade is 'unclear'. Practical advice: If deficiency is suspected, measure serum 25(OH)D and supplement according to guidelines, not based on DNA tests. Excessive vitamin D intake can be toxic (hypercalcemia).