Is Vitamin D truly a foundational health pillar — or just another overhyped supplement?

In this episode of Coffeebar, we sit down with Prof. Dr. Pietro Vernazza, former Chief of Infectious Diseases at the Cantonal Hospital of St. Gallen and one of Switzerland’s leading voices in immunology and preventive medicine.

Together, we unpack what Vitamin D actually is, why deficiency is so widespread despite modern lifestyles, and who is most at risk. We explore how Vitamin D functions inside the immune system, its link to respiratory infections, chronic disease, and mental health—and what science really says beyond the headlines.

We also get practical: optimal ranges, evidence-based dosing, absorption, testing, safety, and how to build a simple, sustainable Vitamin D routine.

A grounded, science-first conversation on whether optimizing Vitamin D levels can meaningfully improve resilience, immunity, and long-term health.