Vitamin D: Myths and Realities in Heart, Lung, and Related Diseases

In this episode of Patient Pulse, Dr. Clifford Rosen, Professor of Medicine at Tufts University School of Medicine, talks about the role of vitamin D in heart, lung, and related diseases.

Dr. Rosen explains myths and realities about how Vitamin D works, Vitamin D levels and bone health, Vitamin D and acute and chronic diseases, including heart disease, cancer, obesity, blood clots, and COVID-19, and Vitamin D treatment for acute and chronic diseases.

Overview

Dr. Rosen provides insights into what vitamin D can and cannot do, focusing on its role in bone health, chronic diseases, thrombosis risks, and COVID-19. As an active form of vitamin D, 25-hydroxy vitamin D is produced in the skin from sun exposure and can also be obtained through diet.

The target blood level for vitamin D sufficiency is controversial, but most agree 20 ng/mL is adequate. Vitamin D is essential for calcium absorption, but mega-doses are unnecessary and can be harmful. Randomized trials show vitamin D supplementation does not prevent cancer, heart disease, or fractures in the general population.

Low vitamin D levels are associated with obesity, dark skin, and chronic illness, but a causal link is not established. Some COVID-19 studies suggest low vitamin D correlates with disease severity, but confounding factors like race and weight complicate interpretation. Overall, 800 IU/day of vitamin D is sufficient to maintain adequate levels for most people.

Key Points:

1. Vitamin D is produced in the skin from sun exposure and also obtained through diet. 50-70% comes from the skin, 20-40% from diet.

2. Controversy exists over optimal vitamin D levels. Most agree 20 ng/mL 25-hydroxy vitamin D is a sufficient minimum target. Levels are lower in the elderly, African Americans, Hispanics, and the chronically ill.

3. Vitamin D is essential for calcium absorption in the gut. 800 IU/day is sufficient for most people to maintain adequate levels.

4. Mega-doses of vitamin D are unnecessary and potentially harmful, especially in the elderly. More is not better.

5. Vitamin D supplementation does not prevent cancer, heart disease or fractures in the general population based on large randomized trials.

6. Low vitamin D levels are associated with obesity and chronic illness, but a causal relationship is not established. Screening vitamin D levels to predict disease is not recommended.

7. Some observational studies suggest low vitamin D correlates with COVID-19 incidence and severity, but race and obesity are major confounding factors. Randomized trials are lacking. Vitamin D is not currently recommended to prevent COVID-19.

8. In summary, aim for vitamin D sufficiency with 800 IU/day, but mega-doses and screening for disease prediction are unwarranted based on current evidence. More research is needed, especially regarding COVID-19.