
Vitamin D Deficiency Tied to More Severe Flu Infections
An observational study of 36,258 UK Biobank participants found severe vitamin D deficiency (<15 nmol/L) linked to a 33% higher hospitalization rate for respiratory infections, with each 10 nmol/L increase associated with a 4% drop in hospitalizations; about 18% of Americans have insufficient vitamin D. Experts warn this is not causation, advise testing and doctor guidance before supplementation, and emphasize vaccination and other preventative measures as primary flu defenses.













