What is a vitamin? A physician explains vitamin definitions, deficiencies, supplementation, and why vitamin D is actually a hormone.

Minerals are essential inorganic elements that the human body cannot produce but requires for normal structure, metabolism, and physiologic regulation. They play critical roles in bone formation, nerve and muscle function, fluid and electrolyte balance, enzyme activation, hormone production, and oxygen transport. Minerals differ fundamentally from vitamins and hormones, yet deficiencies and imbalances remain common in modern societies due to processed diets, aging, medical co