Micronutrient

What Is a Micronutrient?

Micronutrients are vitamins and minerals required by the body in small amounts — milligrams or micrograms — but are essential for virtually every physiological process. Unlike macronutrients, micronutrients do not provide energy directly. Instead they function as cofactors for enzymes, components of structural molecules, and regulators of gene expression.

There are 13 essential vitamins (vitamins A, C, D, E, K, and eight B vitamins) and at least 16 essential minerals (including calcium, iron, zinc, iodine, magnesium, and potassium). "Essential" means the body cannot synthesize them in adequate amounts and must obtain them from diet.

Fat-Soluble vs. Water-Soluble Vitamins

• Fat-soluble vitamins (A, D, E, K): Stored in body fat and the liver. Because they accumulate, excessive supplementation can cause toxicity. Absorption requires dietary fat.
• Water-soluble vitamins (C and B vitamins): Not stored in significant amounts. Excess is generally excreted in urine, making toxicity less common but deficiency more likely if dietary intake is inconsistent.

Why Micronutrient Deficiencies Matter

Even mild, subclinical deficiencies of micronutrients can impair health over time. Iron deficiency — the world's most prevalent nutrient deficiency — reduces cognitive function and work capacity before anemia becomes clinically apparent. Iodine deficiency remains the leading preventable cause of intellectual disability globally. Vitamin D insufficiency is associated with bone loss, immune dysfunction, and increased risk of several chronic diseases. Obtaining micronutrients from a varied, whole-food diet generally provides them in forms and ratios that the body can use effectively.