Micronutrient

Micronutrient is a nutrient required by organisms in small amounts for normal growth, development, and health. In human nutrition, micronutrients include vitamins and minerals, distinct from macronutrients (carbohydrates, proteins, fats, and water) that are needed in larger quantities. Vitamins are organic compounds essential in tiny amounts; water-soluble vitamins include the B vitamins and vitamin C, while fat-soluble vitamins include vitamins A, D, E, and K. Minerals are inorganic elements; major minerals such as calcium, phosphorus, potassium, magnesium, sulfur, sodium, and chloride are needed in relatively larger quantities, while trace minerals (iron, zinc, copper, manganese, iodine, selenium, chromium, fluoride, molybdenum, and others) are required in smaller amounts.

Micronutrients support a wide range of physiological processes, including energy metabolism, tissue synthesis, immune function, antioxidant defense, and bone and blood health. Many act as cofactors for enzymes, transporters, or structural components. Absorption and utilization depend on dietary context, bioavailability, age, health status, and interactions with other nutrients or medications. For example, vitamin C can enhance iron absorption, while phytates and tannins can reduce mineral uptake.

Deficiencies or excesses can cause health problems, such as iron deficiency anemia, vitamin A deficiency, iodine deficiency disorders, or vitamin D deficiency. Excess intake of certain fat-soluble vitamins or minerals can be toxic. Adequate intake is typically achieved through a varied diet; fortified foods and supplements may be used in specific cases under professional guidance. National and international guidelines provide reference intakes and upper limits to help balance intake.