Micronutrients are essential elements required by organisms in varying quantities throughout life to orchestrate a range of physiological functions to maintain health. Micronutrient requirements differ between organisms; for example, humans and other animals require numerous vitamins and dietary minerals, whereas plants require specific minerals. For human nutrition, micronutrient requirements are in amounts generally less than 100 milligrams per day, whereas macronutrients are required in gram quantities daily.
The minerals for humans and other animals include 13 elements that originate from Earth's soil and are not synthesized by living organisms, such as calcium and iron. Micronutrient requirements for animals also include vitamins, which are organic compounds required in microgram or milligram amounts. Since plants are the primary origin of nutrients for humans and animals, some micronutrients may be in low levels and deficiencies can occur when dietary intake is insufficient, as occurs in malnutrition.
A multiple micronutrient powder of at least iron, zinc, and vitamin A was added to the World Health Organization's List of Essential Medicines in 2019.