micronutrient micronutrient micronutrients are essential dietary 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. humans at the 1990 world summit for children, the gathered nations identified deficiencies in two microminerals and one micronutrient – iodine, iron, and vitamin a – as being particularly common and posing public health risks in developing countries. the summit set goals for elimination of these deficiencies. the ottawa-based micronutrient initiative was formed in response to this challenge with the mission to undertake research and fund and implement micronutrient programming. as programming around these micronutrients grew, new research in the 1990s led to the implementation of folate and zinc supplementation programs as well. priority programs include supplementation with vitamin a for children 6–59 months, zinc supplementation as a treatment for diarrhoeal disease, iron and folate supplementation for women of child-bearing age, salt iodization, staple food fortification, multiple micronutrient powders, biofortification of crops and behavior-centered nutrition education. there is low-quality evidence that food fortifications with micronutrients may reduce the risk of getting anemia and micronutrient deficiency but there is an uncertain effect on the height and weight of children. meanwhile, there is no data to show adverse effects of micronutrients fortification. fortification of maize flour with iron and other vitamins and minerals has uncertain benefits on reducing the risk of anemia. deficiencies micronutrient deficiencies are considered a public health problem worldwide. for over 30 years it has been estimated that more than two billion people of all ages are affected by this burden, while a recently published study based on individual-level biomarker data estimated that there are 372 million children aged 5 years and younger, and 1.2 billion non-pregnant women of reproductive age with one or more micronutrient deficiencies globally, affecting greatly asia and sub-saharan africa. women of reproductive age (including pregnant and lactating) as well as children and adolescents are at higher risk of micronutrient deficiencies due to their higher demands. similarly, the elderly are among the most vulnerable populations, associated to reduced absorption and utilization, as well as poorer diets. vegans and people reducing animal-source foods in their diets, as recommended by many scientific studies and experts, are also at greater risk of some micronutrient deficiencies if they don't adequately consume supplements or foods substituting animal-sourced micronutrients. the most commonly analyzed micronutrient deficiencies, and therefore the most prevalent, include iodine, iron, zinc, calcium, selenium, fluorine, and vitamins a, b6, b12, b9 (folate) and d, with large variations between countries and populations. impact micronutrient deficiencies are associated to short- and long-term consequences as clinical symptoms and signs will manifest in relation to the body stores for the specific micronutrient and the magnitude of the deficiency. nonetheless, it has been well established that micronutrient deficiencies are major contributors to impaired growth and neurodevelopment, perinatal complications and increased risk of morbidity and mortality. it has also been associated with 10% of all children's deaths, and are therefore of special concern to those involved with child welfare. early childhood micronutrient deficiency leads to stunted growth and impaired cognitive development, which in turn can translate into reduced work capacity, productivity and overall well-being during adulthood. deficiencies can constrain physical and (neurocognitive) development and compromise health in various ways. beyond dangerous health conditions, they can also lead to less clinically notable reductions in energy level, mental clarity and overall capacity. they not only affect the cognition of elderly and children but also that of adults. micronutrients help to resist or to recover from infectious diseases which can have extensive health impacts. causes deficiencies of essential vitamins or minerals such as vitamin a, iron, and zinc may be caused by long-term shortages of nutritious food or by infections such as intestinal worms. they may also be caused or exacerbated when illnesses (such as diarrhoea or malaria) cause rapid loss of nutrients through feces or vomit. interventions