Micronutrients 101
What Are Micronutrients?
The word ‘micronutrient’ might not be in your everyday vocabulary. And you might be asking, ‘what is a micronutrient anyway?’ We can help. Micronutrients are at the core of the Micronutrient Forum. Here, we provide an overview of these tiny, all-powerful vitamins and minerals for your body.
Your body only needs small amounts of micronutrients, such as vitamin A and iron, but these essential nutrients are necessary for growth, immune function, brain development, and other vital functions. We need to obtain micronutrients from food since our bodies cannot produce most vitamins and minerals on our own. Since the micronutrient content of each type of food differs, it is important to eat a variety of foods so that your body has enough vitamins and minerals for optimal health. Nutritious foods, such as fruits, vegetables, and animal source foods, are particularly good sources of micronutrients.
Know Your Key Micronutrients
Vitamin A
Health benefits: Eyes, immune system, skin, genes, growth
Night blindness is one of the first signs of vitamin A deficiency. A leading cause of preventable blindness in children, vitamin A deficiencies also increase the risk of disease and death from severe infections. More than half of all countries, particularly in Africa and South Asia, are experiencing levels of vitamin A deficiency that are a cause of public health concern. Pregnant women and young children in low-income countries are at the greatest risk. A 2021 Lancet series identified eleven evidence-based 'Samurai' interventions that can improve health outcomes and save lives, one of which is periodic high-dose vitamin A supplementation for children under five (10).
Fact Call-Out:
For $0.02 per dose, vitamin A supplementation can boost immunity and protect some of the world's most vulnerable children (11).
Sources
Animal: liver, egg yolk, dairy products
Plant: melon, mango, spinach, carrots
Vitamin A
Vitamin B12
Health benefits: Nerve activity, neurotransmitters
Vitamin B12, also called cobalamin, is a necessary vitamin that your body requires but cannot produce. It supports the normal function of nerve cells and bone growth and helps with red blood formation and anemia prevention. Adequate vitamin B12 levels are also necessary for a healthy pregnancy. As such, the World Health Organization identifies pregnant and lactating women as the groups with the most significant risk for vitamin B12 deficiency. When pregnant women have low levels of vitamin B12, there is an increased risk of congenital disabilities, such as neural tube defects, poor fetal growth, and perinatal morbidity and mortality. Dietary vitamin B12 deficiency is widely prevalent but is a severe public health issue in India, Mexico, Central, and South America, and in some regions of Africa. Intermittent vitamin B12 supplementation during pregnancy can reduce the onset of anemia. When combined with folic acid, B12 supplementation can reduce the risk of spina bifida and other central nervous system defects (19).
Sources
Animal: meat, eggs, dairy products, fish, and shellfish
Vitamin B12
Vitamin B9 (Folate or Folic Acid)
Health benefits: DNA synthesis
Vitamin B9—also known as folate or folic acid—plays a vital role in fetal brain and spinal cord development and the heart and circulatory system. Folic acid, alongside iron supplementation, prevents anemia in pregnancy. Early in pregnancy, folic acid supplementation can reduce the risk of neural-tube defects like spina bifida by up to 70% (22). Supplementation of iron and folic acid supplementation is associated with a reduced risk of anemia and iron deficiency for pregnant women (23).
Fact call-out:
Since 1990, more than 80 countries have introduced mandatory fortification of staple foods, like wheat flour, with folic acid to reduce the prevalence of neural-tube deficiencies (24).
Sources
Animal: liver, dairy products, egg yolk
Plant: leafy vegetables, peanuts, beans, oranges
Folic Acid
Iodine
Health benefits: Thyroid function
A micronutrient not commonly found in food, dietary iodine is a critical component of thyroid hormone, which controls the body's metabolism and is necessary for proper bone and brain development during pregnancy. Thyroid hormones are essential for physiologic processes such as growth, reproductive function, brain development, energy metabolism, central nervous function, and healthy thyroid function. Yet nearly two billion people worldwide have inadequate iodine nutrition (12). Pregnant women and children are most at risk. More than 50 percent of pregnant women and 36% of school-aged children worldwide experience iodine deficiency (13). Universal salt iodization programs have significantly reduced severe iodine deficiency, but 25 countries still face a mild to moderate prevalence of iodine deficiency (14).
Fact Call-Out:
Every dollar spent on salt iodization yields a $30 return through improved learning, which leads to greater productivity later in life (8,15).
Sources
Animal: seafood, dairy products
Other: iodized salt
Iodine
Iron
Health benefits: Blood production
Iron deficiency anemia is a common type of anemia, a condition in which blood does not have enough healthy red blood cells. Red blood cells carry oxygen from the lungs to the body's tissues. Anemia is a serious public health issue and is caused by among others, but not only, insufficient iron intakes: globally, anemia affects 1.62 billion people or 24.8% of the population. Forty-seven percent of children under five years and 40% of pregnant women are anemic (16). For women, multiple factors such as age, parity, socioeconomic status, and diet can determine their stores of iron. Where iron deficiency anemia is highly prevalent, iron supplementation can be an effective intervention to improve iron status for these priority target groups.
Fact Call-Out:
Investment in global nutrition targets to reduce anemia by 50% by 2025 could prevent 265 million cases of anemia in women and avert 800,000 child deaths. Only 3 out of 185 countries with anemia data are on track to meet this target (17,18).
Sources
Animal: red meats, seafood, poultry
Plant: legumes, grains
Iron
Zinc
Health benefits: Gene expression, protein synthesis, immune function, growth and development
Zinc is an essential mineral that your body requires in tiny amounts for proper growth and immune function. It is also necessary for a healthy pregnancy. With at least 17% of the world's population at risk for inadequate zinc intake, zinc deficiency is one of the world's most prevalent micronutrient deficiencies (20). There are several strategies for addressing zinc deficiency. Preventative zinc supplementation can lower the incidence of premature birth, reduce childhood diarrhea and respiratory infections, and increase growth and weight gain for infants and young children (20). Exclusive breastfeeding during the first six months of life, followed by improved complementary feeding practices with zinc-rich food, along with breastfeeding, can improve zinc intake for at-risk infants and young children. Fortification of staple foods—such as wheat flour, maize flour, or rice—with zinc is also an effective strategy for improving zinc levels.
Fact Call-Out:
In 2020, 23 out of 25 countries where national data was available had a zinc deficiency prevalence of 20% or higher (the WHO-recommended threshold for defining zinc deficiency as a public health issue) for at least one physiological group (21).
Sources
Animal: meat, poultry, shellfish
Plant: legumes, mushrooms, whole grains
Zinc
Micronutrient deficiencies are a significant global public health issue
Pregnant women, lactating women, and young children are the most vulnerable to micronutrient deficiencies because a child’s healthy development requires a relatively higher level of vitamins and minerals. The most critical life stage for nutrient-rich diets is known as ‘the first 1,000 days’, which is the period between a woman’s pregnancy and her child’s second birthday.
While there has been progress in reducing the burden of malnutrition over the past two decades, it has been uneven and insufficient: pregnant and lactating women and young children are still disproportionately impacted by deficiencies. Wasting, stunting, and maternal anemia levels are projected to rise (4). In low- and middle-income countries, 63.2% of women of reproductive age were vitamin D deficient, 41.4% were zinc deficient, 31.2% were anemic, and 22.7% were folate deficient, and 15.9% were vitamin A deficient (5). Globally, 2 in 3 children do not have access to the minimum diverse diets needed for healthy growth and development (6). Micronutrient malnutrition has devastating consequences, including increased child mortality, poor child growth and mental development, increased vulnerability to infectious diseases, increased risk of diet-related chronic disease later in life, and a loss of human potential.
The COVID-19 pandemic has further exposed vulnerable populations to food insecurity and exacerbated nutrition challenges by disrupting food systems, reducing income sources, and widening gaps in coverage of essential health and nutrition services. Now is the time for the global nutrition community to deepen its commitment to designing long-term, sustainable reforms to ensure broad access to nutrient-rich diets and resilient food systems.

Micronutrient interventions are one of the world's most cost-effective public health solutions
And yet, we have evidence-based, cost-effective solutions available and ready to scale to reverse the impact of micronutrient deficiencies. In addition to promoting breastfeeding and healthy diets, there are a host of proven micronutrient interventions, such as bio-fortification, fortification, and supplementation. Such interventions are particularly valuable in countries where it might be challenging to improve access to or the availability of nutrient-rich diets or in stages in life when requirements are high and difficult to meet through the diet alone.
A 2021 Lancet series identified eleven ‘Samurai’ interventions that can improve health outcomes and save lives (7). At least eight of these interventions involve micronutrients:
1) vitamin A supplementation for children under the age of 5 years in deficient contexts,
2) preventive and
3) therapeutic zinc supplementation for the treatment of diarrhea,
4) breastfeeding promotion and counseling,
5) maternal calcium supplementation in low intake populations,
6) maternal multiple micronutrient supplementation (MMS),
7) large-scale food fortification, and
8) small-quantity lipid nutrient supplements for children 6-23 months of age.
And these interventions belong to the most cost-effective development solutions we have on hand. Economists have long hailed micronutrient supplementation and fortification and biofortification among the world’s best investments. The cost-benefit ratio for improved health and productivity for these three interventions is a minimum of $10 for every $1 invested, but as high as $55 for every $1 invested, depending on the particular intervention used (8).
Mighty foods are rich in micronutrients
While several proven interventions – will improve micronutrient status, optimal micronutrient security should – also be supported by increasing availability, access and consumption of nutritious diets. Diets rich in nutrients require a diverse and sufficient daily intake of fresh fruits, vegetables, and meat. Young children are the most vulnerable to the consequences of poor diets and have the most difficulties fulfilling their high micronutrient needs from diets alone. Breastmilk is a critical source of micronutrients, especially during the first six months of life so adequate promotion and support of breastfeeding is important, after which the child should continue to get breastfed along with special, micronutrient-dense complementary foods up to at least two years of age. Inadequate nutrition in the first two years of life can cause delays in growth and development. A 2021 UNICEF analysis of 91 countries found that half of children aged 6-23 months are being fed the minimum recommended meals per day. Only a third consume the minimum number of food groups they need for healthy growth and development (9). An insufficient intake of the essential nutrients found in vegetables, fruits, eggs, fish, and meat required for early growth and development puts children at risk for poor brain development, reduced learning, low immunity, increased infections, and ultimately death.
Additional Resources
- Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA)
- Folate Task Team
- Food Fortification Initiative
- Global Alliance for Vitamin A (GAVA)
- Global Fortification Data Exchange (GFDx)
- International Zinc Nutrition Consultative Group (IZiNCG)
- Iodine Global Network (IGN)
- National Institutes of Health. Dietary Supplement Fact Sheet. Available here (Accessed 7 Oct 2021).
- World Health Organization. Micronutrients. Available here (Accessed 7 Oct 2021).
- Nutrition International. Micronutrients: Delivering the critical ingredients we all need to survive and thrive. Available here (Accessed 7 Oct 2021).
- Schmidhuber J, Sur P, Fay K, Huntley B, Salama J, Lee A, Cornaby L, Horino M, Murray C, Afshin A. The Global Nutrient Database: availability of macronutrients and micronutrients in 195 countries from 1980 to 2013. The Lancet Planetary Health. 2018 Aug 1;2(8):e353-68. Available here (Accessed 7 Oct 2021).
References
- Committee on Micronutrient Deficiencies, Board on International Health, Food and Nutrition Board. Prevention of Micronutrient Deficiencies: Tools for Policymakers and Public Health Workers. Washington; 1998.
- Food and Agriculture Organization of the United Nations (FAO). The State of Food Security and Nutrition in the World 2021. Rome; 2021.
- Laborde D, Herforth A, Headey D, de Pee S. COVID-19 pandemic leads to greater depth of unaffordability of healthy and nutrient-adequate diets in low- and middle-income countries. Nat Food. 2021;2(7):473–5.
- Osendarp S, Akuoku JK, Black RE, Headey D, Ruel M, Scott N, et al. The COVID-19 crisis will exacerbate maternal and child undernutrition and child mortality in low- and middle-income countries. Nat Food. 2021;2(7):476–84.
- Black RE, Victora CG, Walker SP, Bhutta ZA, Christian P, De Onis M, et al. Maternal and child undernutrition and overweight in low-income and middle-income countries. Lancet. 2013;382(9890):427–51.
- UNICEF. Food Systems for Children: UNICEF in Action for Food Systems Transformation. Geneva; 2021.
- Heidkamp RA, Piwoz E, Gillespie S, Keats EC, D’Alimonte MR, Menon P, et al. Mobilising evidence, data, and resources to achieve global maternal and child undernutrition targets and the Sustainable Development Goals: an agenda for action. Lancet. 2021.
- Horton S, Alderman H, Rivera JA. The challenge of hunger and malnutrition. Copenhagen Consens. 2008;3–4.
- UNICEF. Fed to Fail? The Crisis of Children’s Diets in Early Life. New York; 2021.
- Victora CG, Christian P, Vidaletti LP, Gatica-Domínguez G, Menon P, Black RE. Revisiting maternal and child undernutrition in low-income and middle-income countries: variable progress towards an unfinished agenda. Lancet. 2021.
- UNICEF. Coverage at a Crossroads: New Directions for Vitamin A Supplementation Programmes. New York; 2018.
- de Benoist B, Andersson M, Takkouche B, Egli I. Prevalence of iodine deficiency worldwide. Lancet. 2003;362(9398):1859–60.
- Patriota ESO, Lima ICC, Nilson EAF, Franceschini SCC, Gonçalves VSS, Pizato N. Prevalence of insufficient iodine intake in pregnancy worldwide: a systematic review and meta-analysis. Eur J Clin Nutr. 2021.
- Pearce EN, Lazarus JH, Moreno-Reyes R, Zimmermann MB. Consequences of iodine deficiency and excess in pregnant women: an overview of current knowns and unknowns. Am J Clin Nutr. 2016;104(suppl_3):918S-923S.
- Iodine Global Network. Why Should We Eliminate Iodine Deficiency? 2021.
- World Health Organization. Vitamins and Mineral Nutrition Information System (VMNIS).
- Strengthening Partnerships Results and Innovations in Nutrition Globally (SPRING) Project. Changing the Way We Think about Micronutrient Assessment and Anemia Programming. Findings from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) Project. Arlington; 2017.
- Shekar M, Kakietek J, Dayton Eberwein J, Walters D. An Investment Framework for Nutrition: Reaching the Global Targets for Stunting, Anemia, Breastfeeding and Wasting [Internet]. World Bank. 2016 [cited 2021 Nov 9]. Available from: http://elibrary.worldbank.org/doi/book/10.1596/25292
- Molloy AM, Kirke PN, Brody LC, Scott JM, Mills JL. Effects of folate and vitamin B12 deficiencies during pregnancy on fetal, infant, and child development. In: Food and Nutrition Bulletin. UnitedNations University Press; 2008.
- Wessells KR, Brown KH. Estimating the global prevalence of zinc deficiency: results based on zinc availability in national food supplies and the prevalence of stunting. PLoS One. 2012;7(11):e50568.
- Gupta S, Brazier AKM, Lowe NM. Zinc deficiency in low‐and middle‐income countries: prevalence and approaches for mitigation. J Hum Nutr Diet. 2020;33(5):624–43.
- Scholl TO, Johnson WG. Folic acid: influence on the outcome of pregnancy. Am J Clin Nutr. 2000;71(5):1295S-1303S.
- Peña-Rosas JP, De-Regil LM, Garcia-Casal MN, Dowswell T. Daily oral iron supplementation during pregnancy. Vol. 2015, Cochrane Database of Systematic Reviews. John Wiley and Sons Ltd; 2015. p. 1–527.
- Haggarty P. UK introduces folic acid fortification of flour to prevent neural tube defects. Lancet. 2021;398(10307):1199–201.