Paeds · gastroenterology-hepatology-and-nutrition
Micronutrient deficiencies
Also known as Micronutrient deficiencies · Vitamin and mineral deficiencies · Iron deficiency · Iron-deficiency anaemia · Vitamin D deficiency · Rickets · Vitamin A deficiency · Zinc deficiency · Vitamin B12 deficiency · Hidden hunger
Fellowship guide to micronutrient deficiencies in children, the so-called hidden hunger: the iron-deficient toddler with pallor, pica and faltering growth screened at twelve months, the exclusively breastfed infant of a vegan mother with vitamin B12 deficiency and developmental regression, the dark-skinned or covered adolescent with vitamin D deficiency and rickets, the malnourished or malabsorbing child with zinc and vitamin A deficiency and impaired immunity, the framework of inadequate intake, malabsorption, increased losses and increased needs, the laboratory confirmation with haemoglobin, ferritin, 25-hydroxyvitamin D and vitamin B12, and the region-aware prevention with supplementation, fortification and dietary diversification.
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- A pale, irritable, tired toddler with pica and a falling growth centile has iron-deficiency anaemia until proven otherwise; universal screening at around twelve months with a haemoglobin and a dietary risk assessment is recommended because iron deficiency harms neurodevelopment long before anaemia appears
- An exclusively breastfed infant of a vegan or deficient mother who presents with apathy, floppiness, feeding difficulty, tremor or developmental regression has vitamin B12 deficiency, a treatable and reversible cause of severe neurological injury; a low maternal and infant serum B12 with high methylmalonic acid confirms it and prompt parenteral replacement is mandatory
- A child with bowing of the legs, bone pain, muscle weakness, delayed walking or skeletal deformity of rickets needs a serum calcium, phosphate, alkaline phosphatase and 25-hydroxyvitamin D; deficiency is commonest in dark-skinned, fully covered, exclusively breastfed infants and adolescents who get little sun
- Vitamin A deficiency threatens sight and immunity: night blindness, Bitot spots, corneal xerosis and ulceration, and a child with severe deficiency is at high risk of severe infections and blindness and needs immediate high-dose treatment
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- Iron-deficiency anaemia and micronutrient deficiencies in children
- Micronutrient deficiencies: iron, vitamin D, vitamin A, zinc and vitamin B12 deficiency, with prevention and treatment
- Micronutrient deficiencies: the iron-deficient toddler, the rachitic infant, and the breastfed infant of a vegan mother with B12 deficiency
- Short case: the child with pallor, pica and faltering growth
- Long case: the adolescent with multiple micronutrient deficiencies and a restricted diet
- Nutrition: micronutrient deficiencies
- Iron, vitamin D and vitamin B12 deficiency in children
- Nutrition and growth: the child with rickets or refractory anaemia
- Nutrition: micronutrient deficiencies in children
- Patient Care: micronutrient deficiencies in children
- Medical Expert: micronutrient deficiencies in children
Overview & Definition
Micronutrients are the vitamins and minerals the body needs in small amounts, and their deficiency is the hidden face of undernutrition. A child can look well-fed and still be depleted, because iron, vitamin D, vitamin A, zinc, vitamin B12, iodine and vitamin C do their work inside cells, blood, bone and nerve long before the deficiency is visible at the bedside. The whole task of the clinician is to recognise the pale toddler with pica, the rachitic infant with bowed legs, the apathetic breastfed baby of a vegan mother, and the malnourished child with recurrent infections, confirm the deficiency with targeted blood tests, and replace what is missing while treating the cause. [11]
The term hidden hunger captures why micronutrient deficiency is so easily missed. Stunting, recurrent infection, faltering growth, developmental delay and poor school performance may be the only clues, and they overlap with poverty, restricted diets and chronic disease. Iron deficiency alone affects a large fraction of the world's infants and young children, vitamin D deficiency is re-emerging in high-income countries, and vitamin A and zinc deficiency remain major causes of preventable blindness, infection and death in low-resource settings. The clinical face changes with the nutrient, but the principle is one: deficiency harms the growing child, and replacement reverses it when it is caught in time. [11] [6]
References12ShowHide
- [1]Baker RD; Greer FR Diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants and young children (0-3 years of age). Pediatrics, 2010.PMID 20923825
- [2]Benson AE; Lo JO; Achebe MO; Aslan JS; Auerbach M; Bannow BTS Management of iron deficiency in children, adults, and pregnant individuals: evidence-based and expert consensus recommendations. Lancet Haematol, 2025.PMID 40306833
- [3]Pasricha SR; Flecknoe-Brown SC; Allen KJ; Gibson PR; McMahon LP; Olynyk JK Diagnosis and management of iron deficiency anaemia: a clinical update. Med J Aust, 2010.PMID 21034387
- [4]Ross AC; Manson JE; Abrams SA; Aloia JF; Brannon PM; Clinton SK The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know. J Clin Endocrinol Metab, 2011.PMID 21118827
- [5]Wagner CL; Greer FR Prevention of rickets and vitamin D deficiency in infants, children, and adolescents. Pediatrics, 2008.PMID 18977996
- [6]Elder CJ; Bishop NJ Rickets. Lancet, 2014.PMID 24412049
- [7]Green R; Allen LH; Bjørke-Monsen AL; Brito A; Guéant JL; Miller JW Vitamin B(12) deficiency. Nat Rev Dis Primers, 2017.PMID 28660890
- [8]Stabler SP Clinical practice. Vitamin B12 deficiency. N Engl J Med, 2013.PMID 23301732
- [9]Song A; Mousa HM; Soifer M; Perez VL Recognizing vitamin A deficiency: special considerations in low-prevalence areas. Curr Opin Pediatr, 2022.PMID 35125379
- [10]Brown KH; Peerson JM; Rivera J; Allen LH Effect of supplemental zinc on the growth and serum zinc concentrations of prepubertal children: a meta-analysis of randomized controlled trials. Am J Clin Nutr, 2002.PMID 12036814
- [11]Black RE; Victora CG; Walker SP; Bhutta ZA; Christian P; de Onis M Maternal and child undernutrition and overweight in low-income and middle-income countries. Lancet, 2013.PMID 23746772
- [12]Zimmermann MB Iodine deficiency and excess in children: worldwide status in 2013. Endocr Pract, 2013.PMID 23757630