e-Library of Evidence for Nutrition Actions (eLENA)

Vitamin D supplementation and respiratory infections in children

Biological, behavioural and contextual rationale

WHO technical staff
April 2011

Acute lower respiratory infections, predominantly pneumonia, kill more children under the age of five in every region of the world1 than any other cause. In 2007, of the estimated nine million child deaths that occurred globally, close to 20% or 1.8 million were attributable to pneumonia. Undernutrition has been shown to both increase the severity and overall prevalence of acute lower respiratory infections and is an important factor in determining the mortality rates from severe forms of respiratory infections1–4.

Poor nutritional status is a well-recognized cause of early childhood susceptibility to acute lower respiratory infections, along with lower socioeconomic status, ethnicity, suboptimal immunization, tobacco exposure, air pollution and other underlying chronic diseases or infant prematurity5–7. Several micronutrient interventions have been proposed to both protect and prevent children from developing acute lower respiratory infections. Vitamin D deficiency in children has been strongly associated with risk of acute lower respiratory infections in a number of settings8–13. In Ethiopia, for example, researchers found that 42% of children in hospital with pneumonia had rickets, or severe vitamin D deficiency14.

Vitamin D is a group of fat-soluble molecules that are important micronutrients for health. Both vitamin D2 and vitamin D3 can be obtained from the diet15, 16 but in relatively low quantity. Only fatty fish such as salmon, tuna, sardines or cod liver oil contain significant amounts of vitamin D3. Most vitamin D3 is synthesized in the skin after exposure to UVB light from the sun. For children, fortified foods such as cereals, cheese and milk represent an important source of vitamin D in some countries, although these items contain low and often fluctuating amounts of vitamin D15, 16, 17. Diet contributes to only 10–20% of vitamin D stores in adults, with this percentage most likely even smaller in children 18.

During the winter months, when vitamin D synthesis is naturally diminished because of the decreasing hours of sunlight, angle of solar radiation and skin exposed, acute lower respiratory infections are more frequent in adults and children19, 20. Vitamin D is thought to play an important role in immune system regulation, and can potentially protect against infections21, 22, in addition to cancer, cardiovascular disease and autoimmune disorders such as type 1 diabetes23–26. Vitamin D supplementation appears to reduce the incidence of and adverse outcomes from these conditions and others such as acute lower respiratory infections, as well as reducing all-cause mortality27, 28.

Nutritional interventions aimed at the treatment or prevention of forms of acute lower respiratory infections have thus far been very few in the published literature. A randomized control trial in Afghanistan showed that one high dose of vitamin D3, combined with antibiotic treatment, given to children aged 1–36 months who were hospitalized for pneumonia, did reduce the reoccurrence of pneumonia among children living in an area of high vitamin D deficiency28.

Future studies, however, need to be undertaken in different settings to confirm these results, especially among populations of children who are not classified as vitamin D deficient living in high-resource settings. Children in more northern latitudes lacking sun exposure, and dark-skinned children, are most at risk of vitamin D deficiency and of developing more severe forms of acute lower respiratory infections29, 30. However, cut-off values for vitamin D sufficiency and recommended daily intake in children are still under debate13, 31, 32. The American Academy of Pediatrics currently recommends supplementation with 400 IU (international units) daily of vitamin D from shortly after birth and continued throughout childhood and adolescence22. Recommendations for increased sun exposure to increase vitamin D3 synthesis in areas where supplementation does not occur must be balanced with concerns over excess exposure to UV radiation33. More data on the role of vitamin D in paediatric infection and immune function are required34.


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2 Roth DE et al. Acute lower respiratory infections in childhood: opportunities for reducing the global burden through nutritional interventions. Bulletin of the World Health Organization, 2008, 86:356–364.

3 Tezer H et al. Early and severe presentation of vitamin D deficiency and nutritional rickets among hospitalized infants and the effective factors. Turkish Journal of Pediatrics, 2009, 51(2):110–115.

4 Banajeh SM. Nutritional rickets and vitamin D deficiency – association with the outcomes of childhood very severe pneumonia: a prospective cohort study. Pediatric Pulmonology, 2009, 44(12):1207–1215.

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8 Roth DE et al. Vitamin D status and acute lower respiratory infection in early childhood in Sylhet, Bangladesh. Acta Paediatrica, 2010, 99(3):389–393.

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19 Linday LA et al. Cod liver oil, the ratio of vitamins A and D, frequent respiratory tract infections, and vitamin D deficiency in young children in the United States. Annals of Otology, Rhinology and Laryngology, 2010, 119(1):64–70.

20 Rockell JE et al. Season and ethnicity are determinants of serum 25-hydroxyvitamin D concentrations in New Zealand children aged 5–14 y. Journal of Nutrition, 2005, 135(11):2602–2608.

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26 Urashima M et al. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. American Journal of Clinical Nutrition, 2010, 91(5):1255–1260.

27 Autier P, Gandini S. Vitamin D supplementation and total mortality: a meta-analysis of randomized controlled trials. Archives of Internal Medicine, 2007, 167:1730–1737.

28 Manaseki-Holland S et al. Effects of vitamin D supplementation to children diagnosed with pneumonia in Kabul: a randomised controlled trial. Tropical Medicine and International Health, 2010, 15(10):1148–1155.

29 Grant CC et al. Child nutrition and lower respiratory tract disease burden in New Zealand: a global context for a national perspective. Journal of Paediatrics and Child Health, 2010.

30 Grant WB. Variations in vitamin D production could possibly explain the seasonality of childhood respiratory infections in Hawaii. Pediatric Infectious Diseases Journal, 2008, 27(9):853.

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32 Ginde AA, Mansbach JM, Camargo CA, Jr. Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Archives of Internal Medicine, 2009, 169(4):384–390.

33 INTERSUN The Global UV Project. A Guide and Compendium. Reduce the burden of disease resulting from exposure to UV radiation while enjoying the sun safely. Geneva, World Health Organization, 2003.

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