Role of Vitamin A in Infancy

By - Danone Nutricia Academy

Vitamin A is an essential nutrient that cannot be produced by the human body internally and therefore it needs to be taken from dietary sources.During infancy, vitamin A plays a key role to support rapid growth and to help prevent infections. Generally, infants are born with low stores of vitamin A and depend on external sources, most important being breast milk. A recent study which focussed on Vitamin A deficiency(VAD) in children aged 12-59 months in India showed that the overall prevalence of VAD in this group of Indian children is 17.54%²

Role of Vitamin A:

Growth & Differentiation³: Vitamin Ais involved in growth and differentiation of various body cells such as cells of the respiratory epithelium, gastrointestinal tract, retina (hence plays an essential role in vision). In addition, Vitamin A also functions in all body tissues systemically to maintain growth and the maintenance of cells. It has a role to play in gene expression and bone growth as well ⁴

Cellular functions & Protein synthesis³: Most biologically active form of Vitamin A - Retinoid acid (RA) is involved in activating receptors for cellular functions and synthesis of proteins for normal physiological functions and hence impacts growth.

Front line of defence against pathogens:Vitamin A plays a crucial role in the morphological formation of the epithelium (lines all outer surface and most inner surfaces of organisms) which functions as the “front line” of defence against pathogen invasion.

Functioning of immune system: Vitamin A has been termed as an anti-infectious vitamin because of its role in regulating human immune function. ⁶Vitamin A is aprimary part of the mucus layer of both the respiratory tract and the intestine. Since Vitamin A helpsin mucin secretion, it supportsantigen non-specific immunity function.³RAis also involved in the regulation of the differentiation, maturation, and function of cells of the innate immune systemand plays a role in adaptive immune system as well.⁴

Effects of Vitamin A deficiency:

The World Health Organization has classified vitamin A deficiency as a public health problem as it affects a vast population of children. Prevalence of VAD is lower in children who are exposed to longer period of breastfeeding. Increase in mother’s education is also associated with lower VAD chances. Children who have poor dietary diversity, are stunted and anaemic have higher prevalence of VAD.²

Vitamin A deficiency results in impairment in mechanical barrier function, thus reducing innate immune function and promoting respiratory tract infections, diarrhoea, and other diseases.⁴VAD can also cause visual impairment in the form of night blindness. VAD is also linked to increase in child mortality mainly due to its detrimental effect on the immune functioning². Vitamin A can increase child's chance of survival by 12–24 %, according to a UNICEF report.²

Recommended Dietary Allowance (RDA) for Vitamin A ⁷

Age

RDA

(mg/day)

0-6 months

350

6-12 months

350

Dietary sources of Vitamin A

Apart from breastmilk, sources of vitamin A for infants are egg yolk, milk and milk products, meat and fish. Green (leafy) vegetables such as spinach, orange and yellow fruits and vegetables like carrots, sweet potatoes, mango, papaya, pumpkin etc are good sources of precursor of vitamin A (beta carotene) which is converted to vitamin A in the body. Vitamin A being a fat soluble vitamin requires adequate fat intake for its absorption⁸. Zinc enhances the absorption and utilization of Vitamin A⁹ .

Vitamin A plays a key role in growth, development and survival. Its deficiency can lead to various health issues like increased chances of infections, vision problems and even stunting. Hence adequate intake of Vitamin A is essential via dietary sources.

References:

WHO. Vitamin A supplementation in infants 1–5 months of age. Retrieved from https://www.who.int/elena/titles/vitamina_infants/en/
Kundu S, Rai B, Shukla A. (2021) Prevalence and determinants of Vitamin A deficiency among children in India: Findings from a national cross-sectional survey. Clinical Epidemiology and Global Health(11): 2213-3984. https://doi.org/10.1016/j.cegh.2021.100768.
Role of Vitamin A in human metabolic processes. Retrieved from http://www.fao.org/3/y2809e/y2809e0d.htm
Awasthi S, Awasthi A. (2020). Role of Vitamin A in child health and nutrition. Clinical epidemiology and Global Health. 1039-1042 DOI https://doi.org/10.1016/j.cegh.2020.03.016
Huang, Z., Liu, Y., Qi, G., Brand, D., & Zheng, S. G. (2018). Role of Vitamin A in the Immune System. Journal of clinical medicine, 7(9), 258. https://doi.org/10.3390/jcm7090258
Imdad, A., Yakoob, M.Y., Sudfeld, C. et al. Impact of vitamin A supplementation on infant and childhood mortality. BMC Public Health 11, S20 (2011). https://doi.org/10.1186/1471-2458-11-S3-S20.
Recommended dietary allowances and estimated average requirements nutrient requirements for Indians – 2020, ICMR-National Institute of Nutrition.
Dietary guidelines for Indians.National Institute of Nutrition . Retrieved from https://www.nin.res.in/downloads/DietaryGuidelinesforNINwebsite.pdf
Christian, P., & West, K. P., Jr (1998). Interactions between zinc and vitamin A: an update. The American journal of clinical nutrition, 68(2 Suppl), 435S–441S. https://doi.org/10.1093/ajcn/68.2.435S