Protein - The pro-growth nutrient for infants

By - Danone Nutricia Academy

Growth and development between birth and weaning are key for long-term well-being and the prevention of non-communicable diseases in the future. Dietary protein requirements are the highest during this period to support maintenance and the high rates of tissue formation. About 87% of dietary protein intake over and above that used for maintenance is utilized for tissue synthesis.¹

World Health Organization (WHO) recommends exclusive breastfeeding for the first 6 months of life as it is the ideal source of nutrients for young infants. The composition of breast milk provides the model for estimated total protein and essential amino acid requirements during infancy. In the second half of infancy, breast milk can provide most of the protein needed, provided a modest protein supply is obtained from weaning foods.¹

The Recommended protein requirements for Indian Infants are³ :

Age Group (Infants)	Body Weight kg)	ICMR 2020
Age Group (Infants)	Body Weight kg)	EAR(g/kg/d)	RDA(g/kg/d)	EAR(g/d)	RDA(g/d)	TUL(PE ratio)
0-6 months	5.8	1.16	1.40	6.7	8.1	<15 %
6- 12 months	8.5	1.04	1.23	8.8	10.5	<15 %

EAR – Estimated Average Requirement, RDA Recommended Dietary Allowance

TUL - Tolerable Upper Limit, PE Ratio –Protein Energy Ratio

The Vicious Protein Energy Malnutrition (PEM) Cycle

The biggest health crisis which India faces is PEM (Protein Energy Malnutrition). PEM affects the child in developmental years and can cause permanent impairment. In India, 34.7% of children under 5 years of age are stunted and wasting accounts to 17.3% in this age group. The nutritional status of the mother has a direct relation to that of the baby. A deficient mother produces a low-birth-weight baby who grows up with infections and compromised feeding. Although the concentration of protein in human milk is not significantly affected by maternal diet, it increases with the better nutritional status of the mother. ⁶

Role of protein in growth and development of infants⁷:

Infants need good quality protein which help perform the following functions:

Building, maintenance, and repairing new tissues, which includes tissues of the skin, eyes, muscles, heart, lungs, brain, and other organs
Manufacturing important enzymes, hormones, antibodies, and other components
Perform very specialized functions in regulating body processes.
Upregulate the immune system

Whey and Casein: How are they different?

Whey and casein are two types of proteins found in breastmilk. They differ in their physiological and biological properties. Casein forms curds in the stomach whereas whey remains as a liquid and is easier to digest. Whey also contains lactoferrin, lysozyme and antibodies which help to protect against infections. Depending on the lactation stage, 80% to 50% of the protein in breast milk is whey. The whey/casein ratio in breast milk fluctuates between 70/30 and 80/20 in early lactation period and decreases to 50/50 in late lactation period.⁸

Importance of whey protein in infants^5,7

The proportion of whey in human milk is significantly greater compared to the milk of other mammals. The main whey proteins are

Alpha-lactalbumin - for lactose synthesis, binding of Ca and Zn ions, antibacterial property
Lactoferrin - Functions with lysozyme to prevent the spread of potentially pathogenic bacteria
Secretory IgA - destroys bacteria and protects the mucosal surface of the gut

Role of casein in infants

Casein concentration in human milk is much lesser than in bovine milk. Casein is a source of amino acids and can be broken down into smaller bioactive peptides. Casein in breastmilk is mainly in form of beta and kappa casein(κ-casein). Glycosylation of κ-casein, is associated with protection against infection by inhibiting the attachment of Helicobacter pylori to human gastric mucosa.⁹ β-casein assists to form masses with calcium and phosphorus and facilitates their absoprtion.⁷

Protein is an important macronutrient that helps in the functioning of all cells in the human body, and adequate protein supply in infants is essential for their growth, development, and function.

For the use of Healthcare Professionals Only

References:

Dupont C. (2003). Protein requirements during the first year of life. The American journal of clinical nutrition, 77(6), 1544S–1549S. https://doi.org/10.1093/ajcn/77.6.1544S
Tang M. (2018). Protein Intake during the First Two Years of Life and Its Association with Growth and Risk of Overweight. International journal of environmental research and public health, 15(8), 1742. https://doi.org/10.3390/ijerph15081742
ICMR-NIN Nutrient RequirementsFor Indians 2020.Available at https://foodfuturefoundation.org/media/i0
ld30zx/recommended-dietary-allowances-rda-for-indians-2020.pdf
Global Nutrition Report 2020. Available at https://globalnutritionreport.org/resources
/nutrition-profiles/asia/southern-asia/india/
Bhutia D. T. (2014). Protein energy malnutrition in India: the plight of our under five children. Journal of family medicine and primary care, 3(1), 63–67.
Kim SY, Yi DY. Components of human breast milk: from macronutrient to microbiome and microRNA. Clin Exp Pediatr. 2020;63(8):301-309. doi:10.3345/cep.2020.00059
Infant nutrition and feeding: A guide for use in the special supplemental nutrition program for women, infants and children (2019). U.S. Department of Agriculture, Food and nutrition service, FNS – 826.
Martin, C. R., Ling, P. R., & Blackburn, G. L. (2016). Review of Infant Feeding: Key Features of Breast Milk and Infant Formula. Nutrients, 8(5), 279. https://doi.org/10.3390/nu8050279
Lönnerdal B. (2003). Nutritional and physiologic significance of human milk proteins. The American journal of clinical nutrition, 77(6), 1537S–1543S. https://doi.org/10.1093/ajcn/77.6.1537S