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Protein requirements of infants and children: growth during recovery from malnutrition
G G Graham1, W C MacLean, K H Brown
1Instituto de Investigación Nutrucional (IIN), Lima, Perú.
Insights
This study found that current protein intake recommendations are adequate for infants and toddlers. Even lower protein intakes, 1.5 g/kg/day for infants and 1.1 g/kg/day for toddlers, are likely safe and support healthy growth.
Area of Science:
- Pediatric Nutrition
- Growth and Development
- Malnutrition Recovery
Background:
- Current protein intake recommendations for infants and toddlers are based on limited data.
- Assessing protein adequacy is crucial for optimal growth and development in early childhood.
Purpose of the Study:
- To evaluate the adequacy of currently recommended safe protein intakes for infants and toddlers.
- To determine the impact of varying protein concentrations on growth parameters in recovering malnourished children.
Main Methods:
- Recruited malnourished infants and toddlers and randomly assigned them to formulas with different energy percentages of protein (whey:casein 60:40).
- Monitored growth indicators including length age, weight age, weight/length ratio, sum of fat folds, and arm muscle/fat areas over 90 days.
- Calculated energy requirements for maintenance, activity, and weight gain, assessing the effect of protein levels.
Main Results:
- No significant protein-related differences in growth were observed within infant and toddler age groups.
- High-energy intakes led to mild obesity, while lean body mass remained deficient in both groups.
- Calculated energy cost of maintenance, activity, and weight gain showed no significant effect of protein percentage.
Conclusions:
- Current protein intake recommendations appear adequate for infants and toddlers.
- Protein intakes of 1.5 g/kg/day for infants and 1.1 g/kg/day for toddlers are likely safe for most children.
- Further attention to lean body mass development is warranted alongside energy and protein intake.
Objective:
To evaluate the adequacy of protein intakes now recommended as safe for infants and toddlers.
Methods:
Subjects were recovering malnourished infants, age 5.3 to 17.9 months, length age (LA) 2.5 to 6.4 months, weight age (WA) 1.5 to 5.2 months, weight/length (W/L) 78% to 100% of National Center for Health Statistics data; and toddlers age 11.4 to 31.6 months, LA 6.1 to 17.9 months, WA 3.9 to 12.0 months, W/L 79% to 99%. Infants were assigned at random to formulas with 5.5%, 6.7%, or 8.0% energy as 60:40 whey:casein protein. The 5.5% was based on FAO-WHO-UNU safe protein and average energy for ages 2.5 to 6.0 months. Toddlers received 4.7% (recommended for 6 to 18 months), 6.4%, or 8.0%. Identical concentrations (weight/kcal) of other nutrients were maintained; intakes were adjusted weekly to reach, in 90 days, the 50th percentile of weight for a LA 3 months greater than the initial one.
Results:
Infants consumed 125 +/- 11 (SD), 116 +/- 10, and 126 +/- kcal and 1.7 +/- 0.1, 1.9 +/- 0.2, and 2.5 +/- 0.3 g protein kg-1 . d-1; gained 2.4 +/- 0.7, 2.9 +/- 0.7, and 2.6 +/- 0.5 months in LA, and reached a W/L of 105 +/- 5, 103 +/- 6, and 105 +/- 5% of reference. Sum of four fat-folds (sigma FF) grew 13.1 +/- 6.9, 10.4 +/- 4.8, and 11.7 +/- 5.3 mm to 32.5 +/- 5.2, 31.7 +/- 4.7, and 30.5 +/- 5.5 mm; arm muscle areas (AMA) 57%, 51%, 70% to 1004 +/- 109, 1017 +/- 110, and 1004 +/- 116 mm2, still low; arm fat areas (AFA) 93%, 66%, and 93% to higher-than-normal 598 +/- 105, 610 +/- 101, and 541 +/- 116 mm2. Regression of intake on weight gain estimated energy for maintenance + activity to be 81.0 +/- 7.5 (SEM) kcal . kg-1 . d-1, and cost of gain (storage + metabolic cost) as 7.6 +/- 1.7 kcal/g, with no significant effect of % protein. Toddlers consumed 107 +/- 9, 103 +/- 12, and 105 +/- 10 kcal and 1.3 +/- 0.1, 1.6 +/- 0.2, and 2.1 +/- 0.2 g protein . kg-1 . d-1, gained 3.3 +/- 0.7, 2.9 +/- 0.6, and 3.3 +/- 0.7 months in LA; to a W/L of 102 +/- 1, 102 +/- 3, and 101 +/- 4%. Sigma FF grew 9.2 +/- 4.0, 7.4 +/- 4.3, and 6.0 +/- 3.8 to 28.9 +/- 5.2, 30.5 +/- 3.7, and 27.0 +/- 2.7 mm; AMA 31%, 33%, and 34% to 1121 +/- 115, 1124 +/- 110, and 1117 +/- 120 mm2; AFA 53%, 44%, and 45% to higher-than normal 578 +/- 106, 636 +/- 99, and 569 +/- 68 mm2. Cost of maintenance + activity was 70.8 +/- 3.8 (SEM) kcal . kg-1 . d-1, that of weight gain 9.7 +/- 1.35 kcal/g, with no effect of % protein.
Conclusions:
Within age groups, there were no significant protein-related differences in growth. In both infants and toddlers, high-energy intakes resulted in mild obesity, with lean body mass still deficient. Protein intakes two SD below the means in the lowest protein/energy cells, 1.5 g . kg-1 . d-1 for infants and 1.1 g times kg-1 . d-1 for toddlers, should still be safe for nearly all children of comparable biological ages.