|Energy and Protein requirements, Proceedings of an IDECG workshop, November 1994, London, UK, Supplement of the European Journal of Clinical Nutrition (International Dietary Energy Consultative Group - IDECG, 1994, 198 pages)|
|Report of the working group on protein and amino acid requirements|
1. The estimates of the protein intake of breast-fed infants in Table 1 of the paper by Dewey et al are accepted, noting that these values are 10-26% lower than those in the 1985 report. These estimates assume that at least 46% of the non-protein nitrogen in human milk can be utilized.
2. A survey of the literature suggests that the maintenance requirement is approximately 90 mg N/kg/ day. The value of 120 mg N/kg/day adopted in the 1985 report should be lowered. In accepting the model of the breastfed infant as the basis for estimating the requirements in the first 6 months, it should not be assumed that the mean intake equals the mean requirement. The epidemiological probability approach indicates that at 3-4 months the requirement is less than 170 mg/kg/day, whereas the mean intake is 231 mg/kg/day.
3. The use of a 50% augmentation of the protein needs for growth, adopted in the 1985 report to account for day-to-day intra-individual variability in growth, should be abandoned. To allow for this variation, an adjustment could be added to the coefficient of variability for growth. As suggested in the paper of Dewey et al, the CV for growth ranges from 24 to 46% during the first year.
4. The efficiency of utilization of nitrogen for infant growth can continue to be taken as 70%, as in the 1985 report.
5. The factorial model is considered appropriate for calculating' protein needs during the first year of life. When used to calculate dietary recommendations, differences in the efficiency of utilization of various protein sources in this period must be taken into account. In particular, it is possible that the dietary protein requirements of non-breastfed infants may be higher than those for breastfed infants (regardless of growth rate).
6. The approach to estimating the adequacy of protein intakes based on P/E ratios can be used to derive diets that will provide safe levels of intake when infants are no longer exclusively breastfed.
7. In estimating metabolic needs for amino acids of infants, it should not be assumed that the pattern of amino acids in human milk is the same as the pattern of the requirements. Nonetheless, to provide a generous margin of safety with regard to essential amino acids, the pattern in human milk should be acceptable for estimating dietary allowance in most cases. Thus, the estimates in the 1985 report need not be revised at this time, but the rationale for their adoption should be clarified.
8. More information is needed to determine the appropriate composition of infant formulas. Because of the potential differential rates of utilization of proteins of human milk vs infant formulas, it cannot be assumed that a formula that mimics the amino acid composition of human milk will be optimal for the non-breastfed infant. The definition of optimal should include multiple measures including weight gain, linear growth and other indices. Until more information is available, the present recommendation, derived from the breastfed infant, should not be regarded as indicative of the needs of the infant receiving formula as its only source of milk.
Correspondence to: IDECG Secretariat, c/o Nestle Foundation, P.O. Box 581,1001 Lausanne, Switzerland.