A COMPARISON OF THE PATTERN OF HUMAN MILK WITH THE FAO PATTERN IN HUMAN NUTRITION1

Transcription

1 Amino Acid Reference Patterns: A COMPARISON OF THE PATTERN OF HUMAN MILK WITH THE PATTERN IN HUMAN NUTRITION1 SELMA E. SNYDERMAN, L. EMMETT HOLT, JR. ANDAUDREY BOYE] Department of Pediatrics, New York University School of Medicine New York, New York In 1955, a Committee of the Food and Agricultural Organization Nations () described of the United a "provisional" pattern of amino acids which would help in evaluating the protein quality of individ ual foods (, '57). The figures were de rived from the existing information of the amino acid requirements of adult men and women and of infants who seemed to re quire similar proportions of the essential amino acids. This pattern was formulated to take into consideration a proper balance between the amino acids as well as meet ing individual amino acid requirements. The committee noted high quality proteins that such the patterns of as milk or egg were very similar to the provisional pattern except that the natural foods contained considerably more leucine. The present study was designed to deter mine whether a feeding formulated accord ing to the pattern would have any advantages or disadvantages when com pared with a natural In order to control feeding, human milk. conditions as well as possible, a completely synthetic diet was used, the protein moiety of which was a mixture of 18 L-amino acids. Our subjects were premature infants who, because of their rapid rate of growth, might be most sensitive to differences in protein quality. The diets contained 2 gm of protein per kg of body weight. This low level of protein was chosen to exaggerate any differences between the two feedings. METHODS The composition of the two experimental diets was the same except for the ratio of the individual amino acids; in one it was similar to human milk while the other contained the essential amino acids in the TABLE 1 Composition of experimental diet L-Amino acid mixture Corn oil1 Maltose and dextrins* Mineral mixture3 B-vitamin mixture4 Vitamins5 A, C and D % of tota calories ml/day Mazóla, supplied by the Corn Products Re fining Company, New York. 2Dextri-Maltose, supplied by Mead Johnson anc Company. 3Percentage composition of the mineral mix ture: NaCl, 18.9; CaHPO4 (anhydrous), 25.4: MgSO< (anhydrous), 6.8; KHCO3, 44.4; KC1, 2.88Ì Fe»citrate, 2.21; CuSO4 (anhydrous), ; MnSO (anhydrous), ; KI, 0.015; NaF, The B-vitamin mixture provided the followinp daily (in milligrams): thiamine-hcl, 0.38; ribo flavin, 2.0; nicotinamide, 0.85; Ca pantothenate 3.5; pyridoxine-hcl, ; hexahydroxycyclchexane, 180; p-aminobenzoic acid, 0.5; folie acid, ; choline chloride, 147; biotin, 0.03; cyanocobalamine, Trivisol, Mead Johnson and Company. pattern designed by the. In the sec ond diet, the unessential amino acids were provided in the human milk pattern since the was concerned only with the ratic of the essential amino acids. Table 1 shows the composition of the experimental diet. In table 2 are listed the amino acid mix tures. All babies were given 145 Cai. per kg instead of the usual 125 Cai. per kg tc allow for the higher caloric requirement when amino acid mixtures are fed instead of natural protein. The feeding was sus- Received for publication July 18, Supported by grants from the National Dairy Council, the Wyeth Laboratories and the United1 States Public Health Service. 404 J. NDTBITION,72: '60

2 Composition of the amino acid mixtures,-alaniã±e,-arginine.-aspartic acid,-cystine,-glutamic acid,-glycine >Histidine >Isoleucine >Leucine [.-Lysine L,-Methionine L-Phenylalanine L-Proline L-Serine L-Threonine L-Tyrosine L-Tryptophan L-Valine AMINO ACID REFERENCE PATTERNS 405 TABLE 2 Nitro determinations were performed in triplicate on the 4-day stool collection. The beginning and end of the stool col Human milk lection were delineated by carmine and â ~^~ charcoal stool markers. Three of the in fants were females for whom it was im- I'll :26JEW pended in water and divided into 6 equal portions given at 4-hour intervals. In order to be certain that the infant received the entire feeding, bottles were rinsed twice ith water and the rinse water was also ed Ṁetabolic periods were of 4 days duraon. Duplicate nitro determinations â ererun on each day's urine collection. LYN MG/KG/OAY Figure 2 LOP nn NITROGEN RETE MO 'KG /DAYNT10Nnll soo too MG/KG'DAY Figure 1 Figure 3

3 406 SELMA E. SNYDERMAN, L. EMMETT HOLT, JR., AND AUDREY BOYER KEN COR 300 too NITROGEN NilROGEN RETEà à US'RETEN KG/DAYTIONr MG/KG/DAY1ION «et i â oã Ti Figure 4 Figure 5 TOR ~tt SUA ffi MG/KG/DAY 300 NITROG MIN G/ KG/ RETEN DAYTIONr à OO Figure 6 possible to obtain separate urine and stool collections; for these, triplicate determina tions were run on the combined stool and urine 4-day collection. The subjects were 7 premature infants whose birth weights ranged from 1360 to 2030 gm. They were between 6 and 39 days old when they started to receive the Figure 7 experimental diet. All of the subjects re mained in good health during the period of study. Babies were weighed daily and weights plotted on the grid routinely used in oui premature unit (Dancis et al., '48). This grid was originally compiled from the weight curves of 100 premature infants

4 AMINO ACID REFERENCE PATTERNS 407 TABLE 3 Metabolic data for 7 premature infants fed two types of diet: one using a human milk () amino acid pattern, and the other the provisional pattern Subject and date Baby LYN 3/ /30-4/2 4/6-9 Baby JEW 2/ /2-5 Baby? LOP 3/ /23-26 Baby KEN 4/ /4-7 5/ / /25-28 Baby COR 5/ /8-11 6/15-18 Baby? TOR 3/4-7 3/9-12 Baby? SUA 3/ /30-4/3 4/6-10 Average weight Diet Nitro intake kg Urine nitro Stool nitro Nitro reten tion gm/day gm/day gm/day mg/kg/day Bio logical value Net protein utili zation' 1The figures given represent "uncorrected" biological values and net protein utilization, no correc tion being made for endoous excretion on a nitro-free diet who were fed a formula2 which provides between 4 and 5 gm of protein per kg per day. It has been our experience that the weight curve of premature infants usually stays in the channel in which birth weight has placed them and deviations from this are of significance. RESULTS AND DISCUSSION The duced protocols of these infants, in figures 1-7, show the repro weight curves and the nitro retention. Inspec tion of these graphs does not reveal any significant difference in the performance of these infants between the two types of feedings. All the metabolic data are con tained in table 3. Averages for the uncorrected biologic value and the net protein utilization were similar for the two feedings. The average biologic value was 67 for the pattern and 71 for the human milk pattern. The net protein utilization average was for both feedings. Similarly, the average value for the nitro retention with the two types of feedings was very closeâ 210 mg per kg per day for the and 204 mg per kg per day for the human milk amino acid mixture. 2Olac, Mead Johnson and Company.

5 408 SELMA E. SNYDERMAN, L. EMMETT HOLT, JR., AND AUDREY BOYER These findings suggest that the pat tern of amino acids is nutritionally equiva lent to a natural food of high protein qual ityâ human milkâ under rigidly controlled conditions. SUMMARY Seven premature infants were fed a syn thetic diet in which the protein moiety was a mixture of 18 L-amino acids. The amino acids were provided in two ratiosâ that of human milk and that of the pattern. There were no differences in the weight curves or the amount of nitro retained, using the two types of diets. The amino acid pattern of human milk would appear to be quite as satisfactory a standard of reference as the pattern for assaying the nutritional adequacy of protein for the human species. LITERATURE CITED Danois, J., J. R. O'Connell and L. E. Holt, Jr A grid for recording the weight of pre mature infants. J. Pediat., 33: 570. Food and Agriculture Organization of United Na tions 1957 Protein Requirements. Nu tritional Studies no. 16.