Plasma amino acid concentrations in healthy, full-term infants fed hydrolysate infant formula

Protein Digestion of Baby Foods: Study Approaches and Implications for Infant Health

Protein digestion is critical for infants. Dissimilarities between infants and adults in food intake and digestive physiology lead to distinct patterns of proteolysis between individuals. However, such differences are not well represented in many studies on protein digestion of baby foods. The complex biological structures of baby foods and the physiology of the infant digestive system are key factors affecting proteolysis during the first two years of life. Well-controlled in vitro studies have demonstrated that varying digestion conditions alter the specificity, rate, and extent of proteolysis of baby foods. Nonetheless, these models do not completely replicate in vivo proteolysis or the complex biogeography of the gastrointestinal tract. Animal and clinical studies have revealed the fate of dietary proteins along the digestive tract and the overall health impact on subjects. Building comprehensive and annotated datasets from human infants will require innovative and standardized measurement. Now, more systematic evaluations of digestion are emerging to advance the knowledge and its translation as food design for effective diet and health management in infants.

Differential growth patterns among healthy infants fed protein hydrolysate or cow-milk formulas

OBJECTIVE

Infant formulas differ considerably in composition and sensory profiles. In this randomized study, we examined whether healthy infants fed an extensively protein hydrolysate formula (PHF) would differ in feeding behavior and growth from those fed cow-milk formula (CMF).

PATIENTS AND METHODS

Infants were randomly assigned to be fed CMF or PHF between 0.5 and 7.5 months of age. Each month for 7 months, infants were weighed and measured and then videotaped while being fed their assigned formula. Anthropometric z scores were calculated by using World Health Organization growth standards. Multilevel linear growth and piecewise mixed-effects models compared trajectories for growth measures and formula acceptance.

RESULTS

When compared with infants fed CMF, infants fed PHF had significantly lower weight-for-length z scores across ages 2.5 to 7.5 months. There were no differences in length-for-age z scores, which indicate that group differences resulted from gains in weight, not length. Infants fed PHF also had significantly slower weight gain velocity compared with infants fed CMF. During the monthly assessments, PHF-fed infants consumed less formula to satiation than did CMF-fed infants across the study period. Maternal ratings of infants' acceptance of the formula did not differ at any age.

CONCLUSIONS

z-score trajectories indicate that CMF-fed infants' weight gain was accelerated, whereas PHF-fed infants' weight gain was normative. Whether such differences in growth are because of differences in the protein content or amino acid profile of the formulas and, in turn, metabolism is unknown. Research on the long-term consequences of these early growth differences is needed.

[Cow milk protein allergies: primary prevention. Nutritional aspects]

In 2001 the Nutrition Committee of the Spanish Association of Pediatrics, published a position paper on "Recommendations on the use of formulae for the treatment and prevention of adverse reactions to cow milk proteins" (An Esp Pediatr. 2001;54:372-9). Since most of the recommendations given in this report still remain effective, the Nutrition Committee of the Spanish Association of Pediatrics reaffirms its support of the data expressed in it. In the present publication we only approach the aspects that have changed due to new knowledge and the accumulated clinical experience, especially on the primary prevention of allergy to cow milk proteins, and on the basis of it, the present recommendations for this prevention are set out. In addition, the importance of the nutritional aspects in all infants and small children receiving special nutritional formulae and exclusion diets are reviewed.

Baby Foods: Formulations and Interactions (A Review)

Infant foods have a special place among food products mainly because of nutritional aspects and preparations methods. A great increase of baby foods incomes is predicted in near future. Formulation, handling, and storage of baby foods are important to keep nutritional quality and physicochemical properties of these foods. During storage some reactions and interactions occur which change physicochemical and nutritional properties of baby foods. Lactose crystallization, Maillard reaction, oxidation, and interactions between micronutrients and other components are the most important aspect of preparation and storage of baby foods. These reactions and interactions influence physical properties such as flowability of powder, solubility, and other functional properties. Controlling of storage conditions such as temperature and moisture content and oxygen quantity in headspace of product is required to keep product quality. In this paper the composition and interactions of baby foods between major components and their effect on nutritional quality of baby foods are explained.

Nutritional evaluation of protein hydrolysate formulas in healthy term infants: plasma amino acids, hematology, and trace elements

BACKGROUND

Protein hydrolysate formulas are used for infants with food allergy. Most studies of such formulas focus on their effect on allergy and rarely evaluate their capacity to provide normal nutritional status.

OBJECTIVE

We compared plasma aminograms, serum urea nitrogen, and trace element status in breastfed infants, infants fed hydrolysate formulas, and infants fed milk formula.

DESIGN

From 6 wk to 6 mo of age, infants were breastfed or fed regular milk formula (RF), 1 of 2 casein-hydrolysate formulas (CH-1 or CH-2), or whey-hydrolysate formula (WH). Anthropometric measures were taken monthly, and blood samples were collected at 6 wk and 6 mo. Plasma amino acids, serum urea nitrogen, hematologic indexes, plasma zinc, and plasma copper were analyzed.

RESULTS

There were no significant differences in hemoglobin, serum transferrin receptor, copper, or zinc among groups. Serum ferritin was significantly lower in infants fed the CH formulas than in the other groups. Infants fed CH-2 had significantly higher serum urea nitrogen than did all other groups. Plasma threonine, valine, phenylalanine, methionine, and tryptophan were significantly higher in the hydrolysate formula groups than in the breastfed group. Plasma tyrosine was significantly lower in infants fed the CH formulas than in the breastfed group, whereas arginine was significantly higher in the WH group than in all other groups. Plasma proline was lower, whereas threonine and tryptophan were higher, in the WH group than in the CH groups.

CONCLUSIONS

The iron status of infants fed CH formula was lower than that of all other groups. The amounts of amino acids provided by hydrolysate formulas appear excessive compared with regular formula, which is reflected by high serum urea nitrogen (CH-2) and high plasma amino acid concentrations. A reduced and more balanced amino acid content of hydrolysate formulas may be beneficial.

Effects of dietary long-chain polyunsaturated fatty acids on plasma amino acids and indices of protein metabolism in infants: results from a randomized clinical trial

BACKGROUND/AIM

Previous studies in vitro and in animals in vivo found that alpha-linolenic acid (C18:3omega3) may enhance oxidative damage of essential amino acids. We investigated whether the addition of the long-chain polyunsaturated fatty acids (LCPUFA) arachidonate (C20:4omega-6; AA) and docosahexaenoate (C22:6-omega3; DHA) in the form of egg phospholipids to infant formula affects plasma amino acid concentrations and indices of protein metabolism in term infants.

METHODS

In a double-blind, randomized clinical trial, healthy infants were fed from day 5 of life formula with or without preformed LCPUFA (n = 10 and 12, respectively). At the age of 5 days and 1, 2, 3 and 4 months, blood samples were obtained and analyzed for plasma amino acids by high-performance liquid chromatography and for plasma phospholipid fatty acid composition by gas chromatography.

RESULTS

At the age of 3 months, plasma threonine concentrations were significantly lower in infants receiving dietary LCPUFA than in controls (124 +/- 16 vs. 216 +/- 28 micromol/l, p < 0.05). Values of other plasma essential amino acids, total protein, albumin, creatinine and urea nitrogen did not differ between the two feeding groups throughout the study. At the age of 5 days, plasma phospholipid AA and DHA concentrations were inversely correlated with histidine concentrations (AA: r = -0.60, p = 0.01; DHA: r = -0.53, p < 0.05). At the age of 3 months, DHA concentrations were inversely related to plasma histidine, methionine and threonine concentrations (r = -0.66, -0.62, and -0.64, respectively, p < 0.05).

CONCLUSIONS

The dietary LCPUFA supplementation of infant formula used in this study has no adverse effects on infant plasma amino acid concentrations and indicators of protein metabolism. Nonetheless, the apparent interaction of LCPUFA with some amino acids in formula-fed infants warrants further investigation.

Plasma amino acid concentrations, indexes of protein metabolism and growth in healthy, full-term infants fed partially hydrolyzed infant formula

BACKGROUND

It has been reported that feeding extensively hydrolyzed infant formula influenced the availability of arginine, glycine, histidine, lysine and threonine in full-term infants investigated during the first 2 months of life. In the present study, the nutritional effects of feeding partially hydrolyzed formula (PHF) were investigated.

METHODS

Term infants fed conventional formula (F; n = 11) or PHF (n = 11) were investigated at the ages of 5, 30, 60, 90, and 120 days. Anthropometric data were obtained, and plasma amino acid concentrations and biochemical indices of protein metabolism were measured.

RESULTS

Plasma concentrations (in micromoles per liter) of lysine on day 90: 117 (21) versus 143 (24); of threonine on day 30: 140 (53) versus 263 (87); of ornithine on day 90: 56 (21) versus 78 (29); and of tyrosine on day 30: 52 (17) versus 77 (20), on day 60: 56 (14) versus 87 (19) and on day 90: 46 (9) versus 81 (17) were significantly lower in infants receiving PHF than in those fed F. Values are median (range from 1st to 3rd quartile), PHF versus F; p < 0.05. At day 120, infants fed PHF showed significantly lower serum albumin concentrations than did infants receiving F (43.3 +/- 3.4 versus 48.9 +/- 3.5, g/l; mean +/- SD; p < 0.05). Serum creatinine, urea nitrogen, uric acid and total protein concentrations and gain in weight, length, and head circumference did not differ throughout the study.

CONCLUSIONS

In this study, feeding PHF did not affect the majority of plasma amino acid concentrations, some indices of protein metabolism, and basic parameters of growth in full-term infants. However, plasma concentrations of lysine, threonine, tyrosine, ornithine, and albumin were, on at least one occasion, significantly lower in infants fed PHF than in those receiving F.