Composition Of Infant Formulas Research Articles

Substitution of Casein by β-Casein or of Whey Protein Isolate by α-Lactalbumin Does Not Affect Mineral Balance in Growing Rats

Bovine milk protein fractions that enable modification of the protein composition and amino acid profile of infant formulas to mimic those of human milk have recently become available. To determine the effects on protein quality and mineral bioavailability of replacing casein by beta-casein and of whey protein isolate by alpha-lactalbumin, 4 groups of growing rats were fed for 3 wk diets containing 10% protein as 1) casein (control); 2) beta-casein; 3) casein:whey (40:60); or 4) beta-casein:alpha-lactalbumin (40:60). Protein quality, determined as protein efficiency ratio (PER), net protein utilization (NPU), biological value (BV) and protein digestibility (PD), as well as body weight gain, were higher (P < 0.05) with consumption of the whey-adapted diets [casein:whey (40:60); beta-casein:alpha-lactalbumin (40:60)] compared with the casein diets (casein; beta-casein); however, there were no differences between the 2 casein diets or between the 2 whey-adapted diets. Apparent absorption of minerals (Ca, P, Fe, Zn) from the whey-adapted diets was higher than that from the casein diets (P < 0.05); but again, no differences were observed when casein or whey protein isolate were replaced by beta-casein or alpha-lactalbumin, respectively. Thus, substitution of casein by beta-casein or of whey protein isolate by alpha-lactalbumin does not affect protein quality or mineral bioavailability as determined in growing rats.

Update on Nutrition for Preterm and Full-Term Infants

Child health and development are contingent on sound nutrition during the neonatal period. The nutritional needs of all infants include adequate intake of fluid and energy; a balance among proteins, carbohydrates, and fats; and proper vitamin and mineral intake. Preterm infants have similar nutritional requirements but demand more frequent assessment of nutritional health and ongoing adjustment of nutritional intake throughout the neonatal period to ensure appropriate growth and development. Evidence-based nursing practice calls for an update on the specific nutritional requirements of infants, special nutritional needs of preterm infants, and the most recent changes in the composition of infant formula.

Colostrum Protein Concentrate Enhances Intestinal Adaptation After Massive Small Bowel Resection in Juvenile Pigs

Short bowel syndrome (SBS) usually results from the surgical removal of a large segment of small intestine. Patient outcome depends on the extent of intestinal resection and adaptation of the remaining intestine. We evaluated the impact of colostrum protein concentrate (CPC) on intestinal adaptation after massive small bowel resection in a porcine model of infant SBS. Four-week-old piglets underwent an approximate 75% small bowel resection (R, n = 23) or a control transection operation (C, n = 14). Postoperatively, animals from both groups received either pig chow (R = 6, C = 5), polymeric infant formula (R = 6, C = 3) or polymeric infant formula supplemented with CPC (R = 11, C = 6) for 8 weeks until sacrifice. Clinical outcome measures included weight gain and stool consistency. Morphologic measures were intestinal villus height and crypt depth. Functional outcome measure was mucosal disaccharidase activity. Resected animals fed polymeric infant formula alone had reduced weight gain compared with controls fed the same diet (P < 0.005). Despite massive small bowel resection, animals fed pig chow or polymeric infant formula supplemented with CPC grew at an equivalent rate to controls fed polymeric infant formula alone. Resected animals supplemented with CPC had increased villus length and crypt depth in the jejunum (P < 0.001) and ileum (P < 0.001) compared with resected animals fed either pig chow or polymeric infant formula alone. In an animal model of SBS, CPC supplementation of polymeric infant formula resulted in normal weight gain and features of enhanced morphologic adaptation.

O0102 PROTEIN HYDROLYSIS OF INFANT FORMULAS STRONGLY ACTIVATES THE MAILLARD REACTION

Introduction: The particular composition of infant formulas favours the development of the Maillard reaction during processing, inducing nutritional and health hazard effects such as loss of available lysine and promotion of the inflammatory response. Lactose, the main substrate of the reaction in milk, is present at high concentrations. Ascorbate and polyunsaturated fatty acids are oxidable nutrients which give rise upon heat treatment to many other reactive dicarbonyle substrates. These substrates attack the free amino groups of proteins, mainly the e-NH2 group of lysine in milk proteins. Hydrolysis of the proteins induces a tremendous increase of the reactive amino groups, via the terminal a-NH2 of peptides or free amino-acids. The aim of this study is to evaluate the effect of protein hydrolysis on the Maillard reaction in the formula. Four indicators were selected to estimate the nutritional quality and safety of infant formulas. Methods: Hydrolyzed and non hydrolyzed formulas processed as powders or sterilized liquids were purchased from the market (Germany and France). Furosine and free hydroxymethylfurfural were quantified by HPLC-UV; carboxymethyllysine (CML) was estimated by ELISA and fluorescent Maillard products (FMP) were measured directly on the powders or liquid samples by front-face fluorescence. These indicators were also measured on samples stored at 60°C for 4–7 days, to mimic long storage. Results: Hydrolysis of the proteins strongly (2 to 3 times) increased the furosine and CML contents of the formulas. Similarly, FMP were significantly higher indicating that protein hydrolysis is an important parameter for the rate of development of the Maillard reaction. The type of process also had a significant effect, as powders were less altered than sterilized liquid formulas. However, accelerated aging had a much stronger effect on powders, especially when the water content was higher than 6 %. Conclusion: Protein hydrolysis is proposed to decrease the allergenicity to milk proteins. However, the liberation of free reactive amino-groups strongly increases the Maillard reaction with possible nutritional and safety consequences. Milder heat treatments for drying and sterilizing should limit the extent of the Mail-lard reaction.

Selenium content of Spanish infant formulae and human milk: Influence of protein matrix, interactions with other trace elements and estimation of dietary intake by infants

The selenium content of infant formulae varies as a result of differences in the amount of intrinsic selenium compounds. Manufacturers have been gradually changing the protein profile of infant formulae to reflect human milk contents more closely. Because of these variations in infant formula composition and their potential impact on selenium content, this trace element was analysed with regard to the different protein sources. The aims of this study were to determine the selenium content in infant formulae sold commercially in Spain, to estimate a daily dietary intake for infants fed on formulae and to compare with the selenium provided by Spanish breast milk samples used as a reference. We have also identified certain trace elements added to formulae which interact with selenium according to the type and protein matrix of the infant formulae. Selenium concentration was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) with a hydride generator. The selenium concentrations in human milk and infant formulae determined in this study are similar to those found by other researchers in different countries. The daily selenium intake from the formulae studied was estimated according to the recommended doses from the manufacturers. The theoretical selenium intake of nursed infants has been studied in relation to the Recommended Dietary Allowance (RDA: 10 μg Se/day) and the specific recommendations for infant formula nutrient contents (10–35 μg Se/L) set by the Expert Panel of Life Sciences Research Office (LSRO) of the American Society for Nutritional Sciences. According to our results, on an overall view, infants fed on the studied infant formulae have an intake between basal and normative requirements. This might be considered as providing an adequate selenium supply. However, the intake of selenium provided by several formulae included in this research did not reach the RDA for the first month of neonate life.

Selenium composition of cereal-containing infant formulas: assessment of dietary intake status

The selenium (Se) content of 11 infant formulas had been determined using electrothermal and hydride generation atomic absorption spectrometry. The Se content ranged between 0.43 and 17.17 μg/100 g powder infant formulas with wide variations reaching 40.36-fold excess between the poorest RIRI-1 (0.43 μg/100 g) and Milupa-2 (17.2 μg/100 g powder). After reconstituting with water, the adequacies of the 11 studied infant formulas were evaluated with respect to Se supply. Based on the daily adequate intakes (AIs) of 15 and 20 μg Se for children 4-6 and 7-12 months old, respectively, four analyzed infant formulas were found to contain adequate Se content (>75% of the AIs), whereas the other seven formulas could satisfy 63% or less. In conclusion, the national regulation for the trace element (Se) contents in the infant formulas is highly warranted.

Effects of type of fat in the diet on iron bioavailability assessed in suckling and weanling rats

Differences in iron bioavailability from human milk and milk formulas may in part be due to differences in lipid composition. We investigated the short and long term effects of diets based on different fats [corn, coconut, olive, or soy oil, human milk fat (HMF) and a formula fat blend (FF)] on iron absorption in rats. Suckling rat pups dosed with 59Fe-labeled diets containing different fat sources were killed after 6 h, and blood and individual tissues were counted. Iron availability was estimated by % 59Fe in blood. Pups dosed with a more saturated fat (coconut oil) had a higher % 59Fe in blood than those fed other fat sources. Weanling rats were used to determine iron bioavailability from fat sources using both the hemoglobin repletion method and whole body counting. Hemoglobin regeneration was significantly higher for rats fed the HMF diet (8.4 ± 0.5 g/dl) than from the FF diet (6.5±0.6 g/dl) or the corn oil diet (less saturated) (6.4 ± 0.3 g/dl). Rats fed diets based on coconut oil (more saturated) had significantly higher % 59Fe retention (61.6 ± 1.4) than rats fed diets based on FF (49.8 ± 3.4). There was a significant positive association between oleic acid in the diet and oleic acid in the intestinal mucosa (r = 0.95, p < 0.05) and between linoleic acid in the diet and linoleic acid in the intestinal mucosa (r = 0.97, p < 0.05) suggesting that the dietary treatment altered the fatty acid composition of the brush border membrane. Our results suggest that saturated fats may increase iron absorption and that part of this may be achieved by changes in the fatty acid composition of the intestinal mucosa. Hemoglobin regeneration and % 59Fe retention data suggest that differences in iron absorption from infant diets may in part be due to differences in fat composition. Therefore, lipid composition of infant formulas should also be taken into consideration as a factor influencing iron bioavailability.

Infant feeding: a critical look at infant formulas.

Commercially available infant formulas serve as the best alternative to human milk when breastfeeding is not possible. Infant formulas are designed specifically to mimic the composition of human milk or the functional aspects of human milk feeding. This review highlights the issues related to the composition of infant formulas. The most hotly debated issue currently is whether to add long-chain polyunsaturated fatty acids to infant formulas. Other controversial topics include the safety and efficacy of soy-based protein formulas, protein quantity and quality as they relate to the infant's nutritional needs and feeding tolerance, and the replacement of lactose with other carbohydrate sources for specialized infant formulas. Recent modifications in the fat blend of infant formulas have led to improved fat digestibility. However, the full spectrum of benefits associated with the addition of nucleotides awaits further study. Modifications to infant formulas are made when the preponderance of scientific evidence suggests that the compositional change will better meet the nutritional needs of the infant.

Amino Acid Contents of Infant Formulas

The amino acid supply in an infant's first month of life must be sufficient in quantity and quality to fulfil the needs of this period of life. Guidelines, recommendations and minimum and maximum values have been established regarding to amino acid composition of infant formulas. The aim of this study was to determine the amino acid profile of infant formulas of different types marketed in Spain in order to assess the compliance with the recommendations (ESPGAN) and to detect possible differences in the amino acid profiles depending on the protein source. Amino acids were determined by HPLC in ion-pair reversed phase after hydrolysis and derivatization with phenylisothiocyanate. Nearly all the milk-based formulas analysed have higher amino acid contents than the values established by law, except for tryptophan. The soy-based infant formulas analysed have higher methionine contents in all cases than the value corresponding to the standard protein. Comparison of amino acid profiles of infant formulas classified according to their main protein fraction show some statistically significant differences in the essential and semi-essential amino acids.

Evolution of infant nutrition

Homo sapiens has developed during the course of over two million years. The social and physical conditions of life, the availability of milk and infant foods as well as the presence of diseases have all undergone radical transformations from the Stone Age, at first without and then with fire, to the hunter-gatherer, farmer-herder, agricultural and, now, developed societies. These changes in the human environment may have induced modifications in the length of pregnancy, the development of the neonate at birth, the duration of lactation, the composition of breast milk and use of weaning foods and milk substitutes. Darwinian selection for the nutrient, anti-infective and other components of breast milk may have been determined by the effects of nutrition, through genetic variations in milk composition, on the survival of infants and perhaps also on fecundity and disease resistance in later adult life. Today Darwinian selection may no longer be effective in maintaining or modifying human mammary function, because modern hygienic environments, together with the availability of nutritionally adequate breast-milk substitutes, permit infant survival even under conditions of total lactational failure. National and international promulgations strictly control the composition of infant formulas offered as breast-milk substitutes or as weaning foods. These recommendations are modified as beliefs suggest, and research indicates, the effects of nutrients and other factors on the health and well-being of the child. Preliminary observations on child health have often proved valuable in furthering research. Unquestioning acceptance of apparently desirable, but untested, epidemiological associations have led to unexpected but dangerous iatrogenic problems. Recommendations for change cannot safely be made without proper comparisons with present products and procedures under practical conditions. Such tests are time consuming and require protocols of appropriate statistical design and power while still meeting the required sociological and ethical constraints, but are essential to identify possible harmful effects of any proposed change. It is suggested that no novel ingredients should be added, or major changes permitted in any component, until appropriate trials have established the value and safety of the proposed modifications. Breast-feeding is vital to maximize infant survival in developing countries. There are major difficulties in assessing any differences in morbidity and mortality of breast-fed v. artificially reared infants in the developed world. Carefully controlled studies with comparisons of health and well-being, not only in infancy but throughout life, are desirable if the effects of infant nutrition on adult well-being, suggested by epidemiological studies, are to be validated and ultimately applied. There are considerable variations in the composition of breast milk. This variance suggests that it may ultimately be possible to design formulas better able to meet the needs of individual infants than the milk available from the mother's breast.

Lipids and infant formulas

The ultimate goal in the design of infant formula is to achieve the outcome seen in breast fed infants. This review of lipids in infant formulas for term infants begins by referring to the lipid composition of human milk, and relates that to differences in lipid digestion and metabolism which exist between breast fed and formula fed infants and which may significantly influence fatty acid bioavailability. Recommendations are made for the lipid content and fatty acid composition of term infant formulas (especially for lauric, linoleic, alpha-linolenic, long chain 20 and 22C n-3 and n-6 polyunsaturated fatty acids and the trans fatty acids). Further research is required to define more clearly the long term nutritional, growth and developmental effects of structured lipids in formulas for term infants. More information is required on the differential handling of LCPUFA and other fatty acids at the organ and cellular level. There is a need for large (multi-centre) randomized studies to determine the short and long term functional effects of LCPUFA supplementation. Further research and development is required to determine a commercial source of LCPUFA which is safe, effective and economic. Further information is required on the short and long term effects of cholesterol intake during infancy, and in particular its relationship to LCPUFA metabolism. Long term studies should be initiated to determine the relationship of infant diet (especially saturated fatty acid and cholesterol intake) to the development of cardiovascular disease.

Reflections about possible nutritional supplements in infant milk formula.

The composition of infant milk formula intends to mirror breast milk as close as possible. However, there are a variety of substances, like amino acids, fatty acids, polyamines, nucleotides, oligosaccharides, functional proteins, hormones, vitamins, and minerals, which are attributed effects in special situations. A concept is proposed to develop problem oriented "supplementation packages" for infant milk formula.

Approaches and Considerations in Determining the Protein and Amino Acid Composition of Term and Preterm Infant Formula

Abstract Infant formula provides the sole source of protein and amino acids for many infants during the first year of life and thus it is mandatory that formula manufacturers make every effort to produce a formula with the optimal level of protein and mix of amino acids. This paper reviews our approach in determining the protein and amino acid composition of a new infant formula. The perils of simply mimicking the whey to casein ratio or the amino acid composition of human milk are discussed as is the advantage of developing a formula in which the protein and amino acid mixture produces a plasma amino acid profile in the formula-fed term infant that most closely resembles the plasma profile of the breast-fed infant. In contrast, the goal of formulating the protein and amino acid composition of an enteral feeding for the preterm infant is to replicate the intrauterine rate of protein accretion without causing metabolic stress. We discuss theoretical approaches for determining the protein requirements of preterm infants. In addition we review the clinical trials that more precisely help to define the optimal protein intake for premature infants.

Aspects of Mineral Bioavailability in Infant Nutrition

Infant formulae are designed to meet all the nutritional needs of the human neonate. The mineral composition of infant formulae is based primarily on the mineral content of human milk as well as on intra-uterine accretion. There are instances, however, when the mineral concentrations of infant formulae are set higher to address a deficiency such as iron deficiency anemia. Additionally, rapid growth of premature infants necessitate formulae of higher mineral content including trace elements such as zinc and copper and macrominerals such as calcium and phosphorus. A number of factors affect mineral utilization: mineral solubility, mineral–mineral interactions and macronutrient–mineral interactions. All of the above are important considerations when designing an infant formula.

Small Changes of Dietary (n-6) and (n-3)/Fatty Acid Content Ratio Alter Phosphatidylethanolamine and Phosphatidylcholine Fatty Acid Composition During Development of Neuronal and Glial Cells in Rats

It has been suggested that the fat composition of infant formula should provide arachidonic acid [20:4(n-6)] and docosahexaenoic acid [22:6(n-3)] or increased α-linolenic acid [18:3(n-3)] to optimize the (n-3) and (n-6) fatty acid content of brain during infant development. This experiment examined the effects of feeding increased levels of 18:3(n-3), 20:4(n-6) and 22:6(n-3) on brain development in neonatal rats. Diets varying in (n-6) and (n-3) fatty acid content with or without 20:4(n-6) or 22:6(n-3), at levels proposed for infant formula, were fed to nursing dams from parturition and subsequently to weaned pups until 6 wk of age. Neuronal and glial cells were isolated from the frontal region, cerebellum and hippocampus of the brain. Fatty acid analyses of ethanolamine- and choline-phosphoglycerides indicated that small changes in the dietary (n-6)/(n-3) ratio significantly altered neuronal and glial membrane fatty acid composition. Brain regions and cell types varied in amount and rate of 20:4(n-6) and 22:6(n-3) accretion. Fatty acid composition of individual phosphoglycerides was distinct and exhibited changes with age. Inclusion of both 20:4(n-6) and 22:6(n-3) in the diet resulted in alteration of brain fatty acid composition reflecting the fatty acid composition of the diet. If analogous developmental changes occur in human brain, then these results imply that addition of 20:4(n-6) and 22:6(n-3) or a reduced 18:2(n-6):18:3(n-3) ratio in infant formula may result in fatty acid profiles of neuronal and glial cells in formula-fed infants similar to those observed in breast-fed infants.

Importance of milk and diet on the ontogeny and adaptation of the intestine.

Importance of milk and diet on the ontogeny and adaptation of the intestine.

Fatty acid composition of French infant formulas with emphasis on the content and detailed profile oftrans fatty acids

AbstractThe aim of the present study was to identify and quantitatetrans isomers of C18 fatty acids in some French infant formulas. Twenty powdered infant formulas were purchased in pharmacies and supermarkets in order to assess theirtrans mono‐ and poly‐unsaturated fatty acids content. The fatty acid profiles were examined using methyl and isopropyl ester derivatives. The combination of gas‐liquid chromatography, high‐performance liquid chromatography, and silver nitrate thin‐layer chromatography was needed to describe the detailed fatty acid compositions of the samples, includingtrans isomers of unsaturated C18 fatty acids. All the samples containedtrans isomers of C18∶1 acid (mean level 1.97±0.28% of total fatty acids), with vaccenic acid being generally the major isomer (15 out of 20 samples), thus indicating the origin from bovine milk. All the formulas also contained various isomers of linoleic and α‐linolenic acids, but at lower levels.Trans PUFA isomers are the same as those present in deodorized oils. In conclusion, all the infant formulas analyzed in this study contained sometrans fatty acids, including isomers of essential fatty acids. This should be taken into account in the dietary intake of the newborn.

Nutritional considerations in infant formula design

The model used for the design of infant formulas is mature human milk, after making allowances for differences in the bioavailability of nutrients. Although the composition of infant formulas resembles that of human milk, there are still many differences in the nutrient content of these products which may be significant. The differences in energy, protein, lipid and iron content of infant formulas and human milk are discussed in relation to nutritional and biochemical outcome. Further research is required on these nutrients before the optimal content is defined. This information will complement work currently being conducted on novel substances.

The fatty acid composition of banked human milk and infant formulas: the choices of milk for feeding preterm infants.

The fatty acid composition of 48 samples of banked human milk for preterm infants and four standard infants formulas available in Finland were analysed by capillary gas liquid chromatography. The banked milk was collected from mothers who had given birth 0-8 weeks previously. Saturated fatty acids accounted for approximately 50% of the fatty acids in both human milk and the formulas, while the relative content of monoenoic fatty acids tended to be higher in human milk than in the formulas. The relative content of 18:2n-6 was higher in the formulas (range 14.7%-23.2%) than in human milk (median 9.1%, range 6.3%-13.4%). Fat of banked human milk contained 0.9% and 0.7% polyunsaturated fatty acids with 20 and 22 carbon atoms (LCP), respectively, which is comparable to that of fresh mature human milk. In contrast, LCP could not be detected in any of the formulas. Conclusion. Banked human milk is a good source of LCP and offers a good alternative to LCP containing formulas.

Controversies in the Composition of Infant Formulas

Available infant formulas contain a vast assortment of carbohydrate, protein, and fat sources in an effort to emulate the composition of human milk. Although infants receiving commercial formulas thrive, physicians should be cognizant of differences in formula composition and the research that has resulted in the differences. Such awareness permits rational and scientific recommendations both in prescription of formulas and in direction of research on the optimal formula composition for infants.