Secretory IgA antibodies against cow's milk proteins in human milk and their possible effect in mixed feeding

Antibodies of the secretory IgA type against cow's milk proteins were consistently found in human milk. With the assumption that such antibodies can help to prevent or at least diminish the contact between native cow's milk proteins and the lymphoid system of babies on mixed feeding, the levels of antibodies of various immunoglobulin classes against bovine milk proteins were measured in different groups of babies. Those on artificial feeds who had been on mixed feeding of human milk and cow's milk for less than 1 week had significantly higher levels of IgG antibodies to cow's milk proteins than those who had been on mixed feeding for a period longer than 3 weeks.     

Effect of two types of fish oil supplementation on plasma and erythrocyte phospholipids in formula-fed term infants

We studied the effect of docosahexaenoic acid (DHA) supplementation of infant formulas on fatty acid composition of blood phospholipids in term infants. Two fish oil supplemented formulas containing 0.45 wt% DHA and high (0.35%) or low (0.10%) eicosapentaenoic acid (EPA) were fed for 42 days and compared with a standard formula and breast milk. Infants fed supplemented formulas and breast milk had similar time-dependent changes for DHA from birth to day 42, i.e., slight decreases in plasma phospholipids and erythrocyte phosphatidylcholine and no change in erythrocyte phosphatidylethanolamine. Low-EPA formula prevented EPA accumulation but did not limit the significant decrease in arachidonic acid (AA) noted in infants fed high-EPA formula. These results suggest that term infant formulas should be supplemented with DHA-rich EPA, low fish oil and AA to achieve a fatty acid status in formula-fed infants similar to that of breast-fed infants.     

Two-site enzyme immunometric assays for determination of native and denatured beta-lactoglobulin

Two enzyme immunometric assays suitable for measuring native and denatured beta-lactoglobulin (BLg) have been developed. The assays were performed in 96-well microtitre plates and were based on the use of pairs of monoclonal antibodies specific to either the native form or the reduced and carboxymethylated form of BLg (RCM-BLg). Detection limits of 30 and 200 pg/ml were obtained for the native BLg and the RCM-BLg assay, respectively, with very low or negligible cross-reactivity of the other milk proteins and tryptic fragments of BLg. The validity of the assays in different media such as cow's milk and cow's milk products, saline buffer or serum was supported by recovery experiments. The assays were first applied to the determination of BLg and RCM-BLg in PBS and in raw skimmed milk. The ability of the RCM-BLg assay to detect heat-denatured BLg was confirmed by a kinetic study of BLg heat-denaturation in the two media. During heat treatment, the decrease in the concentration of native BLg was associated with an increase in denatured BLg specifically detected by the RCM-BLg assay. By selecting an appropriate monoclonal antibody which failed to recognize caprine BLg, we were able to establish a modified sandwich immunoassay permitting very sensitive detection of cow's milk in goat's milk.     

On cyclins, oocytes, and eggs

We studied the preventive effect against allergies in infants who and whose mothers consumed hypoallergenic formulas until 6 months after birth. Mother and infant pairs were divided into three groups, and the infants were monitored for the development of allergies for the first 2 years. In the MD group (n = 102; n = number of infants), the mothers were given a hypoallergenic formula for mothers (MOM HA), which contained hydrolyzed whey protein as the only protein source, as a substitution for cow's milk during late pregnancy and lactation. In the CD group (n = 127), the mothers were given cow's milk during the corresponding period. All infants in the MD and CD groups were exclusively breast-fed or mixed-fed with breast milk and hypoallergenic infant formula (NAN HA), which contains the same hydrolyzed protein as MOM HA. In the AF group (n = 54), the mothers consumed MOM HA and their infants were mixed-fed with breast milk and a cow's milk-based adopted infant formula during the corresponding period. In the MD group, no infants were positive to cow's milk-specific immunoglobulin E (RAST) at 4 months of age, in contrast to 6% and 3% of infants in the CD and AF groups, respectively. The infants in the MD group showed low incidence of various allergies, especially of eczema, as compared to the CD and AF groups. These results suggest that consumption of cow's milk by mothers and cow's milk-based formula feeding to infants elevate the risk of allergies in infants, and that consumption of hypoallergenic formula for pregnant and lactating women and for infants could be helpful in preventing allergy development in infants.     

Evidence for defective skeletal mineralization in low-birthweight infants: the absorption of calcium and fat

Using serial metabolic balance techniques, the absorption and retention of calcium and the absorption of fat have beem measured over the first 30 to 70 days of life in 11 preterm and 2 full-term light-for-dates infants. They were fed either full-cream cow's milk, half-skimmed cow's milk, the proprietary filled milk S.M.A., or breast milk. The values for calcium intake, absorption and retention were compared with the rate of accumulation of calcium by the fetus in utero, which was calculated from published data on the chemical composition of fetal bodies. Infants fed breast milk had an absolute dietary deficiency of calcium. Those fed other milks ingested sufficient but they did not absorb enough. Though calcium absorption increased with increasing postnatal age, intrauterine rates of calcium retention were never achieved on any of the milks. The average retention of calcium by preterm infants as a percentage of intrauterine accumulation was, for cow's milk 38%, for S.M.A. 27%, and for breast milk 17%. The full-term light-for- dates infants absorbed and retained more calcium than the preterm infants; it was on average 52% of the amount accumulated by the human fetus for an equivalent weight gain. The average absorption of fat by preterm infants was, from the cow's milk preparations 55%, from S.M.A. 61%, and from breast milk 84%. The light-for-dates infants absorbed on average 87% of the breast milk fat. There was no evidence that the amount of calcium absorbed was materially influenced by fat malabsorption. The principal determinants of the amount of calcium absorbed were the length of gestation and postnatal age of the infant.     

In vitro diagnosis of cow's milk protein sensitive enteropathy by organ culture method

The criteria that are used at present to diagnose cow's milk protein sensitive enteropathy (CMPSE) are based on an in vivo milk challenge which can be hazardous and life threatening. We have used an organ culture model to determine the usefulness of this technique in establishing the diagnosis of CMPSE on the basis of a single biopsy with in vitro milk challenge. Fourteen infants with diarrhoea clinically suspected to have CMPSE were studied prospectively. On the basis of milk challenge studies seven infants had CMPSE. They had clinical reaction to cow's milk with associated histological changes and depression of alkaline phosphatase levels in the jejunal mucosa. In all seven cases parallel changes in alkaline phosphatase levels were noted in the organ culture specimens of initial biopsy subjected to in vitro challenge. The seven control infants tolerated cow's milk and did not have histological changes. The alkaline phosphatase levels were moderately increased in the jejunal mucosa in five of the seven infants. The alkaline phosphatase levels in the organ culture specimens of initial biopsy were increased after in vitro challenge in all seven infants. This study suggests that organ culture methods may be useful in the vitro diagnosis of CMPSE, and also obviate the need for in vivo oral milk challenges and repeated biopsies.     

Evaluation of single cell sources of docosahexaenoic acid and arachidonic acid: a 4-week oral safety study in rats

Docosahexaenoic acid (DHA) and arachidonic acid (ARA) are secreted in human milk and consumed by the nursing neonate but are not present in infant formulas currently available in the US. Supplementation of formulas with DHA and ARA may be particularly important for premature infants, who have less accretion of these fatty acids in utero than term infants. Some experts suggest that DHA and ARA should be added to infant formulas. Common sources of these fatty acids (e.g. fish oils, egg yolk lipids) are not optimal for infants in that they contain disproportionate amounts of other fatty acids. This 4-wk study examined the safety of a high-DHA algal oil and a high-ARA fungal oil, blended so that the DHA:ARA ratio approximates that in human milk. Rats were fed the blend at levels representing three, 11 and 22 times the anticipated infant exposure. Control animals were fed either a high-fat diet (13.1%, w/w; equivalent to the fat content of the treated groups) or a low-fat diet (5%, w/w). There were no treatment-related differences in body weight, food intake, organ weights, haematology or clinical chemistry. Thus, this study indicates that a blend of algal and fungal oils is a safe source of DHA and ARA as it produced no adverse effects in rats when administered for 4 wk at levels up to 22 times the expected infant exposure.     

Standards of pediatric electrophysiology

Milk proteins are hydrolyzed to prevent immunological reactions, but immunoreactive epitopes, including the ABBOS epitope of bovine serum albumin (BSA), can still be detected in commercially available milk protein hydrolysates. We used lactococcal cell-envelope proteinase (CEP) for the hydrolysis of the individual milk proteins and of mixtures thereof, or for the hydrolysis of sodium caseinate (contaminated with whey proteins). CEP exclusively degraded casein, leaving the four major whey proteins intact. This property facilitated the removal of the intact whey proteins from the casein fragments by ultrafiltration. Depending on the molecular mass of the whey protein to be removed, membranes with cutoff values between 3 and 30 kDa were used, resulting in casein hydrolysates free of protein fragments with cross-reactive whey-protein-specific IgE (immunoglobulin E) or ABBOS antibody-binding sites. Even the casein itself was degraded in such a way by CEP that cross-reactive casein-specific IgE antibody-binding sites could be eliminated. The product could find application in infant formulas for therapeutic and preventive treatment of children with cow's milk allergy; in addition, the preventive use of such formulas in children genetically susceptible to the development of insulin-dependent diabetes mellitus (IDDM) should be considered if a relationship between the consumption of BSA and IDDM were to become more apparent. The method is also applicable for preparing casein-free whey protein preparations.     

Iron sufficiency in breast-fed infants and the availability of iron from human milk

Four infants were studied who had been exclusively breast-fed for periods varying from 8 to 18 months. All had grown sufficiently to have exhausted their prenatally acquired iron endowment with respect to meeting current needs for maintaining normal hemoglobin levels. All infants had normal hemoglobin values and normal serum iron values. Studies of iron absorption from breast milk and cow's milk were performed in ten normal adults. The absorption of iron from the human milk was significantly higher. These findings suggest that the iron present in human milk is sufficient to meet the iron requirements of the exclusively breast-fed infant until he approximately triples his birthweight.     

Plasma and erythrocyte alpha-tocopherol and plasma retinol concentrations in term infants fed formula enriched with long-chain polyunsaturated fatty acids

OBJECTIVE: To assess the effect of long-chain polyunsaturated fatty acids (LCPUFA)- and vitamin E-supplemented formula feeding on erythrocyte and plasma alpha-tocopherol (VE), and plasma retinol (VA) concentrations in neonates and to compare these values with those found in infants feeding on infant formula without LCPUFA or breast milk SETTING: University Hospital of Granada, Spain. SUBJECTS: 49 full-term infants. DESIGN AND INTERVENTION: Subjects who chose not to breast feed were fed either (i) unsupplemented infant formula (F) or (ii) infant formula supplemented with LCPUFA and vitamin E (FL). Alpha-tocopherol and retinol were measured at 7 days, 1 month and 3 months. RESULTS: Plasma and erythrocyte VE concentrations and plasma VE/total lipids ratio increased significantly in all groups at 1 month of life (P < 0.05), but did not change significantly between 1 month and 3 months in any group (P > 0.05). Erythrocyte VE and VA retinol concentrations were higher in infants fed an infant formula than in breast milk-fed infants at 1 month of life (P < 0.05). Finally, there were no significant differences in plasma or erythrocyte VE levels, plasma VA or plasma VE/total lipid ratio between any groups at 3 months of life (P > 0.05). CONCLUSION: Infants fed on LCPUFA- and vitamin E-supplemented infant formula for 3 months have similar vitamin E and A status to infants fed on breast milk or infant formula without LCPUFA supplementation.     

A double-blind study of paroxetine, fluoxetine, and placebo in outpatients with major depression

Human milk has a higher concentration of nucleotides than bovine milk which is the source of most infant formulas. As the composition of human milk is considered the 'gold standard,' an increasing number of infant formulas are supplemented with nucleotides. This review summarises the biology of human milk nucleotides and evaluates the studies which investigated the clinical benefits of feeding infants with nucleotide-supplemented formulas. Although dietary nucleotides have been suggested to have beneficial gastrointestinal and immunological effects, nucleotide-supplemented formula feeding has not been shown to confer the same benefits as breast feeding, and randomised controlled trials have yet to prove that healthy term infants fed nucleotide-supplemented formulas compared to those fed nonsupplemented formulas, have accelerated physical growth and neurological development, better growth and development of their gastrointestinal tract resulting in improved digestive and absorptive functions, enhanced development of their immune system resulting in increased resistance to infection and lower bacterial and viral infection rates during infancy, and a more favourable intestinal microflora associated with a lower rate of infectious diarrhoea. However, a randomised controlled trial has reported that term infants with severe intrauterine growth retardation do have better catch-up growth with nucleotide supplementation. The hypothesis that nucleotides are semi-essential nutrients needs to be further studied, in particular in the presence of prematurity, fetal growth retardation, intestinal injury and limited nutrient intake. As no deleterious effects have been reported with the use of nucleotide-supplemented formulas, the first of which was introduced over 30 years ago, such products are considered safe when nucleotides are supplemented to an amount equivalent to the free nucleotide concentration of human milk. More basic and clinical research studies are awaited to further define the biology and role of human milk nucleotides, and to critically assess the potential benefits and appropriate level of nucleotide supplementation of infant formula.     

Autoxidation in milk rich in linoleic acid. II. Modification of the initiation system and control of oxidation

Factors contributing to the initiation of lipid oxidation in cow's and mare's milk containing high levels of polyunsaturated fatty acids were studied. Addition of H2O2 just after milking, in slight excess of the stoichiometric amounts required to destroy ascorbic acid, delayed the development of oxidized flavours in cow's milk high in linoleic acid. Hydrogen peroxide treatment followed by the addition of alpha-or gamma-tocopherols prevented lipid oxidation in cow's milk even when 0.1 mg Cu/l milk was added. When used separately in the presence of Cu these treatments were ineffective as was butylated hydroxyanisole treatment. The lipid and ascorbic acid in mare's milk were remarkably stable to oxidation. Addition of 0.05 or 0.1 mg Cu/l, ethylenediamine tetraacetic acid, neocuproine, or H2O2 had very little effect on the loss of ascorbic acid and lipid oxidation in mare's milk.     

Role of the microtubule cytoskeleton in gravisensing Chara rhizoids

Docosahexaenoic acid and arachidonic acid are deposited in large amounts in the developing central nervous system, and concentrations are particularly high in synaptic plasma membrane and retina ethanolamine phospholipids. Arachidonic acid and docosahexaenoic acid are present in human milk. The precursors linoleic [18:2(n-6)] and alpha-linolenic [18:3(n-3)] acid, but not arachidonic acid or docosahexaenoic acid, are present in formulas. Desaturation and elongation of 18:2(n-6) and 18:3(n-3) to arachidonic acid and docosahexaenoic acid, respectively, depend on the dietary content and ratio of 18:2(n-6) and 18:3(n-3), but appropriate levels and ratios of 18:2(n-6) and 18:2(n-3) for formula are not well defined. The effect of formula with 1 or 4% fatty acids 18:3(n-3) and 16, 30 or 35% fatty acids 18:2(n-6) on synaptic plasma membrane and retina ethanolamine phospholipid fatty acids was therefore studied in piglets, with reference to piglets fed milk. Piglets fed 4% fatty acids 18:3(n-3), but not those fed 1% fatty acids 18:3(n-3), had similar central nervous system docosahexaenoic acid levels but had significantly lower brain weights than piglets fed sow milk. Synaptic plasma membrane and retina arachidonic acid were lower in piglets fed the formulas with 4% rather than 1% fatty acids 18:3(n-3). The dietary 18:3(n-3) content, rather than the 18:2(n-6) to 18: 3(n-3) ratio, seemed more important for deposition of docosahexaenoic acid in brain. However, synaptic plasma membrane and retina docosahexaenoic acid levels were further reduced in piglets fed 1% fatty acids 18:3(n-3) (0.4% energy) with 30% rather than with 16% fatty acids 18:2(n-6). The need for further study of upper limits of dietary 18:3(n-3) during development is suggested.     

Dietary modifications versus dicyclomine hydrochloride in the treatment of severe infantile colics

This study examined 120 infants, aged 3-12 weeks, with severe colics and compared the results of a specific hypoallergenic diet (group A) with those of pharmacological treatment (group B). Non-breast-fed group A infants received soy milk and if unresponsive, hydrolyzed milk formulas; mothers of breast-fed infants received a diet without cow's milk, eggs or fish. Breast-fed and non-breast-fed group B infants received dicyclomine hydrochloride 3 mg/kg/day. Results, based on quantitative measurements of crying, indicated that in breast-fed infants there was no significant improvement between group A (62.5%) and group B (66.6%) infants. Among formula-fed infants, comparison of positive results using soy milk (65.9%) with positive results using dicyclomine (53.3%) was not significant; positive results using soy milk and hydrolyzed milk formulas in non-responders to soy milk, provided an improvement in 95.4% of cases. Pharmacological treatment provided an improvement in 53.3% of cases. The difference was significant (p < 0.01).     

Colchicine in breast milk of patients with familial Mediterranean fever

OBJECTIVE: To clarify whether colchicine is excreted in breast milk, and to compare its concentrations in the serum and breast milk of lactating women who have familial Mediterranean fever (FMF). METHODS: Using a specific radioimmunoassay, we determined colchicine concentrations in the serum and breast milk of 4 patients at various time points, following oral administration of the drug. The study evaluated 4 patients with FMF who had been taking colchicine on a long-term basis. RESULTS: Colchicine was found to be excreted in breast milk. Its levels ranged between 1.9 and 8.6 ng/ml, which were similar to those found in the serum (parallel concentration time curves). However, there appeared to be a considerable variation in colchicine milk concentration among the different patients, which might be related to individual breast milk composition and, possibly, to other nutritional or metabolic factors. CONCLUSION: The extensive peripheral tissue binding and relatively low concentration of colchicine in breast milk suggests that the amount ingested by the infant is small. Furthermore, based on our clinical experience, nursing appears to be safe for lactating women with FMF who continue to take colchicine.     

Protein variant separations by cation-exchange chromatography on tentacle-type polymeric stationary phases

A method previously developed for the analysis of organohalogenated compounds in dairy products is now validated for polychlorinated biphenyls (PCBs) determination in soybean infant formulas. The results of this study are consistent with those found for PCBs in powdered full-fat milk. The methodology is based on a solid-liquid extraction step enabling a semi-selective extraction of the apolar lipids of the matrix without affecting the efficiency for the recovery of PCBs. Mean recoveries for the spiked coplanar congeners studied were in the 88-114% range, with relative standard deviations (R.S.D.s) lower than 9.8%. The R.S.D.s related to the determination of endogenous PCBs were in the 1.5-10.0% range. The validated methodology was applied to the PCB analysis in different trademarks of soybean infant formulas commercialised in Spain. Toxic tetraequivalents of tetrachlorodibenzo-p-dioxin and daily intake corresponding to each one were calculated and compared with values previously published and with those found in literature for human breast milk in different countries.     

Removal of amino-terminal and carboxy-terminal extension peptides from procollagen during synthesis of chick embryo tendon collagen

Plasma phytosterol (plant sterol) levels were studied in 26 infants on various commercial formulas, in 36 infants on breast or cow's milk formulas, in 101 normal and 22 hypercholesterolemic children on a free diet, and in 32 hypercholesterolemic children on a low-cholesterol diet. Commercial formulas, poor in animal fats and enriched with vegetable oils, and low-cholesterol, phytosterol-rich diets generally elevated total plasma phytosterol levels in infants and hypercholesterolemic children from normal mean levels of 2 mg/100 ml to about 9 mg/100 ml. The implications of long-term three- to five-fold elevations of the plasma phytosterols (campesterol, stigmasterol, beta-sitosterol) in infancy and childhood are unknown. Watchful prospective analysis of plasma phytosterol levels may be useful, particularly in regards to otherwise unanticipated long-term effects of cholesterol-poor, phytosterol rich diets.     

Effects of diet on the lipid and fatty acid status of full-term infants at 4 months

OBJECTIVE: To compare the effects of the exogenous supply of long-chain polyunsaturated fatty acids (LCP) and cholesterol on the lipid and fatty acid status in full-term, 4-month old infants. METHODS: Twenty-three infants received a standard infant formula while twenty-one were given a formula enriched with LCP and cholesterol in a prospective, randomized study. The composition of the two formulas differed only in fat quality. A group of fifteen breastfed infants fed was used as reference. No one was complemented with solid foods before blood sampling at 4 months of life. RESULTS: Differences in total-cholesterol and low-density lipoprotein-cholesterol (LDL-C) levels between feeding groups were mainly gender-related. Dietary cholesterol tended to increase LDL-C plasma levels. The breastfed and the enriched formula-fed groups had higher levels of circulating LCP than the group that received the standard formula. In the erythrocytes of infants fed the standard formula, C22:6 n-3 levels were less than 50% those of the breastfed and the enriched formula-fed ones. Higher C20:4 n-6 levels were found in the erythrocytes of the enriched formula-fed group. CONCLUSIONS: Formula-fed, full-term infants maintain a lipid and fatty acid status close to that of breastfed infants when supplied with dietary LCP and cholesterol.     

Intestinal barrier function and cow's milk sensitization in guinea pigs fed milk or fermented milk

BACKGROUND: The respective effect of milk and fermented milks on intestinal barrier capacity and on sensitization to beta-lactoglobulin was studied using a guinea pig model of cow's milk allergy. METHODS: Guinea pigs were fed a control diet or the same diet supplemented with milk, fermented milk (Streptococcus thermophilus and Bifidobacterium breve), or dehydrated fermented milk. Intestinal barrier capacity to macromolecules was assessed in an Ussing chamber, and sensitization to cow's milk proteins was measured by systemic anti-beta-lactoglobulin immunoglobulin G1 titers and by intestinal anaphylaxis, the latter assessed by the beta-lactoglobulin-induced increase in short-circuit current of jejunal fragments (deltaIsc(beta-LG)). RESULTS: The electrical resistance of jejunum was similar in the four groups (approximately 80 omega/cm2) suggesting the same paracellular permeability. The transport of 14C-beta-lactoglobulin from mucosa to serosa was significantly decreased in the animals fed dehydrated fermented milk (403+/-131 ng / hr x cm2) compared with that in control animals or animals fed milk (767+/-250 ng / hr x cm2 and 749+/-475 ng / hr x cm2, respectively; p < 0.05). Milk fermentation did not modify native beta-lactoglobulin concentration but anti-beta-lactoglobulin immunoglobulin G1 titers were higher in fermented milk and dehydrated fermented milk (log10 titer = 2.86 and 2.79, respectively) than in guinea pigs fed milk (log10 titer = 2.5; p < 0.007). However, beta-lactoglobulin-induced intestinal anaphylaxis remained the same in the three groups (deltaIsc(beta-LG), 9.6+/-4.1 microA/cm2, 8.5+/-4.3 microA/cm2, and 8.5+/-3.4 microA/cm2 in milk-fed, fermented milk-fed, and dehydrated fermented milk-fed guinea pigs, respectively). CONCLUSIONS: The intestinal barrier capacity to milk proteins seems to be reinforced by dehydrated fermented milk, but milk and fermented milks are equally efficient in inducing cow's milk allergy in guinea pigs.