Low-Protein Infant Formula Enriched with Alpha-Lactalbumin during Early Infancy May Reduce Insulin Resistance at 12 Months: A Follow-Up of a Randomized Controlled Trial.

High protein intake during infancy results in accelerated early weight gain and potentially later obesity. The aim of this follow-up study at 12 months was to evaluate if modified low-protein formulas fed during early infancy have long-term effects on growth and metabolism. In a double-blinded RCT, the ALFoNS study, 245 healthy-term infants received low-protein formulas with either alpha-lactalbumin-enriched whey (α-lac-EW; 1.75 g protein/100 kcal), casein glycomacropeptide-reduced whey (CGMP-RW; 1.76 g protein/100 kcal), or standard infant formula (SF; 2.2 g protein/100 kcal) between 2 and 6 months of age. Breastfed (BF) infants served as a reference. At 12 months, anthropometrics and dietary intake were assessed, and serum was analyzed for insulin, C-peptide, and insulin-like growth factor 1 (IGF-1). Weight gain between 6 and 12 months and BMI at 12 months were higher in the SF than in the BF infants (p = 0.019; p < 0.001, respectively), but were not significantly different between the low-protein formula groups and the BF group. S-insulin and C-peptide were higher in the SF than in the BF group (p < 0.001; p = 0.003, respectively), but more alike in the low-protein formula groups and the BF group. Serum IGF-1 at 12 months was similar in all study groups. Conclusion: Feeding modified low-protein formula during early infancy seems to reduce insulin resistance, resulting in more similar growth, serum insulin, and C-peptide concentrations to BF infants at 6-months post intervention. Feeding modified low-protein formula during early infancy results in more similar growth, serum insulin, and C-peptide concentrations to BF infants 6-months post intervention, probably due to reduced insulin resistance in the low-protein groups.

Iron Fortification and Inulin Supplementation in Early Infancy: Evaluating the Impact on Iron Metabolism and Trace Mineral Status in a Piglet Model.

Background: Infant formula in the United States contains abundant iron, raising health concerns about excess iron intake in early infancy. Objectives: Using a piglet model, we explored the impact of high iron fortification and prebiotic or synbiotic supplementation on iron homeostasis and trace mineral bioavailability. Methods: Twenty-four piglets were stratified and randomly assigned to treatments on postnatal day 2. Piglets were individually housed and received an iron-adequate milk diet (AI), a high-iron milk diet (HI), HI supplemented with 5% inulin (HI with a prebiotic [HIP]), or HIP with an oral gavage of Ligilactobacillus agilis YZ050, an inulin-fermenting strain, every third day (HI with synbiotic [HIS]). Milk was provided in 14 meals daily, mimicking formula feeding in infants. Fecal consistency score and body weight were recorded daily or every other day. Blood and feces were sampled weekly, and tissues collected on postnatal day 29. Data were analyzed using mixed model analysis of variance with repeated measures whenever necessary. Results: Diet did not affect growth. HI increased hemoglobin, hematocrit, and serum iron compared to AI. Despite marginal adequacy, AI upregulated iron transporter genes and maintained satisfactory iron status in most pigs. HI upregulated hepcidin gene expression in liver, caused pronounced tissue iron deposition, and markedly increased colonic and fecal iron. Inulin supplementation, regardless of L. agilis YZ050, not only attenuated hepatic iron overload but also decreased colonic and fecal iron without altering pH or the expression of iron regulatory genes. HI lowered zinc (Zn) and copper (Cu) in the duodenum and liver compared to AI, whereas HIP and HIS further decreased Zn and Cu in the liver and diminished colonic and fecal trace minerals. Conclusions: Early-infancy excessive iron fortification causes iron overload and compromises Zn and Cu absorption. Inulin decreases trace mineral absorption likely by enhancing gut peristalsis and stool frequency.

Effect of pH and protein composition on proteolysis of goat milk proteins by pepsin and pancreatin.

The roles of protein composition, pH and enzymes in goat milk protein hydrolysis is still unclear and the proteolysis of low abundant goat milk proteins has received limited attention. The aim of this study was to study the impact of protein composition and proteolytic conditions on goat milk protein hydrolysis in a simplified digestion model. Both whole milk and infant formula were hydrolyzed at pH 2 and 4, using pepsin as well as pepsin combined with pancreatin. Intact proteins were separated from digests using spin filters, followed by bottom-up proteomics of the separated proteins. Results show that under all conditions, caseins are hydrolyzed quickly. Goat casein hydrolysis in infant formula was slightly faster than in goat whole milk, possibly due to less casein coagulation during pepsin hydrolysis at both pH 2 and 4. Several low abundant immunoactive goat milk proteins, especially immunoglobulins, GLYCAM-1 and osteopontin, resisted proteolysis more than high abundant proteins, independent of the pH and enzyme used for hydrolysis. Fast hydrolysis of casein and slow hydrolysis of immunoactive proteins may indicate a good balance between protein utilization and protection of the infant by goat milk proteins.

Milk osteopontin promotes intestinal development by up-regulating the expression of integrin αvß3 and CD44.

Osteopontin (OPN) is a pleiotropic protein involved in numerous biological processes such as cell proliferation and differentiation. Since OPN is abundantly present in milk and is known to be relatively resistant to in vitro gastrointestinal digestion, the current study aimed to investigate the roles of oral intake of milk OPN in intestinal development using an established OPN knockout (KO, OPN-/- ) mouse model, in which wild-type (WT, OPN+/+ ) mouse pups were nursed by either WT (OPN+/+ OPN+ group) or OPN KO dams (OPN+/+ OPN- group; +/+ indicates genotype and - indicates milk without OPN), receiving milk with or without OPN from postnatal days 0 to 21 (P0-P21). Our results showed that milk OPN is resistant to in vivo digestion. Compared to OPN+/+ OPN- pups, OPN+/+ OPN+ pups at P4 and P6 had significantly longer small intestines, at P10 and P20 had larger inner jejunum surfaces, and at P30 exhibited more mature/differentiated intestines, as revealed by higher activities of alkaline phosphatase in brush border and more goblet cells, enteroendocrine cells, and Paneth cells. qRT-PCR and immunoblotting results showed that milk OPN increased the expression of integrin αv, integrin ß3, and CD44 in jejunum of mouse pups (P10, P20, and P30). Immunohistochemistry analysis showed that both integrin αvß3 and CD44 are localized in jejunum crypts. In addition, milk OPN increased the phosphorylation/activation of the ERK, PI3K/Akt, Wnt, and FAK signaling pathways. In summary, oral intake of milk OPN in early life promotes intestinal proliferation and differentiation by upregulating the expression of integrin αvß3 and CD44 and thus regulates OPN-integrin αvß3 and OPN-CD44 mediated cellular signaling pathways.

Evidence for human milk as a biological system and recommendations for study design-a report from "Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN)" Working Group 4.

Human milk contains all of the essential nutrients required by the infant within a complex matrix that enhances the bioavailability of many of those nutrients. In addition, human milk is a source of bioactive components, living cells and microbes that facilitate the transition to life outside the womb. Our ability to fully appreciate the importance of this matrix relies on the recognition of short- and long-term health benefits and, as highlighted in previous sections of this supplement, its ecology (i.e., interactions among the lactating parent and breastfed infant as well as within the context of the human milk matrix itself). Designing and interpreting studies to address this complexity depends on the availability of new tools and technologies that account for such complexity. Past efforts have often compared human milk to infant formula, which has provided some insight into the bioactivity of human milk, as a whole, or of individual milk components supplemented with formula. However, this experimental approach cannot capture the contributions of the individual components to the human milk ecology, the interaction between these components within the human milk matrix, or the significance of the matrix itself to enhance human milk bioactivity on outcomes of interest. This paper presents approaches to explore human milk as a biological system and the functional implications of that system and its components. Specifically, we discuss study design and data collection considerations and how emerging analytical technologies, bioinformatics, and systems biology approaches could be applied to advance our understanding of this critical aspect of human biology.

A randomized, controlled trial of a Nordic, protein-reduced complementary diet in infants: effects on body composition, growth, biomarkers, and dietary intake at 12 and 18 months.

BACKGROUND: High intake of protein and low intake of plant-based foods during complementary feeding can contribute to negative long-term health effects. OBJECTIVES: To investigate the effects of a protein-reduced, Nordic complementary diet on body composition, growth, biomarkers, and dietary intake, compared with current Swedish dietary recommendations for infants at 12 and 18 mo. METHODS: Healthy, term infants (n = 250) were randomly allocated to either a Nordic group (NG) or a conventional group (CG). From 4 to 6 mo, NG participants received repeated exposures of Nordic taste portions. From 6 to 18 mo, NG was supplied with Nordic homemade baby food recipes, protein-reduced baby food products, and parental support. CG followed the current Swedish dietary recommendations. Measurements of body composition, anthropometry, biomarkers, and dietary intake were collected from baseline and at 12 and 18 mo. RESULTS: Of the 250 infants, 82% (n = 206) completed the study. There were no group differences in body composition or growth. In NG, protein intake, blood urea nitrogen and plasma IGF-1 were lower compared to CG at 12 and 18 mo. Infants in NG consumed 42% to 45% more fruits and vegetables compared to CG at 12 and 18 mo, which was reflected in a higher plasma folate at 12 and 18 mo. There were no between-group differences in EI or iron status. CONCLUSIONS: Introduction of a predominantly plant-based, protein-reduced diet as part of complementary feeding is feasible and can increase fruit and vegetable intake. This trial was registered at clinicaltrials.gov as NCT02634749.

Low-Protein Formulas with Alpha-Lactalbumin-Enriched or Glycomacropeptide-Reduced Whey: Effects on Growth, Nutrient Intake and Protein Metabolism during Early Infancy: A Randomized, Double-Blinded Controlled Trial.

Protein intake is higher in formula-fed than in breast-fed infants during infancy, which may lead to an increased risk of being overweight. Applying alpha-lactalbumin (α-lac)-enriched whey or casein glycomacropeptide (CGMP)-reduced whey to infant formula may enable further reduction of formula protein by improving the amino acid profile. Growth, nutrient intake, and protein metabolites were evaluated in a randomized, prospective, double-blinded intervention trial where term infants received standard formula (SF:2.2 g protein/100 kcal; n = 83) or low-protein formulas with α-lac-enriched whey (α-lac-EW;1.75 g protein/100 kcal; n = 82) or CGMP-reduced whey (CGMP-RW;1.76 g protein/100 kcal; n = 80) from 2 to 6 months. Breast-fed infants (BF; n = 83) served as reference. Except between 4 and 6 months, when weight gain did not differ between α-lac-EW and BF (p = 0.16), weight gain was higher in all formula groups compared to BF. Blood urea nitrogen did not differ between low-protein formula groups and BF during intervention, but was lower than in SF. Essential amino acids were similar or higher in α-lac-EW and CGMP-RW compared to BF. Conclusion: Low-protein formulas enriched with α-lac-enriched or CGMP-reduced whey supports adequate growth, with more similar weight gain in α-lac-enriched formula group and BF, and with metabolic profiles closer to that of BF infants.

Milk-Derived miR-22-3p Promotes Proliferation of Human Intestinal Epithelial Cells (HIECs) by Regulating Gene Expression.

MicroRNA (miRNA) is small non-coding RNA involved in gene silencing and post-transcriptional regulation of gene expression. Milk exosomes are microvesicles containing microRNAs (miRNAs). miR-22-3p (miR-22) is plentiful in human milk exosomes and may contribute to intestinal development since milk exosomes and microRNAs are resistant to gastrointestinal digestion in infants. After miR-22 mimics were transfected to human intestinal crypt-like epithelial cells (HIECs) using Lipofectamine for 24 h, RNA was isolated for microarray assay. Microarray results show that miR-22 markedly regulates gene expression, and the roles of miR-22 include promotion of proliferation, regulation of immune functions, and inhibition of apoptosis. Based on the microarray results and miR-22 predicted target genes, CCAAT/enhancer-binding protein δ (C/EBPδ) may be an important direct target of miR-22. C/EBPδ is a transcription factor that regulates numerous biological processes including cell proliferation. In miR-22 transfected HIECs, expression of the C/EBPδ gene was significantly inhibited. Silencing of the C/EBPδ gene by siRNA resulted in increased proliferation of HIECs. A luciferase assay showed that miR-22 specifically binds to the 3'-untranslated region of C/EBPδ mRNA. In summary, milk-derived miR-22 promotes intestinal proliferation by modifying gene expression, and C/EBPδ may be an important target for miR-22 involved in this effect.

Trace Element Interactions, Inflammatory Signaling, and Male Sex Implicated in Reduced Growth Following Excess Oral Iron Supplementation in Pre-Weanling Rats.

Iron supplements are frequently provided to infants in high-income countries despite low incidence of iron deficiency. There is growing concern regarding adverse health and development outcomes of excess iron provision in early life. Excess iron may directly damage developing organs through the formation of reactive oxygen species, alter systemic inflammatory signaling, and/or dysregulate trace mineral metabolism. To better characterize the in vivo effects of excess iron on development, we utilized a pre-weanling rat pup model. Lewis rat litters were culled to eight pups (four males and four females) and randomly assigned to daily supplementation groups receiving either vehicle control (CON; 10% w/v sucrose solution) or ferrous sulfate (FS) iron at one of the following doses: 10, 30, or 90 mg iron/kg body weight-FS-10, FS-30, and FS-90, respectively-from postnatal day (PD) 2 through 9. FS-90 litters, but not FS-30 or FS-10, failed to thrive compared to CON litters and had smaller brains on PD 10. Among the groups, FS-90 liver iron levels were highest, as were white blood cell counts. Compared to CON, circulating MCP-1 and liver zinc were increased in FS-90 pups, whereas liver copper was decreased. Growth defects due to excess FS provision in pre-weanling rats may be related to liver injury, inflammation, and altered trace mineral metabolism.

Benefits and Risks of Early Life Iron Supplementation.

Infants are frequently supplemented with iron to prevent iron deficiency, but iron supplements may have adverse effects on infant health. Although iron supplements can be highly effective at improving iron status and preventing iron deficiency anemia, iron may adversely affect growth and development, and may increase risk for certain infections. Several reviews exist in this area; however, none has fully summarized all reported outcomes of iron supplementation during infancy. In this review, we summarize the risks and benefits of iron supplementation as they have been reported in controlled studies and in relevant animal models. Additionally, we discuss the mechanisms that may underly beneficial and adverse effects.

Characterization of an intelectin-1 (Itln1) knockout mouse model.

Intelectins are carbohydrate-binding proteins implicated in innate immunity and highly conserved across chordate evolution, including both ascidians and humans. Human intelectin-1 (ITLN1) is highly abundant within the intestinal mucosa and binds microbial but not host glycans. Genome-wide association studies identified SNPs in ITLN1 that are linked to susceptibility for Crohn's disease. Moreover, ITLN1 has been implicated in the pathophysiology of obesity and associated metabolic disease. To gain insight on biological activities of human ITLN1 in vivo, we developed a C57BL/6 mouse model genetically targeting the gene encoding the functional mouse ortholog. In wild-type C57BL/6 mice, both mRNA and protein analysis showed high expression of Itln1 in the small intestine, but manifold lower levels in colon and other extraintestinal tissues. Whereas intestinal expression of human ITLN1 localizes to goblet cells, our data confirm that mouse Itln1 is expressed in Paneth cells. Compared to wild-type littermate controls, mice homozygous for the Itln1 hypomorphic trapping allele had reduced expression levels of Itln1 expression (~10,000-fold). The knockout mice exhibited increased susceptibility in an acute model of experimentally induced colitis with 2% w/v dextran sulfate sodium (DSS). In a model of chronic colitis using a lower dose of DSS (1.5% w/v), which enabled a detailed view of disease activity across a protracted period, no differences were observed in body weight, fecal texture, hemoccult scores, food/water intake, or colon length at necropsy, but there was a statistically significant genotype over time effect for the combined fecal scores of disease activity. In model of diet-induced obesity, using two western-style diets, which varied in amounts of sugar (as sucrose) and saturated fat (as lard), mice with Itln1 expression ablated showed no increased susceptibility, in terms of weight gain, food intake, plasma markers of obesity compared to wildtype littermates. While the mouse genetic knockout model for Itln1 holds promise for elucidating physiological function(s) for mammalian intelectins, results reported here suggest that Itln1, a Paneth cell product in C57BL/6 mice, likely plays a minor role in the pathophysiology of chemically induced colitis or diet-induced obesity.

Correction: McMillen et al. Gut Microbiome Alterations following Postnatal Iron Supplementation Depend on Iron Form and Persist into Adulthood. Nutrients 2022, 14, 412.

Error in Figures and Captions [...].

Effects of a Novel High-Quality Protein Infant Formula on Energetic Efficiency and Tolerance: A Randomized Trial.

OBJECTIVES: Protein overfeeding in infants can have negative effects, such as diabetes and childhood obesity; key to reducing protein intake from formula is improving protein quality. The impact of a new infant formula [study formula (SF)] containing alpha-lactalbumin, lactoferrin, partially hydrolyzed whey, and whole milk on growth and tolerance compared to a commercial formula (CF) and a human milk reference arm was evaluated. METHODS: This randomized, double-blind trial included healthy, singleton, term infants, enrollment age ≤14 days. Primary outcome was mean daily weight gain. Secondary outcomes were anthropometrics, formula intake, serum amino acids, adverse events, gastrointestinal characteristics, and general disposition. RESULTS: Non-inferiority was demonstrated. There were no differences between the formula groups for z scores over time. Formula intake [-0.33 oz/kg/day, 95% confidence interval (CI): -0.66 to -0.01, P = 0.05] and mean protein intake (-0.13 g/kg/day, 95% CI: -0.26 to 0.00, P = 0.05) were lower in the SF infants, with higher serum essential amino acid concentrations (including tryptophan) compared to the CF infants. Energetic efficiency was 14.0% (95% CI: 8.3%, 19.7%), 13.0% (95% CI: 6.0%, 20.0%), and 18.1% (95% CI: 9.4%, 26.8%) higher for weight, length, and head circumference, respectively, in SF infants compared to the CF infants. SF infants had significantly fewer spit-ups and softer stool consistency than CF infants. CONCLUSIONS: The SF resulted in improved parent-reported gastrointestinal tolerance and more efficient growth with less daily formula and protein intake supporting that this novel formula may potentially reduce the metabolic burden of protein overfeeding associated with infant formula.

The role of orally ingested milk fat globule membrane on intestinal barrier functions evaluated with a suckling rat pup supplementation model and a human enterocyte model.

Milk fat globule membrane (MFGM), the membrane surrounding secreted fat droplets in milk, contains components involved in a wide range of bioprocesses including cell proliferation and differentiation. The intestine is relatively immature and permeable at birth. Since MFGM is partly resistant to digestion in infancy, we hypothesized that orally ingested MFGM promotes intestinal development by enhancing intestinal barrier functions in early life. An established suckling rat model was used; Sprague-Dawley rats were bred, and litters were culled to 10 pups/dam. Pups were supplemented orally with MFGM (0, 100, or 300 mg/kg/d) from postnatal day 1-20. Intestine samples were collected for histology, real-time quantitative PCR, immunoblotting, and immunohistochemistry analysis. Additionally, differentiated Caco-2 cells were used to assess effects of MFGM on the human intestinal barrier. Control and MFGM-supplemented rat pups showed similar growth. Intestinal differentiation and expression of tight junction proteins in jejunum and colon were significantly increased by orally ingested MFGM, and MFGM supplementation significantly activated PI3K/Akt/mTOR, mitogen-activated protein kinases, and myosin light chain kinase signaling pathways, suggesting that MFGM promotes intestinal development by triggering various signaling pathways. In human enterocytes (polarized Caco-2 cells), MFGM (400 µg/mL for 72 h) decreased permeability, as revealed by increased transepithelial electrical resistance. In Caco-2 cells, MFGM also enhanced expression of tight junction proteins, including claudin-4 and ZO-2. In conclusion, orally ingested MFGM may exert beneficial roles in intestinal development by activating various cell signaling pathways to upregulate tight junction proteins and thereby increasing intestinal barrier functions.

Metabolic Phenotype and Microbiome of Infants Fed Formula Containing Lactobacillus paracasei Strain F-19.

Early childhood nutrition drives the development of the gut microbiota. In contrast to breastfeeding, feeding infant formula has been shown to impact both the gut microbiota and the serum metabolome toward a more unfavorable state. It is thought that probiotics may alter the gut microbiota and hence create a more favorable metabolic outcome. To investigate the impact of supplementation with Lactobacillus paracasei spp. paracasei strain F-19 on the intestinal microbiota and the serum metabolome, infants were fed a formula containing L. paracasei F19 (F19) and compared to a cohort of infants fed the same standard formula without the probiotic (SF) and a breast-fed reference group (BF). The microbiome, as well as serum metabolome, were compared amongst groups. Consumption of L. paracasei F19 resulted in lower community diversity of the gut microbiome relative to the SF group that made it more similar to the BF group at the end of the intervention (4 months). It also significantly increased lactobacilli and tended to increase bifidobacteria, also making it more similar to the BF group. The dominant genus in the microbiome of all infants was Bifidobacterium throughout the intervention, which was maintained at 12 months. Although the serum metabolome of the F19 group was more similar to the group receiving the SF than the BF group, increases in serum TCA cycle intermediates and decreases in several amino acids in the metabolome of the F19 group were observed, which resulted in a metabolome that trended toward the BF group. Overall, L. paracasei F19 supplementation did not override the impact of formula-feeding but did impact the microbiome and the serum metabolome in a way that may mitigate some unfavorable metabolic impacts of formula-feeding.

Gut Microbiome Alterations following Postnatal Iron Supplementation Depend on Iron Form and Persist into Adulthood.

The gut microbiota is implicated in the adverse developmental outcomes of postnatal iron supplementation. To generate hypotheses on how changes to the gut microbiota by iron adversely affect development, and to determine whether the form of iron influences microbiota outcomes, we characterized gut microbiome and metabolome changes in Sprague-Dawley rat pups given oral supplements of ferrous sulfate (FS), ferrous bis-glycinate chelate (FC), or vehicle control (CON) on postnatal day (PD) 2−14. Iron supplementation reduced microbiome alpha-diversity (p < 0.0001) and altered short-chain fatty acids (SCFAs) and trimethylamine (TMA) in a form-dependent manner. To investigate the long-term effects of iron provision in early life, an additional cohort was supplemented with FS, FC, or CON until PD 21 and then weaned onto standard chow. At ~8 weeks of age, young adult (YA) rats that received FS exhibited more diverse microbiomes compared to CON (p < 0.05), whereas FC microbiomes were less diverse (p < 0.05). Iron provision resulted in 10,000-fold reduced abundance of Lactobacilli in pre-weanling and YA animals provided iron in early life (p < 0.0001). Our results suggest that in pre-weanling rats, supplemental iron form can generate differential effects on the gut microbiota and microbial metabolism that persist into adulthood.

Human intelectin-2 (ITLN2) is selectively expressed by secretory Paneth cells.

Intelectins (intestinal lectins) are highly conserved across chordate evolution and have been implicated in various human diseases, including Crohn's disease (CD). The human genome encodes two intelectin genes, intelectin-1 (ITLN1) and intelectin-2 (ITLN2). Other than its high sequence similarity with ITLN1, little is known about ITLN2. To address this void in knowledge, we report that ITLN2 exhibits discrete, yet notable differences from ITLN1 in primary structure, including a unique amino terminus, as well as changes in amino acid residues associated with the glycan-binding activity of ITLN1. We identified that ITLN2 is a highly abundant Paneth cell-specific product, which localizes to secretory granules, and is expressed as a multimeric protein in the small intestine. In surgical specimens of ileal CD, ITLN2 mRNA levels were reduced approximately five-fold compared to control specimens. The ileal expression of ITLN2 was unaffected by previously reported disease-associated variants in ITLN2 and CD-associated variants in neighboring ITLN1 as well as NOD2 and ATG16L1. ITLN2 mRNA expression was undetectable in control colon tissue; however, in both ulcerative colitis (UC) and colonic CD, metaplastic Paneth cells were found to express ITLN2. Together, the data reported establish the groundwork for understanding ITLN2 function(s) in the intestine, including its possible role in CD.

Human milk cholesterol is associated with lactation stage and maternal plasma cholesterol in Chinese populations.

BACKGROUND: Milk cholesterol concentrations throughout lactation were analyzed, and the relationship between maternal plasma cholesterol and milk cholesterol in various Chinese populations was examined. METHODS: A sub-sample of 1138 lactating women was randomly selected from a large cross-sectional study in China (n = 6481). Milk cholesterol concentrations were determined by HPLC, and concentrations of maternal plasma lipids were determined by an automated biochemical analyzer. RESULTS: The mean cholesterol concentrations were 200, 171, and 126 mg/L for colostrum, transitional milk, and mature milk, respectively. Cholesterol concentrations differed significantly between stages of lactation (colostrum vs. transitional milk, colostrum vs. mature milk, transitional milk vs. mature milk, all p < 0.001). Concentrations of maternal plasma total cholesterol (TC) (p = 0.02) and low-density lipoprotein cholesterol (LDL-C) (p = 0.03) were significantly associated with milk cholesterol. Milk cholesterol concentrations varied among different ethnicities (Tibetan vs. Hui: 164 vs. 131 mg/L, p = 0.027) but not among different geographic regions. CONCLUSIONS: The concentration of cholesterol in human milk changes dynamically throughout lactation. Milk cholesterol concentrations are significantly associated with maternal plasma concentrations of TC and LDL-C, and milk cholesterol concentrations vary across ethnicities in China. IMPACT: Concentrations of milk cholesterol were measured in various Chinese populations. Cholesterol concentrations differ significantly between stages of lactation. Maternal plasma total cholesterol and low-density lipoprotein cholesterol are associated with milk cholesterol. Milk cholesterol concentrations vary across ethnicities in China.

Immunological Effects of Adding Bovine Lactoferrin and Reducing Iron in Infant Formula: A Randomized Controlled Trial.

OBJECTIVES: Compared to formula-fed infants, breastfed infants have a lower risk of infections. Two possible reasons for this are the presence of the anti-infective and anti-inflammatory protein lactoferrin and the lower level of iron in breast milk. We explored how adding bovine lactoferrin and reducing the iron concentration in infant formula affect immunology and risk of infections in healthy infants. METHODS: In a double-blind controlled trial, term formula-fed (FF) Swedish infants (n = 180) were randomized to receive, from 6 weeks to 6 months of age, a low-iron formula (2 mg/L) with added bovine lactoferrin (1.0 g/L) (Lf+; n = 72); low-iron formula with no added lactoferrin (Lf-; n = 72); and standard formula at 8 mg/L iron and no added lactoferrin (control formula [CF]; n = 36). Cytokines, infections, and infection related treatments were assessed until 12 months of age. RESULTS: No adverse effects were observed. There were no apparent effects on transforming growth factor beta (TGF-ß)1, TGF-ß2, tumor necrosis factor alfa (TNF-α) or interleukin2 (IL-2) at 4, 6, or 12 months, except of higher TGF-ß2 at 6 months in the CF group in comparison to the low iron groups combined (P = 0.033). No significant differences in otitis, respiratory infections, gastroenteritis, or other monitored infections and treatments were detected for any of the study feeding groups during the first 6 months and only a few and diverging effects were observed between 6 and 12 months. CONCLUSIONS: Adding bovine lactoferrin and reducing iron from 8 to 2 mg/L in infant formula was safe. No clinically relevant effects on cytokines or infection related morbidity were observed in this well-nourished and healthy population.