To use a quantitative approach to evaluate the literature for quantity, quality, and consistency of studies of maternal and infant characteristics in association with breastfeeding initiation and ...continuation, and to conduct a meta-analysis to produce summary relative risks (RRs) for selected factors.
A systematic review using PubMed and CINAHL through March 2016 was conducted to identify relevant observational studies in developed nations, reporting a measure of risk for 1 or more of 6 quantitatively derived, high impact factors in relation to either breastfeeding initiation or continuation. One author abstracted data using a predesigned database, which was reviewed by a second independent author; data evaluation and interpretation included all co-authors. These factors were summarized using standard meta-analysis techniques.
Six high impact factors were identified (smoking 39 papers, mode of delivery 47 papers, parity 31 papers, dyad separation 17 papers, maternal education 62 papers, and maternal breastfeeding education 32 papers). Summary RR from random-effects models for breastfeeding initiation were highest for high vs low maternal education (RR 2.28 95% CI 1.92-2.70), dyad connection vs not (RR 2.01 95% CI 1.38-2.92), and maternal nonsmoking vs smoking (RR = 1.76 95% CI 1.59-1.95); results were similar for breastfeeding continuation.
Despite methodological heterogeneity across studies, relatively consistent results were observed for these perinatally identifiable factors associated with breastfeeding initiation and continuation, which may be informative in developing targeted interventions to provide education and support for successful breastfeeding in more families.
Requirements for iron and docosahexaenoic acid (DHA) content of infant formula varies by country. Powdered full-term infant formula purchase data from all major physical stores in the US between ...2017-2019 were obtained from CIRCANA, Inc. Iron and DHA composition and scoop sizes for each formula were obtained from manufacturers. The equivalent liquid ounces of prepared formula were calculated. Average iron and DHA content were compared between formula types and to both US and European formula composition requirements. These data represent 55.8 billion ounces of formula. The average iron content of all formula purchased was: 1.80 mg/100 kcal. This iron concentration is within the FDA regulations. However, it exceeds the maximum allowable iron concentration of infant formula (Stage 1) set by the European Commission of 1.3 mg/100 kcal. A total of 96% of formula purchased had an iron concentration of >1.3 mg/100 kcal. DHA is not a required ingredient in US formulas. The average DHA content of all formula purchased was: 12.6 mg/100 kcal. This DHA concentration is far below the minimum required DHA concentrations of infant formula (Stage 1) and follow-on formula (Stage 2) set by the European Commission of 20 mg/100 kcal. These are novel insights into the iron and DHA intake of formula-fed infants in the US. As international infant formulas have entered the US market due to the formula shortage, parents and providers need to be aware of regulatory differences in formula nutrient composition.
IMPORTANCE: Long-term effect of parental COVID-19 infection vs vaccination on human milk antibody composition and functional activity remains unclear. OBJECTIVE: To compare temporal IgA and IgG ...response in human milk and microneutralization activity against SARS-CoV-2 between lactating parents with infection and vaccinated lactating parents out to 90 days after infection or vaccination. DESIGN, SETTING, AND PARTICIPANTS: Convenience sampling observational cohort (recruited July to December 2020) of lactating parents with infection with human milk samples collected at days 0 (within 14 days of diagnosis), 3, 7, 10, 28, and 90. The observational cohort included vaccinated lactating parents with human milk collected prevaccination, 18 days after the first dose, and 18 and 90 days after the second dose. EXPOSURES: COVID-19 infection diagnosed by polymerase chain reaction within 14 days of consent or receipt of messenger RNA (mRNA) COVID-19 vaccine (BNT162b2 or mRNA-1273). MAIN OUTCOMES AND MEASURES: Human milk anti–SARS-CoV-2 receptor-binding domain IgA and IgG and microneutralization activity against live SARS-CoV-2 virus. RESULTS: Of 77 individuals, 47 (61.0%) were in the infection group (mean SD age, 29.9 4.4 years), and 30 (39.0%) were in the vaccinated group (mean SD age, 33.0 3.4 years; P = .002). The mean (SD) age of infants in the infection and vaccinated group were 3.1 (2.2) months and 7.5 (5.2) months, respectively (P < .001). Infection was associated with a variable human milk IgA and IgG receptor-binding domain–specific antibody response over time that was classified into different temporal patterns: upward trend and level trend (33 of 45 participants 73%) and low/no response (12 of 45 participants 27%). Infection was associated with a robust and quick IgA response in human milk that was stable out to 90 days after diagnosis. Vaccination was associated with a more uniform IgG-dominant response with concentrations increasing after each vaccine dose and beginning to decline by 90 days after the second dose. Vaccination was associated with increased human milk IgA after the first dose only (mean SD increase, 31.5 32.6 antibody units). Human milk collected after infection and vaccination exhibited microneutralization activity. Microneutralization activity increased throughout time in the vaccine group only (median IQR, 2.2 0 before vaccine vs 10 4.0 after the first dose; P = .003) but was higher in the infection group (median IQR, 20 67 at day 28) vs the vaccination group after the first-dose human milk samples (P = .002). Both IgA and non-IgA (IgG-containing) fractions of human milk from both participants with infection and those who were vaccinated exhibited microneutralization activity against SARS-CoV-2. CONCLUSIONS AND RELEVANCE: In this cohort study of a convenience sample of lactating parents, the pattern of IgA and IgG antibodies in human milk differed between COVID-19 infection vs mRNA vaccination out to 90 days. While infection was associated with a highly variable IgA-dominant response and vaccination was associated with an IgG-dominant response, both were associated with having human milk that exhibited neutralization activity against live SARS-CoV-2 virus.
Young et al respond to the comments of Zhou et al on their study about the association of SARS-CoV-2 antibodies in human breast milk induced by natural infection or messenger RNA vaccination with ...SARS-CoV-2 infection in vitro. They explain that the authors make an excellent point that some of the neutralization activity of human breast milk against SARS-CoV-2 may be attributed to other nonimmunoglobulin factors in breast milk. They agree it is interesting that 4 of 20 prevaccination samples of breast milk exhibited neutralization activity. They also agree that previous research makes a compelling case that other nonspecific and nonimmunoglobulin components of breast milk may contribute to neutralization capacity against SARS-CoV-2. They emphatically agree that future research detailing such components is a valuable endeavor to identify novel therapeutics and optimize recipient infant protection.
Background
The protein and carbohydrate composition of formula fed infants' diets in the United States (US) has not been described. The aims of this study were to characterize these dietary exposures ...in infant formula purchased in the US and to estimate the proportion of formula purchased which is hypoallergenic or lactose‐reduced formula.
Methods
Powdered infant formula purchase data from all major physical stores in the US prior to the COVID‐19 pandemic, between 2017 and 2019, were obtained from Information Resources, Inc. Protein and carbohydrate composition and scoop sizes for each formula were obtained from manufacturers. Ready to feed liquid products, products for premature infants and products for over 1 year old were not included.
Results
Total volumes of term formula purchased were 216 million kg of formula powder (equivalent to 1.65 billion litres) over 3 years. Intact protein formula was 67.9% of formula purchased, 26.6% was partially hydrolysed and 5.5% was hypoallergenic (5.2% extensively hydrolysed protein; 0.3% amino acid based). Soy protein formula represented 5.1% of formula purchased. Carbohydrate content overall was 52.7% lactose, 42.3% glucose polymers and 5.0% sucrose. 23.7% of formula purchased included sucrose as a carbohydrate. Of all formula purchased, 59.0% was lactose reduced, containing a non‐lactose carbohydrate. Of ‘standard’ formula, defined as intact protein, non‐thickened, cow's milk formula, 32.3% was lactose reduced. The proportion of hypoallergenic formula purchased significantly exceeded the prevalence of cow's milk protein allergy and increased over the 3‐year study period from 4.9% to 7.6% of all formula sold.
Conclusions
US infants are exposed to unnecessarily high levels of non‐lactose carbohydrates and hypoallergenic formula, and this may represent a significant nutritional health risk.
Powdered infant formula sales from all major physical stores in the US between 2017 and 2019, representing approximately 1.65 billion litres of formula. 5.5% of infant formula sold was hypoallergenic (which is greater than estimates of cow's milk protein allergy in infants of 1.3%, p < .0002). 59.0% of infant formula sold was lactose reduced. ‘Standard’ formula represents intact‐protein, dairy, non‐thickened formulae. There is no medical indication for lactose reduction in this category and yet 32.3% of all standard formula purchased were lactose reduced.
Gestational diabetes mellitus (GDM) is a worldwide public health problem affecting up to 27% of pregnancies with high predictive values for childhood obesity and inflammatory diseases. Compromised ...seeding of the infant gut microbiota is a risk factor for immunologic and metabolic diseases in the offspring; however, how GDM along with maternal obesity interact to alter colonization remains unknown. We hypothesized that GDM individually and in combination with maternal overweight/obesity would alter gut microbial composition, diversity, and short-chain fatty acid (SCFA) levels in neonates. We investigated 46 full-term neonates born to normal-weight or overweight/obese mothers with and without GDM, accounting for confounders including cesarean delivery, lack of breastfeeding, and exposure to antibiotics. Gut microbiota in 2-week-old neonates born to mothers with GDM exhibited differences in abundance of 26 microbial taxa; 14 of which showed persistent differential abundance after adjusting for pre-pregnancy BMI. Key pioneering gut taxa, including potentially important taxa for establishing neonatal immunity, were reduced.
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were significantly reduced in neonates from mothers with GDM. GDM was associated with an increase in microbes involved in suppressing early immune cell function (
). No differences in infant stool SCFA levels by maternal phenotype were noted; however, significant correlations were found between microbial abundances and SCFA levels in neonates. Our results suggest that GDM alone and together with maternal overweight/obesity uniquely influences seeding of specific infant microbiota in patterns that set the stage for future risk of inflammatory and metabolic disease.
To characterize the macronutrient, energy, and zinc composition of pasteurized donor human milk pools and evaluate how composition varies based on pooling practices and “time postpartum” (ie, elapsed ...time from parturition to expression date) of individual milk donations.
The Mothers' Milk Bank (Arvada, Colorado) donated 128 donor human milk pools. Caloric density was assessed via mid-infrared spectroscopy, and zinc concentration was measured by atomic absorption spectroscopy. Pool time postpartum was calculated as the unweighted average of the time postpartum of all milk donations included in any given pool.
Time postpartum of donor human milk pools ranged from 3 days to 9.8 months. The majority (91%) of donor human milk pools included milk from either 1 donor or 2 donors. Pool energy density ranged from 14.7 to 23.1 kcal/oz, and protein ranged from 0.52 to 1.43 g/dL. Milk zinc concentrations were higher in preterm pools and were negatively correlated with pool time postpartum. We present an equation that estimates donor human milk pool zinc content based on time postpartum and explains 49% of the variability in zinc concentrations (P < .0001). Including more donors in donor human milk pools decreased the variability in protein, but not zinc, concentrations.
Donor human milk pools were lower in calories than is normally assumed in standard human milk fortification practices. Zinc concentrations were related to donor human milk time postpartum and were on average insufficient to meet preterm and term infants' needs without fortification or supplementation.
Human milk is universally recognized as the preferred food for infants during the first 6 mo of life because it provides not only essential and conditionally essential nutrients in necessary amounts ...but also other biologically active components that are instrumental in protecting, communicating important information to support, and promoting optimal development and growth in infants. Despite decades of research, however, the multifaceted impacts of human milk consumption on infant health are far from understood on a biological or physiological basis. Reasons for this lack of comprehensive knowledge of human milk functions are numerous, including the fact that milk components tend to be studied in isolation, although there is reason to believe that they interact. In addition, milk composition can vary greatly within an individual as well as within and among populations. The objective of this working group within the Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN) Project was to provide an overview of human milk composition, factors impacting its variation, and how its components may function to coordinately nourish, protect, and communicate complex information to the recipient infant. Moreover, we discuss the ways whereby milk components might interact such that the benefits of an intact milk matrix are greater than the sum of its parts. We then apply several examples to illustrate how milk is better thought of as a biological system rather than a more simplistic “mixture” of independent components to synergistically support optimal infant health.
Breastfeeding and human milk (HM) are critically important to maternal, infant and population health. This paper summarizes the proceedings of a workshop that convened a multidisciplinary panel of ...researchers to identify key priorities and anticipated breakthroughs in breastfeeding and HM research, discuss perceived barriers and challenges to achieving these breakthroughs and propose a constructive action plan to maximize the impact of future research in this field. Priority research areas identified were as follows: (1) addressing low breastfeeding rates and inequities using mixed methods, community partnerships and implementation science approaches; (2) improving awareness of evidence‐based benefits, challenges and complexities of breastfeeding and HM among health practitioners and the public; (3) identifying differential impacts of alternative modes of HM feeding including expressed/pumped milk, donor milk and shared milk; and (4) developing a mechanistic understanding of the health effects of breastfeeding and the contributors to HM composition and variability. Key barriers and challenges included (1) overcoming methodological limitations of epidemiological breastfeeding research and mechanistic HM research; (2) counteracting ‘breastfeeding denialism’ arising from negative personal breastfeeding experiences; (3) distinguishing and aligning research and advocacy efforts; and (4) managing real and perceived conflicts of interest. To advance research on breastfeeding and HM and maximize the reach and impact of this research, larger investments are needed, interdisciplinary collaboration is essential, and the scientific community must engage families and other stakeholders in research planning and knowledge translation.
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