Food in an evolutionary context: insights from mother's milk

When it comes to feeding the newborn, human milk is, from an evolutionary perspective, the biological norm, the time-tested standard of care. The health benefits to the infant of breast-feeding have been amply documented; numerous studies strongly indicate significantly decreased risks of infection, allergy, asthma, arthritis, diabetes, obesity, cardiovascular disease, and various cancers in both childhood and adulthood. Among the more fundamental disadvantages of not being breastfed is a loss of immunologic protection afforded by maternal colostrum, a “pre-milk” fluid secreted only during the first days after delivery, as well as numerous other bioactive factors that help protect the infant through the first two years of life, when the immune and nervous systems are incompletely developed. Nevertheless, given the tendency for persistent organic pollutants (POPs), pesticides, heavy metals, and other contaminants to accumulate in human milk, researchers and parents alike are asking whether the nursling’s exposure to these pollutants might reduce or even override the health benefits.

It is widely acknowledged that breast milk is the first choice for infant. The presence of complex commensal bacteria in human breast milk has been confirmed by traditional culture-dependent methods, while in recent years, some advanced technologies, such as next-generation sequencing, have revealed that a complex microbial ecosystem exist in human milk. Microbes in human breast milk has different origins, and its composition is influenced by various factors. Moreover, the micro-ecosystem of human breast milk, which is considered as an important source of infant intestinal flora, is vital for infants’ growth and long-term health because of its antibacterial effect and abilities of promoting the growth of beneficial bacteria and regulating the immune system as well as intestinal nutrition metabolism. Hence, in-depth research on the complex micro-ecosystem of human breast milk will be of great value. Key words: Milk, human; Microbiota

Objective To explore the expression levels of immune-related microRNA-146b(miR-146b), microRNA-155(miR-155) and microRNA-30b(miR-30b) in human breast milk and its relationship with maternal and infant's health. Methods One hundred and thirty-four mothers and their infants from obstetrical department were recruited in the study after delivery.The subjects were divided into 2 groups, breast feeding group(n=86) and formula-fee-ding group(n=48), and were followed up 3 months after delivery.Breast milk samples were collected at 2-5 days after delivery(colostrum) and 3 months after delivery(mature milk). The expression levels of microRNAs in milk samples were detected by real-time PCR.The relationship between levels of microRNAs and maternal and infant-related factors was analyzed. Results 1.MiR-146b, miR-155 and miR-30b expressions were abundant both in human colostrums(5.950±0.823, 3.899±0.920, 4.057±0.604) and mature milk(4.840±0.805, 2.128±0.969, 4.929±0.566). The levels of miR-146b and miR-155 were higher in colostrum than that of mature milk(t=7.716, 10.215, all P<0.01), while the level of miR-30b was higher in mature milk than that of colostrums(t=-8.626, P<0.01).2.Additionally, the level of miR-30b was negatively correlated with maternal pre-pregnancy body mass index(r=-0.298, P<0.01).3.The levels of miR-146b and miR-30b were higher in mothers giving birth by vaginal delivery than those who underwent cesarean section(t=2.356, 3.108, all P<0.05).4.The levels of miR-146b and miR-155 were higher in colostrum-fed girls than boys(t=-2.204, -2.985, all P<0.05).5.The level of miR-146b in mature milk was negatively correlated with 3-month-old infant's Z score of body weight(r=-0.425, P<0.05) and body length(r=-0.569, P<0.01).6.During follow-up, the incidence of baby eczema in breast feeding group(8.82%, 3/34 cases) was lower than that in formula milk feeding group(29.17%, 14/48 cases) (χ2 = 5.012, P=0.025). Conclusions The levels of immunocompetent microRNAs in human milk are influenced by the lactation period, maternal pre-pregnancy body mass index, mode of delivery and infant sex.The immune-related microRNAs in human milk could be involved in the regulation of infant's immunity and growth. Key words: Human milk; Immunity; MicroRNA-146b; MicroRNA-155; MicroRNA-30b; Maternal and infant health

Modulation of the Gastrointestinal Tract of Infants by Human Milk. Interfaces and Interactions. An Evolutionary Perspective

Objective To analyze Holder pasteurization, temperature and duration of frozen, duration of continuous breast milk pumping and types of pumping tube on macronutrients and total energy in breast milk and the circadian variation of macronutrients and energy content of breast milk. Methods Two hundred and two breast milk samples were collected from healthy mothers of 188 infants who were hospitalized in Department of Pediatrics, Obstetrics and Gynecology Hospital Affiliated to Nanjing Medical University from April 2016 to December 2016. Fat, protein, carbohydrate and energy contents of the breast milk samples were detected both before and after various processes to analyze the influence of Holder pasteurization, frozen storage conditions (temperature and time), duration of continuous pumping and types of pumping tube and to observe the variations within a single day. Paired t-test, repeated-measures analysis of variance, one-way analysis of variance and LSD-t test were used for statistical analysis. Results The contents of fat, protein and energy in breast milk were significantly decreased [(3.69±0.98) vs (4.22±1.00) g/dl, t=9.405; (2.12±0.34) vs (2.21±0.34) g/dl, t=4.785; (69.77±9.35) vs (74.94±9.53) kcal/dl (1 kcal=4.184 kJ), t=9.470], while the carbohydrate content was increased [(6.66±0.17) vs (6.62±0.17) g/dl, t=-3.442] after Holder pasteurization comparing with those before (all P<0.01). Breast milk frozen at -80 ℃ had higher protein content than that frozen at -20 ℃(Ftemperature=4.990, Ptemperature=0.027). Breast milk stored at -20 ℃ for 7, 15, 30, 60 and 90 days showed significantly decreased fat, protein and energy contents as compared with those in fresh breast milk, while the carbohydrate contents in the breast milk samples stored at -20 ℃ for 15, 30 and 60 days were significantly increased and that kept for 90 days were lower than those at 30 and 60 days (LSD-t test, P<0.05). Compared with fresh breast milk, breast milk stored at -80 ℃ showed significantly decreased fat, protein and energy contents at 60 d and 90 d, but increased carbohydrate content at 60 d (LSD-t test, P<0.05). Compared with fresh breast milk, breast milk which was pumped at 1, 2 or 3 h through gastric tube (size 6,8 or 10) or transfusion connecting pipe had lower fat content (LSD-t test, P<0.05). Compared with fresh milk, breast milk had lower energy content on condition that it was pumped through gastric tube size 6 at 2 or 3 h or through gastric tube size 8 or 10 or transfusion connecting pipe at 1, 2 or 3 h (LSD-t test, P<0.05). Breast milk secreted from 12:01 to 15:00 had higher fat and energy contents [(5.16±0.93) g/dl and (86.96±9.35) kcal/dl] than that secreted from 00:01 to 03:00[(4.54±0.75) g/dl and (80.77±7.75) kcal/dl], from 03:01 to 06:00 [(4.61±0.75) g/dl and (81.44±7.69) kcal/dl] or from 21:01 to 24:00 [(4.71±0.88) g/dl and (82.44±8.82) kcal/dl]. Moreover, breast milk secreted from 09:01 to 12:00 had higher fat and energy contents [(5.01±0.94) g/dl and (85.31±9.62) kcal/dl] than that secreted from 00:01 to 03:00, and that secreted from 09:01 to 12:00 had higher fat contents than that secreted from 03:01 to 06:00 (LSD-t test, P<0.05). Conclusions Fresh breast milk is better than processed milk to meet the infantile need for growth and development. Key words: Milk, human; Breast milk expression; Time; Fats; Proteins; Carbohydrates

Triclosan (TCS) is a broad spectrum antibacterial agent present as an active ingredient in some personal care products such as soaps, toothpastes and sterilizers. It is an endocrine disrupting compound and its increasing presence in water resources as well as in biosolid-amended soils used in farming, its potential for bioaccumulation in fatty tissues and toxicity in aquatic organisms are a cause for concern to human and environmental health. TCS has also been detected in blood, breast milk, urine and nails of humans. The significance of this is not precisely understood. Data on its bioaccumulation in humans are also lacking. Cell based studies however showed that TCS is a pro-oxidant and may be cytotoxic via a number of mechanisms. Uncoupling of oxidative phosphorylation appears to be prevailing as a toxicity mechanism though the compound’s role in apoptosis has been cited. TCS is not known to be carcinogenic per se in vitro but has been reported to promote tumourigenesis in the presence of a carcinogen, in mice. Recent laboratory reports appear to support the view that TCS oestrogenicity as well as its anti-oestrogenicity play significant role in cancer progression. Results from epidemiological studies on the effect of TCS on human health have implicated the compound as responsible for certain allergies and reproductive defects. Its presence in chlorinated water also raises toxicity concern for humans as carcinogenic metabolites such as chlorophenols may be generated in the presence of the residual chlorine. In this paper, we carried out a detailed overview of TCS pollution and the implications for human and environmental health.

Non-communicable diseases continue to increase globally and have their origins early in life. Early life obesity tracks from childhood to adulthood, is associated with obesity, inflammation, and metabolic dysfunction, and predicts non-communicable disease risk in later life. There is mounting evidence that these factors are more prevalent in infants who are formula-fed compared to those who are breastfed. Human milk provides the infant with a complex formulation of lipids, many of which are not present in infant formula, or are present in markedly different concentrations, and the plasma lipidome of breastfed infants differs significantly from that of formula-fed infants. With this knowledge, and the knowledge that lipids have critical implications in human health, the lipid composition of human milk is a promising approach to understanding how breastfeeding protects against obesity, inflammation, and subsequent cardiovascular disease risk. Here we review bioactive human milk lipids and lipid metabolites that may play a protective role against obesity and inflammation in later life. We identify key knowledge gaps and highlight priorities for future research.

Donkey milk is acknowledged as a valuable nutritional source in the human diet, well known for its bioactive and functional properties. Therefore, the main goal of this research was to investigate the similarities between donkey and human milk after six months of lactation with respect to the lipid composition, milk fat globule particle size distribution, antioxidant activity, and mineral content. These components are related to the nutritional properties of milk and they are important for the dairy industry as well to human health. The obtained results showed that the most dominant fatty acids in both types of milk were oleic, palmitic, and linoleic followed by lauric, capric, and alpha-linolenic acids. Donkey milk had a desirable fatty acid composition due to its high alpha-linolenic acid content and especially low omega-6/omega-3 ratio. After the fat globule distribution was analysed, it was found that fat globules smaller than 2 μm had the highest percentage in both human and donkey milk. The antioxidant activity of human milk was significantly higher at 42.95% compared to donkey milk at 35.83%. Predominant mineral in both types of milk was Ca, followed by P, Zn, Fe and Cu. Highlighting the similarity between donkey milk and human milk encourages the use of donkey milk as a potential substitute for human milk in the future.

Origin of the Recommended Intake of L-Histidine by Infants

Breast milk is the only source of the essential amino acid tryptophan (TRP) in breast-fed infants. Low levels of TRP could have implications for infant neurodevelopment. The objectives of the present study were to compare the relationship of TRP and its neuroactive pathway metabolites kynurenine (Kyn) and kynurenic acid (KynA) in preterm and term expressed breast milk (EBM) in the first 14 d following birth, and the relationship of TRP metabolism to maternal stress and immune status. A total of twenty-four mothers were recruited from Cork University Maternity Hospital: twelve term (>38 weeks) and twelve preterm (<35 weeks). EBM samples were collected on days 7 and 14. Free TRP, Kyn and KynA were measured using HPLC, total TRP using MS, cytokines using the Meso Scale Discovery (MSD) assay system, and cortisol using a cortisol ELISA kit. Although total TRP was higher in preterm EBM in comparison with term EBM (P < 0·05), free TRP levels were lower (P < 0·05). Kyn, KynA and the Kyn:TRP ratio increased significantly in term EBM from day 7 to day 14 (P < 0·05), but not in preterm EBM. TNF-α, IL-6 and IL-8 were higher in day 7 preterm and term EBM in comparison with day 14. There were no significant differences between term and preterm EBM cortisol levels. Increased availability of total TRP, lower levels of free TRP and alterations in the temporal dynamics of TRP metabolism in preterm compared with term EBM, coupled with higher EBM inflammatory markers on day 7, may have implications for the neurological development of exclusively breast-fed preterm infants.

Milk is an important food of the daily diet. Many countries include it in their dietary recommendations due to its content in several important nutrients that exert beneficial effects on human health. Human milk is a newborn's first food and plays an important role in the growth, development, and future health of every individual. Cow milk is the type of milk most consumed in the world. However, its relatively high content of saturated fats raises concerns about potential adverse effects on human health, although epidemiological studies have disproved this association. Indeed, dairy consumption appear to be linked to a lower risk of mortality and major cardiovascular disease events. In the last few years many researchers have begun to focus their attention on both the production and quality of cow milk as well as the analysis of milk from other animal species to evaluate their effect on human health. The need to investigate the composition and metabolic effects of milk from other animal species arises from the adverse reactions of individuals in several groups to certain components of cow milk. It has emerged that donkey milk compared with that of other animal species, is the nearest to human milk and an excellent substitute for it. Milk from various animal species shows substantial differences in nutritional composition and distinct metabolic effects. In this review, we discussed the main compositional features and metabolic effects of 3 types of milk: human, cow, and donkey milk.

Breast milk is the best, most complete form of nutrition for newborns and infants. However, human milk can contain aflatoxin M1 (AFM1) upon ingestion of dietary mycotoxin contaminants, namely, aflatoxin B1 (AFB1), by lactating mothers. AFB1 and its hydroxylated metabolite AFM1 are potent carcinogens and thus an important issue in food safety and public health. This study is the first to explore the presence of AFM1 in breast milk samples from Bangladesh and assess infant exposure to this toxin, as a consequence of maternal mycotoxin intake. A total of 62 breast milk samples were collected from nursing mothers in Sylhet region of Bangladesh. The milk samples were collected between October 2019 and March 2020 and analyzed by a sensitive enzyme-linked immunosorbent assay. AFM1 was detected in 51.6% of the breast milk samples (colostrum, transitional and mature milk), with a mean concentration of 4.42 ± 0.56 pg/mL, and in the range between LOD (4.0 pg/mL) and 6.66 pg/mL. The frequent detection of AFM1 in breast milk indicates widespread dietary exposure to mycotoxins in our cohort. The estimated average daily intake of AFM1 for all nursed infants was 0.49 ng/kg b.w./day. No significant correlations were observed between AFM1 levels in human milk and food items regularly consumed by nursing women. Overall, AFM1 levels in breast milk samples from the Sylhet region of Bangladesh are moderate, and lower than the permissible levels established for AFM1 in dairy milk or infant formulae (50 and 25 ng/kg, respectively). Yet, this first data for AFM1 breast milk contaminant levels just reflect the recent situation in one cohort, and monitoring should be continued.

Review of the state of the art of human biomonitoring for chemical substances and its application to human exposure assessment for food safety

Dioxin Emissions and Human Exposure in China: A Brief History of Policy and Research

The COVID-19 pandemic has underscored the critical role of public health education in promoting maternal and neonatal well-being. This systematic review examines the impact of SARS-CoV-2 infection and COVID-19 vaccination on breastfeeding practices, with a focus on viral transmission, the transfer of antibodies, and the broader implications for health education and early physical development. A comprehensive literature search covering studies from 2020 to 2024 was conducted. The review analyzed research on the presence of SARS-CoV-2 in breast milk, antibody responses following natural infection and vaccination, and the subsequent effects on newborn health. The results indicate that active transmission of SARS-CoV-2 via breast milk is extremely rare, with detected viral RNA not corresponding to infectious virus particles. Importantly, breast milk from both infected and vaccinated mothers contains significant levels of IgA and IgG antibodies, which confer passive immunity to newborns. Beyond immediate nutritional and immunological benefits, breastfeeding plays a pivotal role in fostering early physical development—a foundation that may influence later engagement in sports and active lifestyles. Moreover, the excellent safety profile of COVID-19 vaccines for breastfeeding women reinforces the integration of vaccination into public health education strategies aimed at promoting comprehensive maternal and child health. These findings support the continued promotion of breastfeeding during the COVID-19 pandemic, not only for its direct health benefits but also for its broader educational and developmental impacts. The study advocates for interdisciplinary public health initiatives that integrate health education, vaccination campaigns, and the encouragement of early physical activity as essential elements in optimizing long-term health outcomes. Objective: The aim of this study is to provide an in-depth analysis of the impact of SARS-CoV-2 infection and COVID-19 vaccination on breastfeeding, with a focus on the potential transmission of the virus and the transfer of antibodies through breast milk to newborns. Materials and Methods: A systematic review of current scientific literature from 2020 to 2024 was conducted, focusing on studies examining the presence of SARS-CoV-2 in breast milk, levels of anti SARS-CoV-2 antibodies after infection and vaccination, and the clinical implications for newborn health. The search utilized a combination of keywords and logical operators such as "SARS-CoV-2, "“COVID-19, "“coronavirus, "“breastfeeding, "“lactation, "“human milk, " “transmission, "“antibodies, "“vaccination, " and”immunization." Electronic databases searched included PubMed, Scopus, Web of Science, and Embase. The review encompassed publications released from January 2020 to September 2024. Conclusions: The analysis of available data indicates that the transmission of active virus through breast milk is extremely rare and does not pose a significant risk to the newborn. Detection of viral RNA in breast milk does not equate to the presence of replication-competent virus. Additionally, studies have shown that breast milk from both SARS-CoV-2-infected and COVID-19-vaccinated mothers contains specific antibodies, predominantly IgA and IgG. These antibodies may provide passive immunity to the newborn, potentially protecting against infection or mitigating disease severity. COVID-19 vaccination in breastfeeding women has been proven safe, with no significant adverse effects observed in mothers or their infants. The findings suggest that the benefits of breastfeeding outweigh the potential risks of SARS-CoV-2 transmission. Breastfeeding is recommended both during maternal infection and after COVID-19 vaccination. The available scientific evidence supports policies promoting breastfeeding as a safe and beneficial practice in the context of the COVID-19 pandemic.