The Role of Short-Chain Fatty Acids in Mediating Very Low-Calorie Ketogenic Diet-Infant Gut Microbiota Relationships and Its Therapeutic Potential in Obesity

As the very low-calorie ketogenic diet (VLCKD) gains increased interest as a therapeutic approach for many diseases, little is known about its therapeutic use in childhood obesity. Indeed, the role of VLCKD during pregnancy and lactation in influencing short chain fatty acid (SCFA)-producing bacteria and the potential mechanisms involved in the protective effects on obesity are still unclear. Infants are characterized by a diverse gut microbiota composition with higher abundance of SCFA-producing bacteria. Maternal VLCKD during pregnancy and lactation stimulates the growth of diverse species of SCFA-producing bacteria, which may induce epigenetic changes in infant obese gene expression and modulate adipose tissue inflammation in obesity. Therefore, this review aims to determine the mechanistic role of SCFAs in mediating VLCKD-infant gut microbiota relationships and its protective effects on obesity.     

Maternal Linoleic Acid Overconsumption Alters Offspring Gut and Adipose Tissue Homeostasis in Young but Not Older Adult Rats

Maternal n-6 polyunsaturated fatty acids (PUFA) consumption during gestation and lactation can predispose offspring to the development of metabolic diseases such as obesity later in life. However, the mechanisms underlying the potential programming effect of n-6 PUFA upon offspring physiology are not yet all established. Herein, we investigated the effects of maternal and weaning linoleic acid (LA)-rich diet interactions on gut intestinal and adipose tissue physiology in young (3-month-old) and older (6-month-old) adult offspring. Pregnant rats were fed a control diet (2% LA) or an LA-rich diet (12% LA) during gestation and lactation. At weaning, offspring were either maintained on the maternal diet or fed the other diet for 3 or 6 months. At 3 months of age, the maternal LA-diet favored low-grade inflammation and greater adiposity, while at 6 months of age, offspring intestinal barrier function, adipose tissue physiology and hepatic conjugated linoleic acids were strongly influenced by the weaning diet. The maternal LA-diet impacted offspring cecal microbiota diversity and composition at 3 months of age, but had only few remnant effects upon cecal microbiota composition at 6 months of age. Our study suggests that perinatal exposure to high LA levels induces a differential metabolic response to weaning diet exposure in adult life. This programming effect of a maternal LA-diet may be related to the alteration of offspring gut microbiota.     

Are Probiotics and Prebiotics Safe for Use during Pregnancy and Lactation? A Systematic Review and Meta-Analysis

Probiotic and prebiotic products have shown potential health benefits, including for the prevention of adverse pregnancy outcomes. The incidence of adverse effects in pregnant people and their infants associated with probiotic/prebiotic/synbiotic intake, however, remains unclear. The objectives of this study were to evaluate the evidence on adverse effects of maternal probiotic, prebiotic, and/or synbiotic supplementation during pregnancy and lactation and interpret the findings to help inform clinical decision-making and care of this population. A systematic review was conducted following PRISMA guidelines. Scientific databases were searched using pre-determined terms, and risk of bias assessments were conducted to determine study quality. Inclusion criteria were English language studies, human studies, access to full-text, and probiotic/prebiotic/synbiotic supplementation to the mother and not the infant. In total, 11/100 eligible studies reported adverse effects and were eligible for inclusion in quantitative analysis, and data were visualised in a GOfER diagram. Probiotic and prebiotic products are safe for use during pregnancy and lactation. One study reported increased risk of vaginal discharge and changes in stool consistency (relative risk [95% CI]: 3.67 [1.04, 13.0]) when administering Lactobacillus rhamnosus and L. reuteri. Adverse effects associated with probiotic and prebiotic use do not pose any serious health concerns to mother or infant. Our findings and knowledge translation visualisations provide healthcare professionals and consumers with information to make evidence-informed decisions about the use of pre- and probiotics.     

The Impact of Probiotics,Prebiotics, and Synbiotics during Pregnancy or Lactation on the Intestinal Microbiota of Children Born by Cesarean Section: A Systematic Review

The gut microbiota is a key factor in the correct development of the gastrointestinal immune system. Studies have found differences between the gut microbiota of newborns delivered by cesarean section compared to those vaginally delivered. Our objective was to evaluate the effect of ingestion of probiotics, prebiotics, or synbiotics during pregnancy and/or lactation on the development of the gut microbiota of the C-section newborns. We selected experimental studies in online databases from their inception to October 2021. Of the 83 records screened, 12 met the inclusion criteria. The probiotics used belonged to the genera Lactobacillus, Bifidobacterium, Propionibacterium, and Streptococcus, or a combination of those, with dosages varying between 2 × 10⁶ and 9 × 10¹¹ CFU per day, and were consumed during pregnancy and/or lactation. Probiotic strains were combined with galacto-oligosaccharides, fructo-oligosaccharides, or bovine milk-derived oligosaccharides in the synbiotic formulas. Probiotic, prebiotic, and synbiotic interventions led to beneficial gut microbiota in cesarean-delivered newborns, closer to that in vaginally delivered newborns, especially regarding Bifidobacterium colonization. This effect was more evident in breastfed infants. The studies indicate that this beneficial effect is achieved when the interventions begin soon after birth, especially the restoration of bifidobacterial population. Changes in the infant microbial ecosystem due to the interventions seem to continue after the end of the intervention in most of the studies. More interventional studies are needed to elucidate the optimal synbiotic combinations and the most effective strains and doses for achieving the optimal gut microbiota colonization of C-section newborns.     

Early Gut Microbiota Colonisation of Premature Infants Fed with Breastmilk or Formula with or without Probiotics: A Cohort Study

Premature infants have a fragile ecology of the gut microbiota, which is associated with many health problems and may be influenced by formula versus breast feeding. The present study investigated differences in the process of gut microbiota colonisation in preterm infants fed with breastmilk or formula with or without probiotics before 12 weeks. This cohort study recruited 138 premature infants; 31 in the breastmilk (BM) group, 59 in the probiotics formula (PF) group and 48 in the non-probiotics formula (NPF) group, according to the feeding practice they received at birth. Gut bacterial composition was identified with 16S rRNA gene sequencing in faecal samples collected at 1 week, 6 weeks and 12 weeks after birth. The alpha diversity was higher in the PF group compared to the other groups at week 1 and 6 (both p < 0.01) but showed no difference at week 12. The beta diversity of the three groups showed a trend towards similarity at the first two stages (p < 0.001 and p = 0.009, respectively) and finally showed no difference at week 12. Canonical redundancy analysis showed that feeding type could explain the difference in gut microbiota composition at week one and six (both p < 0.01). At genus level, Bifidobacterium was enriched in the PF group, while the Enterococcus and Streptococcus was enriched in the NPF group. In summary, formula with probiotics feeding after birth can affect gut microbiota colonisation and lead to a bacterial community with less potential pathogens.     

A. muciniphila Supplementation in Mice during Pregnancy and Lactation Affects the Maternal Intestinal Microenvironment

During pregnancy and lactation, considerable factors that affect the maternal microbiome are associated with the advancement of numerous diseases, which can potentially affect offspring health. Probiotics have shown potential for the maintenance of microbiota homeostasis of mothers in this period. The specific objective of this study was to investigate whether the application of Akkermansia muciniphila (A. muciniphila) during pregnancy and lactation impacts maternal and offspring health. Here we show that dams fed with A. muciniphila is safe, enhances the intestinal barrier and alters gut microbiota composition and diversity at the end of lactation, including the significant enrichment of A. muciniphila and Ruminococcus_1 in offspring from probiotic-fed dams. However, compared with the control group, the fecal metabolites of the A. muciniphila group only changed slightly. Additionally, A. muciniphila supplementation did not significantly increase the abundance of A. muciniphila in the fecal microbiota of offspring mice. Compared with the control group, the fecal metabolic profile of three-week-old offspring of mice fed with A. muciniphila were significantly changed, containing the D-glutamine and D-glutamate metabolism pathways. These results provided evidence that A. muciniphila supplementation in mice during pregnancy and lactation is safe and seemed to have a more beneficial effect on dams. In the future, using probiotics to regulate maternal microbiomes during pregnancy and lactation could be shown to have a more lasting and beneficial effect.     

Effects of Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 on Overweight and the Gut Microbiota in Humans: Randomized,Double-Blinded,Placebo-Controlled Clinical Trial

Obesity and overweight are closely related to diet, and the gut microbiota play an important role in body weight and human health. The aim of this study was to explore how Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 supplementation alleviate obesity by modulating the human gut microbiome. A randomized, double-blind, placebo-controlled study was conducted on 72 individuals with overweight. Over a 12-week period, probiotic groups consumed 1 × 10¹⁰ colony-forming units of HY7601 and KY1032, whereas the placebo group consumed the same product without probiotics. After treatment, the probiotic group displayed a reduction in body weight (p < 0.001), visceral fat mass (p < 0.025), and waist circumference (p < 0.007), and an increase in adiponectin (p < 0.046), compared with the placebo group. Additionally, HY7601 and KY1032 supplementation modulated bacterial gut microbiota characteristics and beta diversity by increasing Bifidobacteriaceae and Akkermansiaceae and decreasing Prevotellaceae and Selenomonadaceae. In summary, HY7601 and KY1032 probiotics exert anti-obesity effects by regulating the gut microbiota; hence, they have therapeutic potential for preventing or alleviating obesity and living with overweight.     

Pregnancy and lactation: physiological adjustments,nutritional requirements and the role of dietary supplements

Nutritional needs are increased during pregnancy and lactation for support of fetal and infant growth and development along with alterations in maternal tissues and metabolism. Total nutrient needs are not necessarily the sum of those accumulated in maternal tissues, products of pregnancy and lactation and those attributable to the maintenance of nonreproducing women. Maternal metabolism is adjusted through the elaboration of hormones that serve as mediators, redirecting nutrients to highly specialized maternal tissues specific to reproduction (i.e., placenta and mammary gland). It is most unlikely that the heightened nutrient needs for successful reproduction can always be met from the maternal diet. Requirements for energy-yielding macronutrients increase modestly compared with several micronutrients that are unevenly distributed among foods. Altered nutrient utilization and mobilization of reserves often offset enhanced needs but sometimes nutrient deficiencies are precipitated by reproduction. There are only limited data from well-controlled intervention studies with dietary supplements and with few exceptions (iron during pregnancy and folate during the periconceptional period), the evidence is not strong that nutrient supplements confer measurable benefit. More research is needed and in future studies attention must be given to subject characteristics that may influence ability to meet maternal and infant demands (genetic and environmental), nutrient-nutrient interactions, sensitivity and selectivity of measured outcomes and proper use of proxy measures. Consideration of these factors in future studies of pregnancy and lactation are necessary to provide an understanding of the links among maternal diet; nutritional supplementation; and fetal, infant and maternal health.     

Effect of Probiotic Supplementation on Newborn Birth Weight for Mother with Gestational Diabetes Mellitus or Overweight/Obesity: A Systematic Review and Meta-Analysis

High birth weight indicates the future risk of obesity and increased fat mass in childhood. Maternal gestational diabetes mellitus (GDM) or overweight are powerful predictors of high birth weight. Studies on probiotic supplementation during pregnancy have reported its benefits in modulating gut microbiota composition and improving glucose and lipid metabolism in pregnant women. Therefore, probiotic intervention during pregnancy was proposed to interrupt the transmission of obesity from mothers to newborns. Thus, we performed a meta-analysis to investigate the effect of probiotic intervention in pregnant women with GDM or overweight on newborn birth weight. We searched PubMed, EMBASE, Cochrane Library, and Web of Science databases up to 18 December 2019. Randomized controlled trials (RCTs) comparing pregnant women with GDM or overweight who received probiotic intervention during pregnancy with those receiving placebo were eligible for the analysis. Newborn birth weights were pooled to calculate the mean difference with a 95% confidence interval (CI). Two reviewers assessed the trial quality and extracted data independently. Seven RCTs involving 1093 participants were included in the analysis. Compared with the placebo, probiotics had little effect on newborn birth weight of pregnant women with GDM or overweight (mean difference = −10.27, 95% CI = −90.17 to 69.63, p = 0.801). The subgroup analysis revealed that probiotic intake by women with GDM decreased newborn birth weight, whereas probiotic intake by obese pregnant women increased newborn birth weight. Thus, no evidence indicates that probiotic intake by pregnant women with GDM or overweight can control newborn birth weight.     

Vitamin D Supplementation in Exclusively Breastfed Infants Is Associated with Alterations in the Fecal Microbiome

Breastfeeding and introduction of solid food are the two major components of infant feeding practices that influence gut microbiota composition in early infancy. However, it is unclear whether additional factors influence the microbiota of infants either exclusively breastfed or not breastfed. We obtained 194 fecal samples from infants at 3–9 months of age, extracted DNA, and sequenced the V4 region of the 16S rRNA gene. Feeding practices and clinical information were collected by questionnaire and abstraction of birth certificates. The gut microbiota of infants who were exclusively breastfed displayed significantly lower Shannon diversity (p-adjust < 0.001) and different gut microbiota composition compared to infants who were not breastfed (p-value = 0.001). Among the exclusively breastfed infants, recipients of vitamin D supplements displayed significantly lower Shannon diversity (p-adjust = 0.007), and different gut microbiota composition structure than non-supplemented, breastfed infants (p-value = 0.02). MaAslin analysis identified microbial taxa that associated with breastfeeding and vitamin D supplementation. Breastfeeding and infant vitamin D supplement intake play an important role in shaping infant gut microbiota.     

The Bacon Chow study: effect of nutritional supplementation on maternal weight and skinfold thicknesses during pregnancy and lactation

Effects of a feeding programme on maternal weight, triceps and subscapular skinfolds during pregnancy and lactation were assessed in a marginally undernourished population of rural Taiwan. Mothers participated during two pregnancy and lactation periods. At 3 weeks after the delivery of the first infant, one group of 114 mothers began consuming a nutrient-dense supplement (A), while another group of 111 received a placebo (B). There was no significant A-B difference in pregnancy weight gain (A 7.52 kg, B 7.75 kg) or in mean maternal weight, triceps or subscapular skinfolds at any time during pregnancy or lactation. Despite a general trend toward moderate weight loss during lactation, one-third of mothers in both groups gained weight. Highly significant increases in weight and skinfold thicknesses from one lactation period to the next characterized both groups. The absence of demonstrable supplement-effects on maternal anthropometry concomitant with increments in infant birth weight supports the notion that infants can benefit from maternal supplementation without changes in maternal nutritional status.     

Association of the Maternal Gut Microbiota/Metabolome with Cord Blood CCL17

Chemokine (C-C motif) ligand 17 (CCL17) is a pro-allergic factor: high CCL17 levels in cord blood (CB) precede later allergic predisposition. Short-chain fatty acid (SCFA) treatment during pregnancy has been shown to protect mouse pups against allergic diseases. The maternal microbial metabolome during pregnancy may affect fetal allergic immune responses. We therefore examined the associations between CB CCL17 and gut SCFA levels in healthy pregnant Japanese women. CB CCL17 serum levels at birth, and maternal non-specific IgE levels in maternal sera at 32 weeks of gestation were measured. Maternal stool samples were collected at 12 (n = 59) and 32 (n = 58) weeks of gestation for gut microbiota analysis, based on barcoded 16S rRNA sequencing and metabolite levels. The CB CCL17 levels correlated negatively with butyrate concentrations and positively with isobutyrate at 12 weeks; CB CCL17 correlated positively with valerate and lactate at 32 weeks. Similarly, butyrate levels correlated negatively with maternal non-specific IgE levels, whereas the lactate concentration correlated positively with IgE levels. At 32 weeks, the Shannon diversity index (SDI) of Firmicutes and Proteobacteria correlated negatively with CB CCL17 levels, while those of the total microbiota correlated positively with the CB CCL17 levels. These metabolites may alter fetal immune responses. This study provides the first link between maternal metabolites during pregnancy and the risk of allergic diseases in human offspring.     

Maternal fish oil supplementation ameliorates maternal high-fructose diet-induced dyslipidemia in neonatal mice with suppression of lipogenic gene expression in livers of postpartum mice

Maternal fructose consumption during pregnancy and lactation is associated with metabolic dysregulation in offspring. We tested the hypothesis that fish oil (FO) supplementation during pregnancy and lactation improves fructose-induced metabolic dysregulation in postpartum dams and offspring mice. We therefore aimed to determine the effects of FO supplementation on metabolic disruption in neonatal mice and dams induced by a maternal high-fructose diet (HFrD). The weight of the offspring of dams fed with HFrD on postnatal day 5 was significantly low, but this was reversed by adding FO to the maternal diet. Feeding dams with HFrD significantly increased plasma concentrations of triglycerides, uric acid, and total cholesterol, and decreased free fatty acid concentrations in offspring. Maternal supplementation with FO significantly suppressed HFrD-induced hypertriglyceridemia and hyperuricemia in the offspring. Maternal HFrD induced remarkable mRNA expression of the lipogenic genes Srebf1, Fasn, Acc1, Scd1, and Acly in the postpartum mouse liver without affecting hepatic and plasma lipid levels. Although expression levels of lipogenic genes were higher in the livers of postpartum dams than in those of nonmated mice, HFrD feeding increased the hepatic lipid accumulation in nonmated mice but not in postpartum dams. These findings suggest that although hepatic lipogenic activity is higher in postpartum dams than nonmated mice, the lipid consumption is enhanced in postpartum dams during pregnancy and lactation. Maternal FO supplementation obviously suppressed the expression of these lipogenic genes. These findings coincide with reduced plasma triglyceride concentrations in the offspring. Therefore, dietary FO apparently ameliorated maternal HFrD-induced dyslipidemia in offspring by suppressing maternal lipogenic gene expression and/or neonatal plasma levels of uric acid.     

Use of lipid-based nutrient supplements by HIV-infected Malawian women during lactation has no effect on infant growth from 0 to 24 weeks

The Breastfeeding, Antiretrovirals, and Nutrition Study evaluated the effect of daily consumption of lipid-based nutrient supplements (LNS) by 2121 lactating, HIV-infected mothers on the growth of their exclusively breast-fed, HIV-uninfected infants from 0 to 24 wk. The study had a 2 × 3 factorial design. Malawian mothers with CD4(+) ≥250 cells/mm(3), hemoglobin ≥70 g/L, and BMI ≥17 kg/m(2) were randomized within 36 h of delivery to receive either no LNS or 140 g/d of LNS to meet lactation energy and protein needs, and mother-infant pairs were assigned to maternal antiretroviral drugs (ARV), infant ARV, or no ARV. Sex-stratified, longitudinal, random effects models were used to estimate the effect of the 6 study arms on infant weight, length, and BMI. Logistic regression models were used to calculate the odds of growth faltering [decline in weight-for-age Z-score (WAZ) or length-for-age Z-score (LAZ) >0.67] using the control arm as the reference. Although some differences between study arms emerged with increasing infant age in boys, there were no consistent effects of the maternal supplement across the 3 growth outcomes in longitudinal models. At the ages where differences were observed, the effects on weight and BMI were quite small (≤200 g and ≤0.4 kg/m(2)) and unlikely to be of clinical importance. Overall, 21 and 34% of infants faltered in WAZ and LAZ, respectively. Maternal supplementation did not reduce the odds of infant weight or length faltering from 0 to 24 wk in any arm. These results indicate that blanket supplementation of HIV-infected lactating women may have little impact on infant growth.     

Benefits of Docosahexaenoic Acid, Folic Acid, Vitamin D and Iodine on Foetal and Infant Brain Development and Function Following Maternal Supplementation during Pregnancy and Lactation

Scientific literature is increasingly reporting on dietary deficiencies in many populations of some nutrients critical for foetal and infant brain development and function. Purpose: To highlight the potential benefits of maternal supplementation with docosahexaenoic acid (DHA) and other important complimentary nutrients, including vitamin D, folic acid and iodine during pregnancy and/or breast feeding for foetal and/or infant brain development and/or function. Methods: English language systematic reviews, meta-analyses, randomised controlled trials, cohort studies, cross-sectional and case-control studies were obtained through searches on MEDLINE and the Cochrane Register of Controlled Trials from January 2000 through to February 2012 and reference lists of retrieved articles. Reports were selected if they included benefits and harms of maternal supplementation of DHA, vitamin D, folic acid or iodine supplementation during pregnancy and/or lactation. Results: Maternal DHA intake during pregnancy and/or lactation can prolong high risk pregnancies, increase birth weight, head circumference and birth length, and can enhance visual acuity, hand and eye co-ordination, attention, problem solving and information processing. Vitamin D helps maintain pregnancy and promotes normal skeletal and brain development. Folic acid is necessary for normal foetal spine, brain and skull development. Iodine is essential for thyroid hormone production necessary for normal brain and nervous system development during gestation that impacts childhood function. Conclusion: Maternal supplementation within recommended safe intakes in populations with dietary deficiencies may prevent many brain and central nervous system malfunctions and even enhance brain development and function in their offspring.     

Breastfeeding Practices Influence the Breast Milk Microbiota Depending on Pre-Gestational Maternal BMI and Weight Gain over Pregnancy

Breastfeeding is critical for adequate neonatal microbial and immune system development affecting neonate health outcomes in the short and long term. There is a great interest in ascertaining which are the maternal factors contributing to the milk microbiota and the potential relevance for the developing infant. Thus, our study aimed to characterize the effect of mixed and exclusive breastfeeding practices on the milk microbiota and to determine the impact of pre-pregnancy body mass index (BMI) and weight gain over pregnancy on its composition. Breast milk samples from 136 healthy women were collected within the first month post-partum and milk microbiota profiling was analyzed by 16S rRNA gene sequencing. Information on breastfeeding habits and maternal-infant clinical data were recorded. Breastfeeding practices (exclusive vs. mixed), maternal pre-gestational BMI, and weight gain over pregnancy contributed to the milk microbiota variation. Pre-gestational normal-weight women with exclusive breastfeeding habits harbored a significantly higher abundance of Bifidobacterium genus, and also, higher alpha-diversity compared to the rest of the women. Our results confirm the importance of controlling weight during pregnancy and breastfeeding practices in terms of milk microbiota. Further studies to clarify the potential impact of these maternal factors on milk and infant development and health will be necessary.     

2,4-Dinitrofluorobenzene-induced contact hypersensitivity response in NC/Nga mice fed fructo-oligosaccharide

Strategies to manipulate gut microbiota in infancy have been considered to prevent the development of allergic diseases later in life. We previously demonstrated that maternal dietary supplementation with fructo-oligosaccharide (FOS) during pregnancy and lactation modulated the composition of gut microbiota and diminished the severity of spontaneously developing atopic dermatitis-like skin lesions in the offspring of NC/Nga mice. The present study tested whether dietary FOS affects contact hypersensitivity (CHS), another model for allergic skin disease, in NC/Nga mice. In experiment 1, 5-wk-old female NC/Nga mice were fed diets either with or without FOS supplementation for 3 wk and then received 2,4-dinitrofluorobenzene (DNFB) on the ear auricle 5 times at 7-d intervals. FOS supplementation reduced CHS response as demonstrated by ear swelling. Quantitative RT-PCR analysis showed that mRNA levels for interleukin (IL)-10, IL-12p40, and IL-17 in the lesional ear skin were significantly lower in mice fed FOS. In experiment 2, female NC/Nga mice were fed diets either with or without FOS during pregnancy and lactation. After weaning, offspring were fed the diets supplemented with or without FOS. Three weeks after weaning, offspring received DNFB on the ear auricle 4 times at 7-d intervals. Although FOS supplementation after weaning reduced ear swelling, maternal FOS consumption was ineffective in offspring. The present data suggest that dietary FOS reduces CHS while maternal FOS consumption is ineffective in offspring of DNFB-treated NC/Nga mice.     

Diet,Probiotics and Their Impact on the Gut Microbiota during the COVID-19 Pandemic

SARS-CoV-2 infection is associated with diverse clinical manifestations, immune dysfunction, and gut microbiota alterations. The nutritional and biochemical quality of one’s diet can influence the intestinal microbiota, which may play a role in the defense mechanisms against potential pathogens, by promoting a wide variety of immune–host interactions. In the COVID-19 pandemic, besides the development of pharmacological therapies, a healthy balanced diet, rich with food-derived antioxidants, may be a useful strategy. Many studies demonstrated that vitamins and probiotic therapies have positive effects on the treatment and prevention of oxidative stress and inflammation in COVID-19. The ecology of the gut microbiota in the digestive tract has been linked to the transport function of the host receptor known as angiotensin converting enzyme 2 (ACE2), suggesting that COVID-19 may be related to the gut microbiota. The angiotensin converting enzyme (ACE), and its receptor (ACE2), play central roles in modulating the renin–angiotensin system (RAS). In addition, ACE2 has functions that act independently of the RAS. ACE2 is the receptor for the SARS coronavirus, and ACE2 is essential for the expression of neutral amino acid transporters in the gut. In this context, ACE2 modulates innate immunity and influences the composition of the gut microbiota. Malnutrition is one of the leading underlying causes of morbidity and mortality worldwide and, including comorbidities, may be a major cause of worse outcomes and higher mortality among COVID-19 patients. This paper reviews the research on dietary components, with particular emphasis on vitamins, antioxidants, and probiotic therapies, and their impacts on the intestinal microbiota’s diversity during the SARS-CoV-2 pandemic.     

Effects of galactooligosaccharide and long-chain fructooligosaccharide supplementation during pregnancy on maternal and neonatal microbiota and immunity--a randomized, double-blind, placebo-controlled study

BACKGROUND: Galactooligosaccharides (GOS) and long-chain fructooligosaccharides (lcFOS) proliferate bifidobacteria in infant gut microbiota. However, it is not known how GOS and FOS influence the microbiota of pregnant women and whether a potential prebiotic effect is transferred to the offspring. OBJECTIVES: We aimed to test how supplementation with GOS and lcFOS (GOS/lcFOS) in the last trimester of pregnancy affects maternal and neonatal gut microbiota. Variables of fetal immunity were assessed as a secondary outcome. DESIGN: In a randomized, double-blind, placebo-controlled pilot study, 48 pregnant women were supplemented 3 times/d with 3 g GOS/lcFOS (at a ratio of 9:1) or maltodextrin (placebo) from week 25 of gestation until delivery. Percentages of bifidobacteria and lactobacilli within total bacterial counts were detected by fluorescent in situ hybridization and quantitative polymerase chain reaction in maternal and neonatal (days 5, 20, and approximately 182) stool samples. Variables of fetal immunity were assessed in cord blood by using flow cytometry and cytokine multiplex-array analysis. RESULTS: The proportions of bifidobacteria in the maternal gut were significantly higher in the supplemented group than in the placebo group (21.0% and 12.4%, respectively; P = 0.026); the proportion of lactobacilli did not differ between the groups. In neonates, bifidobacteria and lactobacilli percentages, diversity and similarity indexes, and fetal immune parameters did not differ significantly between the 2 groups. Mother-neonate similarity indexes of bifidobacteria decreased over time. CONCLUSIONS: GOS/lcFOS supplementation has a bifidogenic effect on maternal gut microbiota that is not transferred to neonates. The increased maternal bifidobacteria did not affect fetal immunity as measured by a comprehensive examination of cord blood immunity variables.     

Maternal Vegetable and Fruit Consumption during Pregnancy and Its Effects on Infant Gut Microbiome

Maternal nutrition intake during pregnancy may affect the mother-to-child transmission of bacteria, resulting in gut microflora changes in the offspring, with long-term health consequences in later life. Longitudinal human studies are lacking, as only a small amount of studies showing the effect of nutrition intake during pregnancy on the gut microbiome of infants have been performed, and these studies have been mainly conducted on animals. This pilot study explores the effects of high or low fruit and vegetable gestational intake on the infant microbiome. We enrolled pregnant women with a complete 3-day dietary record and received postpartum follow-up. The 16S rRNA gene sequence was used to characterize the infant gut microbiome at 2 months (n = 39). Principal coordinate analysis ordination revealed that the infant gut microbiome clustered differently for high and low maternal fruit and vegetable consumption (p < 0.001). The linear discriminant analysis effect size and feature selection identified 6 and 17 taxa from both the high and low fruit and vegetable consumption groups. Among the 23 abundant taxa, we observed that six maternal intake nutrients were associated with nine taxa (e.g., Erysipelatoclostridium, Isobaculum, Lachnospiraceae, Betaproteobacteria, Burkholderiaceae, Sutterella, Clostridia, Clostridiales, and Lachnoclostridium). The amount of gestational fruit and vegetable consumption is associated with distinct changes in the infant gut microbiome at 2 months of age. Therefore, strategies involving increased fruit and vegetable consumption during pregnancy should be employed for modifying the gut microbiome early in life.