Human milk (HM) appetite hormones and macronutrients may mediate satiety in breastfed infants. This study investigated associations between maternal adiposity and concentrations of HM leptin, adiponectin, protein and lactose, and whether these concentrations and the relationship between body mass index and percentage fat mass (%FM) in a breastfeeding population change over the first year of lactation. Lactating women (n = 59) provided milk samples (n = 283) at the 2nd, 5th, 9th and/or 12th month of lactation. Concentrations of leptin, adiponectin, total protein and lactose were measured. Maternal %FM was measured using bioimpedance spectroscopy. Higher maternal %FM was associated with higher leptin concentrations in both whole (0.006 ± 0.002 ng/mL, p = 0.008) and skim HM (0.005 ± 0.002 ng/mL, p = 0.007), and protein (0.16 ± 0.07 g/L, p = 0.028) concentrations. Adiponectin and lactose concentrations were not associated with %FM (0.01 ± 0.06 ng/mL, p = 0.81; 0.08 ± 0.11 g/L, p = 0.48, respectively). Whole milk concentrations of adiponectin and leptin did not differ significantly over the first year of lactation. These findings suggest that the level of maternal adiposity during lactation may influence the early appetite programming of breastfed infants by modulating concentrations of HM components.

Preterm infants may show a higher risk of adverse health outcomes, such as the development of metabolic syndrome and cognitive impairment. The most recent evidence highlights that nutrition, body composition development, and early postnatal growth may play a role in the programming of these processes. Human milk feeding has been recommended as the natural feeding for preterm infants and as a cost-effective strategy for reducing disease and economic burden. Considering that the postnatal growth retardation and aberrant body composition shown by preterm infants at the time of hospital discharge still remain important issues, we performed a literature review, aiming to provide an update about the effect of human milk feeding on these processes. On the basis of our findings, human milk feeding in preterm infants, although related to a slower weight gain than formula feeding, is associated with a better recovery of body composition through the promotion of fat-free mass deposition, which may ultimately lead to better metabolic and neurodevelopmental outcomes. Promotion and support of human milk feeding should be considered a priority in preterm infants' care.

Human milk (HM) components may influence infant growth and development. This study aimed to investigate relationships between infant body composition (BC) and HM lactose, insulin, and glucose (concentrations and calculated daily intakes (CDI)) as well as 24-h milk intake and maternal BC at 3 months postpartum. HM samples were collected at 2 months postpartum. Infant and maternal BC was assessed with bioimpedance spectroscopy. Statistical analysis used linear regression accounting for infant birth weight. 24-h milk intake and CDI of lactose were positively associated with infant anthropometry, lean body mass and adiposity. Higher maternal BC measures were associated with lower infant anthropometry, z-scores, lean body mass, and adiposity. Maternal characteristics including BC and age were associated with concentrations and CDI of HM components, and 24-h milk intake. In conclusion, 24-h intake of HM and lactose as well as maternal adiposity are related to development of infant BC.

Gut-derived serotonin (5-HT) is released from enterochromaffin (EC) cells in response to nutrient cues, and acts to slow gastric emptying and modulate gastric motility. Rodent studies also evidence a role for gut-derived 5-HT in the control of hepatic glucose production, lipolysis and thermogenesis, and in mediating diet-induced obesity. EC cell number and 5-HT content is increased in the small intestine of obese rodents and human, however, it is unknown whether EC cells respond directly to glucose in humans, and whether their capacity to release 5-HT is perturbed in obesity. We therefore investigated 5-HT release from human duodenal and colonic EC cells in response to glucose, sucrose, fructose and α-glucoside (αMG) in relation to body mass index (BMI). EC cells released 5-HT only in response to 100 and 300 mM glucose (duodenum) and 300 mM glucose (colon), independently of osmolarity. Duodenal, but not colonic, EC cells also released 5-HT in response to sucrose and αMG, but did not respond to fructose. 5-HT content was similar in all EC cells in males, and colonic EC cells in females, but 3 to 4-fold higher in duodenal EC cells from overweight females (p < 0.05 compared to lean, obese). Glucose-evoked 5-HT release was 3-fold higher in the duodenum of overweight females (p < 0.05, compared to obese), but absent here in overweight males. Our data demonstrate that primary human EC cells respond directly to dietary glucose cues, with regional differences in selectivity for other sugars. Augmented glucose-evoked 5-HT release from duodenal EC is a feature of overweight females, and may be an early determinant of obesity.

Polyphenols, a complex group of secondary plant metabolites, including flavonoids and phenolic acids, have been studied in depth for their health-related benefits. The activity of polyphenols may, however, be hampered when consumed together with protein-rich food products, due to the interaction between polyphenols and proteins. To that end we have tested the bioavailability of representatives of a range of polyphenol classes when consumed for five days in different beverage matrices. In a placebo-controlled, randomized, cross-over study, 35 healthy males received either six placebo gelatine capsules consumed with 200 mL of water, six capsules with 800 mg polyphenols derived from red wine and grape extracts, or the same dose of polyphenols incorporated into 200 mL of either pasteurized dairy drink, soy drink (both containing 3.4% proteins) or fruit-flavoured protein-free drink . At the end of the intervention urine and blood was collected and analysed for a broad range of phenolic compounds using Gas Chromatography-Mass Spectrometry (GC-MS), Liquid Chromatography-Multiple Reaction Monitoring-Mass Spectrometry (LC-MRM-MS), and Nuclear Magnetic Resonance (NMR) spectroscopy techniques. The plasma and urine concentrations of the polyphenols identified increased with all formats, including the protein-rich beverages. Compared to capsule ingestion, consumption of polyphenol-rich beverages containing either dairy, soy or no proteins had minor to no effect on the bioavailability and excretion of phenolic compounds in plasma (118% ± 9%) and urine (98% ± 2%). We conclude that intake of polyphenols incorporated in protein-rich drinks does not have a major impact on the bioavailability of a range of different polyphenols and phenolic metabolites.

Targeting gut microbiota with synbiotics (probiotic supplements containing prebiotic components) is emerging as a promising intervention in the comprehensive nutritional approach to reducing obesity. Weight loss resulting from low-carbohydrate high-protein diets can be significant but has also been linked to potentially negative health effects due to increased bacterial fermentation of undigested protein within the colon and subsequent changes in gut microbiota composition. Correcting obesity-induced disruption of gut microbiota with synbiotics can be more effective than supplementation with probiotics alone because prebiotic components of synbiotics support the growth and survival of positive bacteria therein. The purpose of this placebo-controlled intervention clinical trial was to evaluate the effects of a synbiotic supplement on the composition, richness and diversity of gut microbiota and associations of microbial species with body composition parameters and biomarkers of obesity in human subjects participating in a weight loss program. The probiotic component of the synbiotic used in the study contained Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium longum, and Bifidobacterium bifidum and the prebiotic component was a galactooligosaccharide mixture. The results showed no statistically significant differences in body composition (body mass, BMI, body fat mass, body fat percentage, body lean mass, and bone mineral content) between the placebo and synbiotic groups at the end of the clinical trial (3-month intervention, 20 human subjects participating in weight loss intervention based on a low-carbohydrate, high-protein, reduced energy diet). Synbiotic supplementation increased the abundance of gut bacteria associated with positive health effects, especially Bifidobacterium and Lactobacillus, and it also appeared to increase the gut microbiota richness. A decreasing trend in the gut microbiota diversity in the placebo and synbiotic groups was observed at the end of trial, which may imply the effect of the high-protein low-carbohydrate diet used in the weight loss program. Regression analysis performed to correlate abundance of species following supplementation with body composition parameters and biomarkers of obesity found an association between a decrease over time in blood glucose and an increase in Lactobacillus abundance, particularly in the synbiotic group. However, the decrease over time in body mass, BMI, waist circumstance, and body fat mass was associated with a decrease in Bifidobacterium abundance. The results obtained support the conclusion that synbiotic supplement used in this clinical trial modulates human gut microbiota by increasing abundance of potentially beneficial microbial species.

Intra-cortical myelin is a myelinated part of the cerebral cortex that is responsible for the spread and synchronization of neuronal activity in the cortex. Recent animal studies have established a link between obesity and impaired oligodendrocyte maturation vis-à-vis cells that produce and maintain myelin; however, the association between obesity and intra-cortical myelination remains to be established. To investigate the effects of obesity on intra-cortical myelin in living humans, we employed a large, demographically well-characterized sample of healthy young adults drawn from the Human Connectome Project (n = 1066). Intra-cortical myelin was assessed using a novel T1-w/T2-w ratio method. Linear regression analysis was used to investigate the association between body mass index (BMI), an indicator of obesity, and intra-cortical myelination, adjusting for covariates of no interest. We observed BMI was related to lower intra-cortical myelination in regions previously identified to be involved in reward processing (i.e., medial orbitofrontal cortex, rostral anterior cingulate cortex), attention (i.e., visual cortex, inferior/middle temporal gyrus), and salience detection (i.e., insula, supramarginal gyrus) in response to viewing food cues (corrected p < 0.05). In addition, higher BMIs were associated with more intra-cortical myelination in regions associated with somatosensory processing (i.e., the somatosensory network) and inhibitory control (i.e., lateral inferior frontal gyrus, frontal pole). These findings were also replicated after controlling for key potential confounding factors including total intracranial volume, substance use, and fluid intelligence. Findings suggested that altered intra-cortical myelination may represent a novel microstructure-level substrate underlying prior abnormal obesity-related brain neural activity, and lays a foundation for future investigations designed to evaluate how living habits, such as dietary habit and physical activity, affect intra-cortical myelination.

In recent years, the consumption of energy drinks by young adults and athletes has risen significantly, but concerns have been raised about the potential health risks associated with excessive consumption. These concerns include cardiovascular problems, nervous system disorders, and the potential for addiction. This review aims to examine the reported effects of acute or chronic abuse of energy drinks on human health. The analysis shows a significant prevalence of adverse effects, particularly on the cardiovascular and neurovegetative systems. In particular, the analysis identified nine cases of cardiac arrest, three of which were fatal. The aetiology of these adverse effects is attributed to the inherent neurostimulant properties of these beverages, of which caffeine is the predominant component. A comparison of documented effects in humans with experimental studies in animal models showed an overlap in results. This review highlights the need for greater rigour in the assessment of sudden cardiac death, particularly in young people, as legal substances such as energy drinks may be involved. We propose stricter limits on the consumption of these beverages than for caffeine, based on the evidence found and the data in the literature. This review also calls for the establishment of regulations governing the consumption of these products in view of their potential impact on human health.

Human milk (HM) adipokines may influence infant feeding patterns, appetite regulation, and body composition (BC). The associations between concentrations/calculated daily intakes (CDI) of HM adipokines in the first 12 months postpartum and maternal/term infant BC, and infant breastfeeding parameters were investigated. BC of breastfeeding dyads (n = 20) was measured at 2, 5, 9, and/or 12 months postpartum with ultrasound skinfolds (infants) and bioimpedance spectroscopy (infants/mothers). 24-h milk intake and feeding frequency were measured along with whole milk adiponectin and skim and whole milk leptin (SML and WML) and CDI were calculated. Statistical analysis used linear regression/mixed effects models; results were adjusted for multiple comparisons. Adipokine concentrations did not associate with infant BC. Higher CDI of adiponectin were associated with lower infant fat-free mass (FFM; p = 0.005) and FFM index (FFMI; p = 0.009) and higher fat mass (FM; p < 0.001), FM index (FMI; p < 0.001), and %FM (p < 0.001). Higher CDI of SML were associated with higher infant FM (p < 0.001), FMI (p < 0.001), and %FM (p = 0.002). At 12 months, higher CDI of WML were associated with larger increases in infant adiposity (2⁻12 month: FM, p = 0.0006; %FM, p = 0.0004); higher CDI of SML were associated with a larger decrease in FFMI (5⁻12 months: p = 0.0004). Intakes of HM adipokines differentially influence development of infant BC in the first year of life, which is a critical window of infant programming and may potentially influence risk of later disease via modulation of BC.

Human milk provides all of the elements necessary for infant growth and development. Previous studies have reported associations between breastfeeding and a reduced risk of developing obesity and late-onset metabolic disorders; however, the underlying mechanisms are poorly understood. Recently, intakes of human milk components have been associated with infant body composition, which is likely partially implicated in the reduced risk of developing childhood obesity among breastfed infants. In this systematic review, we searched electronic bibliographic databases for studies that explored relationships between the 24 h intakes of human milk macronutrients and bioactive components and infant body composition and/or growth parameters. Of 13 eligible studies, 10 assessed relationships of infant body composition and growth outcomes with human milk macronutrients, while 8 studies assessed relationships with human milk bioactive components. Significant time-dependent relationships with infant anthropometrics and body composition were found for intakes and no relationships for concentrations of several human milk components, such as lactose, total protein, and human milk oligosaccharides, suggesting that measuring concentrations of human milk components without quantifying the intake by the infant may provide a limited understanding. Future studies investigating the effect of human milk components on infant growth and body composition outcomes should consider measuring the actual intake of components and employ standardised methods for measuring milk intake.

Human milk (HM) influences infant feeding patterns and body composition (BC). This small proof-of concept longitudinal study investigated relationships between infant/maternal BC and HM casein, whey and total protein during the first 12 months of lactation. BC of breastfeeding dyads (n = 20) was measured at 2 (n = 15), 5 (n = 20), 9 (n = 19), and/or 12 (n = 18) months postpartum with ultrasound skinfolds (infants) and bioimpedance spectroscopy (infants/mothers). Proteins concentrations and 24-h milk intake were measured and calculated daily intakes (CDI) determined. Higher maternal weight, body mass index, fat-free mass, fat-free mass index, and fat mass index were associated with higher concentration of whey protein (p ≤ 0.034, n = 20). There were no associations between infant BC and concentrations of all proteins, and CDI of whey and total protein. Higher CDI of casein were associated with lower infant fat-free mass (p = 0.003, n = 18) and higher fat mass (p < 0.001), fat mass index (p = 0.001, n = 18), and % fat mass (p < 0.001, n = 18) measured with ultrasound skinfolds. These results show a differential effect of HM casein on development of infant BC during the first year of life, suggesting that there is a potential to improve outcome for the infant through interventions, such as continuation of breastfeeding during the first 12 months of life and beyond, which may facilitate favourable developmental programming that could reduce risk of non-communicable diseases later in life.

L. fermentum strains K7-Lb1, K8-Lb1 and K11-Lb3 were found to suppress Th1 and Th2 response and to enhance defensin release by enterocytes, respectively. Based on these anti-inflammatory actions, we investigated the effect of these strains on traits of metabolic syndrome, which is driven by low-grade inflammation. In a double-blind, randomised, placebo-controlled clinical trial with three parallel arms, 180 individuals with abdominal overweight were administered for 3 months with (1) placebo; (2) probiotic, comprising L. fermentum strains; or (3) synbiotic, comprising the strains + acacia gum (10 g daily). The effects were evaluated using Kruskal-Wallis one-way analysis of variance on ranks and post hoc tests (Holm-Sidak and Dunn's tests). The alteration (∆) in body fat mass (kg) (primary parameter) during intervention was significantly (p = 0.039) more pronounced in the Probiotic group (-0.61 ± 1.94; mean ± SD) compared with the Placebo group (+0.13 ± 1.64). Accordingly, differences were found in ∆ body weight (p = 0.012), BMI (p = 0.011), waist circumference (p = 0.03), waist-to-height ratio (p = 0.033), visceral adipose tissue (SAD) (p < 0.001) and liver steatosis grade (LSG) (p < 0.001), as assessed using sonography. In the Synbiotic group, ∆SAD (p = 0.002), ∆LSG (p < 0.001) and ∆constipation score (p = 0.009) were improved compared with Placebo. The probiotic mixture and the synbiotic improved the parameters associated with overweight.

It is unclear whether different processing methods change the biological functions of foods and how these functions are evaluated in the human body. Here, steamed bread and baked bread, the traditional staple foods in China and many Western countries, were made by steaming and baking, respectively, using one piece of fermented wheat dough and then consumed by 16 healthy young volunteers. By detecting 38 cytokines, 12 metabolic enzymes, glucose, lactate, and nicotinamide adenine dinucleotide (NADH) in the serum, the cytokine network and central metabolic pathway network were investigated to compare the effects of the two staple foods on immunity and metabolism. Compared with steamed bread, baked bread increased (p < 0.05) concentrations of fractalkine and macrophage-derived chemokine, decreased (p < 0.05) the concentration of interleukin-1RA, increased (p < 0.05) the expression level of phosphofructokinase, and decreased (p < 0.05) the expression level of glucose-6-phosphate dehydrogenase in the serum. Two network analyses indicated that baked bread, as compared to the steamed bread, enhanced communication between immune cells, increased catabolism, and decreased anabolism. Further, a correlation analysis of cytokines and metabolic enzymes suggested that the two staple foods may affect metabolism by regulating the secretion of cytokines. These findings highlight how the same raw food material processed by different methods may have different impacts on immunity and metabolism in humans.

Diets utilising intermittent fasting (IF) as a strategic method to manipulate body composition have recently grown in popularity, however, dietary practices involving fasting have also been followed for centuries for religious reasons (i.e., Ramadan). Regardless of the reasons for engaging in IF, the impacts on lean body mass (LBM) may be detrimental. Previous research has demonstrated that resistance training promotes LBM accrual, however, whether this still occurs during IF is unclear. Therefore, the objective of this review is to systematically analyse human studies investigating the effects of variations of IF combined with resistance training on changes in LBM in previously sedentary or trained (non-elite) individuals. Changes in body weight and fat mass, and protocol adherence were assessed as a secondary objective. This review followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. MEDLINE, CINAHL, PubMed and SportDiscus databases were searched for articles investigating IF, combined with resistance training that reported measures of body composition. Eight studies met the eligibility criteria. LBM was generally maintained, while one study reported a significant increase in LBM. Body fat mass or percentage was significantly reduced in five of eight studies. Results suggest that IF paired with resistance training generally maintains LBM, and can also promote fat loss. Future research should examine longer-term effects of various forms of IF combined with resistance training compared to traditional forms of energy restriction. Prospero registration CRD42018103867.

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by complex symptoms. To treat AD without adverse effects, alternative therapeutic agents are required. The tubers of Helianthus tuberosus L. (Jerusalem artichoke) have been used in folk remedies for diabetes and rheumatism. However, its effect on AD development remains unknown. Therefore, this study examined the inhibitory effect of H. tuberosus (HT) on AD skin symptoms using an NC/Nga mouse model and HaCaT keratinocytes. The effect of HT and associated molecular mechanisms were evaluated in Dermatophagoides farina body (Dfb)-induced AD mice and tumor necrosis factor (TNF)-α/interferon (IFN)-γ-stimulated HaCaT keratinocytes by ELISA, western blot, and histological analysis. Topical HT administration attenuated AD skin symptoms in Dfb-induced AD mice, with a significant reduction in the dermatitis score and production of inflammatory mediators. HT also decreased epidermal thickness and mast cell infiltration. Moreover, HT restored filaggrin expression and inhibited adhesion molecules in the mice. These effects were confirmed in vitro. Furthermore, HT suppressed the activation of NF-κB, Akt, and mitogen-activated protein kinase (MAPK) signaling pathways induced by TNF-α/IFN-γ. These results suggest that HT is a potential therapeutic agent or supplement for skin allergic inflammatory diseases such as AD.

The first oral form of the glucagon-like peptide-1 receptor agonist, oral semaglutide, has recently been launched and potently controls glycemia and body weight in subjects with type 2 diabetes. This drug carries the absorption enhancer and requires specific protocols of administration. The mechanism of action of oral semaglutide is not fully understood, for which an appropriate experimental model is required. This study explores the metabolic effects of oral semaglutide in mice under human protocols and doses. Oral semaglutide was bolus and once daily injected into high-fat diet-induced obese (DIO) mice under human protocols, followed by monitoring blood glucose, food intake, and body weight. Oral semaglutide 0.23 mg/kg, a comparable human dose (14 mg) in a small volume of water under human protocols rapidly decreased blood glucose and food intake and continuously reduced food intake and weight gain for 3 days in DIO mice. At 0.7 mg/kg (42 mg), this drug was somewhat more potent. Oral semaglutide with human protocols and doses rapidly reduces blood glucose and food intake and continuously suppresses feeding and weight in DIO mice. This study establishes mice as a model suitable for analyzing the mechanism of anti-obesity/diabetes actions of oral semaglutide.

Breakfast is often described as "the most important meal of the day" and human studies have revealed that post-prandial responses are dependent on meal timing, but little is known of the effects of meal timing per se on human circadian rhythms. We evaluated the effects of skipping breakfast for 6 days on core body temperature, dim light melatonin onset, heart rate variability, and clock gene expression in 10 healthy young men, with a repeated-measures design. Subjects were provided an isocaloric diet three times daily (3M) or two times daily (2M, i.e., breakfast skipping condition) over 6 days. Compared with the 3M condition, the diurnal rhythm of the core body temperature in the 2M condition was delayed by 42.0 ± 16.2 min (p = 0.038). On the other hand, dim light melatonin onset, heart rate variability, and clock gene expression were not affected in the 2M condition. Skipping breakfast for 6 days caused a phase delay in the core body temperature in healthy young men, even though the sleep-wake cycle remained unchanged. Chronic effects of skipping breakfast on circadian rhythms remain to be studied.

The optimal method for human milk (HM) fortification has not yet been determined. This study assessed whether fortification relying on measured HM macronutrient content (Miris AB analyzer, Upsala, Sweden) composition is superior to fortification based on assumed HM macronutrient content, to optimize the nutrition support, growth, and body composition in infants born at <33 weeks' gestation. In a mixed-cohort study, 57 infants fed fortified HM based on its measured content were compared with 58 infants fed fortified HM based on its assumed content, for a median of 28 and 23 exposure days, respectively. The ESPGHAN 2010 guidelines for preterm enteral nutrition were followed. Growth assessment was based on body weight, length, and head circumference Δ z-scores, and the respective growth velocities until discharge. Body composition was assessed using air displacement plethysmography. Fortification based on measured HM content provided significantly higher energy, fat, and carbohydrate intakes, although with a lower protein intake in infants weighing ≥ 1 kg and lower protein-to-energy ratio in infants weighing < 1 kg. Infants fed fortified HM based on its measured content were discharged with significantly better weight gain, length, and head growth. These infants had significantly lower adiposity and greater lean mass near term-equivalent age, despite receiving higher in-hospital energy and fat intakes, with a mean fat intake higher than the maximum recommended and a median protein-to-energy ratio intake (in infants weighing < 1 kg) lower than the minimum recommended.

The emotional consequences of excessive body mass, associated with body image and acceptance, have become a global public health challenge as they may decrease the general well-being and hinder weight loss in overweight and obese individuals. Therefore, this study aimed to analyze the influence of age, body mass index (BMI), and waist-to-height ratio (WHtR) on body mass acceptance, attitudes, and motivation toward body mass reduction in overweight and obese Caucasian women with excessive abdominal fat. The previously validated BodyMass⁻DRama (Body Mass⁻Dietary Restrictions: Acceptance, Motivation, Attitudes) questionnaire was applied in this study. The declared acceptance, attitudes and motivation towards body mass reduction were compared between subgroups based on age (20⁻40, 40⁻50, and 50⁻60 years), BMI (25.0⁻30.0, 30.0⁻35.0, and ≥35.0 kg/m²), and quartiles of WHtR. The age, BMI and WHtR were stated to be associated with declared acceptance, attitudes, and motivation towards body mass reduction. The different age groups indicated the following as the reasons for excessive body mass: young respondents-low physical activity and consumption of sweets; middle-aged ones-large/irregular meals; aging ones-large/irregular meals and low physical activity (p = 0.0161). While describing motivation toward body mass reduction, young respondents indicated the role of a physician or dietitian (p = 0.0012) or someone who can control them (p = 0.0044), as well as their expectation to be more successful at work after body mass reduction (p = 0.0045), while the aging ones indicated appreciation and plaudits from others (p = 0.0264) as a motivating factor. Respondents with the highest BMI declared having spending free time actively constricted (p = 0.0007); they declared more often than others of feeling exhausted (p = 0.0395) or tired all the time (p = 0.0445), but less often of feeling full of joy (p = 0.0457) or full of energy (p <0.0001). Respondents with moderate WHtR declared less often than others that they expect to enjoy socializing (p = 0.0376), but more often to be able to have a better vacation after body mass reduction (p = 0.0128), while those with the lowest WHtR expected to be more physically active (p = 0.0487). Women with the highest WHtR most commonly indicated external pressure from relatives or co-workers as a motivating factor for body mass reduction (p = 0.0435). Due to these differences between Caucasian women with excessive body mass, the approach of physicians and dietitians, as well as methods applied to motivate patients, need to be customized.

Diet modulates gut microbiota and plays an important role in human health. The aim of this study was to test the effect of a low-fat vegan diet on gut microbiota and its association with weight, body composition, and insulin resistance in overweight men and women. We enrolled 168 participants and randomly assigned them to a vegan (n = 84) or a control group (n = 84) for 16 weeks. Of these, 115 returned all gut microbiome samples. Gut microbiota composition was assessed using uBiome Explorer™ kits. Body composition was measured using dual energy X-ray absorptiometry. Insulin sensitivity was quantified with the predicted clamp-derived insulin sensitivity index from a standard meal test. Repeated measure ANOVA was used for statistical analysis. Body weight decreased in the vegan group (treatment effect -5.9 kg [95% CI, -7.0 to -4.9 kg]; p < 0.001), mainly due to a reduction in fat mass (-3.9 kg [95% CI, -4.6 to -3.1 kg]; p < 0.001) and in visceral fat (-240 cm3 [95% CI, -345 to -135 kg]; p < 0.001). PREDIcted M, insulin sensitivity index (PREDIM) increased in the vegan group (treatment effect +0.83 [95% CI, +0.48 to +1.2]; p < 0.001). The relative abundance of Faecalibacterium prausnitzii increased in the vegan group (+5.1% [95% CI, +2.4 to +7.9%]; p < 0.001) and correlated negatively with changes in weight (r = -0.24; p = 0.01), fat mass (r = -0.22; p = 0.02), and visceral fat (r = -0.20; p = 0.03). The relative abundance of Bacteroides fragilis decreased in both groups, but less in the vegan group, making the treatment effect positive (+18.9% [95% CI, +14.2 to +23.7%]; p < 0.001), which correlated negatively with changes in weight (r = -0.44; p < 0.001), fat mass (r = -0.43; p < 0.001), and visceral fat (r = -0.28; p = 0.003) and positively with PREDIM (r = 0.36; p < 0.001), so a smaller reduction in Bacteroides fragilis was associated with a greater loss of body weight, fat mass, visceral fat, and a greater increase in insulin sensitivity. A low-fat vegan diet induced significant changes in gut microbiota, which were related to changes in weight, body composition, and insulin sensitivity in overweight adults, suggesting a potential use in clinical practice.