The associations between sarcopenia and metabolic syndrome (MetS) in non-obese middle-aged and older adults remain controversial. Thus, this meta-analysis aimed to evaluate the overall prevalence of MetS and the correlations between sarcopenia and MetS in middle-aged and older non-obese adults. We performed a systematic searched strategy using PUBMED, EMBASE and Web of Science databases for relevant observational studies investigating sarcopenia and MetS up to 11 May 2017. The polled prevalence of MetS and odds ratios with 95% confidence intervals (CI), as well as subgroup analyses were calculated using a random effects model. Twelve articles with a total of 35,581 participants were included. The overall prevalence of MetS was 36.45% (95% CI, 28.28–45.48%) in middle-aged and older non-obese adults with sarcopenia. Our analysis demonstrated a positive association between sarcopenia and MetS (OR = 2.01, 95% CI, 1.63–2.47). The subgroup analysis showed that both larger cohort size and the use of dual-energy X-ray absorptiometry to measure body composition can enhance the relationship. Our study revealed that a higher proportion of MetS in middle-aged and older non-obese people with sarcopenia. Moreover, sarcopenia was positively associated with MetS in this population. Further large-scale prospective cohort studies are needed to investigate the causality between sarcopenia and MetS.

Diabetes mellitus is associated with gut microbiota disturbance and intestinal mucosal injuries. This study investigated the influence of propolis on the gut microbiota and intestinal mucosa in rats with diabetes. Sprague-Dawley (SD) rats were randomly assigned to the control group, model group, and three propolis groups (supplemented with 80, 160, and 240 mg/kg·bw propolis, respectively). A high-fat diet combined with a streptozotocin (STZ) abdominal injection were used to induce diabetes in the rats. After 4 weeks, the intestinal histopathological analysis of the ileum was observed by transmission electron microscopy. The fasting blood glucose (FBG), plasma insulin, glucose tolerance (OGTT) and glycosylated hemoglobin (HbA1c) levels were measured. The expression of tight junction (TJ) proteins in the ileum was measured using western blotting. The molecular ecology of the fecal gut microbiota was analyzed by 16S rDNA high-throughput sequencing. The contents of the short-chain fatty acids (SCFAs) in feces were measured using high-performance liquid chromatography (HPLC). After propolis treatment, compared to the model group, FBG and HbA1c levels declined, while the glucose tolerance and insulin sensitivity index (ISI) increased. The levels of TJ proteins in the ileum increased in the propolis groups. The tight junctions and gap junctions of the intestinal epithelium were also improved in the propolis groups. The contents of the feces acetic acid, propionic acid and butyrate were increased in the propolis groups. 16S rDNA high-throughput sequencing revealed that the composition of the gut microbiota of rats in the propolis supplement group was significantly improved. Compared to the model group, propolis exerted hypoglycemic effects in diabetic rats, and it repaired intestinal mucosal damage, benefited the communities of the gut microbiota and increased SCFA levels in diabetic rats.

Accumulating evidence points to a critical role of the brain gut axis as an important paradigm for many central nervous system diseases. Recent studies suggest that propolis has obvious neuroprotective properties and functionality in regulating intestinal bacteria flora, hinting at a potential key effect at both terminals of this axis regulation. However, currently no clear evidence confirms the effects of propolis on alcohol-induced depression. Here, we establish an alcoholic depression model with C57BL/6J mice and demonstrate that treatment with propolis protects against alcohol-induced depressive symptoms by behavioral tests. In addition, propolis attenuates the injury of nerve cells in the hippocampal region and restores the serum levels of brain-derived neurotrophic factor (BDNF) and dopamine (DA) in mice with alcohol-induced depression. Pathology and biotin tracer assays show that propolis repairs the intestinal leakage caused by alcohol. Additionally, propolis treatment increases the expression levels of intestinal intercellular tight junctions’ (TJs’) structural proteins Claudin-1, Occludin and zona occludens-1 (ZO-1), as well as the activation state of the liver kinase B1/AMP-activated protein kinase (LKB1/AMPK) signaling pathway, which is closely related to the intestinal permeability. Furthermore, propolis can reduce the levels of pro-inflammatory, lipopolysaccharide (LPS) and fatty-acid-binding protein 2 (FABP2), suggesting the significance of the inflammatory response in alcoholic depression. Collectively, our findings indicate that propolis exerted an improving effect on alcohol-induced depressive symptoms by ameliorating brain gut dysfunction.

Maternal dietary patterns during pregnancy have been demonstrated to impact the structure of the gut microbiota in offspring, altering their susceptibility to diseases. This study is designed to elucidate whether the impact of folic acid supplementation during pregnancy on hepatic steatosis in male offspring of rat dams exposed to a high-fat diet (HFD) is related to gut–liver axis homeostasis. In this study, female rats were administered a HFD and simultaneously supplemented with 5 mg/kg folic acid throughout their pregnancy. Histopathological examination showed that folic acid supplementation effectively ameliorated hepatic lipid accumulation and inflammatory infiltrate in male offspring subjected to a maternal HFD. Maternal folic acid supplementation reduced the abundance of Desulfobacterota and the Firmicutes/Bacteroidota (F/B) ratio in male offspring. The expression of tight junction proteins in the colon was significantly upregulated, and the serum LPS level was significantly reduced. Furthermore, there was a notable reduction in the hepatic expression of the TLR4/NF-κB signaling pathway and subsequent inflammatory mediators. Spearman’s correlation analysis revealed significant associations between hepatic inflammation-related indices and several gut microbiota, particularly Desulfobacterota and Lactobacillus. With a reduction in hepatic inflammation, the expression of PPAR-α was upregulated, and the expression of SREBP-1c and its downstream lipid metabolism-related genes was downregulated. In summary, folic acid supplementation during pregnancy modulates gut microbiota and enhances intestinal barrier integrity in male offspring of HFD dams. This helps reduce the LPS leakage and suppress the expression of TLR4/NF-κB pathway in the liver, thereby improving lipid metabolism disorders, and alleviating hepatic steatosis.

The placenta is particularly susceptible to inflammation and oxidative stress, leading to placental vascular dysfunction and placental insufficiency, which is associated with fetal intrauterine growth restriction (IUGR). It is unknown whether folic acid (FA) supplementation can alleviate high-fat diet-induced IUGR in rats by improving placental function. In this study, pregnant rats were randomized into one of four diet-based groups: (1) control diet (CON), (2) control diet supplemented with FA, (3) high-fat diet (HFD), and (4) high-fat diet supplemented with FA (HFD + FA). Dams were sacrificed at gestation day 18.5 (GD18.5). The results indicated that dietary FA supplementation normalized a maternal HFD-induced decrease in fetal weight. The decrease in placental efficiency, labyrinth zone (LZ) area, blood sinusoid area, vascular density, and the levels of angiogenesis factors induced by a maternal HFD were alleviated by the addition of FA, suggesting that FA supplementation can alleviate placental vascular dysplasia. Furthermore, FA supplementation increased the protein expressions of SIRT1, inhibited NF-κB transcriptional activation, attenuated the levels of NF-κB/downstream pro-inflammatory cytokines, induced Nrf2 activation, and increased downstream target protein expression. In conclusion, we found that dietary FA supplementation during pregnancy could improve maternal HFD-induced IUGR by alleviating placental inflammation and oxidative stress, which may be associated with the regulation of SIRT1 and its mediated NF-κB and Nrf2 signaling pathways.

Aims: The effect of algae and its extract supplementation on glycolipid metabolism has not been finalized. Therefore, the purpose of the meta-analyses was to assess the effects of its supplementation on glycolipid metabolism concentration. Methods: We have systematically searched PubMed, Web of Science, the Cochrane Library and Embase to identify randomized controlled trials (RCTs) that investigated the impact of algae and its extracts supplementation on glycolipid metabolism. Effect size analysis was performed using weighted mean difference (WMD) and 95% CI between the methods of the experiment group and the control group. Subgroup analyses were performed to explore the possible influences of study characteristics. Publication bias and sensitivity analysis were also performed. Results: A total of 27 RCTs (31 trials) with 1221 participants were finally selected for the meta-analysis. The algae and its extract intervention significantly decreased glycosylated hemoglobin (HbA1c, WMD = −0.18%; 95% CI: −0.27 to −0.10; p < 0.001), high-density lipoprotein cholesterol (HDL-C, WMD = −0.22 mmol/L; 95% CI: −0.38 to −0.06; p = 0.008), and triglycerides (TC, WMD = −0.31 mmol/L; 95% CI: −0.37 to −0.25; p < 0.001) levels and increased insulin (WMD = 6.05 pmol/mL; 95% CI: 4.01 to 8.09; p < 0.001) levels. It did not significantly change the blood glucose, homeostasis model assessment-insulin resistance index (HOMA-IR), 2-h post-meal blood glucose (2hPBG) and other lipid profiles. Subgroup analyses based on the duration of intervention and subjects demonstrated that the intervention of algae and its extracts for 10 weeks or fewer and more than 40 subjects decreased TC levels (p < 0.05). Moreover, the intervention reduced TC and 2hPBG concentrations for East Asians (p < 0.05). Conclusions: Our findings provided evidence that algae and its extract interventions were beneficial for the regulation of human glycolipid metabolism. More precise RCTs on subjects are recommended to further clarify the effect of algae, seaweed polysaccharide, seaweed polypeptide, algae polyphenol and its products intervention on glycolipid metabolism.