The growing worldwide epidemic of obesity and associated metabolic health comorbidities has resulted in an urgent need for safe and efficient nutritional solutions. The research linking obesity with gut microbiota dysbiosis has led to a hypothesis that certain bacterial strains could serve as probiotics helping in weight management and metabolic health. In the search for such strains, the effect of Bifidobacterium animalis subsp. lactis 420 (B420) on gut microbiota and metabolic health, and the mechanisms of actions, has been investigated in a variety of in vitro, pre-clinical, and clinical studies. In this review, we aim to highlight the research on B420 related to obesity, metabolic health, and the microbiota. Current research supports the hypothesis that gut dysbiosis leads to an imbalance in the inflammatory processes and loss of epithelial integrity. Bacterial components, like endotoxins, that leak out of the gut can invoke low-grade, chronic, and systemic inflammation. This imbalanced state is often referred to as metabolic endotoxemia. Scientific evidence indicates that B420 can slow down many of these detrimental processes via multiple signaling pathways, as supported by mechanistic in vitro and in vivo studies. We discuss the connection of these mechanisms to clinical evidence on the effect of B420 in controlling weight gain in overweight and obese subjects. The research further indicates that B420 may improve the epithelial integrity by rebalancing a dysbiotic state induced by an obesogenic diet, for example by increasing the prevalence of lean phenotype microbes such as Akkermansia muciniphila. We further discuss, in the context of delivering the health benefits of B420: the safety and technological aspects of the strain including genomic characterization, antibiotic resistance profiling, stability in the product, and survival of the live probiotic in the intestine. In summary, we conclude that the clinical and preclinical studies on metabolic health suggest that B420 may be a potential candidate in combating obesity; however, further clinical studies are needed.

Scope High‐fat diets are a likely cause of low‐grade inflammation and obesity‐related pathologies. This study measures the effects of a high‐fat diet, in combination with two dietary supplements—betaine and polydextrose—on metabolism and inflammation in the adipose tissue of diet‐induced obese mice. Methods and Results Forty male C57BL/6J mice are fed a high‐fat diet for 8 weeks and compared with low‐fat‐diet‐fed control animals (n = 10). For the last 4 weeks, the high‐fat‐diet‐fed animals are supplemented with 1% betaine, 3.33% polydextrose, their combination, or plain water. Fat depots from subcutaneous and visceral adipose tissue are analyzed for inflammatory markers and nontargeted metabolomics by quantitative PCR and LC–QTOF‐MS. The high‐fat diet significantly increases adipose tissue inflammation in both fat depots. By metabolic profiling, clear differences are noted between low‐fat‐diet and high‐fat‐diet groups with regard to the levels of several metabolite species—primarily carnitines, lipids, and amino acids. Dietary betaine mitigates the high‐fat‐diet‐induced IL‐6 expression and significantly increases betaine and butyrobetaine levels in adipose tissue. Conclusions The high‐fat diet induces patent changes in carnitine and lipid metabolism in adipose tissue. Betaine supplementation elevates the levels of betaine and its derivatives and certain carnitine species, as reported in muscle and liver, and moderately reduces inflammation.

Selected strains of lactobacilli and bifidobacteria are known to ameliorate constipation-related symptoms and have previously shown efficacy on digestive health. In this clinical trial, the safety and effectiveness of a probiotic blend containing lactobacilli and bifidobacteria were evaluated in adults with self-reported bloating and functional constipation. Constipation was diagnosed by the Rome III criteria. A total of 156 adults were randomised into this double-blind and placebo-controlled trial. Participants consumed the combination of Lactobacillus acidophilus NCFM (1010 cfu), Lactobacillus paracasei Lpc-37 (2.5×109 cfu), Bifidobacterium animalis subsp. lactis strains Bl-04 (2.5×109 cfu), Bi-07 (2.5×109 cfu) and HN019 (1010 cfu) (n=78), or placebo (microcrystalline cellulose) (n=78) for two weeks. After treatment the following were measured: primary outcome of bloating and secondary outcomes of colonic transit time, bowel movement frequency, stool consistency, other gastrointestinal symptoms (flatulence, abdominal pain, and burbling), constipation-related questionnaires (PAC-SYM and PAC-QoL) and product satisfaction. Faecal recovery of consumed strains was determined. The enrolled population was defined as constipated, however, the initial bloating severity was lower than in previous similar studies. No clinically significant observations related to the safety of the product were reported. Product efficacy was not shown in the primary analysis for bloating nor for the secondary efficacy analyses. The placebo functioned similarly as the probiotic product. In post-hoc analysis, a statistically significant decrease in flatulence in favour of the probiotic group was observed; day 7 (intention-to-treat (ITT): P=0.0313; per-protocol (PP): 0.0253) and on day 14 (ITT: P=0.0116; PP: P=0.0102) as measured by area under the curve (AUC) analysis. The mean AUC of all symptoms decreased in favour of the probiotic group, indicating less digestive discomfort. The study was registered at the ISRCTN registry (ISRCTN41607808).

The past two decades of research have raised gut microbiota composition as a contributing factor to the development of obesity, and higher abundance of certain bacterial species has been linked to the lean phenotype, such as Akkermansia muciniphila. The ability of pre- and probiotics to affect metabolic health could be via microbial community alterations and subsequently changes in metabolite profiles, modulating for example host energy balance via complex signaling pathways. The aim of this mice study was to determine how administration of a prebiotic fiber, polydextrose (PDX) and a probiotic Bifidobacterium animalis ssp. lactis 420 (B420), during high fat diet (HFD; 60 kcal% fat) affects microbiota composition in the gastrointestinal tract and adipose tissue, and metabolite levels in gut and liver. In this study C57Bl/6J mice (N = 200) were split in five treatments and daily gavaged: 1) Normal control (NC); 2) HFD; 3) HFD + PDX; 4) HFD + B420 or 5) HFD + PDX + B420 (HFD+S). At six weeks of treatment intraperitoneal glucose-tolerance test (IPGTT) was performed, and feces were collected at weeks 0, 3, 6 and 9. At end of the intervention, ileum and colon mucosa, adipose tissue and liver samples were collected. The microbiota composition in fecal, ileum, colon and adipose tissue was analyzed using 16S rDNA sequencing, fecal and liver metabolomics were performed by nuclear magnetic resonance (NMR) spectroscopy. It was found that HFD+PDX intervention reduced body weight gain and hepatic fat compared to HFD. Sequencing the mice adipose tissue (MAT) identified Akkermansia and its prevalence was increased in HFD+S group. Furthermore, by the inclusion of PDX, fecal, lleum and colon levels of Akkermansia were increased and liver health was improved as the detoxification capacity and levels of methyl-donors were increased. These new results demonstrate how PDX and B420 can affect the interactions between gut, liver and adipose tissue.