Postbiotics against Obesity: Perception and Overview Based on Pre-Clinical and Clinical Studies

Postbiotics: As a Promising Tools in the Treatment of Celiac Disease

Celiac disease (CD) can be considered an autoimmune problem, a disease caused by gluten sensitivity in the body. Gluten is found in foods such as barley, wheat, and rye. This ailment manifests in individuals with hereditary susceptibility and under the sway of environmental stimulants, counting, in addition to gluten and intestinal microbiota dysbiosis. Currently, the only recommended treatment for this condition is to follow a gluten-free diet for life. In this review, we scrutinized the studies of recent years that focused on the use of postbiotics in vitro and in vivo in CD. The investigation of postbiotics in CD could be intriguing to observe their diverse effects on several pathways. This study highlights the definitions, characteristics, and safety issues of postbiotics and their possible biological role in the prevention and treatment of CD, as well as their application in the food and drug industry.

Investigating the Antibacterial, Antioxidant, and Cholesterol-lowering Properties of Yogurt Fortified with Postbiotic of Lactobacillus acidophilus and Lactiplantibacillus plantarum in the Wistar Rat Model

Postbiotics have gained attention in the food industry due to their functional properties and ease of use compared to their live parent cells. Postbiotics are the metabolic byproducts of probiotic microorganisms, offering advantages such as antimicrobial and anti-diabetic effects. The study aimed to explore the potential antibacterial, antioxidant, and cholesterol-lowering effects of postbiotics from Lactobacillus acidophilus (LA) and Lactiplantibacillus plantarum (LbP) through in vitro and in vivo studies. Freeze-dried postbiotics from L. acidophilus BLAC 258 and L. plantarum were used in yogurt to inhibit foodborne pathogens over a 21-day storage period at 4 °C. The cholesterol-lowering effects of the postbiotic yogurt were assessed in Wistar rats fed with Normal Basal Diet (NBD) and High Cholesterol Diet (HCD). All experiments were performed in triplicate, and the collected data were analyzed with a one-way ANOVA using SPSS v.20 (2021) software. The Tukey Honestly Significant Difference (HSD) test was used for means differences at the 95% confidence interval. The results showed that postbiotic-fortified yogurt exhibited significant antioxidant and antibacterial effects. The antioxidant capacity of the yogurt increasingly peaked at 48.81% on day 14. Also, Listeria monocytogenes counts in the postbiotic yogurt decreased by approximately 2 Log10 on day 3. High-cholesterol-fed rats receiving postbiotic yogurt experienced significant reductions in total cholesterol, triglycerides, and LDL levels. Overall results indicate that postbiotics functional yogurt might be a safe and effective strategy for managing cholesterol levels and inhibiting foodborne pathogens.

Antioxidant Properties of Postbiotics: An Overview on the Analysis and Evaluation Methods

Antioxidants found naturally in foods have a significant effect on preventing several human diseases. However, the use of synthetic antioxidants in studies has raised concerns about their potential link to liver disease and cancer. The findings show that postbiotics have the potential to act as a suitable alternative to chemical antioxidants in the food and pharmaceutical sectors. Postbiotics are bioactive compounds generated by probiotic bacteria as they ferment prebiotic fibers in the gut. These compounds can also be produced from a variety of substrates, including non-prebiotic carbohydrates such as starches and sugars, as well as proteins and organic acids, all of which probiotics utilize during the fermentation process. These are known for their antioxidant, antibacterial, anti-inflammatory, and anti-cancer properties that help improve human health. Various methodologies have been suggested to assess the antioxidant characteristics of postbiotics. While there are several techniques to evaluate the antioxidant properties of foods and their bioactive compounds, the absence of a convenient and uncomplicated method is remarkable. However, cell-based assays have become increasingly important as an intermediate method that bridges the gap between chemical experiments and in vivo research due to the limitations of in vitro and in vivo assays. This review highlights the necessity of transitioning towards more biologically relevant cell-based assays to effectively evaluate the antioxidant activity of postbiotics. These experiments are crucial for assessing the biological efficacy of dietary antioxidants. This review focuses on the latest applications of the Caco-2 cell line in the assessment of cellular antioxidant activity (CAA) and bioavailability. Understanding the impact of processing processes on the biological properties of postbiotic antioxidants can facilitate the development of new food and pharmaceutical products.

New clues for postbiotics to improve host health: a review from the perspective of function and mechanisms

Strain activity and stability severely limit the beneficial effects of probiotics in modulating host health. Postbiotics have emerged as a promising alternative as they can provide similar or even enhanced efficacy to probiotics, even under inactivated conditions. This review introduces the ingredients, preparation, and identification techniques of postbiotics, focusing on the comparison of the advantages and limitations between probiotics and postbiotics based on their mechanisms and applications. Inactivation treatment is the most significant difference between postbiotics and probiotics. We highlight the use of emerging technologies to inactivate probiotics, optimize process conditions to maintain the activity of postbiotics, or scale up their production. Postbiotics have high stability which can overcome unfavorable factors, such as easy inactivation and difficult colonization of probiotics after entering the intestine, and are rapidly activated, allowing continuous and rapid optimization of the intestinal microecological environment. They provide unique mechanisms, and multiple targets act on the gut-organ axis, co-providing new clues for the study of the biological functions of postbiotics. We summarize the mechanisms of action of inactivated lactic acid bacteria, highlighting that the NF-κB and MAPK pathways can be used as immune targeting pathways for postbiotic modulation of host health. Generally, we believe that as the classification, composition, and efficacy mechanism of postbiotics become clearer they will be more widely used in food, medicine, and other fields, greatly enriching the dimensions of food innovation. © 2024 Society of Chemical Industry.

Microbial Contamination of Food: Probiotics and Postbiotics as Potential Biopreservatives

Microbial contamination of food and alimentary toxoinfection/intoxication in humans are commonly caused by bacteria such as Salmonella spp., Escherichia coli, Yersinia spp., Campylobacter spp., Listeria monocytogenes, and fungi (Aspergillus, Fusarium). The addition of probiotic cultures (bacterial strains Lactobacillus and Bifidobacterium and the yeast Saccharomyces cerevisiae var. boulardii) to food contributes primarily to food enrichment and obtaining a functional product, but also to food preservation. Reducing the number of viable pathogenic microorganisms and eliminating or neutralizing their toxins in food is achieved by probiotic-produced antimicrobial substances such as organic acids (lactic acid, acetic acid, propionic acid, phenylacetic acid, and phenyllactic acid), fatty acids (linoleic acid, butyric acid, caproic acid, and caprylic acid), aromatic compounds (diacetyl, acetaldehyde, reuterin), hydrogen peroxide, cyclic dipeptides, bacteriocins, and salivabactin. This review summarizes the basic facts on microbial contamination and preservation of food and the potential of different probiotic strains and their metabolites (postbiotics), including the mechanisms of their antimicrobial action against various foodborne pathogens. Literature data on this topic over the last three decades was searched in the PubMed, Scopus, and Google Scholar databases, systematically presented, and critically discussed, with particular attention to the advantages and disadvantages of using probiotics and postbiotics as food biopreservatives.

Nutritional aphrodisiacs: Biochemistry and Pharmacology

In 2022, the global prevalence of erectile dysfunction (ED) was estimated to be at least 150 million cases. This number is greatly suspected to be underestimate as most men withhold information about ED. Also, about 15% of world population have infertility troubles, and male factors are responsible for almost half of these cases. Studies have shown that the quality of semen has decreased in the past several decades owing to various health factors and environmental toxicants. The current medical interventions involve the inhibition of phosphodiesterase 5 which suffer from serious side effects and costly. One of the popular and most sought interventions are the natural and nutritional remedies as they are foods in essence and potentially with no harm to the body. Therefore, the goal of this paper is to provide a review of the most common nutritional aphrodisiacs with increasing libido and fertility highlighting the potential active constituents as well as the underlying mechanisms.

Heat-killed Lactiplantibacillus plantarum Shinshu N-07 exerts antiobesity effects in western diet-induced obese mice

AIMS

The aim of this study was to evaluate the antiobesity effects of heat-killed Lactiplantibacillus plantarum Shinshu N-07 (N-07) isolated from fermented Brassica rapa L.

METHODS AND RESULTS

Male mice were divided into three groups (n = 10/group); normal diet, western diet (WD), or WD + N-07 (N-07) group and administered each diet for 56 days. The N-07 group showed significant suppression of body weight gain and epididymal fat, perirenal fat, and liver weights compared with the WD group. Higher levels of fecal total cholesterol, triglyceride (TG), and free fatty acid (FFA) were observed in the N-07 group than in the WD group. The mRNA expression of the cholesterol transporter ATP-binding cassette transporter G5 (ABCG5) was significantly increased in the small intestine of N-07-fed mice compared with WD-fed mice. Moreover, N-07 supplementation significantly increased the mRNA expression of ABCG5 and ABCG8 in Caco-2 cells. Furthermore, the TG- and FFA-removal ability of N-07 was confirmed to evaluate its soybean oil- and oleic acid-binding capacities in in vitro experiments.

CONCLUSIONS

The antiobesity effects of N-07 might be due to its ability to promote lipid excretion by regulating cholesterol transporter expression and lipid-binding ability.

Potential of postbiotics for the treatment of metabolic disorders

Postbiotics, the next generation of probiotics, are extracts that are free of living and nonviable bacteria and show strong modulatory effects on the gut flora. Examples include vitamin B12, vitamin K, folate, lipopolysaccharides, enzymes, and short-chain fatty acids (SCFAs), representing a subset of essential nutrients commonly found in the human diet. Postbiotics have been observed to demonstrate antiobesity and antidiabetic effects through a variety of mechanisms. These pathways primarily involve an elevation in energy expenditure, a decrease in the formation and differentiation of adipocytes and food intake, modification of lipid and carbohydrate absorption and metabolism, and regulation of gut dysbiosis. Based on these above effects and mechanisms, the use of postbiotics can be considered as potential strategy for the treatment of metabolic disorders.

Postbiotic potential of Bacillus velezensis KMU01 cell-free supernatant for the alleviation of obesity in mice

Attention toward the preventive effects of postbiotics on metabolic diseases has increased because of greater stability and safety over probiotics. However, studies regarding the bioactive effects of postbiotics, especially from probiotic Bacillus strains, are relatively limited. The anti-obesity effects of the cell-free culture supernatant of Bacillus velezensis KMU01 (CFS-B.vele) were evaluated using high-fat-diet (HFD)-induced mice. HFD-induced mice (n = 8 per group) received equal volumes of (1) CFS-B.vele (114 mg/kg) in PBS, (2) Xenical in PBS, or (3) PBS alone by oral gavage daily for 13 weeks. The results demonstrated that CFS-B.vele changed the gut microbiota and showed anti-obesity effects in HFD-induced obese mice. The elevated Firmicutes/Bacteroidota ratio induced by HFD was decreased in the CFS-B.vele group compared to the other groups (p < 0.05). The CFS-B.vele intervention led to the enrichment of SCFA-producers, such as Roseburia and Eubacterium, in the cecum, suggesting their potential involvement in the amelioration of obesity. Due to these changes, the various obesity-related biomarkers (body weight, fat in tissue, white adipose tissue weight and size, serum LDL-cholesterol level, hepatic lipid accumulation, and adipogenesis/lipogenesis-related gene/protein expression) were improved. Our findings suggest that CFS-B.vele has potential as a novel anti-obesity agent through modulation of the gut microbiota.

Microbial-Based Bioactive Compounds to Alleviate Inflammation in Obesity

The increased prevalence of obesity with several other metabolic disorders, including diabetes and non-alcoholic fatty liver disease, has reached global pandemic proportions. Lifestyle changes may result in a persistent positive energy balance, hastening the onset of these age-related disorders and consequently leading to a diminished lifespan. Although suggestions have been raised on the possible link between obesity and the gut microbiota, progress has been hampered due to the extensive diversity and complexities of the gut microbiota. Being recognized as a potential biomarker owing to its pivotal role in metabolic activities, the dysregulation of the gut microbiota can give rise to a persistent low-grade inflammatory state associated with chronic diseases during aging. This chronic inflammatory state, also known as inflammaging, induced by the chronic activation of the innate immune system via the macrophage, is controlled by the gut microbiota, which links nutrition, metabolism, and the innate immune response. Here, we present the functional roles of prebiotics, probiotics, synbiotics, and postbiotics as bioactive compounds by underscoring their putative contributions to (1) the reduction in gut hyperpermeability due to lipopolysaccharide (LPS) inactivation, (2) increased intestinal barrier function as a consequence of the upregulation of tight junction proteins, and (3) inhibition of proinflammatory pathways, overall leading to the alleviation of chronic inflammation in the management of obesity.

Postbiotics: the new horizons of microbial functional bioactive compounds in food preservation and security

In recent decades, consumers, manufacturers, and researchers have been more interested in functional foods, which include probiotics, prebiotics, and postbiotics. Probiotics are live microbes that, when regulated in enough quantities, provide health benefits on the host, while the prebiotics are substrates that host microorganisms selectively use. Postbiotics are metabolites and cell-wall components that are beneficial to the host and are released by living bacteria or after lysis. Postbiotic dietary supplements are more stable than probiotics and prebiotics. Many bioactivities of postbiotics are unknown or poorly understood. Hence, this study aims to present a synopsis of the regular elements and new developments of the postbiotics including health-promoting effects, production, conceptualization of terms, bioactivities, and applications in the field of food safety and preservation. Postbiotics aid in bio preservation and the reduction of biofilm development in food due to their organic acids, bacteriocins, and other antibacterial activities. The present study examines the production of postbiotic metabolites in situ in food and the effects of external and internal food components. The antimicrobial roles, removal of biofilms, and its applications in preservation and food safety have also been discussed. This paper also explored the various aspects like manipulation of postbiotic composition in the food system and its safety measures.

Graphical Abstract

Decoding the role of the gut microbiome in gut-brain axis, stress-resilience, or stress-susceptibility: A review

Increased exposure to stress is associated with stress-related disorders, including depression, anxiety, and neurodegenerative conditions. However, susceptibility to stress is not seen in every individual exposed to stress, and many of them exhibit resilience. Thus, developing resilience to stress could be a big breakthrough in stress-related disorders, with the potential to replace or act as an alternative to the available therapies. In this article, we have focused on the recent advancements in gut microbiome research and the potential role of the gut-brain axis (GBA) in developing resilience or susceptibility to stress. There might be a complex interaction between the autonomic nervous system (ANS), immune system, endocrine system, microbial metabolites, and bioactive lipids like short-chain fatty acids (SCFAs), neurotransmitters, and their metabolites that regulates the communication between the gut microbiota and the brain. High fiber intake, prebiotics, probiotics, plant supplements, and fecal microbiome transplant (FMT) could be beneficial against gut dysbiosis-associated brain disorders. These could promote the growth of SCFA-producing bacteria, thereby enhancing the gut barrier and reducing the gut inflammatory response, increase the expression of the claudin-2 protein associated with the gut barrier, and maintain the blood-brain barrier integrity by promoting the expression of tight junction proteins such as claudin-5. Their neuroprotective effects might also be related to enhancing the expression of brain-derived neurotrophic factor (BDNF) and glucagon-like peptide (GLP-1). Further investigations are needed in the field of the gut microbiome for the elucidation of the mechanisms by which gut dysbiosis contributes to the pathophysiology of neuropsychiatric disorders.

Weight Loss Supplements

Being overweight or obese can predispose people to chronic diseases and metabolic disorders such as cardiovascular illnesses, diabetes, Alzheimer's disease, and cancer, which are costly public health problems and leading causes of mortality worldwide. Many people hope to solve this problem by using food supplements, as they can be self-prescribed, contain molecules of natural origin considered to be incapable of causing damage to health, and the only sacrifice they require is economic. The market offers supplements containing food plant-derived molecules (e.g., primary and secondary metabolites, vitamins, and fibers), microbes (probiotics), and microbial-derived fractions (postbiotics). They can control lipid and carbohydrate metabolism, reduce appetite (interacting with the central nervous system) and adipogenesis, influence intestinal microbiota activity, and increase energy expenditure. Unfortunately, the copious choice of products and different legislation on food supplements worldwide can confuse consumers. This review summarizes the activity and toxicity of dietary supplements for weight control to clarify their potentiality and adverse reactions. A lack of research regarding commercially available supplements has been noted. Supplements containing postbiotic moieties are of particular interest. They are easier to store and transport and are safe even for people with a deficient immune system.

Aging Changes the Efficacy of Central Urocortin 2 to Induce Weight Loss in Rats

Middle-aged obesity and aging cachexia present healthcare challenges. Central responsiveness to body-weight-reducing mediators, e.g., to leptin, changes during aging in a way, which may promote middle-aged obesity and aging cachexia. Leptin is connected to urocortin 2 (Ucn2), an anorexigenic and hypermetabolic member of the corticotropin family. We aimed to study the role of Ucn2 in middle-aged obesity and aging cachexia. The food intake, body weight and hypermetabolic responses (oxygen consumption, core temperature) of male Wistar rats (3, 6, 12 and 18 months) were tested following intracerebroventricular injections of Ucn2. Following one central injection, Ucn2-induced anorexia lasted for 9 days in the 3-month, 14 days in the 6-month and 2 days in the 18-month group. Middle-aged 12-month rats failed to show anorexia or weight loss. Weight loss was transient (4 days) in the 3-month, 14 days in the 6-month and slight but long-lasting in the 18-month rats. Ucn2-induced hypermetabolism and hyperthermia increased with aging. The age-dependent changes in the mRNA expression of Ucn2 detected by RNAscope in the paraventricular nucleus correlated with the anorexigenic responsiveness. Our results show that age-dependent changes in Ucn2 may contribute to middle-aged obesity and aging cachexia. Ucn2 shows potential in the prevention of middle-aged obesity.