Reducing the risk of infection in the elderly by dietary intake of yoghurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1

Draft genome sequences of eight strains isolated from homemade yogurts and cheeses from Bulgaria

Here, we report draft genome sequences of eight strains isolated from naturally processed, homemade dairy foods or human milk in Bulgaria; strains Lactobacillus gasseri AM-LG-29, Lactiplantibacillus plantarum AM-LP-81, Lactobacillus helveticus AM-LH-32, Lactobacillus delbrueckii subsp. bulgaricus AM-LB-13, Streptococcus thermophilus AM-ST-89, Lactobacillus acidophilus AM-LA-19, Bifidobacterium longum AM-BL-55, and Lacticaseibacillus rhamnosus AM-LR-51.

Heyndrickxia coagulans strain SANK70258 suppresses symptoms of upper respiratory tract infection via immune modulation: a randomized, double-blind, placebo-controlled, parallel-group, comparative study

Probiotic consumption strongly influences local intestinal immunity and systemic immune status. Heyndrickxia coagulans strain SANK70258 (HC) is a spore-forming lactic acid bacterium that has immunostimulatory properties on peripheral tissues. However, few reports have examined the detailed effectiveness of HC on human immune function and its mechanism of action. Therefore, we conducted a randomized, double-blind, placebo-controlled, parallel-group study to comprehensively evaluate the effects of HC on immunostimulatory capacity, upper respiratory tract infection (URTI) symptoms, and changes in intestinal organic-acid composition. Results of a questionnaire survey of URTI symptoms showed that runny nose, nasal congestion, sneezing, and sore throat scores as well as the cumulative number of days of these symptoms were significantly lower in the HC group than in the placebo group during the study period. Furthermore, the salivary secretory immunoglobulin A (sIgA) concentration was significantly higher, and the natural killer (NK) cell activity tended to be higher in the HC group than in the placebo group. In addition, we performed an exposure culture assay of inactivated influenza virus on peripheral blood mononuclear cells (PBMCs) isolated from the blood of participants in the HC and placebo groups. Gene-expression analysis in PBMCs after culture completion showed that IFNα and TLR7 expression levels were significantly higher in the HC group than in the placebo group. In addition, the expression levels of CD304 tended to be higher in the HC group than in the placebo group. On the other hand, the HC group showed a significantly higher increase in the intestinal butyrate concentration than the placebo group. HC intake also significantly suppressed levels of IL-6 and TNFα produced by PBMCs after exposure to inactivated influenza virus. Collectively, these results suggest that HC activated plasmacytoid dendritic cells expressing TLR7 and CD304 and strongly induced IFNα production, subsequently activating NK cells and increasing sIgA levels, and induced anti-inflammatory effects via increased intestinal butyrate levels. These changes may contribute to the acquisition of host resistance to viral infection and URTI prevention.

Polysaccharides from a Fermented Beverage Induce Nitric Oxide and Cytokines in Murine Macrophage Cell Line

Super Ohtaka®, a fermented beverage of plant extracts, is prepared from approximately 50 kinds of fruits and vegetables. Natural fermentation is mainly performed by lactic acid bacteria (Leuconostoc spp.) and yeast (Zygosaccharomyces spp.). Four water-soluble polysaccharide fractions were obtained from Super Ohtaka® by dialysis, ion exchange chromatography, and gel filtration chromatography; these fractions were designated as OEP1-1, OEP1-2, OEP2, and OEP3. OEP1-1 is a polysaccharide composed solely of glucose. The other fractions contained polysaccharides composed of glucose, galactose, mannose, and a small amount of arabinose. OEP2 and OEP3 contained phosphorus, which was not detected in OEP1-1 and OEP1-2. Furthermore, the immunomodulatory activity of the polysaccharides was investigated in murine macrophage cell lines. OEP2 and OEP3 significantly induced nitric oxide (NO) secretion by macrophages in a dose-dependent manner (concentration range of 4 to 100 µg/mL). When the concentration of OEP3 was 100 µg/mL, NO production was almost identical to lipopolysaccharide (LPS; 10 ng/mL) used as a positive control. Notably, OEP3 induced NO secretion more strongly than OEP2. This trend was also observed for TNF-α, IL-1β, IL-6, and IL-12 p40 secretion. Overall, our in vitro studies on polysaccharides isolated from Super Ohtaka® suggest that the fermented beverage stimulates macrophages and activates the immune system.

The Influence of Probiotic Lactobacilli on COVID-19 and the Microbiota

This comprehensive review explores the potential of using lactobacilli as a probiotic in the management of COVID-19. Our findings suggest that lactobacilli show promise in reducing the risk of death, gastrointestinal and overall symptoms, and respiratory failure, as well as in lowering cytokines and inflammatory markers associated with the disease. The molecular mechanisms by which lactobacilli protect against COVID-19 and other viral infections may be related to the reduction in inflammation, modulation of the immune response, and direct interaction with viruses to produce antiviral substances. However, the selected studies demonstrate the presence of mixed findings for various clinical, biochemical, hematological, and immunological parameters, which may be attributed to methodological differences among studies. We highlight the importance of clearly describing randomization processes to minimize bias and caution against small sample sizes and inappropriate statistical tests that could lead to errors. This review offers valuable insights into the therapeutic potential of lactobacilli in the context of COVID-19 and identifies avenues for further research and applications. These findings hold promise for the development of novel approaches to managing COVID-19 and warrant further investigation into the potential benefits of lactobacilli in combating the disease.

The effect of bovine dairy products and their components on the incidence and natural history of infection: a systematic literature review

BACKGROUND

Dairy products and their components may impact immune function, although the current evidence base has some research gaps. As part of a larger systematic literature review of dairy products/components (including probiotics, dairy proteins, and dairy fats) and immune function, we identified the available epidemiologic research on the impact of dairy products/components on incidence and natural history of infectious diseases.

METHODS

PubMed and Embase databases were systematically searched through May 2022 to identify eligible studies using pre-defined Population, Intervention, Comparator, Outcomes, and Study design criteria. Herein, we focused on describing the impacts of dairy product/component on infectious disease outcomes, including the effect on leukocyte and cytokine response in humans. Risk of bias assessment was performed using the Academy of Nutrition and Dietetics Quality Criteria Checklist. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed.

RESULTS

Among 9,832 studies identified from the larger literature search, 133 relevant publications from 128 studies reported on dairy product/component and infectious disease outcomes. Few studies are available on the impact of non-fermented milk and traditional yogurt on infectious disease. Evidence was identified to suggest milk and yogurt drinks fermented with Lactobacillus strains reduce the risk and burden of common infectious diseases (CIDs), although the findings are mixed and difficult to reconcile due to heterogenous study populations, bacterial strains, and study methods. Few studies are available on the impact of dairy products/components on the natural history of infection, with the available findings indicating probiotics may both improve gastrointestinal symptoms among HIV-infected persons and help eradicate and alleviate the symptoms of Heliobacter (H.) pylori. The available evidence also suggests lactoferrin may reduce the virological burden of COVID-19 and hepatitis C virus. No consistent changes in leukocytes or cytokine production were observed for any type of dairy product or their components, but probiotics appeared to enhance natural killer cell levels/activity and the phagocytic process.

CONCLUSIONS

Dairy products, particularly those with added probiotics, may represent an easily accessible nutritional intervention to prevent and improve the course of infectious diseases. This review highlights the need for additional research in this potentially impactful area.

PROSPERO REGISTRATION

CRD42022333780.

Lactobacilli in COVID-19: A Systematic Review Based on Next-Generation Sequencing Studies

The global pandemic was caused by the SARS-CoV-2 virus, known as COVID-19, which primarily affects the respiratory and intestinal systems and impacts the microbial communities of patients. This systematic review involved a comprehensive search across the major literature databases to explore the relationship between lactobacilli and COVID-19. Our emphasis was on investigations employing NGS technologies to explore this connection. Our analysis of nine selected studies revealed that lactobacilli have a reduced abundance in the disease and an association with disease severity. The protective mechanisms of lactobacilli in COVID-19 and other viral infections are likely to be multifaceted, involving complex interactions between the microbiota, the host immune system, and the virus itself. Moreover, upon closely examining the NGS methodologies and associated statistical analyses in each research study, we have noted concerns regarding the approach used to delineate the varying abundance of lactobacilli, which involves potential biases and the exclusion of pertinent data elements. These findings provide new insight into the relationship between COVID-19 and lactobacilli, highlighting the potential for microbiota modulation in COVID-19 treatment.

Overview of anti-viral effects of probiotics via immune cells in pre-, mid- and post-SARS-CoV2 era

The COVID-19 outbreak has caused significant global changes and increased public awareness of SARS-CoV-2. Substantial progress in developing vaccines, enhancing sanitation practices, and implementing various measures to combat the virus, including the utilization of probiotics has been made. This comprehensive review examined the medical impact of clinically proven probiotics on infectious diseases, considering three crucial time periods: before (pre-), during (mid-), and after (post-) COVID-19 pandemic era. This review also showed a perspective on the use of probiotics to stimulate the innate immune system and prevent infectious diseases. In pre-COVID-19 era, several probiotic strains were found to be clinically effective in addressing gastrointestinal infectious diseases, the common cold and flu. However, the mechanism by which probiotics exerted their antiviral effects remained relatively unclear during that period. Nevertheless, probiotics, Lactococcus lactis strain Plasma (LC-Plasma), and others have gained attention for their unique ability to modulate the immune system and demonstrate antiviral properties. While some probiotics have shown promise in alleviating gastrointestinal symptoms linked to COVID-19, their direct effectiveness in treating or preventing COVID-19 progression has not yet been conclusively established. As we transition into the post-COVID-19 era, the relationship between COVID-19 and plasmacytoid dendritic cells (pDCs), a vital component of the innate immune system, has been gradually elucidated. These findings are now being applied in developing novel vaccines and treatments involving interferons and in immune activation research using probiotics as adjuvants, comparable to CpG-DNA through TLR9. The role of the local innate immune system, including pDCs, as the first line of defense against viral infections has gained increasing interest. Moving forward, insight of the immune system and the crosstalk between probiotics and the innate immune system is expected to highlight the role of probiotics in adjunctive immunoregulatory therapy. In combination with drug treatments, probiotics may play a more substantial role in enhancing immune responses. The immunoregulatory approach using probiotics such as LC-Plasma, which can induce anti-infectious factors such as interferons, holds promise as a viable therapeutic and prophylactic option against viral infectious diseases due to their good safety profile and protective efficacy.

Probiotics in prevention and treatment of COVID-19: a systematic review of current evidence

Introduction. Clinical evidence suggests that certain probiotics may help treat and prevent viral infections. To date, the effectiveness of probiotics in the alleviation of COVID-19 has not been established. The aim of this systematic review was to assess the role of probiotics in the prevention and treatment of COVID-19. Materials and methods. An extensive search of four electronic databases was performed which included Embase, Scopus, Web of Science, and PubMed from November 2019 to June 2022. After reviewing the references list of related articles additional studies were identified. A multiple combination of keywords validated by MESH were used to search the databases. Study selection was performed according to an inclusion and exclusion criteria. Results. Twenty-three articles met the study inclusion criteria. Six articles were conducted in vitro while the remaining studies were conducted in the human population (in vivo). The type of probiotic was defined in eighteen studies. There were two studies that used supplements (vitamins, herbals, minerals, etc.) in addition to probiotics. The largest sample size was 445 850 participants which were from a study that used an application-based survey. The majority of studies found that probiotics had a positive effect on the COVID-19 disease. The benefits included early remission of COVID-19 symptoms and a shorter duration of sickness (10 studies), lower mortality rates (3 studies), and decreased hospitalization and length of stay (3 studies). Six in vitro studies found that probiotics were beneficial against SARS-CoV-2 through antiviral effects. There were only two studies that found probiotics to be ineffective or caused negative effects when consumed in COVID-19 patients. Conclusion. Available evidence supports the antiviral role of probiotics on prevention and treatment of COVID-19. The antiviral potential of Lactobacillus paracasei metabolite PlnE and PlnF against SARS-CoV-2 may explain the effectiveness of probiotics on COVID-19.

Lactic Acid Bacteria and Aging: Unraveling the Interplay for Healthy Longevity

Lactic Acid Bacteria (LAB) are beneficial microorganisms widely utilized in food fermentation processes and as probiotic supplements. They offer multifarious health benefits, including enhancing digestion, strengthening immune mechanisms, and mitigating inflammation. Recent studies suggest that LAB might be instrumental in the anti-aging domain, modulating key molecular pathways involved in the aging continuum, such as IL-13, TNF-α, mTOR, IFN-γ, TGF-β, AMPK, and GABA. The TLR family, particularly TLR2, appears pivotal during the primary cellular interactions with bacteria and their byproducts. Concurrently, the Sirtuin family, predominantly Sirtuin-1, plays diverse roles upon cellular stimuli by bacterial components. The potential anti-aging benefits postulated include restoring gut balance, enhancing antioxidant potential, and fortifying cognitive and mental faculties. However, the current body of evidence is still embryonic and calls for expansive human trials and deeper mechanistic analyses. The safety and optimal consumption metrics for LAB also warrant rigorous evaluation. Future research trajectories should identify specific LAB strains with potent anti-aging properties and unravel the underlying biological pathways. Given the promising implications, LAB strains stand as potential dietary contenders to foster healthy aging and enrich the quality of life among the elderly population.

The Potential of Probiotics as Ingestible Adjuvants and Immune Modulators for Antiviral Immunity and Management of SARS-CoV-2 Infection and COVID-19

Probiotic bacteria are able to modulate general antiviral responsiveness, including barrier functionality and innate and adaptive immune responses. The COVID-19 pandemic, resulting from SARS-CoV-2 infection, has created a need to control and treat this viral infection and its ensuing immunopathology with a variety of approaches; one such approach may involve the administration of probiotic bacteria. As with most viral infections, its pathological responses are not fully driven by the virus, but are significantly contributed to by the host's immune response to viral infection. The potential adoption of probiotics in the treatment of COVID-19 will have to appreciate the fine line between inducing antiviral immunity without over-provoking immune inflammatory responses resulting in host-derived immunopathological tissue damage. Additionally, the effect exerted on the immune system by SARS-CoV-2 evasion strategies will also have to be considered when developing a robust response to this virus. This review will introduce the immunopathology of COVID-19 and the immunomodulatory effects of probiotic strains, and through their effects on a range of respiratory pathogens (IAV, SARS-CoV, RSV), as well as SARS-CoV-2, will culminate in a focus on how these bacteria can potentially manipulate both infectivity and immune responsiveness via barrier functionality and both innate and adaptive immunity. In conclusion, the harnessing of induction and augmentation of antiviral immunity via probiotics may not only act as an ingestible adjuvant, boosting immune responsiveness to SARS-CoV-2 infection at the level of barrier integrity and innate and adaptive immunity, but also act prophylactically to prevent infection and enhance protection afforded by current vaccine regimens.

The Multi-Strain Probiotic OMNi-BiOTiC® Active Reduces the Duration of Acute Upper Respiratory Disease in Older People: A Double-Blind, Randomised, Controlled Clinical Trial

Immunosenescence is the adverse change in the human immune function during aging, leaving older people more prone to an increased risk of infections and morbidity. Acute upper respiratory tract infections (URTIs) are very common among older people, often resulting in continued morbidity and mortality. Therefore, approaches, such as consuming probiotics, that shorten the duration or even reduce the incidence of URTIs in older people are being studied. The aim of this study was to determine the effects of a multi-strain probiotic OMNi-BiOTiC^® Active, which contains 11 live probiotic strains, on the incidence, duration, and severity of URTIs in older people. In this randomized double-blinded placebo-controlled study, 95 participants, with an average age of 70.9 years in the probiotic group and 69.6 years in the placebo group, were randomly allocated to two groups: 10¹⁰ cfu per day of the multi-strain probiotic intervention OMNi-BiOTiC^® Active (49) or placebo (46). The incidence of URTIs in older people after 12 weeks supplementation with OMNi-BiOTiC^® showed no statistically significant difference between the two groups (p = 0.5244). However, the duration of the URTI infections was statistically significantly different between the groups (p = 0.011). The participants that consumed the probiotic had an average duration of illness of 3.1 ± 1.6 days, whilst participants that received the placebo had symptoms for an average of 6.0 ± 3.8 days (p = 0.011). Statistically significant differences in lymphocyte counts in both groups after supplementation (p = 0.035 for the probiotic group and p = 0.029 for the placebo group) and between both groups were found (p = 0.009). Statistically significant differences in eosinophil (p = 0.002) and basophil counts (p = 0.001) in the probiotic groups before and after supplementation with probiotics were also found. Supplementation with the multi-strain probiotic OMNi-BiOTiC^® Active may benefit older people with URTIs. Larger randomised controlled clinical trials are warranted. Clinical Trial Registration; identifier NCT05879393.

The Impact of (COVID)-19 on Beverage Purchasing Behaviors in Korea

Objective: In this study, we examined changes in purchase behavior of alcoholic beverages (ie, soju, beer, wine, traditional Korean liquor, and liquor) and non-alcoholic beverages (ie, fruit and vegetable juices, coffee, tea, bottled water, milk, yogurt, and plant-based milk) before and after the COVID-19 pandemic. Methods: Monthly beverage expenditure data, based on Korean household demographic information, was used for 3 years and 6 months. The 2-part model was used for analysis. To examine the effect of COVID-19, beverage expenditure was analyzed after dividing it into short-term and long-term effects. Results: Our results show that the probability of purchasing alcoholic beverages increased owing to the long-term effect of the COVID-19 pandemic. The amounts of beer, wine, and traditional Korean liquor purchased increased in the long-term. The purchase of sweet drinks decreased (ie, fruit and vegetable juices and yogurt) in the long-term because of the effect of the pandemic. On the other hand, tea, water, and plant-based milk expenditures increased. Conclusion: This beverage consumption pattern reflects both unhealthy (ie, an increase in alcoholic beverage purchases) and healthy drinking behaviors (ie, a decrease in sweet beverage purchases and an increase in tea, water, and plant-based milk purchases).

Effect of probiotics as an immune modulator for the management of COVID-19

COVID-19, an acute respiratory viral infection conveyed by pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected millions of individuals globally, and is a public health emergency of international concern. Till now, there are no highly effective therapies for this infection without vaccination. As they can evolve quickly and cross the strain level easily, these viruses are causing epidemics or pandemics that are allied with more severe clinical diseases. A new approach is needed to improve immunity to confirm the protection against emerging viral infections. Probiotics can modify gut microbial dysbiosis, improve the host immune system, and stimulate immune signaling, increasing systemic immunity. Several probiotic bacterial therapies have been proven to decrease the period of bacterial or viral infections. Superinduction of inflammation, termed cytokine storm, has been directly linked with pneumonia and severe complications of viral respiratory infections. In this case, probiotics as potential immunomodulatory agents can be an appropriate candidate to improve the host's response to respiratory viral infections. During this COVID-19 pandemic, any approach that can induce mucosal and systemic immunity could be helpful. Here, we summarize contexts regarding the effectiveness of various probiotics for preventing virus-induced respiratory infectious diseases, especially those that could be employed for COVID-19 patients. In addition, the effects of probiotics, their mechanisms on different aspects of immune responses against respiratory viral infection, and their antiviral properties in clinical findings have been described in detail.

Probiotic therapy, African fermented foods and food-derived bioactive peptides in the management of SARS-CoV-2 cases and other viral infections

The current paper focuses on the impact of probiotics, African fermented foods and bioactive peptides on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection severity and related viral infections. Using probiotics or bioactive peptides as therapeutic adjuncts appears superior to standard care alone. Probiotics play critical roles in innate and adaptive immune modulation by balancing the gut microbiota to combat viral infections, secondary bacterial infections and microbial dysbiosis. African fermented foods contain abundant potential probiotic microorganisms such as the lactic acid bacteria (LAB), Saccharomyces, and Bacillus. More so, fermented food-derived bioactive peptides play vital roles in preventing cardiovascular diseases, hypertension, lung injury, diabetes, and other COVID-19 comorbidities. Regularly incorporating potential probiotics and bioactive peptides into diets should enable a build-up of the benefits in the body system that may result in a better prognosis, especially in COVID-19 patients with underlying complexities. Despite the reported therapeutic potentials of probiotics and fermented foods, numerous setbacks exist regarding their application in disease management. These shortfalls underscore an evident need for more studies to evaluate the specific potentials of probiotics and traditional fermented foods in ameliorating SARS-CoV-2 and other viral infections.

Change in the Gut Microbiome and Immunity by Lacticaseibacillus rhamnosus Probio-M9

With the exploding growth of the global market for probiotics and the rapid awakening of public awareness to manage health by probiotic intervention, there is still an active debate about whether the consumption of probiotics is beneficial for nonpatients, which is due to the lack of systematic analysis based on time series multiomics data sets. In this study, we recruited 100 adults from a college in China and performed a random case-control study by using a probiotic (Lacticaseibacillus rhamnosus Probio-M9) as an intervention for 6 weeks, aiming to achieve a comprehensive evaluation and understanding of the beneficial effect of Probio-M9 consumption. By testing advanced blood immunity indicators, sequencing the gut microbiome, and profiling the gut metabolome at baseline and the end of the study, we found that although the probiotic intervention has a limited impact on the human immunity and the gut microbiome and metabolome, the associations between the immunity indicators and multiomics data were strengthened, and further analysis of the gut microbiome's genetic variations revealed inhibited generation of single nucleotide variants (SNVs) by probiotic consumption. Taken together, our findings indicated an underestimated influence of the probiotic, not on altering the microbial composition but on strengthening the association between human immunity and commensal microbes and stabilizing the genetic variations of the gut microbiome. IMPORTANCE Although the global market for probiotics is growing explosively, there is still an active debate about whether the consumption of probiotics is beneficial for nonpatients. In this study, we recruited 100 adults from a college in China and performed 6 weeks of intervention for half of the volunteers. By analyzing the time series multiomics data in this study, we found that the probiotic intervention (i) has a limited effect on human immunity or the global structure of the gut microbiome and metabolome, (ii) can largely influence the correlation of the development between multiomics data and immunity, which was not able to be discovered by conventional differential abundance analysis, and (iii) can inhibit the generation of SNVs in the gut microbiome instead of promoting it.

Consumption of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 augments serum antibody titers against seasonal influenza vaccine in healthy adults

Seasonal influenza is a major upper respiratory tract infection occurring in winter. Vaccination is the best method for preventing this infection. We conducted two randomized, double-blind, placebo-controlled trials to examine whether consumption of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1, which has been reported to reduce the risk of catching the common cold, augments serum antibody titers against seasonal influenza vaccines. In the first trial, which included university students, serum antibody titers against influenza A (H3N2) and B viruses were significantly higher in the yogurt group than in the placebo group. According to the guidelines established by the European Medicines Agency (EMA) for the assessment of vaccines, the seroconversion rate and mean geometric increase of influenza A (H3N2) and seroprotection of influenza B met the criteria only in the yogurt group. In the second trial, which included healthy adults, serum antibody titers against influenza A (H1N1) and B viruses were significantly higher in the yogurt group than in the placebo group. The seroconversion rate and mean geometric increase of influenza B met the EMA criteria only in the yogurt group. Furthermore, the cumulative days of ill health, such as throat complaints, upper respiratory inflammation, and cold, were significantly lower in the yogurt group than in the placebo group. Therefore, daily intake of yogurt fermented with L. bulgaricus OLL1073R-1 could reduce the duration of symptoms caused by respiratory infections and act as a mucosal adjuvant enhancing acquired immune responses against vaccines, leading to the improvement of public health.

Anti-Influenza Virus Potential of Probiotic Strain Lactoplantibacillus plantarum YML015 Isolated from Korean Fermented Vegetable

Lactic acid bacteria are one of the potential natural remedies used worldwide, commonly known as probiotics. Here, the aim of this research investigation was to isolate a probiotic Lactobacilli strain, YLM015, from the popular Korean fermented vegetable “Kimchi” and to evaluate its anti-viral potential against influenza virus A (IFVA) H1N1 using the MDCK cell line in vitro, and in embryonated eggs in ovo. The YML015 strain was selected from among the 1200 Lactobacilli isolates for further studies based on its potent anti-viral efficacy. YML015 was identified and characterized as Lactoplantibacillus plantarum YML015 based on the 16S rRNA gene sequencing and biochemically with an API 50 CHL Kit. In ovo assay experienced with embryonated eggs and the hemagglutination inhibition method, as well as cytopathogenic reduction assay, was performed individually to observe anti-influenza viral activity of YML015 against influenza virus A H1N1. Additionally, YML015 was classified for its non-resistance nature as safe for humans and animals as confirmed by the antibiotic susceptibility (MIC) test, cell viability, and hemolysis assay. The heat stability test was also experienced by using different heat-treated cell-free supernatant (CFS) samples of YML015. As a result, YML015 showed highly potent anti-viral activity against influenza virus A H1N1 in vitro in the MDCK cell line. Overall findings suggest that anti-influenza viral activity of L. plantarum YML015 makes it a potential candidate of choice for use as an influential probiotic in pharmacological preparations to protect humans and animals from flu and viral infection.

Probiotics for preventing acute upper respiratory tract infections

BACKGROUND

Probiotics are live micro-organisms that may give a beneficial physiological effect when administered in adequate amounts. Some trials show that probiotic strains can prevent respiratory infections. Even though our previously published review showed the benefits of probiotics for acute upper respiratory tract infections (URTIs), several new studies have been published. This is an update of a review first published in 2011 and updated in 2015.

OBJECTIVES

To assess the effectiveness and safety of probiotics (any specified strain or dose), compared with placebo or no treatment, in the prevention of acute URTIs in people of all ages, at risk of acute URTIs.

SEARCH METHODS

We searched CENTRAL (2022, Issue 6), MEDLINE (1950 to May week 2, 2022), Embase (1974 to 10 May 2022), Web of Science (1900 to 10 May 2022), the Chinese Biomedical Literature Database, which includes the China Biological Medicine Database (from 1978 to 10 May 2022), the Chinese Medicine Popular Science Literature Database (from 2000 to 10 May 2022), and the Master's Degree Dissertation of Beijing Union Medical College Database (from 1981 to 10 May 2022). We searched the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov for completed and ongoing trials on 10 May 2022.

SELECTION CRITERIA

We included individual randomised controlled trials (RCTs) and cluster-RCTs comparing probiotics with placebo or no treatment to prevent acute URTIs. The participants were children, adults, or the elderly in the community, care facilities, schools, or hospitals. Our main outcomes were the number of participants diagnosed with URTIs (at least one event and at least three events), the incidence rate (number of cases/person year) of acute URTIs, and the mean duration of an episode of URTIs. Our secondary outcomes were the number of participants who were absent from childcare centre, school, or work due to acute URTIs; the number of participants who used prescribed antibiotics for acute URTIs; and the number of participants who experienced at least one adverse event from probiotics. We excluded studies if they did not specify acute respiratory infections as 'upper'; studies with more than 50% of participants vaccinated against influenza or other acute URTIs within the last 12 months; and studies with significantly different proportions of vaccinated participants between the probiotics arm and the placebo or no treatment arm.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility of trials and extracted data using standard Cochrane methodological procedures. We analysed both intention-to-treat and per-protocol data and used a random-effects model. We expressed results as risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, both with 95% confidence intervals (CIs). We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 23 individual RCTs and one cluster-RCT. As one of the individual RCTs did not report outcomes in a usable way, we could only meta-analyse data from 23 trials, involving a total of 6950 participants including children (aged from one month to 11 years old), adults (mean age 37.3), and older people (mean age 84.6 years). One trial reported 22.5% flu-vaccine participants within the last 12 months, and 25.4% flu-vaccine participants during the intervention. Probiotics were more likely to be given with milk-based food in children; administered in powder form in adults; and given with milk-based food or in capsules in the elderly. Most of the studies used one or two strains (e.g. Lactobacillus plantarum HEAL9, Lactobacillus paracasei (8700:2 or N1115)) and 109 or 1011 colony-forming units (CFU)/day of probiotics for more than three months. We found that probiotics may reduce the number of participants diagnosed with URTIs (at least one event) (RR 0.76, 95% CI 0.67 to 0.87; P < 0.001; 16 studies, 4798 participants; low-certainty evidence); likely reduce the number of participants diagnosed with URTIs (at least three events) (RR 0.59, 95% CI 0.38 to 0.91; P = 0.02; 4 studies, 763 participants; moderate-certainty evidence); may reduce the incidence rate (number of cases/person year) of URTIs (rate ratio 0.82, 95% CI 0.73 to 0.92, P = 0.001; 12 studies, 4364 participants; low-certainty evidence); may reduce the mean duration of an episode of acute URTIs (MD -1.22 days, 95% CI -2.12 to -0.33; P = 0.007; 6 studies, 2406 participants; low-certainty evidence); likely reduce the number of participants who used prescribed antibiotics for acute URTIs (RR 0.58, 95% CI 0.42 to 0.81; P = 0.001; 6 studies, 1548 participants; moderate-certainty evidence); and may not increase the number of participants who experienced at least one adverse event (RR 1.02, 95% CI 0.90 to 1.15; P = 0.79; 8 studies, 2456 participants; low-certainty evidence). Evidence showing a decrease in the number of people absent from childcare centre, school, or work due to acute URTIs with probiotics is very uncertain (RR 0.14, 95% CI 0.03 to 0.59; 1 study, 80 participants; very low-certainty evidence). Adverse events from probiotics were minor, and most commonly gastrointestinal symptoms, such as vomiting, flatulence, diarrhoea, and bowel pain.  AUTHORS' CONCLUSIONS: Overall, we found that probiotics were better than placebo or no treatment in preventing acute URTIs.

Bioactive metabolites in functional and fermented foods and their role as immunity booster and anti-viral innate mechanisms

Live microorganisms in the fermented foods termed probiotics and their secondary metabolites with bioactive potential were considered as potential anti-viral capabilities through various mechanisms. Given the importance of functional and fermented foods in disease prevention, there is a need to discuss the contextualization and deep understanding of the mechanism of action of these foods, particularly considering the appearance of coronavirus (COVID-19) pandemic, which is causing health concerns and increased social services globally. The mechanism of probiotic strains or their bioactive metabolites is due to stimulation of immune response through boosting T-lymphocytes, cytokines, and cell toxicity of natural killer cells. Proper consumption of these functional and fermented foods may provide additional antiviral approaches for public benefit by modulating the immune functions in the hosts.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05528-8.

Red yeast rice dietary intervention reduces oxidative stress-related inflammation and improves intestinal microbiota

Inflammation and oxidative stress play key roles in the aging process, while red yeast rice (RYR), a traditional Chinese fermented food, has anti-oxidant and anti-inflammatory effects. To understand the anti-aging function of RYR in vivo, this study established a D-galactose-induced aging mouse model to verify the positive effects of RYR dietary intervention on aging and explore the related underlying mechanism. Eight weeks of RYR dietary intervention was shown to have a significant inhibitory effect on cognitive decline and hippocampal damage. The molecular mechanistic studies showed that the anti-aging effects of RYR were achieved by (i) improving the oxidative stress-related damage (increasing SOD, CAT, and GSH, and reducing MDA), (ii) regulating the NF-κB inflammation pathway induced by oxidative stress (decreasing the pro-inflammatory cytokines IL-6, TNF-α, IFN-γ, iNOs, and IL-1β, increasing the anti-inflammatory cytokine IL-10, and decreasing the expression of the NF-κB protein), (iii) slowing down apoptosis caused by oxidative stress (reducing the expression of P21 and P53), (iv) restoring the abundance of Lactobacillus, Lachnospiraceae and Rikenellaceae downregulated by D-galactose, and (v) reducing the abundance of Akkermansia and Helicobacter enriched by D-galactose. Mass spectrometry revealed orange pigments (rubropunctatin and monascorubrin) as the main antioxidant components in RYR, which might play key roles in aging inhibition. This study provides theoretical support for the wide application of orange pigments as an antioxidant dietary supplement.

Fermented Foods and Their Role in Respiratory Health: A Mini-Review

Fermented foods (FFs) hold global attention because of their huge advantages. Their health benefits, palatability, preserved, tasteful, and aromatic properties impart potential importance in the comprehensive evaluation of FFs. The bioactive components, such as minerals, vitamins, fatty acids, amino acids, and other phytochemicals synthesized during fermentation, provide consumers with several health benefits. Fermentation of food is an ancient process that has met with many remarkable changes owing to the development of scientific technologies over the years. Initially, fermentation relied on back-slapping. Nowadays, starter cultures strains are specifically chosen for the type of fermentation process. Modern biotechnological methods are being implemented in the fermentation process to achieve the desired product in high quality. Respiratory and gastrointestinal tract infections are the most severe health issues affecting human beings of all age groups, especially children and older adults, during this COVID-19 pandemic period. Studies suggest that the consumption of probiotic Lactobacillus strains containing fermented foods protects the subjects from common infectious diseases (CIDs, which is classified as upper respiratory tract infections, lower respiratory tract infections and gastrointestinal infections) by improving the host’s immune system. Further studies are obligatory to develop probiotic-based functional FFs that are effective against CIDs. Presently, we are urged to find alternative, safe, and cost-effective prevention measures against CIDs. The current manuscript briefs the production of FFs, functional properties of FFs, and their beneficial effects against respiratory tract infections. It summarizes the outcomes of clinical trials using human subjects on the effects of supplementation of FFs.

Potential Antiviral Activity of Lactiplantibacillus plantarum KAU007 against Influenza Virus H1N1

The development of antiviral resistance has exacerbated a growing threat to public health. As a result, there is increasing demand for unconventional antivirals that can effectively replace the presently in-use drugs. Lactic acid-producing bacteria (LAB) are among the most common bacteria used in the food industry. These bacteria play an essential role in the fermentation of many foods and feed. Additionally, these bacteria are considered more economical, efficient, and safe “nutraceuticals” in the health care arsenal. Therefore, we carried out the screening and molecular characterization of raw camel milk LAB isolates and tested their inhibitory activity against influenza virus H1N1. The strain that exhibited the highest antiviral activity against the H1N1 virus, confirmed by hemagglutination assay, was identified as Lactiplantibacillus plantarum KAU007. The study also confirmed the non-cytotoxic behavior of CFCS isolated from KAU007 against MDCK cells, approving its safety concern against the mammalian cells. Besides, CFCS at 5 and 10 mg/mL significantly decreased the level of IFN-γ (p < 0.001 and p < 0.001) and IL-6 (p < 0.001 and p < 0.005) in a dose-dependent manner, respectively. This is a preliminary report about the anti-influenza activity of KAU007 isolated from camel milk. This study reinforces that camel milk contains beneficial LAB isolates with antagonistic properties against the H1N1 influenza virus.

Emerging Technologies and Coating Materials for Improved Probiotication in Food Products: a Review

From the past few decades, consumers' demand for probiotic-based functional and healthy food products is rising exponentially. Encapsulation is an emerging field to protect probiotics from unfavorable conditions and to deliver probiotics at the target place while maintaining the controlled release in the colon. Probiotics have been encapsulated for decades using different encapsulation methods to maintain their viability during processing, storage, and digestion and to give health benefits. This review focuses on novel microencapsulation techniques of probiotic bacteria including vacuum drying, microwave drying, spray freeze drying, fluidized bed drying, impinging aerosol technology, hybridization system, ultrasonication with their recent advancement, and characteristics of the commonly used polymers have been briefly discussed. Other than novel techniques, characterization of microcapsules along with their mechanism of release and stability have shown great interest recently in developing novel functional food products with synergetic effects, especially in COVID-19 outbreak. A thorough discussion of novel processing technologies and applications in food products with the incorporation of recent research works is the novelty and highlight of this review paper.

Effectiveness of Multistrain Probiotic Formulation on Common Infectious Disease Symptoms and Gut Microbiota Modulation in Flu-Vaccinated Healthy Elderly Subjects

The decline of the immune system with aging leads elderly people to be more susceptible to infections, posing high risk for their health. Vaccination is thus important to cope with this risk, even though not always effective. As a strategy to improve protection, adjuvants are used in concomitance with vaccines, however, occasionally producing important side effects. The use of probiotics has been proposed as an alternative to adjuvants due to their efficacy in reducing the risk of common infections through the interactions with the immune system and the gut microbiota. A placebo-controlled, randomized, double-blind, clinical trial was carried out on fifty elderly subjects, vaccinated for influenza, to determine the efficacy of a probiotic mixture in reducing common infection symptoms. The incidence of symptoms was evaluated after 28 days of probiotic intake (namely, T28) and after further 28 days of follow-up (namely, T56). The number of subjects, as well as the number of days with symptoms, was remarkably reduced at T28, and even more at T56 in the probiotic group. Furthermore, the influence of probiotics on immunological parameters was investigated, showing a significant positive improvement of total antioxidant capacity and β-defensin2 levels. Finally, faecal samples collected from participants were used to assess variations in the gut microbiota composition during the study, showing that probiotic intake enhanced the presence of genera related to a healthy status. Therefore, the collected results suggested that the treatment with the selected probiotic mixture could help in reducing common infectious disease symptom incidence through the stimulation of the immune system, improving vaccine efficacy, and modulating the composition of the resident gut microbiota by enhancing beneficial genera.

Selection of Probiotics in the Prevention of Respiratory Tract Infections and Their Impact on Occupational Health: Scoping Review

The occupational health impact of respiratory infectious diseases is costly to the economy and the health care system. Probiotics are non-pathogenic live microorganisms that, when ingested in adequate amounts, can colonize the intestinal tract, and enhance the immune system. In recent years, numerous studies have described the possible usefulness of certain probiotic strains in the treatment and prevention of respiratory tract infections, with disparate results. In order to assess the possible efficacy and safety of these microorganisms to prevent or ameliorate respiratory tract infections, we systematically searched the bibliographic databases MEDLINE (via Pubmed), EMBASE, The Cochrane library, Scopus, and Web of science, using the descriptors "Respiratory Tract Infections", "Probiotics", "Occupational Health", "Humans", and "Clinical Trials". After applying our inclusion and exclusion criteria, 18 studies were accepted for review and critical analysis. Our analysis suggests that a combination of different probiotics, most of them in the genus Bifidobacterium sp. and Lactobacillus sp., could be a good mix to strengthen the immune system and reduce the symptoms of URTIs in the healthy working population.

The efficacy of probiotics on virus titres and antibody production in virus diseases: A systematic review on recent evidence for COVID-19 treatment

BACKGROUND & AIMS

There are some studies indicating the effects of probiotic-containing foods or supplements on viral diseases. We aimed to conduct a rapid review of probiotics with specific emphasis on their potential for early administration in patients at greater risk of SARS-CoV-2 infection.

METHODS

We searched on PubMed, EMBASE, Google Scholar, Science Direct, Scopus and Web of Science up to February 2021 to identify interventional and observational studies documenting the effects of probiotics strains on interleukins, virus titers, and antibody production with a focus on probiotic-containing foods (PROSPERO Registration ID. CRD42020181453) RESULTS: From a total of 163 records, 21 studies were classified into three domains based on the efficacy of probiotics on 1) the level of interleukins (n = 7), 2) virus titers (n = 2), and 3) interferon (IFN) and antibody production (n = 12). The suppuration of pro-inflammatory interleukins and type I INF production seemed to be the main anti-viral effect of probiotics. Nine studies also indicated the beneficial effects of probiotics and fermented foods on viral diseases.

CONCLUSION

Based on evidence, some probiotic strains may be useful in viral infections; randomized trials are needed to confirm these findings.

Evaluation of the Function of Probiotics, Emphasizing the Role of their Binding to the Intestinal Epithelium in the Stability and their Effects on the Immune System

Due to the importance of using cost-effective methods for therapeutic purposes, the function of probiotics as safe microorganisms and the study of their relevant functional mechanisms have recently been in the spotlight. Finding the mechanisms of attachment and stability and their beneficial effects on the immune system can be useful in identifying and increasing the therapeutic effects of probiotics. In this review, the functional mechanisms of probiotics were comprehensively investigated. Relevant articles were searched in scientific sources, documents, and databases, including PubMed, NCBI, Bactibace, OptiBac, and Bagel4. The most important functional mechanisms of probiotics and their effects on strengthening the epithelial barrier, competitive inhibition of pathogenic microorganisms, production of antimicrobials, binding and interaction with the host, and regulatory effects on the immune system were discussed.

In this regard, the attachment of probiotics to the epithelium is very important because the prerequisite for their proper functioning is to establish a proper connection to the epithelium. Therefore, more attention should be paid to the binding effect of probiotics, including sortase A, a significant factor involved in the expression of sortase-dependent proteins (SDP), on their surface as mediators of intestinal epithelial cell binding. In general, by investigating the functional mechanisms of probiotics, it was concluded that the mechanism by which probiotics regulate the immune system and adhesion capacity can directly and indirectly have preventive and therapeutic effects on a wide range of diseases. However, further study of these mechanisms requires extensive research on various aspects.

Modulation of gut microbiota protects against viral respiratory tract infections: a systematic review of animal and clinical studies

BACKGROUND

Earlier studies suggest that probiotics have protective effects in the prevention of respiratory tract infections (RTIs). Whether such benefits apply to RTIs of viral origin and mechanisms supporting the effect remain unclear.

AIM

To determine the role of gut microbiota modulation on clinical and laboratory outcomes of viral RTIs.

METHODS

We conducted a systematic review of articles published in Embase and MEDLINE through 20 April 2020 to identify studies reporting the effect of gut microbiota modulation on viral RTIs in clinical studies and animal models. The incidence of viral RTIs, clinical manifestations, viral load and immunological outcomes was evaluated.

RESULTS

We included 58 studies (9 randomized controlled trials; 49 animal studies). Six of eight clinical trials consisting of 726 patients showed that probiotics administration was associated with a reduced risk of viral RTIs. Most commonly used probiotics were Lactobacillus followed by Bifidobacterium and Lactococcus. In animal models, treatment with probiotics before viral challenge had beneficial effects against influenza virus infection by improving infection-induced survival (20/22 studies), mitigating symptoms (21/21 studies) and decreasing viral load (23/25 studies). Probiotics and commensal gut microbiota exerted their beneficial effects through strengthening host immunity.

CONCLUSION

Modulation of gut microbiota represents a promising approach against viral RTIs via host innate and adaptive immunity regulation. Further research should focus on next generation probiotics specific to viral types in prevention and treatment of emerging viral RTIs.

Theoretical benefits of yogurt-derived bioactive peptides and probiotics in COVID-19 patients - A narrative review and hypotheses

The world is currently facing a frightening coronavirus disease-2019 (COVID-19) epidemic. Severity of COVID-19 presentation is highly variable among infected individuals with increasingly recognized risk factors. Although observational studies suggested lower COVID-19 severity in populations consuming fermented foods, no controlled study investigated the role of diet. Yogurt, a fermented dairy product, exhibits interesting properties related to the presence of bioactive peptides and probiotics that may play a beneficial role in COVID-19 presentation and outcome. Peptides contained in yogurt are responsible for angiotensin-converting enzyme-inhibitory, bradykinin potentiating, antiviral, anti-inflammatory, antithrombotic, and antioxidant effects. The types and activity of these peptides vary widely depending on their amino acid sequence, on the probiotics used in yogurt production and on intestinal digestion. Additionally, probiotics used in yogurt exhibit direct angiotensin-converting enzyme-inhibitory, antiviral and immune boosting activities. Since COVID-19 pathogenesis involves angiotensin II accumulation and bradykinin deficiency, yogurt bioactive peptides appear as potentially beneficial. Therefore, epidemiological investigations and randomized controlled clinical trials to evaluate the exact role of yogurt consumption on COVID-19 manifestations and outcome should be encouraged.

The Antiviral Potential of Probiotics—A Review on Scientific Outcomes

A rich repertoire of research studies on probiotics has been documented as one of the therapeutic agents or adjuvants for vaccines in treating viral infections. It is well known that the immunomodulatory properties of probiotics reduce the severity of viral infections. The efficacy of probiotics alone and combined boost up the host’s innate immunity, thereby developing a robust antiviral paradigm. As dietary and therapeutic measures, probiotics potentially work as an alternative for those who lack access to vaccines or antiviral drugs. Potential probiotic mechanisms include competing with pathogens for nutrients and colonization sites, producing antimicrobial metabolites and enhancing protective immune responses. The live probiotics can reach and colonize the host animals’ intestines then confer the health benefits by improving the host’s natural defence against viral infections. The research studies on probiotics suggest that they reduce the risk of viral infections, yet the innermost mechanisms are still unknown. The reason for scripting this review is to discuss the current developments in probiotic therapeutic measures and their probable insights into antiviral agents.

Potential Dietary Interventions for COVID-19 Infection Based on the Gut-Immune Axis: An Update Review on Bioactive Component of Macronutrients

Recently emerged coronavirus, known as SARS-CoV-2 or Covid-19 is considered as a serious threat for human health. Due to unavailable specific drugs for this virus, there is an urgent need for supportive cares. Epigenetic immune boosting approaches and developing anti-inflammatory agents by gut-associated bioactive macronutrients can be plausible protective cares for COVID-19. Suitable intake of bioactive macronutrients including prebiotics, fatty acids, proteins and branched-chain amino acids may result in anti-viral responses through modulating macrophages and dendritic cells via Toll-like receptors, decreasing viral load, inactivating the enveloped viruses, increasing the anti-inflammatory metabolites and inhibiting the proliferation of microbial organisms. Bioactive macronutrients may help in promotion of immunological responses and recovery acceleration against Covid-19. This review focuses on the mechanisms of bioactive macronutrients and related clinical trials on enveloped viruses with emphasis on gut-microbiome-immune axis. Macronutrients and this axis may be conducive strategies to protect host against the viral infection.

Identification of genes encoding a novel ABC transporter in Lactobacillus delbrueckii for inulin polymers uptake

Lactobacillus delbrueckii JCM 1002^T grows on highly polymerized inulin-type fructans as its sole carbon source. When it was grown on inulin, a > 10 kb long gene cluster inuABCDEF (Ldb1381-1386) encoding a plausible ABC transporter was suggested to be induced, since a transcriptome analysis revealed that the fourth gene inuD (Ldb1384) was up-regulated most prominently. Although Bacillus subtilis 168 is originally unable to utilize inulin, it became to grow on inulin upon heterologous expression of inuABCDEF. When freshly cultured cells of the recombinant B. subtilis were then densely suspended in buffer containing inulin polymers and incubated, inulin gradually disappeared from the buffer and accumulated in the cells without being degraded, whereas levan-type fructans did not disappear. The results imply that inuABCDEF might encode a novel ABC transporter in L. delbrueckii to "monopolize" inulin polymers selectively, thereby, providing a possible advantage in competition with other concomitant inulin-utilizing bacteria.

Accomplishment of probiotics in human health pertaining to immunoregulation and disease control

It is a well-established fact that the microbiome harboring the human body plays a critical role in maintaining human health and can influence treatments against various ailments. Human microbiome-based research contemplates the possibility of selecting and administering specific commensal bacterial strains to modulate the gut microbiota to attain favorable outcomes to the therapies. Consumption of probiotics and probiotic-based dietary supplements as functional foods has been a promising treatment strategy against various diseases. Clinical studies demonstrate that probiotic administration alters gut microbiota composition and instigates immune modulation in the host. The benefits of probiotics are reported to be strain-specific and depend on the host's baseline immune competence. This review explores the role of probiotics in alleviating symptoms of allergy, cancer, cardio vascular (CV) diseases, diabetes mellitus (DM), bowel diseases (IBD and IBS), periodontal disease, diseases affecting liver and kidney, neuroinflammatory diseases, and viral infections. Also, it surveyed the broad spectrum bioactive compounds produced by probiotics and possible mechanisms that trigger the immune system.

Effect of probiotic fermented dairy products on incidence of respiratory tract infections: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Previous studies have suggested that the consumption of probiotic fermented dairy products (PFDP) may have a protective effect on respiratory tract infections (RTIs). However, the results of studies are inconclusive. We aimed to systematically investigate the effect of PFDP on RTIs by performing a meta-analysis of randomized controlled trials (RCTs).

METHODS

PubMed and Scopus databases were systematically searched up to October 2020 to identify eligible RCTs. Meta-analysis outcomes were risk of incidence of upper (URTIs ) and lower (LRTIs ) respiratory tract infections. A random-effects model was used to pool the relative risks (RR) and corresponding 95 % confidence intervals (CI) for outcomes following conception of PFDP.

RESULTS

A total of 22 RCTs, with a total sample size of 10,190 participants, were included in this meta-analysis. Compared with placebo, consumption of PFDP had a significant protective effect against RTIs in the overall analysis (RR = 0.81, 95 %CI: 0.74 to 0.89) and in children (RR = 0.82, 95 %CI: 0.73 to 0.93), adults (RR = 0.81, 95 %CI: 0.66 to 1.00), and elderly population (RR = 0.78, 95 %CI: 0.61 to 0.98). The significant decreased risk of RTIs was also observed for URTIs (RR = 0.83, 95 %CI: 0.73 to 0.93), while, this effect was marginal for LRTIs (RR = 0.78, 95 %CI: 0.60 to 1.01, P = 0.06). The disease-specific analysis showed that PFDP have a protective effect on pneumonia (RR = 0.76, 95 %CI: 0.61 to 0.95) and common cold (RR = 0.68, 95 %CI: 0.49 to 0.96).

CONCLUSIONS

Consumption of PFDP is a potential dietary approach for the prevention of RTIs.

The Effect of Probiotics on Health Outcomes in the Elderly: A Systematic Review of Randomized, Placebo-Controlled Studies

Increasing evidence suggests that probiotic supplementation may be efficacious in counteracting age-related shifts in gut microbiota composition and diversity, thereby impacting health outcomes and promoting healthy aging. However, randomized controlled trials (RCTs) with probiotics in healthy older adults have utilized a wide variety of strains and focused on several different outcomes with conflicting results. Therefore, a systematic review was conducted to determine which outcomes have been investigated in randomized controlled trials with probiotic supplementation in healthy older adults and what has been the effect of these interventions. For inclusion, studies reporting on randomized controlled trials with probiotic and synbiotic supplements in healthy older adults (defined as minimum age of 60 years) were considered. Studies reporting clinical trials in specific patient groups or unhealthy participants were excluded. In addition to assessment of eligibility and data extraction, each study was examined for risk of bias and quality assessment was performed by two independent reviewers. Due to the heterogeneity of outcomes, strains, study design, duration, and methodology, we did not perform any meta-analyses and instead provided a narrative overview of the outcomes examined. Of 1997 potentially eligible publications, 17 studies were included in this review. The risk of bias was low, although several studies failed to adequately describe random sequence generation, allocation concealment, and blinding. The overall study quality was high; however, many studies did not include sample calculations, and the majority of studies had a small sample size. The main outcomes examined in the trials included microbiota composition, immune-related measurements, digestive health, general well-being, cognitive function, and lipid and other biomarkers. The most commonly assessed outcome with the most consistent effect was microbiota composition; all but one study with this outcome showed significant effects on gut microbiota composition in healthy older adults. Overall, probiotic supplementation had modest effects on markers of humoral immunity, immune cell population levels and activity, as well as the incidence and duration of the common cold and other infections with some conflicting results. Digestive health, general-well-being, cognitive function, and lipid and other biomarkers were investigated in a very small number of studies; therefore, the impact on these outcomes remains inconclusive. Probiotics appear to be efficacious in modifying gut microbiota composition in healthy older adults and have moderate effects on immune function. However, the effect of probiotic supplementation on other health outcomes remains inconclusive, highlighting the need for more well-designed, sufficiently-powered studies to investigate if and the mechanisms by which probiotics impact healthy aging.

Probiotics for the Prevention of Acute Respiratory-Tract Infections in Older People: Systematic Review

The aim of this systematic review was to present the indirect influence of probiotics on the incidence and duration of acute upper respiratory-tract infections in older people, by regulating the immune system. Eight randomized, placebo-controlled clinical trials met the inclusion criteria, considering the threshold of older people being 60 years and over. Single strain probiotics were used in all studies, including three probiotic strains used in fermented foods: Lactobacillus delbrueckii subsp. bulgaricus OLL1073R-1, Lacticaseibacillus paracasei subsp. paracasei CNCM I-1518 and Lacticaseibacillusparacasei Shirota, and three probiotic strains used as food supplements: Loigolactobacillus coryniformis K8 CECT5711, Bacillus subtilis CU1 and Lacticaseibacillus rhamnosus GG. Current evidence showed that certain probiotic strains were better than a placebo in lowering the incidence or number of older people experiencing acute upper respiratory tract infections; however, not all probiotic strains were efficient, and not all studies reported statistically significant outcomes. More high quality large-scale properly controlled clinical studies focusing on older people are warranted.

Consumption of OLL1073R-1 yogurt improves psychological quality of life in women healthcare workers: secondary analysis of a randomized controlled trial

Background

We conducted a randomized controlled trial to investigate the effects of consumption of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 in women healthcare workers. In a previous study we used these data to investigate hypothesized preventive effects against flu, however any effects on improving mental quality of life were not analyzed at that time. In the present study, we focus on that aspect.

Methods

The participants (961 women; mainly nurses, aged 20–71 years) were randomly allocated to either the yogurt group (n = 479) or the control group (n = 482). Participants in the yogurt group drank 112 mL of OLL1073R-1 yogurt for 16 weeks, while those in the control group did not consume any yogurt. All participants were prohibited from consuming other yogurt or fermented dairy products during the study period. The participants answered the Pittsburgh Sleep Quality Index (PSQI), Short Form-8 Health Survey (SF-8), and Gastrointestinal Symptom Rating Scale (GSRS) questionnaires at baseline and after 16 weeks.

Results

The PSQI score showed significant improvement after the intake of yogurt (p < 0.01). SF-8 results showed significant intervention effects in the General Health and Vitality scores (p = 0.02 and p = 0.01, respectively). In other subscales of SF-8, we did not observe significant effects of the yogurt. In the GSRS, daily intake of yogurt exerted a preventive effect on constipation (p = 0.03).

Conclusions

Consumption of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 enhances subjective psychological quality of life by improving quality of sleep and gastrointestinal condition among women healthcare workers.

The Efficacy of Short-Term Weight Loss Programs and Consumption of Natural Probiotic Bryndza Cheese on Gut Microbiota Composition in Women

Weight loss interventions with probiotics have favourable effects on gut microbiota composition and derived metabolites. However, little is known about whether the consumption of natural probiotics, such as Bryndza cheeses, brings similar benefits. The purpose of the study was to find the effect of short-term weight loss programs and Bryndza cheese consumption on the structure of the gut microbiota, microbiota-derived metabolites and body composition in middle-aged women. We conducted a randomised controlled intervention study. Twenty-two female participants with a body fat percentage ≥25% underwent a short weight loss program (4 weeks). Subjects were randomised to either the control or intervention group according to diet. The intervention group comprised 13 participants, whose diet contained 30 g of “Bryndza” cheese daily (WLPB). The control group comprised nine participants without the regular consumption of Bryndza cheese (WLP) in their diet. Both interventions lead to a significant and favourable change of BMI, body fat, waist circumference and muscle mass. Moreover, the relative abundance of Erysipelotrichales significantly increased in both groups. However, the relative abundance of lactic acid bacteria (Lactobacillales, Streptococcaceae, Lactococcus and Streptococcus) significantly increased only in the WLPB group. Furthermore, short-chain fatty acid producers Phascolarctobacterium and Butyricimonas increased significantly in the WLPB group. A short-term weight loss program combined with Bryndza cheese consumption improves body composition and increases the abundance of lactic acid bacteria and short-chain fatty acid producers in middle-aged women.

Nutrition for Older Athletes: Focus on Sex-Differences

Regular physical exercise and a healthy diet are major determinants of a healthy lifespan. Although aging is associated with declining endurance performance and muscle function, these components can favorably be modified by regular physical activity and especially by exercise training at all ages in both sexes. In addition, age-related changes in body composition and metabolism, which affect even highly trained masters athletes, can in part be compensated for by higher exercise metabolic efficiency in active individuals. Accordingly, masters athletes are often considered as a role model for healthy aging and their physical capacities are an impressive example of what is possible in aging individuals. In the present review, we first discuss physiological changes, performance and trainability of older athletes with a focus on sex differences. Second, we describe the most important hormonal alterations occurring during aging pertaining regulation of appetite, glucose homeostasis and energy expenditure and the modulatory role of exercise training. The third part highlights nutritional aspects that may support health and physical performance for older athletes. Key nutrition-related concerns include the need for adequate energy and protein intake for preventing low bone and muscle mass and a higher demand for specific nutrients (e.g., vitamin D and probiotics) that may reduce the infection burden in masters athletes. Fourth, we present important research findings on the association between exercise, nutrition and the microbiota, which represents a rapidly developing field in sports nutrition.

The effect of probiotics on respiratory tract infection with special emphasis on COVID-19: Systemic review 2010-20

To evaluate the effects of probiotics on respiratory tract infection (RTI) a systematic review of randomized controlled trials (RCTs) from January 2010 to January 2020 was conducted. The PubMed, Google Scholar, Embase, Scopus, Clinicaltrials.gov, and International Clinical Trials Registry Platform databases were systematically searched for the following keywords: respiratory tract infection, probiotics, viral infection, COVID-19, and clinical trial. A total of 27 clinical trials conducted on 9433 patients with RTI plus 10 ongoing clinical studies of probiotics intervention in Coronavirus disease 2019 (COVID-19) were reviewed. The review looked at the potency of probiotics for the hindrance and/or treatment of RTI diseases, this may also apply to COVID-19. The review found that probiotics could significantly increase the plasma levels of cytokines, the effect of influenza vaccine and quality of life, as well as reducing the titer of viruses and the incidence and duration of respiratory infections. These antiviral and immune-modulating activities and their ability to stimulate interferon production recommend the use of probiotics as an adjunctive therapy to prevent COVID-19. Based on this extensive review of RCTs we suggest that probiotics are a rational complementary treatment for RTI diseases and a viable option to support faster recovery.

Review of probiotic use in otolaryngology

OBJECTIVE

Probiotics have garnered considerable attention as an intervention for various conditions common to otolaryngology. The purpose of this review is to evaluate the current literature to offer recommendations about the safety and efficacy of probiotic management in otolaryngologic conditions.

STUDY DESIGN

Narrative review.

METHODS

PubMed and Google Scholar were queried using pertinent keywords to retrieve relevant studies with particular focus in the recent 5 years. All abstracts were assessed and studies, reviews and meta-analyses achieving evaluation of probiotic therapies or characterization of microbiome changes were included for further review. Studies were categorized by condition or anatomic region across various subspecialties. Key data parameters were extracted and evaluated across studies and treatment types.

RESULTS

Strong evidence exists for the use probiotic agents to improve symptoms for allergic rhinitis, chronic rhinosinusitis and certain dental conditions. Despite promising results, further investigation is needed to evaluate and optimize probiotic delivery for mitigating otitis media, oropharyngeal inflammation and upper respiratory tract infections. Preclinical studies suggest that probiotics may potentially offer benefit for voice prosthesis maintenance, wound healing and mitigation of oral dysplasia.

CONCLUSION

Probiotic therapies may offer clinical benefit in a variety of contexts within the field of otolaryngology, especially for short-term relief of certain inflammatory conditions of the oral cavity, auditory and nasal cavities. Further investigation is warranted for evaluation of long-term outcomes and pathogenic deterrence.

Traditional Bulgarian Dairy Products: Ethnic Foods with Health Benefits

The reported health effects of fermented dairy foods, which are traditionally manufactured in Bulgaria, are connected with their microbial biodiversity. The screening and development of probiotic starters for dairy products with unique properties are based exclusively on the isolation and characterization of lactic acid bacterial (LAB) strains. This study aims to systematically describe the LAB microbial content of artisanal products such as Bulgarian-type yoghurt, white brined cheese, kashkaval, koumiss, kefir, katak, and the Rhodope's brano mliako. The original technologies for their preparation preserve the valuable microbial content and improve their nutritional and probiotic qualities. This review emphasises the features of LAB starters and the autochthonous microflora, the biochemistry of dairy food production, and the approaches for achieving the fortification of the foods with prebiotics, bioactive peptides (ACE2-inhibitors, bacteriocins, cyclic peptides with antimicrobial activity), immunomodulatory exopolysaccharides, and other metabolites (indol-3-propionic acid, free amino acids, antioxidants, prebiotics) with reported beneficial effects on human health. The link between the microbial content of dairy foods and the healthy human microbiome is highlighted.

Role of Probiotics, Prebiotics, and Synbiotics in the Elderly: Insights Into Their Applications

Elderly people are an important part of the global population who suffer from the natural processes of senescence, which lead to changes in the gut microbiota composition. These modifications have a great impact on their quality of life, bringing a general putrefactive and inflammatory status as a consequence. Some of the most frequent conditions related to this status are constipation, undernutrition, neurodegenerative diseases, susceptibility to opportunistic pathogens, and metabolic disbalance, among others. For these reasons, there is an increasing interest in improving their quality of life by non-invasive treatments such as the consumption of probiotics, prebiotics, and synbiotics. The aim of the present mini-review is to describe the benefits of these functional supplements/food according to the most recent clinical and pre-clinical studies published during the last decade. In addition, insights into several aspects we consider relevant to improve the quality of future studies are provided.

Interactions between commensal bacteria and viral infection: insights for viral disease control in farmed animals

Viral diseases cause serious economic loss in farmed animals industry. However, the efficacy of remedies for viral infection in farmed animals is limited, and treatment strategies are generally lacking for aquatic animals. Interactions of commensal microbiota and viral infection have been studied in recent years, demonstrating a third player in the interaction between hosts and viruses. Here, we discuss recent developments in the research of interactions between commensal bacteria and viral infection, including both promotion and inhibition effect of commensal bacteria on viral pathogenesis, as well as the impact of viral infection on commensal microbiota. The antiviral effect of commensal bacteria is mostly achieved through priming or regulation of the host immune responses, involving differential microbial components and host signaling pathways, and gives rise to various antiviral probiotics. Moreover, we summarize studies related to the interaction between commensal bacteria and viral infection in farmed animals, including pigs, chickens, fish and invertebrate species. Further studies in this area will deepen our understanding of antiviral immunity of farmed animals in the context of commensal microbiota, and promote the development of novel strategies for treatment of viral diseases in farmed animals.

The emerging role of probiotics as a mitigation strategy against coronavirus disease 2019 (COVID-19)

COVID-19 is an acute respiratory infection accompanied by pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has affected millions of people globally. To date, there are no highly efficient therapies for this infection. Probiotic bacteria can interact with the gut microbiome to strengthen the immune system, enhance immune responses, and induce appropriate immune signaling pathways. Several probiotics have been confirmed to reduce the duration of bacterial or viral infections. Immune fitness may be one of the approaches by which protection against viral infections can be reinforced. In general, prevention is more efficient than therapy in fighting viral infections. Thus, probiotics have emerged as suitable candidates for controlling these infections. During the COVID-19 pandemic, any approach with the capacity to induce mucosal and systemic reactions could potentially be useful. Here, we summarize findings regarding the effectiveness of various probiotics for preventing virus-induced respiratory infectious diseases, especially those that could be employed for COVID-19 patients. However, the benefits of probiotics are strain-specific, and it is necessary to identify the bacterial strains that are scientifically established to be beneficial.