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Could Vitamins Help in the Fight Against COVID-19?
Jovic, TH, Ali, SR, Ibrahim, N, Jessop, ZM, Tarassoli, SP, Dobbs, TD, Holford, P, Thornton, CA, Whitaker, IS
Nutrients. 2020;12(9)
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Immunonutrition is the role of nutrient supplementation in modulating the immune system. While there are limited approaches to the prevention and treatment of Covid-19, the aim of this review was to critically assess the current evidence to identify vitamins in the context of respiratory disease and extrapolate the evidence to evaluate the role of immunonutrition in Covid-19. Over 200 studies were included in this review to assess the physiological role, therapeutic application in respiratory disease and relevance to Covid-19 of each vitamin. Based on the existing literature, the authors conclude the there is a potential preventative and supportive role for vitamin supplementation in fighting Covid-19, specifically vitamin A, E and D.
Abstract
There are limited proven therapeutic options for the prevention and treatment of COVID-19. The role of vitamin and mineral supplementation or "immunonutrition" has previously been explored in a number of clinical trials in intensive care settings, and there are several hypotheses to support their routine use. The aim of this narrative review was to investigate whether vitamin supplementation is beneficial in COVID-19. A systematic search strategy with a narrative literature summary was designed, using the Medline, EMBASE, Cochrane Trials Register, WHO International Clinical Trial Registry, and Nexis media databases. The immune-mediating, antioxidant and antimicrobial roles of vitamins A to E were explored and their potential role in the fight against COVID-19 was evaluated. The major topics extracted for narrative synthesis were physiological and immunological roles of each vitamin, their role in respiratory infections, acute respiratory distress syndrome (ARDS), and COVID-19. Vitamins A to E highlighted potentially beneficial roles in the fight against COVID-19 via antioxidant effects, immunomodulation, enhancing natural barriers, and local paracrine signaling. Level 1 and 2 evidence supports the use of thiamine, vitamin C, and vitamin D in COVID-like respiratory diseases, ARDS, and sepsis. Although there are currently no published clinical trials due to the novelty of SARS-CoV-2 infection, there is pathophysiologic rationale for exploring the use of vitamins in this global pandemic, supported by early anecdotal reports from international groups. The final outcomes of ongoing trials of vitamin supplementation are awaited with interest.
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The Role of Bacteria and Its Derived Metabolites in Chronic Pain and Depression: Recent Findings and Research Progress.
Li, S, Hua, D, Wang, Q, Yang, L, Wang, X, Luo, A, Yang, C
The international journal of neuropsychopharmacology. 2020;23(1):26-41
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Depression is closely associated with chronic pain yet the connection between these comorbidities is ambiguous. Recent studies have shown alterations in the gut microbiome may contribute to cognitive dysfunction via the microbiota-gut-brain axis. The aim of this systematic review is to summarize the existing evidence of the role of the gut microbiome in chronic pain and depression and explore potential mechanisms of gut dysbiosis in the development of these conditions. This review found metabolic products from the gut microbiota can mediate neuro-inflammation and neuro-immunity pathways in pain and depression, and that dysbiosis in the gut may contribute to the cause of chronic pain and depression. The authors conclude the metabolic products from the gut bacteria offer new insights to the connection between the gut microbiota and mechanisms of pain and depression, while showing potential as a therapeutic target.
Abstract
BACKGROUND Chronic pain is frequently comorbid with depression in clinical practice. Recently, alterations in gut microbiota and metabolites derived therefrom have been found to potentially contribute to abnormal behaviors and cognitive dysfunction via the "microbiota-gut-brain" axis. METHODS PubMed was searched and we selected relevant studies before October 1, 2019. The search keyword string included "pain OR chronic pain" AND "gut microbiota OR metabolites"; "depression OR depressive disorder" AND "gut microbiota OR metabolites". We also searched the reference lists of key articles manually. RESULTS This review systematically summarized the recent evidence of gut microbiota and metabolites in chronic pain and depression in animal and human studies. The results showed the pathogenesis and therapeutics of chronic pain and depression might be partially due to gut microbiota dysbiosis. Importantly, bacteria-derived metabolites, including short-chain fatty acids, tryptophan-derived metabolites, and secondary bile acids, offer new insights into the potential linkage between key triggers in gut microbiota and potential mechanisms of depression. CONCLUSION Studying gut microbiota and its metabolites has contributed to the understanding of comorbidity of chronic pain and depression. Consequently, modulating dietary structures or supplementation of specific bacteria may be an available strategy for treating chronic pain and depression.
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Enhancing immunity in viral infections, with special emphasis on COVID-19: A review.
Jayawardena, R, Sooriyaarachchi, P, Chourdakis, M, Jeewandara, C, Ranasinghe, P
Diabetes & metabolic syndrome. 2020;14(4):367-382
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A healthy immune system is one of the most important weapons in relation to the current pandemic of COVID-19 where no effective preventive and curative medicine is available. The main aim of this study was to evaluate the evidence on enhancing immunity in viral infections. This review focuses on influenza-like viral infections; however, other studies on viral infections have also been included. It included 43 articles of which 13 were on vitamins, 8 on minerals, 18 on nutraceuticals and 4 on probiotics. Results indicate that: - vitamin supplementation, especially vitamin D may be beneficial in people who are either deficient or insufficient. - adverse effects of vitamin E supplementation on the immune response have been reported. - there are several beneficial nutraceuticals, however their efficacy and safety depend on their ingredients, as well as various other factors including, methods of extraction. - in addition to basic hygienic practices, proper dietary and lifestyle behaviours are essential for prevention and treatment of respiratory viral diseases. Authors conclude that achieving recommended amounts of calories and micronutrient will be a challenge and elective micronutrient supplementations may be beneficial especially for vulnerable populations such as the elderly.
Abstract
BACKGROUND AND AIMS Balanced nutrition which can help in maintaining immunity is essential for prevention and management of viral infections. While data regarding nutrition in coronavirus infection (COVID-19) are not available, in this review, we aimed to evaluate evidence from previous clinical trials that studied nutrition-based interventions for viral diseases (with special emphasis on respiratory infections), and summarise our observations. METHODS A systematic search strategy was employed using keywords to search the literature in 3 key medical databases: PubMed®, Web of Science® and SciVerse Scopus®. Studies were considered eligible if they were controlled trials in humans, measuring immunological parameters, on viral and respiratory infections. Clinical trials on vitamins, minerals, nutraceuticals and probiotics were included. RESULTS A total of 640 records were identified initially and 22 studies were included from other sources. After excluding duplicates and articles that did not meet the inclusion criteria, 43 studies were obtained (vitamins: 13; minerals: 8; nutraceuticals: 18 and probiotics: 4). Among vitamins, A and D showed a potential benefit, especially in deficient populations. Among trace elements, selenium and zinc have also shown favourable immune-modulatory effects in viral respiratory infections. Several nutraceuticals and probiotics may also have some role in enhancing immune functions. Micronutrients may be beneficial in nutritionally depleted elderly population. CONCLUSIONS We summaries possible benefits of some vitamins, trace elements, nutraceuticals and probiotics in viral infections. Nutrition principles based on these data could be useful in possible prevention and management of COVID-19.
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The Role of Glutamine in the Complex Interaction between Gut Microbiota and Health: A Narrative Review.
Perna, S, Alalwan, TA, Alaali, Z, Alnashaba, T, Gasparri, C, Infantino, V, Hammad, L, Riva, A, Petrangolini, G, Allegrini, P, et al
International journal of molecular sciences. 2019;20(20)
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Glutamine is an amino acid, one of the building blocks of protein, and is the most abundant free amino acid in the body. Research shows that glutamine plays an important role in digestive health and immunity by supporting the integrity of the intestinal lining and suppressing inflammation. This review looks at glutamine and its mechanism on gut microbiota; the commensal bacteria which populate the gastro-intestinal tract. Glutamine supplementation was shown to beneficially affect the composition of gut bacteria in obese and overweight subjects, reduce bacterial overgrowth and more specifically reduce harmful strains of Clostridium spp. and Helicobacter spp. The subsequent increase in intestinal-friendly microbiota after supplementation aided symptoms of constipation. This same mechanism may help prevent bacterial infections in chemotherapy cancer patients which is a common side effect of the treatment. Glutamine also supports immune cell activity. White blood cells were shown to use a four-fold amount of glutamine versus glucose. There are indications of glutamine-mediated crosstalk between intestinal microbes and the immune system and that glutamine appears to be helpful in patients with severe digestive disturbances as well as metabolic stress, trauma, infection, burns and muscle-wastage.
Abstract
The scientific literature has demonstrated that glutamine is one of the main beneficial amino acids. It plays an important role in gut microbiota and immunity. This paper provides a critical overview of experimental studies (in vitro, in vivo, and clinical) investigating the efficacy of glutamine and its effect on gut microbiota. As a result of this review, we have summarized that glutamine could affect gut microbiota via different mechanisms including the reduction in the ratio of Firmicutes to Bacteroidetes, with the activation of NF-κB and PI3K-Akt pathways, reducing the intestinal colonization (Eimeria lesions) and bacterial overgrowth or bacterial translocation, increasing the production of secretory immunoglobulin A (SIgA) and immunoglobulin A+ (IgA+) cells in the intestinal lumen, and decreasing asparagine levels. The potential applications of glutamine on gut microbiota include, but are not limited to, the management of obesity, bacterial translocation and community, cytokines profiles, and the management of side effects during post-chemotherapy and constipation periods. Further studies and reviews are needed regarding the effects of glutamine supplementation on other conditions in humans.
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Neurological Manifestations of Neuropathy and Ataxia in Celiac Disease: A Systematic Review.
Mearns, ES, Taylor, A, Thomas Craig, KJ, Puglielli, S, Leffler, DA, Sanders, DS, Lebwohl, B, Hadjivassiliou, M
Nutrients. 2019;11(2)
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Coeliac disease (CD) is a chronic, immune-mediated enteropathy in which dietary gluten triggers an inflammatory reaction of the small intestine in genetically predisposed individuals. The clinical presentation of the disease varies broadly and may include both intestinal symptoms and extra-intestinal manifestations, including iron-deficiency anaemia, osteoporosis, dermatitis herpetiformis, and neurological disorders, such as peripheral neuropathies and ataxia (a condition that affects co-ordination, balance and speech). Many patients who present with neurological manifestations of CD have no gastrointestinal symptoms, commonly leading to a delay in diagnosis. The aim of this systematic review was to assess the prevalence of peripheral neuropathies and gluten ataxia. Nine studies on gluten ataxia and 13 on gluten neuropathy were included in this review. The prevalence of both, neuropathy and ataxia, in the general population is very low, but this risk is increased in patients with CD. Estimates of the prevalence of neuropathy in CD patients ranged from 0% to 39%, with an increased risk in older and female patients. Prevalence of gluten ataxia varied from 0% to 6%. Symptoms of gluten neuropathy improve when patients with CD follow a gluten free diet (GFD), whilst the benefits of a GFD for ataxia vary between studies, possibly due to differences in study design. The authors note that this review primarily concentrated on patients with CD (i.e. those with evidence of enteropathy). However, neurological manifestations may exist in the presence of anti-gliadin antibodies alone (gluten sensitivity without evidence of enteropathy), and such patients benefit equally from a GFD. The authors conclude that patients with CD have an increased risk of gluten ataxia and gluten neuropathy, and that clinicians should check for gluten sensitivity in patients with ataxia and neuropathy of unknown origin.
Abstract
Celiac disease (CD) is an immune-mediated gastrointestinal disorder driven by innate and adaptive immune responses to gluten. Patients with CD are at an increased risk of several neurological manifestations, frequently peripheral neuropathy and gluten ataxia. A systematic literature review of the most commonly reported neurological manifestations (neuropathy and ataxia) associated with CD was performed. MEDLINE, Embase, the Cochrane Library, and conference proceedings were systematically searched from January 2007 through September 2018. Included studies evaluated patients with CD with at least one neurological manifestation of interest and reported prevalence, and/or incidence, and/or clinical outcomes. Sixteen studies were included describing the risk of gluten neuropathy and/or gluten ataxia in patients with CD. Gluten neuropathy was a neurological manifestation in CD (up to 39%) in 13 studies. Nine studies reported a lower risk and/or prevalence of gluten ataxia with a range of 0%⁻6%. Adherence to a gluten-free diet appeared to improve symptoms of both neuropathy and ataxia. The prevalence of gluten neuropathy and gluten ataxia in patients with CD varied in reported studies, but the increased risk supports the need for physicians to consider CD in patients with ataxia and neurological manifestations of unknown etiology.
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Vitamin B12 in Relation to Oxidative Stress: A Systematic Review.
van de Lagemaat, EE, de Groot, LCPGM, van den Heuvel, EGHM
Nutrients. 2019;11(2)
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Research suggests that vitamin B12 may possess antioxidant properties (i.e. they neutralise free radicals that can cause damage to cells or ‘oxidative stress’). The triage theory suggests that nutrients may be reallocated to necessary functions for survival if there is not enough for all processes. As such, lower than optimum levels of B12 may contribute to oxidative stress and free radicals which may relate to age-related disease development. This systematic review explores if low vitamin B12 is related to increased oxidative stress. The systematic review included 15 articles and found evidence to suggest there is a relationship between lower vitamin B12, low antioxidant status and oxidative stress. However, there is a lack of robust studies (in the form of randomised controlled trials and prospective studies) in humans suggesting that further research is needed to establish cause and effect.
Abstract
The triage theory posits that modest micronutrient deficiencies may induce reallocation of nutrients to processes necessary for immediate survival at the expense of long-term health. Neglected processes could in time contribute to the onset of age-related diseases, in which oxidative stress is believed to be a major factor. Vitamin B12 (B12) appears to possess antioxidant properties. This review aims to summarise the potential antioxidant mechanisms of B12 and investigate B12 status in relation to oxidative stress markers. A systematic query-based search of PubMed was performed to identify eligible publications. The potential antioxidant properties of B12 include: (1) direct scavenging of reactive oxygen species (ROS), particularly superoxide; (2) indirect stimulation of ROS scavenging by preservation of glutathione; (3) modulation of cytokine and growth factor production to offer protection from immune response-induced oxidative stress; (4) reduction of homocysteine-induced oxidative stress; and (5) reduction of oxidative stress caused by advanced glycation end products. Some evidence appears to suggest that lower B12 status is related to increased pro-oxidant and decreased antioxidant status, both overall and for subclinically deficient individuals compared to those with normal B12 status. However, there is a lack of randomised controlled trials and prospective studies focusing specifically on the relation between B12 and oxidative stress in humans, resulting in a low strength of evidence. Further work is warranted.
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The Efficacy of Probiotics, Prebiotic Inulin-Type Fructans, and Synbiotics in Human Ulcerative Colitis: A Systematic Review and Meta-Analysis.
Astó, E, Méndez, I, Audivert, S, Farran-Codina, A, Espadaler, J
Nutrients. 2019;11(2)
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It is thought that ulcerative colitis (UC) may be caused by an excessive immune response to endogenous bacteria in genetically predisposed individuals, and therefore that manipulating of the gut flora may be of benefit. Microbial diversity and intestinal microbiota stability are lower in patients with inflammatory bowel disease (including UC), than in healthy people. This systematic review and metanalysis looked at clinical trials using probiotics, prebiotics and synbiotics (a combination of pro- and prebiotics) in UC. 18 papers were included, with a total of 1491 adult and 69 children. 16 of these were on probiotics, one on prebiotics and one on synbiotics. Outcomes considered in this systematic review were the effects on short chain fatty acids (SCFAs, metabolic end products of gut bacteria which have a beneficial effect on immune and gut health), inflammation levels, composition of faecal microbiota and UC remission. In trials on inactive UC patients, the faecal concentration of SCFAs did not differ significantly between the probiotic and placebo groups, whilst in trials with active UC patients, SCFAs significantly increased after probiotic supplementation. All studies reported a significant reduction in inflammation. Meta-analysis of studies which looked at induction/maintenance of remission by probiotics showed that this depends on a) the type of disease activity score used to assess remission, and b) the type of probiotics used, with bifidobacteria containing probiotics, VSL3 and Mutaflor showing benefits, but studies without bifidobacteria being no different from placebo. The authors conclude that bifidobacteria containing probiotics seem to be beneficial in terms of reaching remission in patients with UC, although there is insufficient information on necessary dose and duration of treatment. They note that there are only few studies on prebiotics and synbiotics and are calling for a standardisation of scales to assess remission.
Abstract
Studies of probiotics, fructan-type prebiotics, and synbiotics in patients with ulcerative colitis (UC) show significant heterogeneity in methodology and results. Here, we study the efficacy of such interventions and the reasons for the heterogeneity of their results. Eligible random controlled trials were collected from the PUBMED and SCOPUS databases. A total of 18 placebo-controlled and active treatment-controlled (i.e., mesalazine) studies were selected with a Jadad score ≥ 3, including 1491 patients with UC. Data for prebiotics and synbiotics were sparse and consequently these studies were excluded from the meta-analysis. The UC remission efficacy of probiotics was measured in terms of relative risk (RR) and odds ratio (OR). Significant effects were observed in patients with active UC whenever probiotics containing bifidobacteria were used, or when adopting the US Food and Drug Administration (FDA)-recommended scales (UC Disease Activity Index and Disease Activity Index). By the FDA recommended scales, the RR was 1.55 (CI95%: 1.13⁻2.15, p-value = 0.007, I² = 29%); for bifidobacteria-containing probiotics, the RR was 1.73 (CI95%: 1.23⁻2.43, p-value = 0.002, I² = 35%). No significant effects were observed on the maintenance of remission for placebo-controlled or mesalazine-controlled studies. We conclude that a validated scale is necessary to determine the state of patients with UC. However, probiotics containing bifidobacteria are promising for the treatment of active UC.
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The influence of prebiotic or probiotic supplementation on antibody titers after influenza vaccination: a systematic review and meta-analysis of randomized controlled trials.
Yeh, TL, Shih, PC, Liu, SJ, Lin, CH, Liu, JM, Lei, WT, Lin, CY
Drug design, development and therapy. 2018;12:217-230
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Influenza vaccination is widely used although concerns regarding its efficacy exist. Both prebiotics and probiotics have been shown to produce protective effects against influenza infection and may enhance the immune response to the vaccination, especially in the elderly. The aim of this systematic review and meta-analysis was to determine the effect of pre- and probiotics on immune response to the influenza vaccination. According to the existing literature, participants who took prebiotics or probiotics were found to have higher hemagglutination inhibition (HI) antibodies, meaning a reduced likelihood of the virus attaching to the host’s red blood cells. Based on these results, the authors conclude both pre- or probiotic supplementation may enhance immune response in three influenza strains. While these results are promising, larger controlled trials are warranted to confirm the effectiveness and establish best clinical practice for supplementation.
Abstract
BACKGROUND Influenza infection is a common disease with a huge disease burden. Influenza vaccination has been widely used, but concerns regarding vaccine efficacy exist, especially in the elderly. Probiotics are live microorganisms with immunomodulatory effects and may enhance the immune responses to influenza vaccination. METHODS We conducted a systematic review and meta-analysis to determine the influence of prebiotics/probiotics/synbiotics supplementation on vaccine responses to influenza vaccination. Studies were systematically identified from electronic databases up to July 2017. Information regarding study population, influenza vaccination, components of supplements, and immune responses were extracted and analyzed. Twelve studies, investigating a total of 688 participants, were included in this review. RESULTS Patients with prebiotics/probiotics supplements were found to have higher influenza hemagglutination inhibition antibody titers after vaccination (for A/H1N1, 42.89 vs 35.76, mean difference =7.14, 95% CI =2.73, 11.55, P=0.002; for A/H3N2, 105.4 vs 88.25, mean difference =17.19, 95% CI =3.39, 30.99, P=0.01; for B strain, 34.87 vs 30.73, mean difference =4.17, 95% CI =0.37, 7.96, P=0.03). CONCLUSION Supplementation with prebiotics or probiotics may enhance the influenza hemagglutination inhibition antibody titers in all A/H1N1, A/H3N2, and B strains (20%, 19.5%, and 13.6% increases, respectively). Concomitant prebiotics or probiotics supplementation with influenza vaccination may hold great promise for improving vaccine efficacy. However, high heterogeneity was observed and further studies are warranted.
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The Effect of Bifidobacterium animalis ssp. lactis HN019 on Cellular Immune Function in Healthy Elderly Subjects: Systematic Review and Meta-Analysis.
Miller, LE, Lehtoranta, L, Lehtinen, MJ
Nutrients. 2017;9(3)
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Elderly individuals are more susceptible to infections and cancer, due to lowered immune system function. The gut bacteria play a key role in human immune system function and there is an interest in a potential role for probiotics in strengthening the immune system through manipulation of the microbiome. This systematic review and meta-analysis of 4 randomised controlled trials aimed to examine the efficacy of Bifidobacterium animalis lactis HN019 on the cellular immune activity of healthy elderly adults age 60-70 years. The authors concluded that supplementation with this bacterial strain at a range of potencies for 3-6 weeks duration had a significant positive impact on the part of the immune system that is responsible for removing pathogens and cell debris (phagocytosis) and a lesser but nevertheless significant impact on natural killer cells responsible for tumour destruction.
Abstract
Elderly people have increased susceptibility to infections and cancer that are associated with decline in cellular immune function. The objective of this work was to determine the efficacy of Bifidobacterium (B.) animalis ssp. lactis HN019 (HN019) supplementation on cellular immune activity in healthy elderly subjects. We conducted a systematic review of Medline and Embase for controlled trials that reported polymorphonuclear (PMN) cell phagocytic capacity or natural killer (NK) cell tumoricidal activity following B. lactis HN019 consumption in the elderly. A random effects meta-analysis was performed with standardized mean difference (SMD) and 95% confidence interval between probiotic and control groups for each outcome. A total of four clinical trials were included in this analysis. B. lactis HN019 supplementation was highly efficacious in increasing PMN phagocytic capacity with an SMD of 0.74 (95% confidence interval: 0.38 to 1.11, p < 0.001) and moderately efficacious in increasing NK cell tumoricidal activity with an SMD of 0.43 (95% confidence interval: 0.08 to 0.78, p = 0.02). The main limitations of this research were the small number of included studies, short-term follow-up, and assessment of a single probiotic strain. In conclusion, daily consumption of B. lactis HN019 enhances NK cell and PMN function in healthy elderly adults.
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Effect of Probiotics and Prebiotics on Immune Response to Influenza Vaccination in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Lei, WT, Shih, PC, Liu, SJ, Lin, CY, Yeh, TL
Nutrients. 2017;9(11)
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The influenza virus causes three to five million severe cases per year and currently the main way to minimise both morbidity and mortality is the influenza vaccine. Both prebiotics and probiotics have been shown to demonstrate protective effects against influenza infection. The aim of this systematic review and meta-analysis is to explore the effectiveness of probiotics and prebiotics on immune function in adults after an influenza vaccine. According to the existing literature, participants who took prebiotics or probiotics showed significant improvements in the immune response for three different strains of influenza vaccine. According to these results, the authors conclude that both pre- and pro- biotics can be used in adults prior to a seasonal influenza vaccine. Further large trials are required to both validate these findings as well as have a better understanding of the optimal dose and duration of supplementation.
Abstract
We conducted a meta-analysis to evaluate the effects of probiotics and prebiotics on the immune response to influenza vaccination in adults. We conducted a literature search of Pubmed, Embase, the Cochrane Library, the Cumulative Index to Nursing and Allied Health (CINAHL), Airiti Library, and PerioPath Index to Taiwan Periodical Literature in Taiwan. Databases were searched from inception to July 2017. We used the Cochrane Review risk of bias assessment tool to assess randomized controlled trial (RCT) quality. A total of 20 RCTs comprising 1979 adults were included in our systematic review. Nine RCTs including 623 participants had sufficient data to be pooled in a meta-analysis. Participants who took probiotics or prebiotics showed significant improvements in the H1N1 strain seroprotection rate (with an odds ratio (OR) of 1.83 and a 95% confidence interval (CI) of 1.19-2.82, p = 0.006, I² = 0%), the H3N2 strain seroprotection rate (OR = 2.85, 95% CI = 1.59-5.10, p < 0.001, I² = 0%), and the B strain seroconversion rate (OR = 2.11, 95% CI = 1.38-3.21, p < 0.001, I² = 0%). This meta-analysis suggested that probiotics and prebiotics are effective in elevating immunogenicity by influencing seroconversion and seroprotection rates in adults inoculated with influenza vaccines.