1.
Probiotics fortify intestinal barrier function: a systematic review and meta-analysis of randomized trials.
Zheng, Y, Zhang, Z, Tang, P, Wu, Y, Zhang, A, Li, D, Wang, CZ, Wan, JY, Yao, H, Yuan, CS
Frontiers in immunology. 2023;14:1143548
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Intestinal barrier function is closely related to the pathogenesis of various immune and inflammatory diseases. The intestinal microbiota plays an essential role in maintaining gut homeostasis and functionality in the presence of pro-inflammatory and anti-inflammatory microbes. The aim of this study was to comprehensively evaluate the role of probiotics in contributing to intestinal barrier function, and the related immune function, inflammatory status, and gut microbiota composition. This study was a systematic review of 28 articles (qualitative synthesis), and a meta-analysis of 26 randomised controlled trials. Results showed that probiotics could significantly improve intestinal barrier function according to specific indicators. The meta-analysis also indicated that probiotic supplementation could reduce inflammatory factors. Furthermore, it also demonstrated that probiotics could modulate gut microbiota compositions by elevating the abundances of Bifidobacterium and Lactobacillus. Authors conclude that probiotics could improve intestinal barrier function to some extent, but more high-quality randomised controlled studies are needed to reach a solid conclusion.
Expert Review
Conflicts of interest:
None
Take Home Message:
The probiotics Bifidobacterium and Lactobacillus may be beneficial for health by addressing imbalances in gut bacteria (dysbiosis), reducing inflammation in the gut and improving the integrity and function of the gut barrier
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
Probiotics are microorganisms that are considered beneficial to health. The aim of this study was to assess the role of probiotics in protecting intestinal barrier function as well as their effects on the composition of gut microbiota, inflammatory status, and immune function for reducing the risk of related diseases.
Methods
26 randomised controlled trials (RCTs) published between 2005-2021 with a total population of n=1891 (n = 955 Intervention, n = 936 controls)) were included in the meta-analysis. Outcome measures were categorised under indicators relating to intestinal barrier function, inflammatory markers, immune function and microbiota composition. Studies were conducted worldwide with participants being healthcare patients or athletes. Study durations ranged from 3 days to 6 months. Different dosages and forms of probiotics were used. Data was pooled for Bifidobacterium, Lactobacillus, Enterobacteriaceae and Enterococcus species.
Results
Gut barrier function in the probiotic groups was improved as measured by transepithelial resistance (TER) mean difference (MD) 5.27 {95% CI, 3.82 to 6.72, p = < 0.00001], lipopolysaccharide (LPS) standardised mean difference (SMD) -0.47 (95% CI, -0.85 to -0.09, p = 0.02), serum zonulin SMD -1.58 (95% CI,-2.49 to -0.66, p = 0.0007), and endotoxin SMD -3.20 (95% CI, -5.41 to - 0.98, p = 0.005).
The inflammatory markers interleukin 6 (IL-6), C-reactive protein (CRP) and tumour necrosis factor-alpha (TNF-a) were also improved compared to control groups. Lactobacillus (95% CI p=0.02) and Bifidobacterium (95% CI, p=0.01) enhanced microbial composition, however, Enterobacteriaceae and Enterococcus species did not. Immune function as measured by Immunoglobulin A (IgA), Immunoglobulin G IgG and Immunoglobulin M (IgM) were not improved.
Conclusion
The findings of this study suggest that intestinal barrier function and microbial composition could be improved using probiotics. They were also found to help alleviate inflammation. Further studies of high quality are however needed to confirm these results.
No conflicts of interest were reported.
Clinical practice applications:
The use of the probiotics Bifidobacterium and Lactobacillus may be beneficial for:
- supporting the integrity of gut barrier function
- improving the composition of gut microbiota
- lowering inflammation
Considerations for future research:
High heterogeneity between studies may affect the applicability of the results. Future research development should focus on the following areas:
- testing methods
- study durations
- measuring indicators
- the type and dose of probiotics
Abstract
BACKGROUND Probiotics play a vital role in treating immune and inflammatory diseases by improving intestinal barrier function; however, a comprehensive evaluation is missing. The present study aimed to explore the impact of probiotics on the intestinal barrier and related immune function, inflammation, and microbiota composition. A systematic review and meta-analyses were conducted. METHODS Four major databases (PubMed, Science Citation Index Expanded, CENTRAL, and Embase) were thoroughly searched. Weighted mean differences were calculated for continuous outcomes with corresponding 95% confidence intervals (CIs), heterogeneity among studies was evaluated utilizing I2 statistic (Chi-Square test), and data were pooled using random effects meta-analyses. RESULTS Meta-analysis of data from a total of 26 RCTs (n = 1891) indicated that probiotics significantly improved gut barrier function measured by levels of TER (MD, 5.27, 95% CI, 3.82 to 6.72, P < 0.00001), serum zonulin (SMD, -1.58, 95% CI, -2.49 to -0.66, P = 0.0007), endotoxin (SMD, -3.20, 95% CI, -5.41 to -0.98, P = 0.005), and LPS (SMD, -0.47, 95% CI, -0.85 to -0.09, P = 0.02). Furthermore, probiotic groups demonstrated better efficacy over control groups in reducing inflammatory factors, including CRP, TNF-α, and IL-6. Probiotics can also modulate the gut microbiota structure by boosting the enrichment of Bifidobacterium and Lactobacillus. CONCLUSION The present work revealed that probiotics could improve intestinal barrier function, and alleviate inflammation and microbial dysbiosis. Further high-quality RCTs are warranted to achieve a more definitive conclusion. CLINICAL TRIAL REGISTRATION https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=281822, identifier CRD42021281822.
2.
The effects of probiotic and synbiotic supplementation on inflammation, oxidative stress, and circulating adiponectin and leptin concentration in subjects with prediabetes and type 2 diabetes mellitus: a GRADE-assessed systematic review, meta-analysis, and meta-regression of randomized clinical trials.
Naseri, K, Saadati, S, Ghaemi, F, Ashtary-Larky, D, Asbaghi, O, Sadeghi, A, Afrisham, R, de Courten, B
European journal of nutrition. 2023;62(2):543-561
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When acute, inflammation is a necessary function of the immune system allowing the body to recognise and remove foreign stimuli. However, when chronic inflammation occurs, it can contribute to and exacerbate diseases such as type 2 diabetes (T2D). The gut microbiota and the use of probiotics has been shown to modulate processes within the body and decrease chronic inflammation, however research has not consistently shown this and an inverse relationship has been shown in some studies. This systematic review and meta-analysis aimed to determine the effect of probiotics and synbiotics on inflammation in individuals with prediabetes and T2D. A total of 32 randomised control trials were included in the meta-analysis and showed that certain, but not all inflammatory markers were reduced. Antioxidants were increased. The effect was especially pronounced in individuals with T2D as opposed to prediabetes. It was concluded that probiotics or synbiotics could be useful for individuals with T2D to reduce inflammation and reduce the risk for other associated diseases such as heart disease.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Probiotic and synbiotic supplementation may significantly reduce inflammation and oxidative stress, potentially lowering the risk of cardiovascular diseases in those with prediabetes and T2DM.
- These supplements may be particularly beneficial for individuals with T2DM and those who are overweight or obese.
- Incorporating probiotics and synbiotics into the diet could be a supportive strategy for improving metabolic health markers.
- The observed benefits vary depending on the type and duration of supplementation, suggesting that consistent, long-term use might be necessary to achieve noticeable health improvements.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
This systematic review meta-analysis and meta-regression assessed the impact of probiotics and synbiotics on inflammation, antioxidants, oxidative stress, and adipokines in prediabetes and type 2 diabetes.
Methodology
The methodology involved searching PubMed/MEDLINE, ISI Web of Science, Scopus, and Cochrane Library databases without date or language restrictions until March 2022. Study quality was evaluated.
- Inclusion criteria: Adults 18+ with prediabetes or type 2 diabetes; interventions with probiotics or synbiotics versus placebo or other treatments; and reporting on inflammatory biomarkers, adipocytokines, and oxidative stress serum biomarkers in RCTs with parallel or cross-over designs.
Results
32 RCTs with 2074 participants were analysed, mostly in Asia (26 studies) and 5 in Europe, Africa, Oceania, and America, over 4 to 24 weeks. Dosages varied, including synbiotic bread with Lactobacillus sporogenes and inulin (1×10^8 CFU, 0.07g/g, thrice daily), 300ml/day fermented milk with L. helveticus, daily synbiotic and probiotic tablets, a probiotic mixture (120g/day), synbiotics (9g, thrice daily), multistrain probiotic yoghurt (300g/day), L. sporogenes-enriched bread (40g, thrice daily), and probiotic honey (2500mg/day). Measurements included CRP (31 RCTs), TNF-α (12 RCTs), GSH (13 RCTs), MDA (12 RCTs), TAC (11 RCTs), and NO levels (8 trials).
Effects of probiotics and synbiotics:
- significantly reduced CRP levels (-0.62 mg/L, 95% CI: -0.80 to -0.44, p < 0.001, 31 RCTs), showing greater efficacy in T2DM than prediabetes, particularly in individuals with overweight.
- TNF-α levels decreased in participants with T2D or overweight (-0.48 pg/mL, 95% CI: -0.81 to -0.15, p = 0.004, 12 RCTs).
- GSH levels significantly rose (69.80, 95% CI: 33.65 to 105.95, p < 0.001, 13 RCTs), independent of trial duration or baseline BMI.
- MDA levels were significantly reduced (-0.51, 95% CI: -0.73 to -0.30, p < 0.001, 12 RCTs) in studies lasting ≥12 weeks.
- TAC significantly increased (73.59, 95% CI: 33.24 to 113.95, p < 0.001, 11 RCTs), with more pronounced effects in longer trials and with probiotics.
- NO levels improved significantly (7.49, 95% CI: 3.12 to 11.86, p = 0.001, 9 trials) in individuals with obesity.
- Positive impacts on CRP, TNF-α, MDA, and TAC were more marked in trials ≥12 weeks.
Conclusions
Probiotic or synbiotic intake may benefit those with prediabetes and T2DM, reducing CRP, TNF-α, MDA, and enhancing TAC, GSH, NO levels, especially in T2DM individuals. Effects are stronger in individuals with overweight or obesity.
Clinical practice applications:
- Probiotic and synbiotic supplementation could be recommended to reduce inflammatory biomarkers like CRP and TNF-α, especially in individuals with T2DM.
- The improvements in oxidative stress markers, such as increased TAC and GSH and decreased MDA, support the use of probiotic and synbiotic supplements in managing oxidative stress in T2DM and prediabetes.
- Longer durations (≥12 weeks) of probiotic or synbiotic supplementation may offer a more pronounced effect on antioxidant capacity.
- The findings can guide personalised nutritional recommendations, as for example improvement in inflammation biomarkers and NO were more evident in individuals with T2DM or overweight suggesting an anti-inflammatory effect primarily in these groups. Moreover, markers related to antioxidant capacity were improved in those diagnosed with prediabetes or T2DM irrespective of BMI.
Considerations for future research:
- The beneficial effects on inflammatory and antioxidant/oxidative stress markers suggest a need for larger and longer-term studies to solidify the role of probiotics and synbiotics in benefiting chronic conditions like T2DM and prediabetes.
- There is potential for investigating the specific strains of probiotics that are most effective, considering varying outcomes observed across different studies.
- Research could explore the mechanisms by which probiotics and synbiotics exert their beneficial effects, contributing to a better understanding of gut-health interactions.
- The varying responses based on BMI categories indicate a need for personalised nutrition research to optimise probiotic therapy for individual needs.
- Future studies should consider standardising the dosage and formulation of probiotics to determine the most effective therapeutic doses and combinations.
Abstract
PURPOSE Probiotics or synbiotics consumption have been suggested to reduce the risk of cardiovascular disease (CVD) through a decline in inflammation and oxidative stress, however, the results from studies are conflicting. This study filled this knowledge gap by evaluating randomized controlled trials (RCTs) investigating probiotics or synbiotics intake on adipokines, inflammation, and oxidative stress in patients with prediabetes and type-2 diabetes mellitus (T2DM). METHODS We systematically did search up to March 2022 in PubMed/Medline, Scopus, ISI Web of Science, and Cochrane library. A random-effect model was applied to estimate the weighted mean difference (WMD) and 95% confidence interval (95% CI) for each outcome. RESULTS A total of 32 RCTs were included in the meta-analysis. This intervention led to a significant decrease in levels of C-reactive protein (CRP) (WMD - 0.62 mg/l; 95% CI - 0.80, - 0.44; p < 0.001), tumor necrosis factor-α (TNF-α) (WMD - 0.27 pg/ml; 95% CI - 0.44, - 0.10; p = 0.002) and malondialdehyde (MDA) (WMD - 0.51 µmol/l; 95% CI - 0.73, - 0.30; p < 0.001), and also a significant increase in levels of glutathione (GSH) (WMD 69.80 µmol/l; 95% CI 33.65, 105.95; p < 0.001), total antioxidant capacity (TAC) (WMD 73.59 mmol/l; 95% CI 33.24, 113.95; p < 0.001) and nitric oxide (NO) (WMD 7.49 µmol/l; 95% CI 3.12, 11.86; p = 0.001), without significant alterations in interleukin-6 (IL-6) and adipokines levels. CONCLUSION A consumption of probiotics or synbiotics could be a useful intervention to improve cardiometabolic outcomes through a reduced inflammation and oxidative stress in patients with prediabetes and T2DM.
3.
A Low-FODMAP Diet Provides Benefits for Functional Gastrointestinal Symptoms but Not for Improving Stool Consistency and Mucosal Inflammation in IBD: A Systematic Review and Meta-Analysis.
Peng, Z, Yi, J, Liu, X
Nutrients. 2022;14(10)
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The low-FODMAP diet eliminates carbohydrates that cannot be easily digested in order to reduce functional gastrointestinal symptoms associated with irritable bowel disease (IBD). The symptoms of irritable bowel disease include abdominal pain and bloating. This systematic review and meta-analysis aimed to evaluate whether a low-FODMAP diet can alleviate functional gastrointestinal symptoms in individuals with inflammatory bowel disease. In comparison with a regular diet, a low-FODMAP diet significantly reduced symptoms of bloating, wind, flatulence, abdominal pain, fatigue, and lethargy in patients with IBD. In addition, patients with Crohn's disease have achieved remission or reduced symptoms after following a low-FODMAP diet. Healthcare professionals can use this study to understand better the effects of a low-FODMAP diet on patients with IBD who have functional gastrointestinal symptoms. Further robust studies are, however, required to evaluate the evidence's robustness and identify the mechanism behind the improvement of symptoms.
Expert Review
Conflicts of interest:
None
Take Home Message:
- LFD use in IBD improved symptoms of bloating, wind or flatulence, borborygmi, abdominal pain, and fatigue or lethargy, but not nausea and vomiting.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
This meta-analysis assesses the efficacy of a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet (LFD) in inflammatory bowel disease [IBD: ulcerative colitis (UC) and Crohn’s disease (UC)] participants with functional gastrointestinal symptoms (FGSs).
Methods
A search was performed on PubMed, Web of Science, EMBASE, Cochrane Central Register of Controlled Trials, Chinese National Knowledge Infrastructure (CNKI), WanFang (Chinese) Database up to March 2022. Quality assessment of all included studies was performed.
Results
9 studies (4 randomised controlled trials, 5 non-randomised studies) with a total of 351 participants diagnosed with IBD were included, and compared LFD with a placebo diet or normal diet (ND), overall and individual
LFD Effects of FGS:
- Overall 9 studies: an improvement (0.47, 0.33–0.66, p = 0.0000)
- No difference in the subgroup classified by disease type
- CD and UC: no improvement
Individual improvement:
- Bloating (0.37, 0,24-0,57, p=0.0000); wind or flatulence (0.38, 0,28-0,51, p=0.0000); borborygmi (0.48, 0,26-0,89, p=0.0000), abdominal pain (0.5, 0,37-0,68, p=0.0000), fatigue/lethargy (0.71, 0,61-0,82, p=0.0000)
- No difference in nausea and vomiting (0.54, 0,22-1,32, p=018)
IBS Quality of Life Score:
- 2 studies: reduced Short IBD Questionnaire (SIBDQ) score (11.24, 6.61-15.87, p=0.0000)
Bristol Stool Form Chart:
- 2 studies: normal stool consistency (type 3-4); no difference (5.99, 0.17-216.51, p=0.33)
- 2 other studies: no difference (-0.17, 0.48 - 0.15, p=0.30)
Diseases activity (Harvey-Bradshaw index):
- 2 studies using the Mayo score: no difference (-32, -1,09-0.45, p=0.41)
- 3 studies using BHi score: reduction (-1.09, -1,77-0.42, p=0.002)
Faecal calprotectin:
- 2 studies: no change (-16.03, -36,78-4.73, p=0.13)
Limitations
- Comparison diets were not standardised, suggesting the potential of different dietary habits to bias results..
- Heterogeneity of included studies, and the relatively small sample size of the studies can reduce the reliability of the results.
Conclusion
While the study found inconsistent definition standards for FGS, all the nine studies showed that LFD was associated with an improvement in some symptoms.
Clinical practice applications:
- This study suggests that IBD patients with FGSs may benefit from LFD treatment with the assistance of a healthcare professional.
Considerations for future research:
- This study has shown that LFD can improve FGSs in IBD, but further research with a larger sample size and more comprehensive analysis is warranted to replicate the results.
- The description of the findings and Quality of Life data are a little unclear. The impact on Quality of Life warrants further investigation, as clinicians need to consider the impact of following a restrictive diet on Quality of Life.
Abstract
BACKGROUND A low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet (LFD) is claimed to improve functional gastrointestinal symptoms (FGSs). However, the role of LFD in inflammatory bowel disease (IBD) patients with FGSs remains unclear. OBJECTIVE To systematically assess the efficacy of LFD in IBD patients with FGSs. METHODS Six databases were searched from inception to 1 January 2022. Data were synthesized as the relative risk of symptoms improvement and normal stool consistency, mean difference of Bristol Stool Form Scale (BSFS), Short IBD Questionnaire (SIBDQ), IBS Quality of Life (IBS-QoL), Harvey-Bradshaw index (HBi), Mayo score, and fecal calprotectin (FC). Risk of bias was assessed based on study types. A funnel plot and Egger's test were used to analyze publication bias. RESULTS This review screened and included nine eligible studies, including four randomized controlled trials (RCTs) and five before-after studies, involving a total of 446 participants (351 patients with LFD vs. 95 controls). LFD alleviated overall FGSs (RR: 0.47, 95% CI: 0.33-0.66, p = 0.0000) and obtained higher SIBDQ scores (MD = 11.24, 95% CI 6.61 to 15.87, p = 0.0000) and lower HBi score of Crohn's disease (MD = -1.09, 95% CI -1.77 to -0.42, p = 0.002). However, there were no statistically significant differences in normal stool consistency, BSFS, IBS-QoL, Mayo score of ulcerative colitis, and FC. No publication bias was found. CONCLUSIONS LFD provides a benefit in FGSs and QoL but not for improving stool consistency and mucosal inflammation in IBD patients. Further well-designed RCTs are needed to develop the optimal LFD strategy for IBD.
4.
Serum vitamin E levels and chronic inflammatory skin diseases: A systematic review and meta-analysis.
Liu, X, Yang, G, Luo, M, Lan, Q, Shi, X, Deng, H, Wang, N, Xu, X, Zhang, C
PloS one. 2021;16(12):e0261259
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Vitiligo, Psoriasis, Acne and Atopic Dermatitis are chronic immune-mediated inflammatory skin conditions characterised by itchy skin. In previous studies, decreased serum vitamin E levels have been associated with an increased risk of skin diseases. Nuts, oils from plants, and vegetables contain vitamin E, which is a dietary bioactive compound that has anti-inflammatory and antioxidant properties. In this systematic review and meta-analysis, twenty case-controlled studies were included, of which thirteen specifically examined alpha-tocopherol levels. Psoriasis, Vitiligo, atopic dermatitis, and acne patient groups had significantly lower levels of serum Vitamin E than the control groups. There is no clear understanding of the pathogenesis of chronic inflammatory skin conditions. One of the underlying mechanisms is the interaction between oxidative stress and the immune system, as well as the accumulation of free radicals in the epidermal layers of the skin. As there is limited evidence regarding the benefits of Vitamin E in improving chronic inflammatory skin conditions, further robust studies are necessary. Healthcare professionals can use this research to gain a better understanding of the potential clinical applications of vitamin E in the treatment of skin disorders.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Low serum vitamin E levels are reported to be associated with several chronic inflammatory skin diseases, such as vitiligo, psoriasis, atopic dermatitis, and acne.
- Practitioners could consider vitamin E therapy in those with low serum concentrations
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
This systematic review and meta-analysis report on the association between serum vitamin E levels and chronic inflammatory skin diseases.
The review which followed PRISMA reporting guidelines, screened 892 studies. After the selection and exclusions, 20 case-control studies were included involving a total of 1172 patients.
The studies that were included focused mainly on chronic inflammatory diseases, including vitiligo, psoriasis, atopic dermatitis, and acne. Eight studies included only adults, five included only children or teenagers and six studies included adults and children. One study had no age description.
Thirteen studies stated that alpha-tocopherol was used in their investigations. However, seven studies did not describe the subunit of vitamin E.
Primary clinical outcomes were:
- Seven studies, with 351 cases and 350 controls reported that compared with the control group, vitiligo patients had lower serum vitamin E concentrations (Standard Mean Difference (SMD):0.70, 95% Cl:121-0.19.
- Six studies investigated the change of serum vitamin E levels in patients with psoriasis, with 278 cases and 257 controls. Compared with the control group, psoriasis patients had lower serum vitamin E concentrations (SMD: -2.37, 95% CI: -3.57 to -1.18).
- The serum vitamin E Levels in patients with atopic dermatitis were observed in 4 studies, with 259 cases and 307 controls. Compared with the control group atopic dermatitis patients had lower serum vitamin E concentrations (SMD: -1.08, 95% CI: -1.80 to -0.36).
Levels of serum vitamin E in acne patients were reported in 3 studies, with 284 cases and 186 controls. Compared with the control group, acne patients had lower serum concentration levels of vitamin E (SMD: -0.67, 95% CI: -1.05 to -0.30).
No publication bias was found in any association (Egger’s test >0.05), though heterogeneity was considerable in every case (I2 > 80%), though this interaction was not significant for acne (p=0.879). Associations were not split by age, or any other cofactor, however sensitivity analyses did not indicate modification of the results.
The authors also assessed the association between skin disease severity and serum vitamin E concentrations. Overall, more severe disease was associated with a lower serum vitamin E concentration (SMD -1.56, 95% CI:-2.53 to -059).
Clinical practice applications:
- Vitamin E has gained the attention of researchers as a potential adjuvant therapy for various skin disorders due to its excellent antioxidant and anti-inflammatory properties.
- This review reports on the low levels of serum vitamin E found in patients with vitiligo, psoriasis, atopic dermatitis, and acne, and also suggests that serum concentrations of vitamin E are lower in those with more severe disease. Based on these findings, practitioners could therefore consider investigating the serum vitamin E levels of patients with inflammatory skin diseases and consider including vitamin E in their treatment protocols if their serum vitamin E levels are low.
Considerations for future research:
- The small number of studies in this review indicates the need for further research to be done on vitamin E and inflammatory skin diseases.
- Although there are reports on the antioxidant and anti-inflammatory properties of vitamin E, further investigations are needed to determine the exact mechanism of action in inflammatory skin diseases.
- Additionally, further investigation is needed to evaluate which chemical forms of vitamin E and their dosage amounts have beneficial effects on inflammatory skin diseases.
Abstract
BACKGROUND Vitamin E has long been linked to skin health, including all of its possible functions in cosmetic products, to its roles in membrane integrity and even the aging process. However, reports on the relationship between serum vitamin E levels and the risk of chronic inflammatory skin diseases have been inconsistent. We performed a systematic review and meta-analysis to evaluate the association between serum vitamin E levels and chronic inflammatory skin diseases. METHODS We searched the PubMed, Web of Science and Scopus databases, with no time limit up to 30.06.2021. Studies examining serum vitamin E levels in patients with chronic inflammatory skin diseases were selected. RESULTS Twenty articles met the inclusion criteria. Compared with controls, a lower vitamin E level was found in patients with vitiligo (SMD: -0.70, 95% CI: -1.21 to -0.19), psoriasis (SMD: -2.73, 95% CI: -3.57 to -1.18), atopic dermatitis (SMD: -1.08, 95% CI: -1.80 to -0.36) and acne (SMD: -0.67, 95% CI: -1.05 to -0.30). CONCLUSIONS Our meta-analysis showed that serum vitamin E levels were lower in patients suffering from vitiligo, psoriasis, atopic dermatitis and acne. This study highlights the need to evaluate vitamin E status to improve its level in patients with skin diseases.