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The Influence of n-3PUFA Supplementation on Muscle Strength, Mass, and Function: A Systematic Review and Meta-Analysis.
Santo André, HC, Esteves, GP, Barreto, GHC, Longhini, F, Dolan, E, Benatti, FB
Advances in nutrition (Bethesda, Md.). 2023;14(1):115-127
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Omega 3 polyunsaturated fatty acids (n-3PUFA) are long-chain polyunsaturated fatty acids essential to human health. They play a role in cell membrane integrity, immune and inflammation regulation, cognition and neuromuscular function. As the human body cannot make these fatty acids, they need to be obtained through diet or supplementation. Regarding skeletal muscle, recent research showed that n-3PUFAs may increase the uptake of amino acids by increasing the membrane fluidity in the muscle, and by activating pathways that inhibit protein breakdown. This led to the hypothesis that n-3PUFAs may enhance muscle mass gain and strength. This systematic review sought to gather all available evidence about the impact of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. The review included 14 studies with a total of 1443 participants. The authors found that n-3PUFA supplementation had no significant effect on muscle mass or muscle function in healthy young and older adults, however, a very small but significant positive effect was noted regarding muscle strength. In the discussion section, the authors explain the challenges of their review and how these findings integrate with the current understanding and other research findings. They concluded more research is needed to get a better insight into the effects of n-3PUFA on muscle function and the variants.
Abstract
The effects of omega 3 polyunsaturated fatty acids (n-3PUFA) supplementation on skeletal muscle are currently unclear. The purpose of this systematic review was to synthesize all available evidence regarding the influence of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. Four databases were searched (Medline, Embase, Cochrane CENTRAL, and SportDiscus). Predefined eligibility criteria were determined according to Population, Intervention, Comparator, Outcomes, and Study Design. Only peer-reviewed studies were included. The Cochrane RoB2 Tool and the NutriGrade approach were used to access risk of bias and certainty in evidence. Effect sizes were calculated using pre-post scores and analyzed using a three-level, random-effects meta-analysis. When sufficient studies were available, subanalyses were performed in the muscle mass, strength, and function outcomes according to participant's age (<60 or ≥60 years), supplementation dosage (<2 or ≥2 g/day), and training intervention ("resistance training" vs. "none or other"). Overall, 14 individual studies were included, total 1443 participants (913 females; 520 males) and 52 outcomes measures. Studies had high overall risk of bias and consideration of all NutriGrade elements resulted in a certainty assessment of moderate meta-evidence for all outcomes. n-3PUFA supplementation had no significant effect on muscle mass (standard mean difference [SMD] = 0.07 [95% CI: -0.02, 0.17], P = 0.11) and muscle function (SMD = 0.03 [95% CI: -0.09, 0.15], P = 0.58), but it showed a very small albeit significant positive effect on muscle strength (SMD = 0.12 [95% CI: 0.006, 0.24], P = 0.04) in participants when compared with placebo. Subgroup analyses showed that age, supplementation dose, or cosupplementation alongside resistance training did not influence these responses. In conclusion, our analyses indicated that n-3PUFA supplementation may lead to very small increases in muscle strength but did not impact muscle mass and function in healthy young and older adults. To our knowledge, this is the first review and meta-analysis investigating whether n-3PUFA supplementation can lead to increases in muscle strength, mass, and function in healthy adults. Registered protocol: doi.org/10.17605/OSF.IO/2FWQT.
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Efficacy and Safety of Curcumin and Curcuma longa Extract in the Treatment of Arthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trial.
Zeng, L, Yang, T, Yang, K, Yu, G, Li, J, Xiang, W, Chen, H
Frontiers in immunology. 2022;13:891822
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Arthritic disease is a chronic inflammatory condition affecting one or more joints. Over 100 different forms of arthritis have been identified. Despite their different causes (i.e. degenerative, autoimmune), they share common symptoms such as joint pain, swelling, stiffness, and reduced mobility, which can be disabling in many cases. Drug treatment focuses mainly on limiting the progression of the disease, reducing joint inflammation and managing pain. However, these drugs are associated with many side effects. The rhizome of Curcuma longa (CL), also known as turmeric, has longstanding use as an anti-inflammatory in traditional Asian medicines. Research has affirmed its anti-inflammatory and immunosuppressive properties. Evidence from multiple clinical trials suggests that curcumin, one of the active compounds of CL, can reduce the subjective experience of pain in some conditions and can also improve the symptoms and inflammation associated with arthritis. Hence this systematic review sought to evaluate the efficacy and safety of CL-extract in 5 types of arthritis (including Ankylosing Spondylitis, Rheumatoid Arthritis, Osteoarthritis, Juvenile idiopathic arthritis and gout). The review included 29 randomized controlled trials involving 2396 participants, with dosages ranging from 120 mg to 1500 mg for a period of 4-36 weeks. Overall, curcumin and CL extract appeared to improve inflammation and pain levels in arthritic subjects whilst demonstrating safety with no increases in adverse effects. CL and its active constituents appeared to favourably change immune and inflammatory responses, as well as serum uric acid levels in the reviewed forms of arthritis. However, due to the small sample numbers in the trials and some lower quality studies, the authors advocate to interpret the results with caution until more solid evidence is available.
Abstract
Background: Modern pharmacological research found that the chemical components of Curcuma longa L. are mainly curcumin and turmeric volatile oil. Several recent randomized controlled trials (RCT) have shown that curcumin improves symptoms and inflammation in patients with arthritis. Methods: Pubmed, Cochran Library, CNKI, and other databases were searched to collect the randomized controlled trials (RCTs). Then, the risk of bias of RCTs were assessed and data of RCTs were extracted. Finally, RevMan 5.3 was utilized for meta-analysis. Results: Twenty-nine (29) RCTs involving 2396 participants and 5 types of arthritis were included. The arthritis included Ankylosing Spondylitis (AS), Rheumatoid Arthritis (RA), Osteoarthritis (OA), Juvenile idiopathic arthritis (JIA) and gout/hyperuricemia. Curcumin and Curcuma longa Extract were administered in doses ranging from 120 mg to 1500 mg for a duration of 4-36 weeks. In general, Curcumin and Curcuma longa Extract showed safety in all studies and improved the severity of inflammation and pain levels in these arthritis patients. However, more RCTs are needed in the future to elucidate the effect of Curcumin and Curcuma longa Extract supplementation in patients with arthritis, including RA, OA, AS and JIA. Conclusion: Curcumin and Curcuma longa Extract may improve symptoms and inflammation levels in people with arthritis. However, due to the low quality and small quantity of RCTs, the conclusions need to be interpreted carefully.
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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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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.
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Body mass index, abdominal fatness, weight gain and the risk of psoriasis: a systematic review and dose-response meta-analysis of prospective studies.
Aune, D, Snekvik, I, Schlesinger, S, Norat, T, Riboli, E, Vatten, LJ
European journal of epidemiology. 2018;33(12):1163-1178
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Psoriasis is an immune-mediated inflammatory skin disease characterised by red, itchy, scaly and flaky skin. Research has shown an association between adiposity and inflammation cytokine release triggered by adipose tissue and increased body mass index and psoriasis. In this meta-analysis, seven prospective studies were included, and the association between BMI, abdominal fat, and psoriasis was examined. According to this meta-analysis, the relative risk of psoriasis increases by 19% for every 5-unit increase in BMI, 24% for a 10 cm increase in waist circumference, 37% for a 0.1-unit increase in waist-to-hip ratio, and 11% for a 5 kg weight gain. The risk of psoriasis was lower for people with a BMI below 20, and it was significantly higher for those with a BMI between 22.5-24. Psoriasis risk was positively associated with waist circumference, waist-to-hip ratio, and weight gain. Psoriasis risk escalates by 2-4 times with an increase in each measure of adiposity. Several potential strategies to reduce the risk of psoriasis are identified in this meta-analysis, including weight loss, dietary factors, and physical activity. To evaluate their effectiveness and develop appropriate strategies, further robust studies are needed. Healthcare professionals can use the results of this study to develop potential therapeutic strategies to reduce the risk of psoriasis by understanding the mechanisms and factors associated with the disease.
Abstract
Greater body mass index (BMI) has been associated with increased risk of psoriasis in case-control and cross-sectional studies, however, the evidence from prospective studies has been limited. We conducted a systematic review and dose-response meta-analysis of different adiposity measures and the risk of psoriasis to provide a more robust summary of the evidence based on data from prospective studies. PubMed and Embase databases were searched for relevant studies up to August 8th 2017. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a random effects model. The summary relative risk (RR) for a 5 unit increment in BMI was 1.19 (95% CI 1.10-1.28, I2 = 83%, n = 7). The association appeared to be stronger at higher compared to lower levels of BMI, pnonlinearity < 0.0001, and the lowest risk was observed at a BMI around 20. The summary RR was 1.24 (95% CI 1.17-1.31, I2 = 0%, pheterogeneity = 0.72, n = 3) per 10 cm increase in waist circumference, 1.37 (95% CI 1.23-1.53, I2 = 0%, pheterogeneity = 0.93, n = 3) per 0.1 unit increase in waist-to-hip ratio, and 1.11 (95% CI 1.07-1.16, I2 = 47%, pheterogeneity = 0.15, n = 3) per 5 kg of weight gain. Adiposity as measured by BMI, waist circumference, waist-to-hip ratio, and weight gain is associated with increased risk of psoriasis.