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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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The effects of multi-nutrient formulas containing a combination of n-3 PUFA and B vitamins on cognition in the older adult: a systematic review and meta-analysis.
Fairbairn, P, Dyall, SC, Tsofliou, F
The British journal of nutrition. 2023;129(3):428-441
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Due to the insidious onset, cognitive impairment often goes unnoticed for several years, with clinical diagnosis being made late into the disease progression. Cognition is critical for functional independence as people age, and intact cognition is vital for humans to communicate effectively. The aims of this study were to (i) investigate whether supplementation with a combination of omega-3 polyunsaturated fatty acids (n-3 PUFA) and B vitamins alone or as part of a multi-nutrient formula can prevent cognitive decline in older adults, and (ii) determine whether the effects of a single nutrient intervention with either n-3 PUFA or B vitamins could be modified by the status of the other nutrient. This study is a systematic review and meta-analysis of fourteen studies of which eleven were randomised controlled trials and the rest were post hoc analysis of randomised controlled trials. Results show a benefit of supplementing with nutrient formulas that contain both n-3 PUFA and B vitamins on global cognition and episodic memory with small to moderate effect sizes. In fact, they can help preserve cognition in the older adults. Authors conclude that more experimental work providing a combination of nutrients including both n-3 PUFA and B vitamins, in healthy older adults or those showing early signs of cognitive decline, is clearly warranted to better explore how nutrition can impact the trajectory of cognition in older adults.
Abstract
There is now evidence to suggest that there may be an interaction between B vitamins and n-3 PUFA, with suggestions that increasing intake of both nutrients simultaneously may benefit cognition in older adults. The aim of this systematic review was to investigate whether supplementation with a combination of n-3 PUFA and B vitamins can prevent cognitive decline in older adults. Randomised controlled trials conducted in older adults that measured cognitive function were retrieved. The included trials provided a combination of n-3 PUFA and B vitamins alone, or in combination with other nutrients. Trials that provided n-3 PUFA alone and also measured B vitamin status or provided B vitamin supplementation alone and measured n-3 PUFA status were also included. The databases searched were The Cochrane Library, EMBASE, CINAHL, Scopus and MEDLINE. A total of 14 papers were included in the analysis (n 4913; age: 60-70 years; follow-up 24 weeks to 4 years). The meta-analysis results found a significant benefit of nutrient formulas, which included both n-3 PUFA and B vitamins alongside other nutrients, v. placebo on global cognition assessed using composite scores from a neuropsychological test battery (G = 0·23, P = 0·002), global cognition using single measures of cognition (G = 0·28, P = 0·004) and episodic memory (G = 0·32, P = 0·001). The results indicate that providing a combination of n-3 PUFA and B vitamins as part of a multi-nutrient formula benefits cognition in older adults v. a placebo, and the potential for an interaction between these key nutrients should be considered in future experimental work.
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Impact of probiotics on muscle mass, muscle strength and lean mass: a systematic review and meta-analysis of randomized controlled trials.
Prokopidis, K, Giannos, P, Kirwan, R, Ispoglou, T, Galli, F, Witard, OC, Triantafyllidis, KK, Kechagias, KS, Morwani-Mangnani, J, Ticinesi, A, et al
Journal of cachexia, sarcopenia and muscle. 2023;14(1):30-44
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Sarcopenia is a progressive skeletal muscle disorder involving accelerated loss of muscle mass, strength and function. It generally occurs in older age groups but can also be seen in younger people. Multiple factors contribute to the development of the condition. Besides nutritional management strategies, probiotics have recently caught the interest of researchers. As probiotics promote metabolic building activity, aid digestion and absorption and reduce muscle breakdown by favourably managing inflammation, they present great potential for the management of sarcopenia. This systematic review and meta-analysis explored the impact of probiotic supplementation on muscle mass, total lean mass and muscle strength in human adults. The review included 24 studies, with probiotics mainly from the Bifidobacteria or Lactobacilli family. The analysis concluded that probiotic supplementation improved muscle mass in comparison to placebos. It also significantly increased overall muscle strength in 6 randomized controlled trials, which was most obvious in age groups of 50 and above. However, no changes were seen concerning total lean mass. It appeared that longer studies, of >12 weeks or more, showed better outcomes in this review. Furthermore, Bifidobacteria species seemed to exhibit more favourable effects, and the authors also noted the beneficial results were more significant in Asian populations. Further research is needed to understand more about the underlying mechanism, best probiotics strains and the specifics of different demographic groups. This article yields a concise overview of sarcopenia, the nutritional aspects of the disease and how probiotics may be beneficial in disease management, strengthened with data from the review.
Expert Review
Conflicts of interest:
None
Take Home Message:
- This was a well-conducted meta-analysis based on its methodological approach that demonstrated that Lactobacillus and Bifidobacterium probiotic supplementation may contribute to improved muscle mass in younger adults and improved muscle strength in older adults.
- Bifidobacterium probiotic supplementation was associated with enhanced muscle mass in younger adults, a potential focus for those considering probiotic supplements.
- The duration of probiotic therapy matters, with longer-term (12 weeks or more) supplementation showing improvements in muscle mass and strength..
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:
Introduction
This systematic review and meta-analysis evaluated the effect of probiotics on muscle mass, total lean mass and muscle strength in both young and older adults.
Methods
- The search encompassed PubMed, Scopus, Web of Science, and Cochrane Library databases, from inception up to June 2022; studies included spanned a period from 2013 to June 2022.
- The study adhered to Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines and included the Risk-of-Bias tool to assess study quality.
- The study focused on changes in muscle mass, total lean mass, and muscle strength.
- Inclusion criteria: randomised controlled trials (RCTs) with adult participants (>18 years); interventions involving any probiotics, and a control group receiving either no treatment or a placebo.
Results
- 24 RCTs were included (709 participants), with studies conducted in Europe, USA, and Asia. Intervention durations: ranged from 3 weeks to 12 months.
- Participants included overweight, untrained healthy and resistance-trained individuals, and those with specific conditions like metabolic syndrome and frailty.
- Body composition assessments were conducted using bioelectrical impedance (BIA) and/or dual-energy X-ray absorptiometry (DXA).
- Probiotic strains employed in the included studies varied, with Lactobacillus the most common, followed by Bifidobacterium; some combined both. 5 of 24 studies also used additional strains.
- Dosages: ranged from 2 × 10^9 to 11.2 × 10^10 colony-forming units (CFU).
- 4 out of 24 studies used fermented food products like cheese and noodles as sources of probiotics.
- 22 RCTs measured muscle mass and total lean mass; 6 RCTs measured global muscle strength.
- Probiotic supplementation (≥12 weeks) moderately increased muscle mass, with a standardised mean difference (SMD) of 0.42. This significant effect (95% CI: 0.10–0.74, P=0.009) was observed only in younger Asian adults (<50 years) after Bifidobacterium supplementation, based on a meta-analysis of 10 studies.
- Probiotic supplementation (≥12 weeks) significantly increased global muscle strength in older adults (>50 years; SMD: 0.69, 95% CI: 0.33–1.06, P = 0.0002).
- Probiotic supplementation showed no significant impact on lean mass (SMD: -0.03, 95% CI: 0.19 – 0.13, P = 0.69).
Conclusion
Probiotic supplementation, especially Lactobacillus and Bifidobacterium may have a positive impact on muscle mass and global strength
Clinical practice applications:
- Consumption of probiotics, mainly Lactobacillus and Bifidobacterium may contribute to improved muscle strength in older individuals (>50y).
- Consumption of Bifidobacterium strains was associated with improved muscle mass in younger individuals (<50y) in Asian countries, in a low number of studies (k=2).
- Bifidobacterium breve B-3 was associated with an improvement in muscle mass in older overweight individuals, although a causal relationship was not established.
- Probiotics may enhance muscle mass or strength by enhancing protein digestion and amino acid absorption for muscle synthesis and function.
- Considering an individual’s goals, a practitioner could consider probiotic supplementation as a complementary intervention when aiming to enhance muscle mass or strength .
Considerations for future research:
- Future research could focus on pinpointing which specific probiotic strains are most effective for muscle strength or muscle mass to tailor more precise interventions.
- Most studies did not exceed 12 weeks, highlighting the need for long-term research on probiotics sustained muscle impact.
- Future research could investigate the effects of probiotics across diverse demographic groups including different ages, sexes, and ethnic backgrounds to understand the impact in different populations.
- Delving deeper into the mechanisms by which probiotics influence muscle health could lead to targeted probiotic therapies that address specific physiological pathways.
- Finally, future research could explore how probiotics can be combined with other interventions, such as exercise or nutritional modifications, to synergistically improve muscle health and function.
Abstract
Probiotics have shown potential to counteract sarcopenia, although the extent to which they can influence domains of sarcopenia such as muscle mass and strength in humans is unclear. The aim of this systematic review and meta-analysis was to explore the impact of probiotic supplementation on muscle mass, total lean mass and muscle strength in human adults. A literature search of randomized controlled trials (RCTs) was conducted through PubMed, Scopus, Web of Science and Cochrane Library from inception until June 2022. Eligible RCTs compared the effect of probiotic supplementation versus placebo on muscle and total lean mass and global muscle strength (composite score of all muscle strength outcomes) in adults (>18 years). To evaluate the differences between groups, a meta-analysis was conducted using the random effects inverse-variance model by utilizing standardized mean differences. Twenty-four studies were included in the systematic review and meta-analysis exploring the effects of probiotics on muscle mass, total lean mass and global muscle strength. Our main analysis (k = 10) revealed that muscle mass was improved following probiotics compared with placebo (SMD: 0.42, 95% CI: 0.10-0.74, I2 = 57%, P = 0.009), although no changes were revealed in relation to total lean mass (k = 12; SMD: -0.03, 95% CI: -0.19 - 0.13, I2 = 0%, P = 0.69). Interestingly, a significant increase in global muscle strength was also observed among six RCTs (SMD: 0.69, 95% CI: 0.33-1.06, I2 = 64%, P = 0.0002). Probiotic supplementation enhances both muscle mass and global muscle strength; however, no beneficial effects were observed in total lean mass. Investigating the physiological mechanisms underpinning different ageing groups and elucidating appropriate probiotic strains for optimal gains in muscle mass and strength are warranted.
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Can dementia risk be reduced by following the American Heart Association's Life's Simple 7? A systematic review and dose-response meta-analysis.
Wu, J, Xiong, Y, Xia, X, Orsini, N, Qiu, C, Kivipelto, M, Rizzuto, D, Wang, R
Ageing research reviews. 2023;83:101788
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The American Heart Association (AHA) has defined ideal levels of seven modifiable cardiovascular health (CVH) factors, known as Life's Simple 7, that consist of smoking, physical activity, diet, body mass index, fasting blood glucose, total cholesterol, and blood pressure. Maintaining ideal levels of these factors has been recommended as a prevention strategy against not only cardiovascular diseases but also neurodegenerative disorders, e.g., cognitive decline and dementia. However, studies exploring the beneficial effects of the AHA’s CVH metrics on cognitive outcomes, especially among older populations, have been uncertain, and solid evidence is lacking in this field. This systematic review and meta-analysis aimed to quantify the relationship between the AHA’s CVH metrics and cognitive outcomes. 14 longitudinal studies were included in the meta-analysis. The results showed a considerable effect of a favourable total CVH score on reduced risk of incident dementia in adults aged 70 years or older. When looking at the individual factors, dementia risk can be reduced significantly if older adults achieved the recommended level of physical activity, blood glucose, or total cholesterol. The association with smoking appeared to be borderline, and there was no association between diet, body mass index hazard ratio or blood pressure and dementia risk. The authors concluded that their findings provide evidence that maintaining a favourable level of CVH score, either in mid- or late- life, would substantially reduce the risk of dementia among older adults. Preserving cardiovascular health by quitting smoking, engaging in physical exercise, controlling blood glucose and total cholesterol might be especially effective for forestalling cognitive decline and dementia.
Abstract
This study aimed to quantify the relationships between the American Heart Association (AHA) Cardiovascular Health (CVH) metrics, namely AHA Life's Simple 7, and cognitive outcomes. We searched PubMed and Embase (January 1, 2010-August 24, 2022) and finally included 14 longitudinal studies (311654 participants with 8006 incident dementia cases). Random-effects meta-analysis and one-stage linear mixed-effects models were performed. Increased CVH score seemed to associate with decreased risk of incident dementia in a linear manner, but this relationship varied by the measurement age of CVH metrics. That is, midlife CVH tended to have a linear association with late-life dementia risk, whereas a J-shaped association was observed between the late-life CVH score and dementia. In addition, late-life dementia risk was reduced significantly if individuals maintained an ideal level of AHA's CVH guidelines of physical activity, fasting plasma glucose, total cholesterol, and smoking. However, our meta-analysis did not show a significant association between CVH score and global cognitive decline rate. Following AHA's CVH guidelines and maintaining CVH at an optimal level would substantially reduce the late-life dementia risk. More research is required to explore the link between a favorable CVH score and cognitive trajectories among cognitively asymptomatic older populations.
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Soluble Fiber Supplementation and Serum Lipid Profile: A Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials.
Ghavami, A, Ziaei, R, Talebi, S, Barghchi, H, Nattagh-Eshtivani, E, Moradi, S, Rahbarinejad, P, Mohammadi, H, Ghasemi-Tehrani, H, Marx, W, et al
Advances in nutrition (Bethesda, Md.). 2023
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Dyslipidaemia is considered an important risk factor for cardiovascular disease incidence, characterised by elevated circulating concentrations of blood lipids such as cholesterol and triglycerides (TG). Dietary fibre, particularly water-soluble fibres, has demonstrated efficacy and tolerability in serum lipid management. The aim of this study was to synthesise data from individual investigations and to determine the overall treatment effect of soluble fibre on serum blood lipids. This study is a comprehensive systematic review and a dose-response meta-analysis of 181 studies with 220 treatment arms, including 14,505 participants (7348 cases and 7157 controls). Results show that soluble fibre supplementation improved serum TG, total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein-B concentrations. However, it did not alter serum high-density lipoprotein cholesterol and apolipoprotein-A levels. Furthermore, the meta-analysis showed a significant effect of soluble fibre supplementation on serum TG, total cholesterol, and high-density lipoprotein cholesterol in 15 g/d and low-density lipoprotein cholesterol in 10 g/d. Authors conclude that increasing fibre intake using soluble fibre supplementation could be an effective intervention in the prevention and management of dyslipidaemia, and consequently may contribute to the risk reduction of cardiovascular diseases.
Abstract
To present a comprehensive synthesis of the effect of soluble fiber supplementation on blood lipid parameters in adults, a systematic search was undertaken in PubMed, Scopus, and ISI Web of Science of relevant articles published before November 2021. Randomized controlled trials (RCTs) evaluating the effects of soluble fibers on blood lipids in adults were included. We estimated the change in blood lipids for each 5 g/d increment in soluble fiber supplementation in each trial and then calculated the mean difference (MD) and 95% CI using a random-effects model. We estimated dose-dependent effects using a dose-response meta-analysis of differences in means. The risk of bias and certainty of the evidence was evaluated using the Cochrane risk of bias tool and the Grading Recommendations Assessment, Development, and Evaluation methodology, respectively. A total of 181 RCTs with 220 treatment arms (14,505 participants: 7348 cases and 7157 controls) were included. There was a significant reduction in LDL cholesterol (MD: -8.28 mg/dL, 95% CI: -11.38, -5.18), total cholesterol (TC) (MD: -10.82 mg/dL, 95% CI: -12.98, -8.67), TGs (MD: -5.55 mg/dL, 95% CI: -10.31, -0.79), and apolipoprotein B (Apo-B) (MD: -44.99 mg/L, 95% CI: -62.87, -27.12) after soluble fiber supplementation in the overall analysis. Each 5 g/d increase in soluble fiber supplementation had a significant reduction in TC (MD: -6.11 mg/dL, 95% CI: -7.61, -4.61) and LDL cholesterol (MD: -5.57 mg/dl, 95% CI: -7.44, -3.69). In a large meta-analysis of RCTs, results suggest that soluble fiber supplementation could contribute to the management of dyslipidemia and the reduction of cardiovascular disease risk.
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Plum supplementation and lipid profile: a systematic review and meta-analysis of randomised controlled trials.
Askarpour, M, Ghalandari, H, Setayesh, L, Ghaedi, E
Journal of nutritional science. 2023;12:e6
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The rate of nutrition-related non-communicable diseases is increasing worldwide. Lipid profile and its alterations have been used both as indicators of metabolic disorders and methods to evaluate patients’ response to dietary interventions. The aim of this study was to investigate the effectiveness of plums on improving parameters of lipid profile. This study is a systematic review and meta-analysis of nine randomised controlled trials with a total of eleven arms and 592 participants. Results show that plum can be beneficial in reducing triacylglycerols [triglycerides] in the unhealthy and low-density lipoprotein cholesterol in all individuals. However, no significant impact regarding blood triacylglycerols and high-density lipoprotein cholesterol levels, could be detected both in crude and subgroup analyses. Authors conclude that further clinical trials, taking advantage of a standard protocol of plum supplementation, should be conducted to elucidate the possible effect that plum supplementation might exert on lipid profile parameters.
Abstract
Plums are abundant in bioactive compounds which have been associated with numerous health benefits. In the present study, we aimed at examining the impact of plum supplementation on lipid profile of individuals. Electronic bibliographical databases were searched for relevant randomised clinical trials. Articles meeting our eligibility criteria were included for data extraction and final analysis. Weighted mean difference (WMD) was estimated using a random-effect model. Of the total articles retrieved in the initial search, nine articles were found to be eligible to be included in the analysis. Our results show that plum supplementation significantly improves total cholesterols levels in the unhealthy individuals. Moreover, plum supplementation reduces the LDL-c levels in the pooled sample (WMD = -11⋅52 mg/dl; 95 % CI -21⋅93, -1⋅11, P = 0⋅03, I 2 = 98⋅7 %) and also in some of the subgroups of individuals (dried plum, unhealthy subjects, duration more than 8 weeks). Moreover, it had a significant reducing effect on TC levels just in unhealthy subjects. Although plum supplementation did not have any significant impact on serum levels of TG nor HDL-c. Our results show that supplementation with plums is potentially effective in reducing serum total cholesterol and LDL-c.
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Effect of omega-3 supplementation on lipid profile in children and adolescents: a systematic review and meta-analysis of randomized clinical trials.
Khorshidi, M, Hazaveh, ZS, Alimohammadi-Kamalabadi, M, Jamshidi, S, Moghaddam, OM, Olang, B, Hatefi, S, Hosseini, A, Jamilian, P, Zarezadeh, M, et al
Nutrition journal. 2023;22(1):9
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Dyslipidaemia is considered as a substantial risk factor for cardiovascular disease (CVD). It is characterised by increased levels of triglyceride and low-density lipoprotein (LDL) and decreased levels of high-density lipoprotein (HDL). Consumption of omega-3 supplements play an important role in reduction of CVD events and its associated mortality by ameliorating lipid profile via lowering triglyceride levels. The aim of this study was to evaluate the effect of omega 3 supplementation on lipid profile in children and adolescents. This study is a systematic review and meta-analysis of fourteen studies. Three trials out of 14 had cross-over design, while others were parallel randomised trials. Results show that omega-3 supplementation may exert therapeutic effects on triglyceride (TG) levels, however, there weren’t any remarkable effects on HDL, LDL, and total cholesterol status. The subgroup analysis showed an improvement in TG levels in studies conducted on participants ≤13 years old and those with hypertriglyceridemia. Furthermore, due to meta-regression results, the omega-3 supplementation improved HDL levels when administered with longer duration. Authors conclude that omega-3 supplementation may have favourable hypolipidemic effects through reduction of TG levels. Additionally, clinical trials with longer duration of intervention and appropriate designs are recommended for younger children and those with hypertriglyceridemia.
Abstract
PURPOSE Dyslipidemia is considered as a known risk factor for cardiovascular disease. Yet various trials with wide ranges of doses and durations have reported contradictory results. We undertook this meta-analysis of randomized controlled trials (RCTs) to determine whether omega-3 supplementation can affect lipid profile in children and adolescents. METHODS Cochrane Library, Embase, PubMed, and Scopus databases were searched up to March 2021. Meta-analysis was performed using random-effect method. Effect size was expressed as weighted mean difference (WMD) and 95% confidence interval (CI). Heterogeneity was assessed using the I2 index. In order to identification of potential sources of heterogeneity, predefined subgroup and meta-regression analysis was conducted. RESULTS A total of 14 RCTs with 15 data sets were included. Based on the combination of effect sizes, there was a significant reduction in TG levels (WMD: -15.71 mg/dl, 95% CI: -25.76 to -5.65, P=0.002), with remarkable heterogeneity (I2=88.3%, P<0.001). However, subgroup analysis revealed that omega-3 supplementation significantly decreased TG only in studies conducted on participants ≤13 years old (WMD=-25.09, 95% CI: -43.29 to -6.90, P=0.007), (I2=84.6%, P<0.001) and those with hypertriglyceridemia (WMD=-28.26, 95% CI: -39.12 to -17.41, P<0.001), (I2=0.0%, P=0.934). Omega-3 supplementation had no significant effect on total cholesterol, HDL, and LDL levels. Also, results of nonlinear analysis showed significant effect of treatment duration on HDL status (Pnon-linearity=0.047). CONCLUSION Omega-3 supplementation may significantly reduce TG levels in younger children and those with hypertriglyceridemia. Also, based on the HDL-related results, clinical trials with longer duration of intervention are recommended in this population.
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Effects of Omega-3 Fatty Acids Supplementation on Serum Lipid Profile and Blood Pressure in Patients with Metabolic Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Liu, YX, Yu, JH, Sun, JH, Ma, WQ, Wang, JJ, Sun, GJ
Foods (Basel, Switzerland). 2023;12(4)
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Metabolic syndrome (MetS) is a group of disorders that cause disturbed metabolism, including abdominal obesity, insulin resistance, hypertension, and dyslipidaemia. People with MetS may have a higher risk of coronary heart disease and stroke than those without MetS. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have cardioprotective, anti-inflammatory, and triglyceride-lowering properties, so they may help treat obesity and improve metabolic syndrome. The aim of this study was to explore the effects of n-3 PUFAs on lipid profile and blood pressure in patients with MetS. This study is a meta-analysis of eight studies. One of the studies was a crossover trial, whereas the remaining seven studies were parallel-controlled trials. The mean age of the participants was 45.54 years old. Results show that following supplementation with n-3 PUFAs in patients with metabolic syndrome: - there weren’t significant changes in serum total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol. - there was a significant reduction in serum triglycerides and blood pressure. Authors conclude that n-3 PUFA supplementation may serve as a potential dietary supplement for improving lipids and blood pressure in patients with metabolic syndrome.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Omega 3 PUFA may be beneficial for patients with metabolic syndrome by improving serum lipid profile and blood pressure.
- Omega-3 rich foods include fatty fish, walnuts, flaxseeds and chia seeds.
- While Omega-3 PUFA may be beneficial, they should be considered as part of a comprehensive approach to managing metabolic syndrome that include physical activity and a balanced diet.
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:
Background
This journal article presents a systematic review and meta-analysis of randomised controlled trials (RCTs) investigating the effects of omega-3 fatty acid supplementation on serum lipid profile and blood pressure in patients with metabolic syndrome. Metabolic syndrome is a cluster of conditions that increase the risk of cardiovascular disease and type 2 diabetes.
Methods
This meta-analysis included 8 RCTs with 387 participants with metabolic syndrome. Participants in the intervention group took omega-3 fatty acid supplements and the outcomes included total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), systolic blood pressure (SBP), and diastolic blood pressure (DBP).
Results
- Based on a meta-analysis of data from the included trials, supplementation with omega 3- PUFAs led to no reduction in serum LDL-c level among patients with metabolic syndrome (Standardised Mean Difference (SMD) = 0.18; 95% CI: −0.18 ~ 0.53, I2 = 55%); did not increase serum high-density lipoprotein cholesterol levels (SMD = 0.02; 95% CI: −0.21 ~ 0.25, I2 = 0%); and had no reduction in serum total cholesterol level (SMD = −0.02; 95% CI: −0.22~0.18, I2 = 24%).
- On the other hand, in patients with metabolic syndrome, supplementation with omega 3- PUFAs may decrease serum triglyceride levels (SMD = −0.39; 95% CI: −0.59 ~ −0.18, I2 = 17.2%); systolic blood pressure (SMD = −0.54; 95% CI: −0.86 ~ −0.22, I2 = 48.6%); and diastolic blood pressure (SMD = −0.56; 95% CI: −0.79~ −0.33, I2 = 14.0%).
- Sensitivity analyses indicated that the pooled estimates wererobust for all outcomes.
- The following mechanisms may explain how PUFAs may reduce the risk of metabolic syndrome. First, adequate intake of omega 3 PUFAs may reduce triglyceride and LDL synthesis in the liver. In addition, they may lower blood pressure by reducing angiotensin-converting enzyme levels in the aorta. Finally, PUFAs can increase insulin sensitivity and prevent hyperglycaemia.
Limitations
This study presents some limitations: The literature search may have some omissions. The conclusions may be hindered by the risk of bias of the trials included. No bias test was performed due to the limited number of studies.
Clinical practice applications:
- Improved serum lipid profile: The findings from the paper indicate that omega-3 fatty acid supplementation can have a positive impact on the serum lipid profile in patients with metabolic syndrome.
- Blood pressure management: omega-3 fatty acid supplementation may help reduce blood pressure in patients with metabolic syndrome.
- Nutritional therapists can use this information to consider omega-3 supplementation as part of nutritional therapy
- Complementary approach: Nutritional therapists can utilise the findings as supportive evidence for a holistic approach to managing metabolic syndrome. By incorporating omega-3 fatty acids into personalized nutrition plans, therapists may be able to offer additional dietary or supplemental interventions for individuals with metabolic syndrome, aiming to lower triglyceride levels and manage blood pressure, alongside other lifestyle modifications.
- Patient education: Nutritional therapists can educate their patients with metabolic syndrome about the benefits of omega-3 fatty acids on lipid profile and blood pressure. By explaining the findings from the systematic review and meta-analysis, therapists can empower patients to make informed choices regarding their dietary habits and supplement use, promoting self-management and improved long-term outcomes.
Considerations for future research:
- Future research could focus on determining the optimum dosage of Omega-3 PUFAs for improving lipid profile and BP.
- More investigation is needed to analyse the long term effect of the supplements. The longest RCT was 90 days.
- Comparative studies comparing the effects of omega-3 fatty acids supplementation with other interventions commonly used in metabolic syndrome management, such as pharmacological approaches or diet, would provide a comprehensive understanding of their relative effectiveness.
- Future research could explore potential variations in the effects of omega-3 fatty acids supplementation based on different patient characteristics, such as age, gender, baseline lipid profile, and blood pressure levels.
- Conducting mechanistic studies could shed light on the underlying pathways through which omega-3 fatty acids exert their effects on serum lipid profile and blood pressure.
Abstract
The purpose of this study was to explore the effect of omega-3 polyunsaturated fatty acids (n-3 PUFAs) supplementation on serum lipid profile and blood pressure in patients with metabolic syndrome. We searched PubMed, Web of Science, Embase, and the Cochrane library from database inception to 30 April 2022. This meta-analysis included eight trials with 387 participants. We found that supplementation of n-3 PUFAs has no significant reduction in TC level (SMD = -0.02; 95% CI: -0.22 ~ 0.18, I2 = 23.7%) and LDL-c level in serum (SMD = 0.18; 95% CI: -0.18 ~ 0.53, I2 = 54.9%) of patients with metabolic syndrome. Moreover, we found no significant increase in serum high-density lipoprotein cholesterol level (SMD = 0.02; 95% CI: -0.21 ~ 0.25, I2 = 0%) in patients with metabolic syndrome after consuming n-3 PUFAs. In addition, we found that n-3 PUFAs can significantly decrease serum triglyceride levels (SMD= -0.39; 95% CI: -0.59 ~ -0.18, I2 = 17.2%), systolic blood pressure (SMD = -0.54; 95% CI: -0.86 ~ -0.22, I2 = 48.6%), and diastolic blood pressure (SMD = -0.56; 95% CI: -0.79 ~ 0.33, I2 = 14.0%) in patients with metabolic syndrome. The results from the sensitivity analysis confirmed that our results were robust. These findings suggest that n-3 PUFA supplementation may serve as a potential dietary supplement for improving lipids and blood pressure in metabolic syndrome. Given the quality of the included studies, further studies are still needed to verify our findings.
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9.
The Influence of Nutritional Intervention in the Treatment of Hashimoto's Thyroiditis-A Systematic Review.
Osowiecka, K, Myszkowska-Ryciak, J
Nutrients. 2023;15(4)
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Hashimoto’s thyroiditis is an autoimmune disorder characterized by the presence of antibodies in the thyroid gland such as thyroid peroxidase (TPO) and thyroglobulin (TG) antibodies. Immune-mediated inflammatory responses eventually lead to the progressive destruction of the gland and impaired thyroid function. The disease has a strong genetic disposition but is also influenced by environmental factors, including diet. Hence diet has been considered a complementary tool to manage thyroid function and disease progression by harnessing the benefits of certain nutrients and anti-inflammatory properties. This systematic review examined the effects of nutrients and dietary interventions on Hashimoto’s disease in current literature. Using antibody levels, thyroid hormone levels and body weight to measure outcomes. The review included 9 studies, all of which compared the intervention group to the control groups. The trials included looked at gluten-free, lactose-free and energy-restricted diets, with or without selected nutrients and foods supplements (ie. Nigella sativa, iodine). The intervention duration ranged from 3 weeks to 12 months. Despite the small number of trials, the data from those studies included in this review showed promising results. Improvements in disease parameters were observed in diets that were energy deficient, eliminated gluten, lactose and goitrogens or added Nigella sativa. Iodine restrictions did not show any improvements. In the discussion section, the authors presented the results in the wider context and the findings from other studies. Ultimately there appears to be a wide variance in outcomes, usually ranging from beneficial to neutral. The authors contributed to such variability due to the complexity of the condition and many influencing factors. Often participants in trials have highly variable thyroid status and function, and differences in regular dietary intakes of nutrients critical to thyroid health can easily distort the results. Hence much more specific research is needed to make firmer conclusions. Whereby no clear conclusions in larger groups could be drawn, potential benefits of dietary interventions in Hashimoto's disease may be much more apparent in clinical settings with personalized approaches that account for such individual variances.
Abstract
Diet can be a complementary treatment for Hashimoto's disease by affecting thyroid function and anti-inflammatory properties. It is still unclear which dietary strategy would be the most beneficial. The aim of this systematic review is to examine all the data currently available in the literature on the effects of nutritional intervention on biochemical parameters (anti-thyroid antibody and thyroid hormones levels) and characteristic symptoms in the course of Hashimoto's thyroiditis. This systematic review was prepared based on PRISMA guidelines. Articles in PubMed and Scopus databases published up to November 2022 were searched. As a result of the selection, out of 1350 publications, 9 were included for further analysis. The nutritional interventions included the following: elimination of gluten (3 articles) or lactose (1 article), energy restriction with or without excluding selected foods (n = 2), consumption of Nigella sativa (n = 2), or dietary iodine restriction (n = 1). The intervention duration ranged from 21 days to 12 months and included individuals with various thyroid function. Of the nine studies, three studies were female only. An improvement was observed during an energy deficit and after the elimination of selected ingredients (e.g., gluten, lactose, or goitrogens), as well as after the intervention of Nigella sativa. These interventions improved antibody levels against peroxidase (anti-TPO), (thyrotropin) TSH, and free thyroxine (fT4). No improvement was seen on the iodine-restricted diet. Varied outcomes of analyzed dietary interventions may be due to the heterogeneous thyroid condition, high variability between patients, and differences in habitual intake of critical nutrients (e.g., iodine, selenium, and iron) in different populations. Therefore, there is a great need for further experimental studies to determine whether any nutritional interventions are beneficial in Hashimoto's disease.
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10.
Therapeutic Properties of Flavonoids in Treatment of Cancer through Autophagic Modulation: A Systematic Review.
de Sousa Silva, GV, Lopes, ALVFG, Viali, IC, Lima, LZM, Bizuti, MR, Haag, FB, Tavares de Resende E Silva, D
Chinese journal of integrative medicine. 2023;29(3):268-279
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Cancer is one of the leading causes of death worldwide. Although there are many different causes for its development, things that can damage the cells such as ultraviolet light and free radicals can be contributors. Protection against cellular damage may be of benefit to the prevention of cancer development and flavonoids, which are natural chemicals found in plants such as fruits and vegetables, have protective properties. This systematic review paper aimed to determine the therapeutic properties of flavonoids in the treatment of cancer. The results showed that all ten studies included in the review were observational studies carried out on human and animal cells. Ten different flavonoids were identified as having a potential role in cancer treatment mainly through promoting cancer cell death; Isolated mimulone-C geranyl flavonoids, baicalein, isoliquiritigenin, wogonin, icariin, fistein, pectolinarigenin, silibinin, sotetsu flavone, and oroxylin A. It was concluded that flavonoids may have a potential therapeutic effect in gall bladder cancer, head and neck squamous cell carcinoma, and oral cancer through it acting on cancer cell death. This study could be used by healthcare professionals to understand that a diet rich in fruits and vegetables may be of benefit to individuals with cancer. However, the results of this study should be interpreted with caution as it was based on animal and human cells and many processes can affect the development of cancer in whole human body systems.
Abstract
Cancers have high morbidity and mortality rates worldwide. Current anticancer therapies have demonstrated specific signaling pathways as a target in the involvement of carcinogenesis. Autophagy is a quality control system for proteins and plays a fundamental role in cancer carcinogenesis, exerting an anticarcinogenic role in normal cells and can inhibit the transformation of malignant cells. Therefore, drugs aimed at autophagy can function as antitumor agents. Flavonoids are a class of polyphenolic secondary metabolites commonly found in plants and, consequently, consumed in diets. In this review, the systematic search strategy was used, which included the search for descriptors "flavonoids" AND "mTOR pathway" AND "cancer" AND "autophagy", in the electronic databases of PubMed, Cochrane Library, Web of Science and Scopus, from January 2011 to January 2021. The current literature demonstrates that flavonoids have anticarcinogenic properties, including inhibition of cell proliferation, induction of apoptosis, autophagy, necrosis, cell cycle arrest, senescence, impaired cell migration, invasion, tumor angiogenesis and reduced resistance to multiple drugs in tumor cells. We demonstrate the available evidence on the roles of flavonoids and autophagy in cancer progression and inhibition. (Registration No. CRD42021243071 at PROSPERO).