What is the influence of policosanol supplementation on liver enzymes? A systematic review and dose-response meta-analysis of randomized controlled trials.

OBJECTIVE: Policosanol is a mixture of long chain alcohols refined from sugar cane. Significant reductions in liver enzymes have been observed in some studies. However, the impact of policosanol on liver enzymes remained controversial. The current meta-analysis aims to evaluate the effect of policosanol supplementation on the levels of alanine transaminase (ALT) and aspartate transaminase (AST). METHODS: The literature was systematically searched for studies published up to November 2023 in PubMed/Medline, Google Scholar, EMBASE, and Scopus. Randomized controlled trial (RCT) studies were included to evaluate the intervention effect of policosanol compared to placebo on ALT and AST. DerSimonian and Laird models were used to calculate effect sizes. RESULTS: Twenty-three trials including 2535 participants were included in the study. The combination of effect sizes, regarding the random-effects model, demonstrated significant changes in ALT serum levels after intervention (WMD: -1.48 U/L; 95% CI: -2.33 to -0.64; P = 0.001), and AST (WMD: -1.10 U/L; 95% CI: -1.70 to -0.51; P < 0.001). Subgroup analysis of AST and ALT showed that this reduction effect was most often observed at the dose of 20 mg/d. The dose-response analysis represented a non-significant non-linear connection between the dosage and duration of policosanol intervention in ALT and AST serum reduction. CONCLUSION: Policosanol supplementation exerts a beneficial effect on liver enzymes as well as ALT and AST concentrations in adults. However, further long-term and well-designed RCTs with better quality are needed to further assess and confirm these results.

The Effects of L-Carnitine Supplementation on Blood Pressure in Adults: A Systematic Review and Dose-response Meta-analysis.

PURPOSE: Hypertension stands as a prominent risk factor for cardiovascular disease, making it of utmost importance to address. Studies have shown that L-carnitine supplementation may lower blood pressure (BP) parameters in different populations. Therefore, we have conducted a systematic review and dose-response meta-analysis of published Randomized Controlled Trials (RCTs), including the most recent articles on the effect of L-carnitine supplementation on BP. METHODS: PubMed, ISI Web of Science, Cochrane databases, and Scopus were used to collect RCT studies published up to October 2022 without limitations in language. Inclusion criteria were adult participants and recipients of L-carnitine in oral supplemental forms. The funnel plot test, Begg's test, and Egger's test were used to examine publication bias. FINDINGS: After the search strategy, 22 RCTs (n = 1412) with 24 effect sizes fulfilled the criteria. It was found L-Carnitine supplementation did not have a significant effect on systolic blood pressure (SBP) (mm Hg) (weighted mean difference [WMD] = -1.22 mm Hg, 95% CI: -3.79, 1.35; P = 0.352; I2 = 85.0%, P < 0.001), and diastolic blood pressure (mm Hg) (WMD = -0.50 mm Hg, 95% CI: -1.49, 0.48; P = 0.318; I2 = 43.4%, P = 0.021) in the pooled analysis. Subgroup analyses have shown that L-carnitine supplementation had no lowering effect on SBP in any subgroup. However, there was a significant reduction in diastolic blood pressure in participants with a baseline body mass index >30 kg/m2 (WMD = -1.59 mm Hg; 95% CI: -3.11, -0.06; P = 0.041; I2 = 41.3%, P = 0.164). There was a significant nonlinear relationship between the duration of L-carnitine intervention and changes in SBP (coefficients = -6.83, P = 0.045). IMPLICATIONS: L-carnitine supplementation in adults did not significantly affect BP. But anyway, more studies should be done in this field on different individuals.

The effects of Garcinia cambogia (hydroxycitric acid) on lipid profile: A systematic review and meta-analysis of randomized controlled trials.

Garcinia cambogia (GC) has antioxidant, anticancer, antihistamine, and antimicrobial properties. To determine the effect of GC on lipid profiles, a systematic review and meta-analysis was carried out. Up to February 9, 2023, six electronic databases (Web of Science, Cochrane Library, Embase, PubMed, Scopus, and Google Scholar) were searched at any time without limitations. Trials examining the impact of GC on serum levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol (HDL-C) in adults were included. The total effect was shown as a weighted mean difference (WMD) and 95% confidence interval (CI) in a random-effects meta-analysis approach. This systematic review and meta-analysis included 14 trials involving 623 subjects. Plasma levels of TC (WMD: -6.76 mg/dL; CI: -12.39 to -0.59, p-value = 0.032), and TG (WMD: -24.21 mg/dL; CI: -37.84 to -10.58, p < 0.001) were significantly reduced after GC use, and plasma HDL-C (WMD: 2.95 mg/dL; CI: 2.01 to 3.89, p < 0.001) levels increased. low-density lipoprotein cholesterol levels (WMD: -1.15 mg/dL; CI: -16.08 to 13.78, p-value = 0.880) were not significantly affected. The effects of lowering TC and TG were more pronounced for periods longer than 8 weeks. Consuming GC has a positive impact on TC, TG, and HDL-C concentrations. The limitations of this study include the short duration of analyzed interventions and significant heterogeneity. Nevertheless, it is imperative to conduct well-structured, and high-quality long-term trials to comprehensively evaluate the clinical effectiveness of GC on lipid profile, and validate these findings.

The effects of conjugated linoleic acid supplementation on glycemic control, adipokines, cytokines, malondialdehyde and liver function enzymes in patients at risk of cardiovascular disease: a GRADE-assessed systematic review and dose-response meta-analysis.

BACKGROUND: The present systematic review and meta-analysis sought to evaluate the effects of conjugated linoleic acid (CLA) supplementation on glycemic control, adipokines, cytokines, malondialdehyde (MDA) and liver function enzymes in patients at risk of cardiovascular disease. METHODS: Relevant studies were obtained by searching the PubMed, SCOPUS and Web of Science databases (from inception to January 2023). Weighted mean differences (WMD) and 95% confidence intervals (CIs) were pooled using a random-effects model. Heterogeneity, sensitivity analysis, and publication bias were reported using standard methods. RESULTS: A pooled analysis of 13 randomized controlled trials (RCTs) revealed that CLA supplementation led to a significant increment in fasting blood glucose (FBG) (WMD: 4.49 mg/dL; 95%CI: 2.39 to 6.59; P < 0.001), and aspartate aminotransferase (AST) (WMD: 2.54 IU/L; 95%CI: 0.06 to 5.01; P = 0.044). Moreover, CLA supplementation decreased leptin (WMD: -1.69 ng/ml; 95% CI: -1.80 to -1.58; P < 0.001), and interleukin 6 (IL-6) (WMD: -0.44 pg/ml; 95%CI: -0.86 to -0.02; P = 0.037). However, there was no effect on hemoglobin A1c (HbA1c), homeostatic model assessment for insulin resistance (HOMA-IR), C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and alanine aminotransferase (ALT) adiponectin compared to the control group. CONCLUSION: Our findings showed the overall favorable effect of CLA supplementation on the adipokines and cytokines including serum IL-6, and leptin, while increasing FBG and AST. It should be noted that the mentioned metabolic effects of CLA consumption were small and may not reach clinical importance. PROSPERO REGISTERATION COD: CRD42023426374.

The effects of L-carnitine supplementation on inflammatory and anti-inflammatory markers in adults: a systematic review and dose-response meta-analysis.

L-carnitine supplementation may be beneficial in improving inflammatory conditions and reducing the level of inflammatory cytokines. Therefore, according to the finding of randomized controlled trials (RCTs), the systematic review and meta-analysis aimed to investigate the effect of L-carnitine supplementation on inflammation in adults. To obtain acceptable articles up to October 2022, a thorough search was conducted in databases including PubMed, ISI Web of Science, the Cochrane Library, and Scopus. A random-effects model was used to estimate the weighted mean difference (WMD). We included the 48 RCTs (n = 3255) with 51 effect sizes in this study. L-carnitine supplementation had a significant effect on C-reactive protein (CRP) (p < 0.001), interleukin-6 (IL-6) (p = 0.001), tumor necrosis factor-α (TNF-α) (p = 0.002), malondialdehyde (MDA) (p = 0.001), total antioxidant capacity (TAC) (p = 0.029), alanine transaminase (ALT) (p < 0.001), and aspartate transaminase (AST) (p < 0.001) in intervention, compared to the placebo group. Subgroup analyses showed that L-carnitine supplementation had a lowering effect on CRP and TNF-α in trial duration ≥ 12 weeks in type 2 diabetes and BMI ≥ 25 kg/m2. L-carnitine supplementation reduced ALT levels in overweight and normal BMI subjects at any trial dose and trial duration ≥ 12 weeks and reduced AST levels in overweight subjects and trial dose ≥ 2 g/day. This meta-analysis revealed that L-carnitine supplementation effectively reduces the inflammatory state by increasing the level of TAC and decreasing the levels of CRP, IL-6, TNF-α and MDA in the serum.

The impact of Emblica Officinalis (Amla) on lipid profile, glucose, and C-reactive protein: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND AND AIMS: Emblica Officinalis (Amla) is a plant often utilized in traditional medicine due to its purported anti-inflammatory, antioxidant, hypoglycemic, and hypolipidemic properties. However, current evidence regarding its potential for preventing and treating metabolic abnormalities associated with chronic diseases remains unclear. METHODS: This systematic review and meta-analysis aimed to examine the effects of Amla supplementation on lipid profile, glucose, and C-reactive protein (CRP) concentrations in adults. We completed a systematic search (current as of December 2022) of all available randomized controlled trials (RCTs) in the database including ISI Web of Science, PubMed, Scopus, and Embase. Any effect's mean difference (MD) was calculated using a random-effects model. Weighted mean difference (WMD) and 95% confidence intervals (CIs) were calculated also calculated using a random-effects model. RESULTS: Five RTCs were included in the meta-analysis. Following Amla supplementation, pooled results showed a significant reduction in CRP (p = 0.002), fasting blood glucose (FBG) (p < 0.001), low-density lipoprotein cholesterol (LDL-c) (p < 0.001), total cholesterol (TC) (p < 0.001), and serum triglyceride (TG) (p < 0.001) concentrations as well as an increase in high-density lipoprotein cholesterol (HDL-c) (p < 0.001). The baseline concentration of biochemical indicators was used for subgroup analysis. CONCLUSION: Amla supplementation shows promise for improving metabolic parameters in adults. In general, the populations included in the analysis were generally 40-58 years with an average BMI of 25.5 and a length of intervention ranging from 3 to 12 weeks. Thus additional investigations are warranted to confirm and expand the findings presented herein.

The Potential Effect of Blueberry on Cognitive Health and Mood State based on Human Intervention Studies: Systematic Review and Mini Meta-Analysis.

BACKGROUND: Blueberries are known for their high content of several bioactive compounds, specifically anthocyanin, which are the most beneficial of the flavonoid family in terms of neuroprotection. Several human interventional studies have been conducted to assess the effects of blueberry intake on cognitive performance; however, the results of clinical trials are inconclusive. Therefore, this systematic review and meta-analysis evaluated the effect of blueberry supplementation on some aspects of cognitive performance and mood parameters using data from clinical trials based on existing evidence. METHODS: Relevant studies, published in April 2021, were searched through PubMed/Medline, Scopus, Embase, and Google Scholar. The random effect size was used to estimate the pooled effect size. Heterogeneity between studies was evaluated by the Cochrane Q test and I-squared (I2). To detect the potential source of heterogeneity, a subgroup analysis was conducted. RESULTS: Fourteenrandomized trials were included in the quantitative analysis, and six were pooled for statistical analysis. Blueberry intervention resulted in no significant change in mood state score (WMD = 0.03; 95% CI: -0.80 to 0.87, P = 0.16). Moreover, no significant effect of blueberry intake was shown in attention task reaction time (WMD = -1.50 ms; 95% CI: -24.75 to -21.75, P = 0.9), percentages of attention task accuracy (WMD = 0.85; 95% CI: -2.57 to 0.86, P = 0.3), one-back test accuracy (WMD = 0.03; 95% CI: -0.04 to 0.09, P = 0.4). Significant effect was indicated (WMD = 0.08; 95% CI: 0.02 to 0.13, P = 0.005) in two-back test accuracy. CONCLUSION: We found a significant effect of blueberry consumption on two-back test accuracy as a cognitive outcome. More high-quality clinical trials according to the challenges mentioned seem to indicate the use of blueberry as a supplement for cognitive and mood health efficiently.

The Association Between Dietary Energy Density and Musculoskeletal Pain in Adult Men and Women.

Musculoskeletal pains (MPs), defined as persistent or recurrent pain, is a complex health problem. High overall calorie and fat intake have been related to obesity and MPs. Dietary energy density (DED), defined as energy content of food and beverages (in kcal) per unit total weight, has been associated with chronic muscle, cartilage, bone damage and pain. Thus, the purpose of this study is to investigate the association between DED and MPs in adult men and women. A total of 175 men and women (> 18 years) with MP participated in the study. A validated short form physical activity (PA) questionnaire, demographic, and McGill Pain Questionnaire were used. Anthropometric measurements were evaluated via standard protocols. Furthermore, a seven-day 24-hour recall of diet was used to determine the dietary intake. Total DED was calculated and divided into quartiles. Linear regression was used to discern the association between DED and MPs in adults. Participants assigned in the highest category of DED were characterized by lower intake of potassium, magnesium, vitamin C, folate, and fiber. However, results showed displayed higher intake of sodium, vitamin E, vitamin B3, fat, protein, cholesterol, saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids (p < 0.001). Finally, after adjustment for confounders such as age, gender, PA, body mass index, waist circumference, education, job, marital status, history of some chronic diseases and vitamin C supplementation, a significant positive association was detected between DED and pain intensity. There was no significant association between DED and pain frequency in all models.

The effects of L-carnitine supplementation on glycemic markers in adults: A systematic review and dose-response meta-analysis.

Background and aims: Hyperglycemia and insulin resistance are concerns today worldwide. Recently, L-carnitine supplementation has been suggested as an effective adjunctive therapy in glycemic control. Therefore, it seems important to investigate its effect on glycemic markers. Methods: PubMed, Scopus, Web of Science, and the Cochrane databases were searched in October 2022 for prospective studies on the effects of L-carnitine supplementation on glycemic markers. Inclusion criteria included adult participants and taking oral L-carnitine supplements for at least seven days. The pooled weighted mean difference (WMD) was calculated using a random-effects model. Results: We included the 41 randomized controlled trials (RCTs) (n = 2900) with 44 effect sizes in this study. In the pooled analysis; L-carnitine supplementation had a significant effect on fasting blood glucose (FBG) (mg/dl) [WMD = -3.22 mg/dl; 95% CI, -5.21 to -1.23; p = 0.002; I 2 = 88.6%, p < 0.001], hemoglobin A1c (HbA1c) (%) [WMD = -0.27%; 95% CI, -0.47 to -0.07; p = 0.007; I 2 = 90.1%, p < 0.001] and homeostasis model assessment-estimate insulin resistance (HOMA-IR) [WMD = -0.73; 95% CI, -1.21 to -0.25; p = 0.003; I 2 = 98.2%, p < 0.001] in the intervention compared to the control group. L-carnitine supplementation had a reducing effect on baseline FBG ≥100 mg/dl, trial duration ≥12 weeks, intervention dose ≥2 g/day, participants with overweight and obesity (baseline BMI 25-29.9 and >30 kg/m2), and diabetic patients. Also, L-carnitine significantly affected insulin (pmol/l), HOMA-IR (%), and HbA1c (%) in trial duration ≥12 weeks, intervention dose ≥2 g/day, and participants with obesity (baseline BMI >30 kg/m2). It also had a reducing effect on HOMA-IR in diabetic patients, non-diabetic patients, and just diabetic patients for insulin, and HbA1c. There was a significant nonlinear relationship between the duration of intervention and changes in FBG, HbA1c, and HOMA-IR. In addition, there was a significant nonlinear relationship between dose (≥2 g/day) and changes in insulin, as well as a significant linear relationship between the duration (weeks) (coefficients = -16.45, p = 0.004) of intervention and changes in HbA1C. Conclusions: L-carnitine could reduce the levels of FBG, HbA1c, and HOMA-IR. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier: CRD42022358692.