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Absence of Effects of L-Arginine and L-Citrulline on Inflammatory Biomarkers and Oxidative Stress in Response to Physical Exercise: A Systematic Review with Meta-Analysis.
Porto, AA, Gonzaga, LA, Benjamim, CJR, Valenti, VE
Nutrients. 2023;15(8)
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L-citrulline is a non-essential amino acid that acts as a precursor to L-arginine. L-arginine is a semi-essential amino acid used for nitric oxide production which is crucial for maintaining physiological function and immune regulation. Previous research has shown that L-citrulline and L-arginine supplementation may offer antioxidant and anti-inflammatory benefits in reducing exercise-related oxidative stress and inflammation. This systematic review and meta-analysis included seven randomised controlled trials to investigate the effect of L-citrulline and L-arginine on antioxidants, oxidative stress, and inflammatory and anti-inflammatory markers. This systematic review and meta-analysis showed no significant improvements in oxidative stress and inflammation followed by the supplementation of L-citrulline and L-arginine before exercise. However, further robust studies that include different dosages and exercise intensities are required to assess the beneficial effects of L-citrulline and L-arginine supplements to support physical exercise-induced oxidative stress and inflammation due to the heterogeneity of the included studies. Healthcare professionals can use the results of this study to understand the potential benefits of L-citrulline and L-arginine supplementation in people prone to producing proinflammatory cytokines.
Abstract
The repercussions on oxidative and inflammatory stress markers under the effects of arginine and citrulline in response to exercise are not fully reached. We completed a systematic review to investigate the effects of L-Citrulline or L-Arginine on oxidative stress and inflammatory biomarkers following exercise. EMBASE, MEDLINE (PubMed), Cochrane Library, CINAHL, LILACS, and Web of Science databases were used to record the trials. This study includes randomized controlled trials (RCTs) and non-RCTs with subjects over 18 years old. Those under the intervention protocol consumed L-Citrulline or L-Arginine, and the controls ingested placebo. We recognized 1080 studies, but only 7 were included (7 studies in meta-analysis). We observed no difference between pre- vs. post-exercise for oxidative stress (subtotal = -0.21 [CI: -0.56, 0.14], p = 0.24, and heterogeneity = 0%. In the sub-group "L-Arginine" we found a subtotal = -0.29 [-0.71, 0.12], p = 0.16, and heterogeneity = 0%. For the "L-Citrulline" subgroup we observed a subtotal = 0.00 [-0.67, 0.67], p = 1.00, and heterogeneity was not applicable. No differences were observed between groups (p = 0.47), and I² = 0%) or in antioxidant activity (subtotal = -0.28 [-1.65, 1.08], p = 0.68, and heterogeneity = 0%). In the "L-Arginine" sub-group, we found a subtotal = -3.90 [-14.18, 6.38], p = 0.46, and heterogeneity was not applicable. For the "L-Citrulline" subgroup, we reported a subtotal = -0.22 [-1.60, 1.16], p = 0.75, and heterogeneity was not applicable. No differences were observed between groups (p = 0.49), and I² = 0%), inflammatory markers (subtotal = 8.38 [-0.02, 16.78], p = 0.05, and heterogeneity = 93%. Tests for subgroup differences were not applicable, and anti-inflammatory markers (subtotal = -0.38 [-1.15, 0.39], p = 0.34 and heterogeneity = 15%; testing for subgroup differences was not applicable). In conclusion, our systematic review and meta-analysis found that L-Citrulline and L-Arginine did not influence inflammatory biomarkers and oxidative stress after exercise.
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Cognitive behavioral therapy for lifestyle changes in patients with obesity and type 2 diabetes: a systematic review and meta-analysis.
Kurnik Mesarič, K, Pajek, J, Logar Zakrajšek, B, Bogataj, Š, Kodrič, J
Scientific reports. 2023;13(1):12793
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Obesity and type 2 diabetes mellitus (T2DM) are two of the most common chronic diseases and lifestyle modification, including diet, exercise and weight management, are recognised as important for prevention. Cognitive behavioural therapy (CBT) has been shown to contribute to lifestyle modification. The aim of this meta-analysis was to evaluate the effect of CBT, compared to no intervention/standard care only, in patients with obesity and/or T2DM, with a focus on health outcomes and implementation of changes long-term. Nine randomised controlled trials (RCT) with 902 participants were included in this meta-analysis. The health outcomes included weight loss and maintenance and glycosylated haemoglobin (HbA1c, a measure of blood glucose control) whilst the lifestyle changes included diet, physical activity, smoking, and compliance with treatments. There was a statistically significant benefit of CBT for weight loss and weight maintenance (based on 3 RCTs each) with a medium effect size, but no significant effect on HbA1c (based on 3 RCTs). In all 3 RCTs that evaluated depression, a significant benefit was observed. As the behavioural outcomes were too heterogenous to be pooled for a meta-analysis, they were reviewed in a descriptive manner only. Benefits were reported in terms of better dietary choices/reduced energy intake, increased physical activity, better adherence to medication and glucose monitoring as well as a reduction in smoking. The authors suggest that CBT appears to be moderately effective in promoting lifestyle modifications and weight loss.
Abstract
The aim of this systematic review and meta-analysis was to examine the contribution of cognitive behavioral therapy (CBT) to the implementation of lifestyle changes, considering health-related and behavioral outcomes. A systematic literature review was performed using multiple databases (PsycInfo, PubMed and MEDLINE). The inclusion criteria comprised randomised controlled trials of CBT for lifestyle changes in patients with obesity and/or type 2 diabetes. The quality of study reporting was assessed with the revised Cochrane Collaboration's risk of bias tool. A meta-analysis was conducted on studies with appropriate outcomes. Nine randomised controlled trials, with a total sample size of 902 participants, met the inclusion criteria. The meta-analysis has shown a medium, significant effect size of CBT interventions for weight loss and weight maintenance, and a low, non-significant effect size of CBT interventions for reducing glycated hemoglobin (HbA1c) levels. A separate, combined, meta-analysis for all nine calculated effect sizes has yielded a medium and significant overall effect size for the model. Our review of the studies about the effectiveness of CBT in implementing lifestyle changes has, in comparison to usual control groups, proven the efficacy of CBT interventions in implementing lifestyle changes, especially for weight loss and weight maintenance.
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Effect of lifestyle intervention on HbA1c levels in overweight and obese adults with type 2 diabetes across ethnicities: A systematic review and meta-analysis of randomized controlled trials.
Yang, J, Xia, Y, Sun, Y, Guo, Y, Shi, Z, Cristina do Vale Moreira, N, Zuo, H, Hussain, A
Diabetes research and clinical practice. 2023;199:110662
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Weight loss can benefit overweight and obese patients with type 2 diabetes mellitus (T2DM) with regards to cardiovascular risk factors, including glycaemic control. This systematic review and meta-analysis of 30 randomised controlled trials, including 7850 patients, aimed to evaluate racial/ethnic differences in response to lifestyle interventions for weight loss on glycosylated haemoglobin (HbA1c, a measure of glycaemic control) in overweight or obese patients with T2DM. Lifestyle interventions were associated with statistically significant reductions in HbA1c in White and Asian, but not in Black/African or Hispanic populations, although the latter were based on only 2 and 3 small trials, respectively, and may have therefore lacked statistical power. Reductions in HbA1c were seen in studies which led to a weight loss of more than 5% as well as those less than 5%, with greater reductions being seen in the former group. The authors conclude that ethnic differences should be taken into account when considering lifestyle interventions for diabetes management.
Abstract
AIMS: Weight reduction is fundamental for the management and remission of diabetes. We aimed to assess ethnic differences in the effects of lifestyle weight-loss interventions on HbA1c levels in overweight or obese adults with type 2 diabetes mellitus (T2DM). METHODS We systematically searched PubMed/MEDLINE and Web of Science online databases up to 31 Dec 2022. Randomized controlled trials using lifestyle weight-loss interventions in overweight or obese adults with T2DM were selected. We performed subgroup analyses to explore the heterogeneity across different ethnicities (Asians, White/Caucasians, Black/Africans and Hispanics). A random effects model was applied to calculate weighted mean difference (WMD) with 95% confidence interval (CI). RESULTS Thirty studies including 7580 subjects from different ethnicities were identified according to the predefined inclusion and exclusion criteria. HbA1c levels were significantly reduced by lifestyle weight-loss intervention. Notably, a significantly beneficial effect on HbA1c was observed in White/Caucasians (WMD = -0.59, 95% CI: -0.90, -0.28, P < 0.001) and Asians (WMD = -0.48, 95% CI: -0.63, -0.33, P < 0.001), but not in the Black/African or Hispanic group (both P > 0.05). The findings remained essentially unchanged in the sensitivity analysis. CONCLUSIONS Lifestyle weight-loss interventions had distinct beneficial effects on HbA1c levels in different ethnic groups with T2DM, especially in Caucasians and Asians.
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Effects of lifestyle interventions on cardiovascular risk factors in South Asians: a systematic review and meta-analysis.
Limbachia, J, Ajmeri, M, Keating, BJ, de Souza, RJ, Anand, SS
BMJ open. 2022;12(12):e059666
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The prevalence of cardiovascular disease (CVD) and associated mortality risk is high in the South Asian population in western countries. Regular physical activity and a healthy diet may modify the risk factors of CVD, such as abdominal fat, high cholesterol, and blood sugar irregularities. This systematic review and meta-analysis included thirty-five randomised controlled trials to evaluate the effectiveness of diet, physical activity interventions or a combination of diet and physical activity interventions on CVD risk factors and compared it against usual care. Combining diet and physical activity interventions reduced CVD risk factors such as systolic and diastolic blood pressure, BMI, weight, waist circumference and fasting plasma glucose (FPG). Dietary interventions reduced diastolic blood pressure, triglycerides, low-density lipoprotein cholesterol, BMI, weight and FPG. Physical activity modifications improved diastolic and systolic blood pressure and high-density lipoprotein cholesterol. Healthcare professionals can use the study results to understand how tailored diet and physical activity modifications improve the CVD risk factors in South Asians. However, further robust studies are required as most of these evidences were of moderate quality and lacked clinical significance.
Abstract
BACKGROUND The cardiovascular disease (CVD) burden among South Asians is high. Lifestyle interventions have been effective in the primary prevention of CVD, but this has not been replicated, through a synthesis of randomised trials, in South Asians. METHODS Four electronic databases (MEDLINE, Embase, CENTRAL and CINAHL), two clinical trial registries and references of included articles were searched through June 2022 (featuring ≥90% South Asian participants). Random-effects pairwise meta-analyses were performed, and heterogeneity was quantified with the I2 statistic. The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) framework was used to report on the quality of evidence (International Prospective Register of Systematic Reviews registration (PROSPERO). RESULTS Thirty-five studies were included. Twelve tested diet and physical activity interventions; 18 tested diet alone; and 5 tested physical activity alone. All reported effects of the intervention(s) on at least one established risk factor for CVD, including blood pressure (systolic blood pressure (SBP), diastolic blood pressure (DBP) and blood lipids (high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc) or triglycerides). No trials reported clinical CVD. There is moderate-quality evidence that diet and physical activity interventions improve SBP (mean difference (MD) -2.72 mm Hg, 95% CI -4.11 to -1.33) and DBP (MD -1.53 mm Hg, 95% CI -2.57 to -0.48); high-quality to moderate-quality evidence that diet-only interventions improve DBP (MD -2.05 mm Hg, 95% CI -2.93 to -1.16) and blood lipids (triglycerides (MD -0.10 mmol/L, 95% CI -0.14 to -0.06) and LDLc (MD -0.19 mmol/L, 95% CI -0.32 to -0.06)); and moderate-quality evidence that physical activity-only interventions improve SBP (MD -9.7 mm Hg, 95% CI -11.05 to -8.35), DBP (MD -7.29 mm Hg, 95% CI -8.42 to -6.16) and HDLc (MD 0.08 mmol/L, 95% CI 0.04 to 0.11) compared with usual care. CONCLUSIONS Lifestyle interventions improve blood pressure and blood lipid profiles in adult South Asians at risk of CVD. Tailored interventions should be used to modify cardiovascular risk factors in this at-risk group. PROSPERO REGISTRATION NUMBER CRD42018090419.
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Prevention of Type 2 Diabetes by Lifestyle Changes: A Systematic Review and Meta-Analysis.
Uusitupa, M, Khan, TA, Viguiliouk, E, Kahleova, H, Rivellese, AA, Hermansen, K, Pfeiffer, A, Thanopoulou, A, Salas-Salvadó, J, Schwab, U, et al
Nutrients. 2019;11(11)
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With Type 2 Diabetes growing globally this paper analyses whether T2D is preventable with lifestyle measures including diet. Seven RCTs were included for review with a total of 4090 participants, and 2466 incidents of T2D, and were chosen on the basis that the lifestyle interventions included both physical exercise and diet (typically Mediterranean Diet). They found that diet and lifestyle intervention reduced the risk of T2D by 47%. Sustained risk reduction was also found in follow-up studies up to 10 years later with participants maintaining improved blood glucose control. Lifestyle interventions may also reduce risk factors for cardiovascular disease. Weight reduction was considered a cornerstone of preventing T2D and adherence to lifestyle changes a key element in long term prevention. Dietary foods reviewed include processed meats, white rice and sugars which correlated highly with T2D whilst leafy greens, berries, wholegrains, legumes, dietary fibre and yoghurt correlate with a lower risk of T2D. Dietary patterns of skipping breakfast and snacking correlate higher with T2D. Different criteria for evaluating physical activity estimate that it reduces risk factors by 50%. In conclusion there is high evidence that lifestyle factors which optimise diet, increase physical activity and promote weight reduction are preventative factors for T2D and can be sustained long term.
Abstract
Prevention of type 2 diabetes (T2D) is a great challenge worldwide. The aim of this evidence synthesis was to summarize the available evidence in order to update the European Association for the Study of Diabetes (EASD) clinical practice guidelines for nutrition therapy. We conducted a systematic review and, where appropriate, meta-analyses of randomized controlled trials (RCTs) carried out in people with impaired glucose tolerance (IGT) (six studies) or dysmetabolism (one study) to answer the following questions: What is the evidence that T2D is preventable by lifestyle changes? What is the optimal diet (with a particular focus on diet quality) for prevention, and does the prevention of T2D result in a lower risk of late complications of T2D? The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was applied to assess the certainty of the trial evidence. Altogether seven RCTs (N = 4090) fulfilled the eligibility criteria and were included in the meta-analysis. The diagnosis of incident diabetes was based on an oral glucose tolerance test (OGTT). The overall risk reduction of T2D by the lifestyle interventions was 0.53 (95% CI 0.41; 0.67). Most of the trials aimed to reduce weight, increase physical activity, and apply a diet relatively low in saturated fat and high in fiber. The PREDIMED trial that did not meet eligibility criteria for inclusion in the meta-analysis was used in the final assessment of diet quality. We conclude that T2D is preventable by changing lifestyle and the risk reduction is sustained for many years after the active intervention (high certainty of evidence). Healthy dietary changes based on the current recommendations and the Mediterranean dietary pattern can be recommended for the long-term prevention of diabetes. There is limited or insufficient data to show that prevention of T2D by lifestyle changes results in a lower risk of cardiovascular and microvascular complications.
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Resistance Training Prevents Muscle Loss Induced by Caloric Restriction in Obese Elderly Individuals: A Systematic Review and Meta-Analysis.
Sardeli, AV, Komatsu, TR, Mori, MA, Gáspari, AF, Chacon-Mikahil, MPT
Nutrients. 2018;10(4)
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Caloric restriction (55% carbohydrate, 15% protein, 30% fat) is associated with increased lifespans and the attenuation of the harmful effects of aging. Furthermore, it has been shown that resistance training increases lean body mass, promotes strength, and attenuates muscle loss and function in elderly people. The aim of the study is to determine the level of lean body mass that can be preserved when resistance training is associated with caloric restriction interventions in elderly obese humans. The study is a meta-analysis, based on data from randomised-controlled trials. The participants were older adults or elderly people with a mean age > 57 year. Results indicate that caloric restriction associated with resistance training prevents 93% lean body mass loss induced by caloric restriction. Authors conclude that caloric restriction with resistance training almost stopped caloric restriction induced lean body mass loss completely.
Abstract
It remains unclear as to what extent resistance training (RT) can attenuate muscle loss during caloric restriction (CR) interventions in humans. The objective here is to address if RT could attenuate muscle loss induced by CR in obese elderly individuals, through summarized effects of previous studies. Databases MEDLINE, Embase and Web of Science were used to perform a systematic search between July and August 2017. Were included in the review randomized clinical trials (RCT) comparing the effects of CR with (CRRT) or without RT on lean body mass (LBM), fat body mass (FBM), and total body mass (BM), measured by dual-energy X-ray absorptiometry, on obese elderly individuals. The six RCTs included in the review applied RT three times per week, for 12 to 24 weeks, and most CR interventions followed diets of 55% carbohydrate, 15% protein, and 30% fat. RT reduced 93.5% of CR-induced LBM loss (0.819 kg [0.364 to 1.273]), with similar reduction in FBM and BM, compared with CR. Furthermore, to address muscle quality, the change in strength/LBM ratio tended to be different (p = 0.07) following CRRT (20.9 ± 23.1%) and CR interventions (−7.5 ± 9.9%). Our conclusion is that CRRT is able to prevent almost 100% of CR-induced muscle loss, while resulting in FBM and BM reductions that do not significantly differ from CR.
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Glycemic index, glycemic load, and risk of type 2 diabetes: results from 3 large US cohorts and an updated meta-analysis.
Bhupathiraju, SN, Tobias, DK, Malik, VS, Pan, A, Hruby, A, Manson, JE, Willett, WC, Hu, FB
The American journal of clinical nutrition. 2014;100(1):218-32
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Carbohydrates are the principle dietary components that effect blood glucose concentrations. The association between Type 2 diabetes (T2D) and diets with different levels of sugars and carbohydrates has been controversial in the prevention of T2D. Foods can be measured for their impact on blood glucose concentration using the Glycaemic Index (GI) and the Glycaemic Load (GL). The objective of this meta-analysis was to update previous studies and evaluate the association between the GI and GL of dietary intake and the risk of T2D. The authors found a significant association between the GI and GL of food intake and T2D risk and conclude that high GI and GL foods increase the risk of T2D. However, GI is more strongly associated to T2D than GL.
Abstract
BACKGROUND Epidemiologic evidence for the relation between carbohydrate quality and risk of type 2 diabetes (T2D) has been mixed. OBJECTIVE We prospectively examined the association of dietary glycemic index (GI) and glycemic load (GL) with T2D risk. DESIGN We prospectively followed 74,248 women from the Nurses' Health Study (1984-2008), 90,411 women from the Nurses' Health Study II (1991-2009), and 40,498 men from the Health Professionals Follow-Up Study (1986-2008) who were free of diabetes, cardiovascular disease, and cancer at baseline. Diet was assessed by using a validated questionnaire and updated every 4 y. We also conducted an updated meta-analysis, including results from our 3 cohorts and other studies. RESULTS During 3,800,618 person-years of follow-up, we documented 15,027 cases of incident T2D. In pooled multivariable analyses, those in the highest quintile of energy-adjusted GI had a 33% higher risk (95% CI: 26%, 41%) of T2D than those in the lowest quintile. Participants in the highest quintile of energy-adjusted GL had a 10% higher risk (95% CI: 2%, 18%) of T2D. Participants who consumed a combination diet that was high in GI or GL and low in cereal fiber had an ~50% higher risk of T2D. In the updated meta-analysis, the summary RRs (95% CIs) comparing the highest with the lowest categories of GI and GL were 1.19 (1.14, 1.24) and 1.13 (1.08, 1.17), respectively. CONCLUSION The updated analyses from our 3 cohorts and meta-analyses provide further evidence that higher dietary GI and GL are associated with increased risk of T2D.