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Effect of Calorie Restriction and Intermittent Fasting Regimens on Brain-Derived Neurotrophic Factor Levels and Cognitive Function in Humans: A Systematic Review.
Alkurd, R, Mahrous, L, Zeb, F, Khan, MA, Alhaj, H, Khraiwesh, HM, Faris, ME
Medicina (Kaunas, Lithuania). 2024;60(1)
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Brain-derived neurotrophic factor (BDNF) is a protein that plays a crucial role in brain development, cognition and metabolism. Intermittent fasting (IF) is a promising therapeutic strategy for managing metabolic disorders and improving cognitive function. Therefore, this systematic review of sixteen experimental and observational studies investigated the effect of IF on BDNF production and improvements in cognition through the BDNF pathway in healthy adults and people with metabolic disorders. Included studies focused on different IF regimens such as calorie restriction (CR), alternate-day fasting (ADF), time-restricted eating (TRE) and Ramadan model of intermittent fasting (RIF) Future, well-controlled, long-term, robust studies are required to assess the effect of different IF regimens on the production of BDNF and cognitive function in people with metabolic disorders, as the current research is inconclusive. However, healthcare professionals can use the review to understand the potential beneficial effects of IF on cognition and metabolic health in humans.
Abstract
Background: The potential positive interaction between intermittent fasting (IF) and brain-derived neurotrophic factor (BDNF) on cognitive function has been widely discussed. This systematic review tried to assess the efficacy of interventions with different IF regimens on BDNF levels and their association with cognitive functions in humans. Interventions with different forms of IF such as caloric restriction (CR), alternate-day fasting (ADF), time-restricted eating (TRE), and the Ramadan model of intermittent fasting (RIF) were targeted. Methods: A systematic review was conducted for experimental and observational studies on healthy people and patients with diseases published in EMBASE, Scopus, PubMed, and Google Scholar databases from January 2000 to December 2023. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statements (PRISMA) for writing this review. Results: Sixteen research works conducted on healthy people and patients with metabolic disorders met the inclusion criteria for this systematic review. Five studies showed a significant increase in BDNF after the intervention, while five studies reported a significant decrease in BDNF levels, and the other six studies showed no significant changes in BDNF levels due to IF regimens. Moreover, five studies examined the RIF protocol, of which, three studies showed a significant reduction, while two showed a significant increase in BDNF levels, along with an improvement in cognitive function after RIF. Conclusions: The current findings suggest that IF has varying effects on BDNF levels and cognitive functions in healthy, overweight/obese individuals and patients with metabolic conditions. However, few human studies have shown that IF increases BDNF levels, with controversial results. In humans, IF has yet to be fully investigated in terms of its long-term effect on BDNF and cognitive functions. Large-scale, well-controlled studies with high-quality data are warranted to elucidate the impact of the IF regimens on BDNF levels and cognitive functions.
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Effects of whey and soy protein supplementation on inflammatory cytokines in older adults: a systematic review and meta-analysis.
Prokopidis, K, Mazidi, M, Sankaranarayanan, R, Tajik, B, McArdle, A, Isanejad, M
The British journal of nutrition. 2023;129(5):759-770
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Reduced muscle mass and reduction in physical activity may lead to sarcopenia in older people. Age-related sarcopenia is associated with increased systemic low-grade inflammation and obesity. Protein supplementation is found to be beneficial in reducing circulating pro-inflammatory cytokines in old people. Previous research has shown that supplementation with isolated whey and soy protein reduces the levels of inflammatory cytokines in older adults. However, there is limited research on intact whey and soy protein supplementation in reducing age-related inflammation. This systematic review and meta-analysis investigated the effect of intact whey and soy protein on serum inflammatory markers such as C-reactive protein (CRP), Interleukin-6 (IL6) and TNF-α in older adults. The results of this meta-analysis show a significant reduction in circulating IL-6 and TNF-α levels after the supplementation with whey and soy protein. The addition of soy isoflavones resulted in a further decline in serum CRP levels. Subgroup analysis showed that the whey protein supplementation significantly improved sarcopenia and pre-frailty. Healthcare professionals can use the result of this systematic review and meta-analysis to understand the anti-inflammatory properties of intact whey and soy protein and soy isoflavones. However, further robust studies are required to assess the anti-inflammatory properties of whey and soy protein due to the high heterogeneity of included studies in this review.
Abstract
BACKGROUND AND AIMS Low-grade inflammation is a mediator of muscle proteostasis. This study aimed to investigate the effects of isolated whey and soy proteins on inflammatory markers. METHODS We conducted a systematic literature search of randomised controlled trials (RCT) through MEDLINE, Web of Science, Scopus and Cochrane Library databases from inception until September 2021. To determine the effectiveness of isolated proteins on circulating levels of C-reactive protein (CRP), IL-6 and TNF-α, a meta-analysis using a random-effects model was used to calculate the pooled effects (CRD42021252603). RESULTS Thirty-one RCT met the inclusion criteria and were included in the systematic review and meta-analysis. A significant reduction of circulating IL-6 levels following whey protein [Mean Difference (MD): -0·79, 95 % CI: -1·15, -0·42, I2 = 96 %] and TNF-α levels following soy protein supplementation (MD: -0·16, 95 % CI: -0·26, -0·05, I2 = 68 %) was observed. The addition of soy isoflavones exerted a further decline in circulating TNF-α levels (MD: -0·20, 95 % CI: -0·31, -0·08, I2 = 34 %). According to subgroup analysis, whey protein led to a statistically significant decrease in circulating IL-6 levels in individuals with sarcopenia and pre-frailty (MD: -0·98, 95 % CI: -1·56, -0·39, I2 = 0 %). These findings may be dependent on participant characteristics and treatment duration. CONCLUSIONS These data support that whey and soy protein supplementation elicit anti-inflammatory effects by reducing circulating IL-6 and TNF-α levels, respectively. This effect may be enhanced by soy isoflavones and may be more prominent in individuals with sarcopenia.
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Modulating the Gut Microbiome in Multiple Sclerosis Management: A Systematic Review of Current Interventions.
Tsogka, A, Kitsos, DK, Stavrogianni, K, Giannopapas, V, Chasiotis, A, Christouli, N, Tsivgoulis, G, Tzartos, JS, Giannopoulos, S
Journal of clinical medicine. 2023;12(24)
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Multiple sclerosis (MS) is an autoimmune disease caused by the altered immune system mistakenly attacking the central nervous system. While genetics play a leading causative role in the manifestation of this disease, other contributing environmental factors can also exist, such as a disruption in the intestinal microbial composition. Previous research has shown that the bidirectional communication between the brain's and gut's health, also known as the gut-brain axis, may contribute to the prognosis of MS. Modulating gut microbial composition can be a therapeutic strategy in MS patients to manage symptoms and prevent disease progression. This systematic review assessed different protocols for modulating gut microbial composition, including dietary modifications, probiotic use, intermittent fasting, and faecal microbial transplantation. The review included thirteen studies that compared the effects of the above gut microbial modulation intervention protocols in MS patients with healthy participants. While different dietary modification strategies improved MS symptoms, probiotic supplementations and intermittent fasting reduced inflammation, and faecal microbial transplantation showed promising positive effects in a few reports. Due to the methodological limitations of the included studies, further robust studies are required to evaluate the beneficial effects of gut microbial modulation strategies in reducing the symptoms of MS patients. However, healthcare professionals can use the results of this study to understand the benefits of gut microbial modulation in MS patients.
Abstract
This review attempted to explore all recent clinical studies that have investigated the clinical and autoimmune impact of gut microbiota interventions in multiple sclerosis (MS), including dietary protocols, probiotics, fecal microbiota transplantation (FMT), and intermittent fasting (IF). Methods: Thirteen studies were held between 2011 and 2023 this demonstrated interventions in gut microbiome among patients with MS and their impact the clinical parameters of the disease. These included specialized dietary interventions, the supply of probiotic mixtures, FMT, and IF. Results: Dietary interventions positively affected various aspects of MS, including relapse rates, EDSS disability scores, MS-related fatigue, and metabolic features. Probiotic mixtures showed promising results on MS-related fatigue, EDSS parameters, inflammation; meanwhile, FMT-though a limited number of studies was included-indicated some clinical improvement in similar variables. IF showed reductions in EDSS scores and significant improvement in patients' emotional statuses. Conclusions: In dietary protocols, clinical MS parameters, including relapse rate, EDSS, MFIS, FSS, and MSQoL54 scales, were significantly improved through the application of a specific diet each time. Probiotic nutritional mixtures promote a shift in inflammation towards an anti-inflammatory cytokine profile in patients with MS. The administration of such mixtures affected disability, mood levels, and quality of life among patients with MS. FMT protocols possibly demonstrate a therapeutic effect in some case reports. IF protocols were found to ameliorate EDSS and FAMS scores. All interventional means of gut microbiome modulation provided significant conclusions on several clinical aspects of MS and highlight the complexity in the relationship between MS and the gut microbiome.
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Advancements in Nutritional Strategies for Gestational Diabetes Management: A Systematic Review of Recent Evidence.
Sánchez-García, JC, Saraceno López-Palop, I, Piqueras-Sola, B, Cortés-Martín, J, Mellado-García, E, Muñóz Sánchez, I, Rodríguez-Blanque, R
Journal of clinical medicine. 2023;13(1)
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Gestational Diabetes Mellitus (GDM) causes hyperglycaemia due to the deficit of insulin during pregnancy. Dietary and lifestyle management plays a vital role in maintaining glycaemic control in women with GDM to avoid health risks to the mother and baby. Therefore, this systematic review of fourteen randomised controlled trials evaluated the latest research advancements to identify effective nutritional strategies for managing hyperglycaemia in women with GDM. Among all the dietary strategies implemented in the included randomised controlled trials, probiotic supplementation and supplementation of probiotics and vitamin D were most effective in GDM. Further robust studies are required to evaluate the potential effectiveness of different nutritional strategies for managing GDM. Healthcare professionals can use the results of this systematic review to understand the latest evidence supporting nutritional strategy for women with GDM and the need for personalised support for managing hyperglycaemia in GDM.
Abstract
Gestational diabetes mellitus (GDM) is defined as hyperglycaemia first detected at any time during pregnancy with values lower than those determined by the WHO for diabetes diagnosis in adults. This pathology, with a worldwide prevalence of 13.4%, causes significant maternal and foetal risks. The first line of treatment consists of maintaining normo-glycaemia through an adequate diet and lifestyle changes. The aim is to synthesize the scientific evidence updating the nutritional recommendations for the effective management of GDM. A systematic review of the scientific literature was conducted following the PRISMA guidelines. Randomized clinical trials published within the last five years and providing information on nutritional recommendations to achieve an effective management of gestational diabetes were selected. The databases searched were PubMed, the WOS Core Collection, SCOPUS, and CINAHL, using the MeSH terms: "Diabetes, Gestational"; "Nutrition Assessment (nutrition*)"; "Diet"; "Eating"; and "Food"; with the Boolean operators "AND" and "OR". The PEDro scale (Physiotherapy Evidence Database) was used to assess the scientific quality of the studies, with a mean score of 8.9, indicating an average good scientific quality. Results: A total of 809 papers were collected, of which, after applying the inclusion and exclusion criteria, 14 randomized clinical trials were selected. Probiotic supplementation and co-supplementation with vitamin D have been found to be the most beneficial options for both mothers with GDM and neonates, but the most effective regimens are not known. Diets enriched with extra virgin olive oil (EVOO) and oat bran, as well as some recommendations focused on carbohydrates also seem effective, as well as diets designed for this group of women with GDM such as "CHOICE". Conclusions: Although there are numerous proposals that have been published in recent years focused on the diet of women with GDM in order to improve their results and those of their children, it is the supplementation with probiotics and the co-supplementation with vitamin D that is most agreed upon as beneficial; however, more research is needed into which protocols are most effective. Other proposals that could also be beneficial should be further studied.
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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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Do Dietary Supplements Affect Inflammation, Oxidative Stress, and Antioxidant Status in Adults with Hypothyroidism or Hashimoto's Disease?-A Systematic Review of Controlled Trials.
Kubiak, K, Szmidt, MK, Kaluza, J, Zylka, A, Sicinska, E
Antioxidants (Basel, Switzerland). 2023;12(10)
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A deficiency of the thyroid hormone causes hypothyroidism (HT), whereas Autoimmune thyroiditis (AIT) is mainly an organ-specific autoimmune condition. Both HT and AIT are characterised by low-grade inflammation and inflammation in the thyroid gland. Dietary supplements may offer health benefits; however, previous research findings are inconclusive. This systematic review evaluated twenty-two controlled studies to understand the effectiveness of dietary supplements in reducing inflammation and oxidative stress and improving antioxidant and thyroid parameters in patients with HT or AIT. The efficacy of dietary supplements in improving thyroid health and reducing inflammation and oxidative stress was inconclusive due to the low quality of the included studies and the limited number of available studies. Selenium supplements might be beneficial in improving thyroid parameters and inflammation in patients with HT or AIT. Even though the therapeutic benefits of dietary supplements in treating thyroid disease were inconclusive, healthcare professionals can use them to address the common nutritional deficiencies in people with HT and AIT. Further, large, long-term, robust studies are required to assess the therapeutic utility of different dietary supplements in promoting the health of the thyroid gland.
Abstract
This systematic review aims to summarise the results of controlled trials on dietary supplements (DS) usage and inflammation, oxidative stress, antioxidant status, and thyroid parameter improvement in hypothyroidism (HT)/Hashimoto's thyroiditis (AIT) patients. The study protocol was registered with PROSPERO (no. CRD42022365149). A comprehensive search of the PubMed, Scopus, and Web of Science databases resulted in the identification of nineteen randomised controlled trials and three non-randomised studies for the review; three studies examined the effect of supplementation with vitamin D, twelve studies-with selenium, and seven studies-with other DS. Based on very limited evidence, the lack of influence of vitamin D supplementation on inflammatory parameters was found, while no studies have examined oxidative stress and antioxidant status parameters, and only one provided results for a single thyroid parameter after an intervention. Some evidence was found proving that selenium supplementation may decrease inflammation and improve thyroid parameters, but reaching a conclusion about its influence on oxidative stress and antioxidant status is not possible because of the insufficient number of studies. Additionally, due to examining other DS (e.g., multicomponent, Nigella sativa, and genistein) only in single studies, conclusions cannot be drawn. Further long-term, high-quality randomised controlled trials are necessary to better understand the influence of DS on inflammation, oxidative stress, and antioxidant status, as well as their potential to improve thyroid gland function in HT/AIT patients.
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Nuts and seeds consumption and risk of cardiovascular disease, type 2 diabetes and their risk factors: a systematic review and meta-analysis.
Arnesen, EK, Thorisdottir, B, Bärebring, L, Söderlund, F, Nwaru, BI, Spielau, U, Dierkes, J, Ramel, A, Lamberg-Allardt, C, Åkesson, A
Food & nutrition research. 2023;67
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Nuts and seeds consumption is associated with a reduced risk of coronary heart disease (CHD) and cardiovascular disease (CVD). Nuts and seeds contain beneficial components to reduce the risk of CVD and CHD; hence dietary addition may benefit heart health. This systematic review and meta-analysis included sixty studies to analyse the effects of the consumption of nuts and seeds on the incidence of mortality from type 2 diabetes (T2D) and CVD and intermediate cardiometabolic risk factors. High nuts and seed consumption showed a 19% reduction in CVD risk and a 23% reduction in CVD mortality. In addition, high consumption lowered the risk of CHD by 25%. Increased nut consumption up to 30 g/day showed a dose-dependent relationship with reduced risk of CVD. Healthcare professionals can use the results of this study to understand the association between nuts and seeds consumption and CHD, CVD and blood lipid levels. However, further robust studies are required to evaluate the effect of specific nuts and seeds on CHD and CVD risk reduction.
Abstract
OBJECTIVES We aimed to systematically review studies and evaluate the strength of the evidence on nuts/seeds consumption and cardiometabolic diseases and their risk factors among adults. METHODS A protocol was pre-registered in PROSPERO (CRD42021270554). We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials and Scopus up to September 20, 2021 for prospective cohort studies and ≥12-week randomized controlled trials (RCTs). Main outcomes were cardiovascular disease (CVD), coronary heart disease (CHD), stroke and type 2 diabetes (T2D), secondary total-/low density lipoprotein (LDL)-cholesterol, blood pressure and glycaemic markers. Data extraction and risk of bias (RoB) assessments (using RoB 2.0 and RoB-NObS) were performed in duplicate. Effect sizes were pooled using random-effects meta-analyses and expressed as relative risk (RR) or weighted mean differences with 95% confidence intervals (CI); heterogeneity quantified as I 2. One-stage dose-response analyses assessed the linear and non-linear associations with CVD, CHD, stroke and T2D. The strength of evidence was classified per the World Cancer Research Fund criteria. RESULTS After screening 23,244 references, we included 42 papers from cohort studies (28 unique cohorts, 1,890,573 participants) and 18 RCTs (2,266 participants). In the cohorts, mainly populations with low consumption, high versus low total nuts/seeds consumption was inversely associated with total CVD (RR 0.81; 95% CI 0.75, 0.86; I 2 = 67%), CVD mortality (0.77; 0.72, 0.82; I 2 = 59.3%), CHD (0.82; 0.76, 0.89; I 2 = 64%), CHD mortality (0.75; 0.65, 0.87; I 2 = 66.9%) and non-fatal CHD (0.85; 0.75, 0.96; I 2 = 62.2%). According to the non-linear dose-response analyses, consumption of 30 g/day of total nuts/seeds was associated with RRs of similar magnitude. For stroke and T2D the summary RR for high versus low intake was 0.91 (95% CI 0.85, 0.97; I 2 = 24.8%) and 0.95 (0.75, 1.21; I 2 = 82.2%). Intake of nuts (median ~50 g/day) lowered total (-0.15 mmol/L; -0.22, -0.08; I 2 = 31.2%) and LDL-cholesterol (-0.13 mmol/L; -0.21, -0.05; I 2 = 68.6%), but not blood pressure. Findings on fasting glucose, HbA1c and insulin resistance were conflicting. The results were robust to sensitivity and subgroup analyses. We rated the associations between nuts/seeds and both CVD and CHD as probable. There was limited but suggestive evidence for no association with stroke. No conclusion could be made for T2D. CONCLUSION There is a probable relationship between consumption of nuts/seeds and lower risk of CVD, mostly driven by CHD, possibly in part through effects on blood lipids. More research on stroke and T2D may affect the conclusions. The evidence of specific nuts should be further investigated.
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Comparative effects of vitamin and mineral supplements in the management of type 2 diabetes in primary care: A systematic review and network meta-analysis of randomized controlled trials.
Xia, J, Yu, J, Xu, H, Zhou, Y, Li, H, Yin, S, Xu, D, Wang, Y, Xia, H, Liao, W, et al
Pharmacological research. 2023;188:106647
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Type 2 diabetes mellitus (T2DM), characterised by sustained hyperglycaemia and insulin resistance, remains a severe driver of chronic metabolic diseases such as cardiovascular diseases. The aim of this study was to investigate and compare the efficacy of vitamin and mineral supplements in the management of glycaemic control and lipid metabolism for type 2 diabetic patients to inform clinical practice. This study is a systematic review and meta-analysis of one hundred and seventy articles with a total of 4223 adults with T2DM. Participants were randomised to either the placebo/no treatment group (n= 6345) or to the treatment group (n= 7878). Results show that: - chromium was the most effective micronutrient for decreasing fasting blood glucose and insulin resistance. - vitamin K was the top-ranked micronutrient in reducing haemoglobin A1C and fasting insulin levels. - vanadium was the top-ranked micronutrient in total cholesterol reductions. - niacin was ranked as the most effective in triglycerides reductions and increasing high-density lipoprotein cholesterol levels. - vitamin E was the top-ranked micronutrient in low-density lipoprotein cholesterol reductions. Authors conclude that micronutrient supplements especially chromium, vitamin E, vitamin K, vanadium, and niacin supplements, may be more effective in the management of T2DM compared with other micronutrients.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Clinicians could consider the adjunctive effect of micronutrients supplements, such as chromium, vitamin E, vitamin K, vanadium, and niacin supplements in a nutrition protocol to manage T2DM and slow or prevent its complications.
- The study authors state that the vitamin and mineral supplements under review had a statistically significant improvement, however they did not reach the study threshold for clinical significance. Therefore they advise caution in utilising micronutrient supplements in the management of glucose and lipid metabolism for T2DM.
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:
Objectives
The aim of this systematic review was to evaluate the comparative effects of vitamin and mineral supplements on managing glycemic control and lipid metabolism for type 2 diabetes mellitus (T2DM).
Methodology
This systematic review is registered with PROSPERO and adhered to PRISMA-2020 guidelines for network meta-analysis
The Cochrane Collaboration’s risk-of-bias tool was used to assess eligible randomised trials
8 prespecified markers identified and assessed in this study : 1) HbA1c (%), 2) fasting blood glucose (mmol/L), 3) total cholesterol (mmol/L), 4) triglycerides (mmol/L), 5) fasting insulin (μIU/mL), 6) HOMA-IR, 7) LDL-c (mmol/L), and 8) HDL-c (mmol/L).
Results
- 170 RCT trials of 14223 participants with T2DM treated with vitamin supplements, mineral supplements, or placebo/no treatment were included
- Low to very low certainty evidence established chromium supplements as the most effective in reducing fasting blood glucose levels and homeostasis model assessment of insulin resistance (SUCRAs: 90.4% and 78.3%, respectively)
- Vitamin K supplements ranked best in reducing glycated haemoglobin A1c and fasting insulin levels (SUCRAs: 97.0% and 82.3%, respectively), with moderate to very low certainty evidence
- Vanadium supplements ranked best in lowering total cholesterol levels with very low evidence certainty (SUCRAs:100%)
- Niacin supplements ranked best in triglyceride reductions and increasing high-density lipo-protein cholesterol levels with low to very low evidence certainty (SUCRAs:93.7% and 94.6%, respectively)
- Vitamin E supplements ranked best in reducing low-density lipoprotein cholesterol levels with very low evidence certainty (SUCRAs:80.0%).
Conclusion
- Micronutrient supplements, such as chromium, vitamin E, vitamin K, vanadium, and niacin supplements, may be efficacious in managing T2DM
- It should be noted that the evidence certainty for all was low.
Clinical practice applications:
- Chromium plays an important role in carbohydrate and lipid metabolism and was the most effective micronutrient for decreasing fasting blood glucose, HbA1c, fasting insulin, and HOMA-IR reductions. More pronounced effects were seen for chromium than vitamin E, vitamin C, niacin, selenium, and magnesium supplements
- Vitamin K was the top-ranked micronutrient in reducing HbA1c and fasting insulin levels. The mechanism through which Vitamin K affects glucose metabolism is proposed as activation of the AMP-activated protein kinase/sirtuin 1, that in turn increases phosphocreatine 3-kinase and glucose transporter 2 to decrease insulin resistance and fasting glucose.
- Vanadium was the top-ranked micronutrient in total cholesterol (TC) reductions, where supplementation dosage should be carefully considered, as vanadium compounds can be moderately or highly toxic. Vanadium supplementation is only recommended in cases of vanadium deficiency or diabetes, hyperlipidemia, and hypertension, where the intake of vanadium from food should be enhanced in preference to supplementation
- Niacin was ranked as the most effective in triglyceride (TG) reductions and increasing HDL cholesterol levels. The dose of niacin could not be determined
- Vitamin E was the top-ranked micronutrient in low-density lipo- protein (LDL) cholesterol reductions.
Considerations for future research:
- Considering the clinical importance of these findings, new research is needed to get better insight into the efficacy of micronutrient supplements in managing T2DM
- Selenium homeostasis, selenoprotein, insulin signaling/secretion, and carbohydrate/lipid metabolism are linked in multiple and complex ways but the authors could not explain why chromium supplementation would lower blood glucose more effectively than selenium supplementation, and suggest more research is needed to clarify this
- While vitamin K status could be an emerging treatment target in T2DM prevention and management, it remains to be determined whether vitamin K supplementation has an advantage over other nutrients in terms of hypoglycemic effect, and further research is necessary
- The beneficial effect of vitamin E and niacin supplements regarding lipid metabolism warrant investigation through more rigorous comparative studies.
Abstract
Medical nutrition treatment can manage diabetes and slow or prevent its complications. The comparative effects of micronutrient supplements, however, have not yet been well established. We aimed at evaluating the comparative effects of vitamin and mineral supplements on managing glycemic control and lipid metabolism for type 2 diabetes mellitus (T2DM) to inform clinical practice. Electronic and hand searches for randomized controlled trials (RCTs) were performed until June 1, 2022. We selected RCTs enrolling patients with T2DM who were treated with vitamin supplements, mineral supplements, or placebo/no treatment. Data were pooled via frequentist random-effects network meta-analyses. A total of 170 eligible trials and 14223 participants were included. Low to very low certainty evidence established chromium supplements as the most effective in reducing fasting blood glucose levels and homeostasis model assessment of insulin resistance (SUCRAs: 90.4% and 78.3%, respectively). Vitamin K supplements ranked best in reducing glycated hemoglobin A1c and fasting insulin levels (SUCRAs: 97.0% and 82.3%, respectively), with moderate to very low certainty evidence. Vanadium supplements ranked best in lowering total cholesterol levels with very low evidence certainty (SUCRAs:100%). Niacin supplements ranked best in triglyceride reductions and increasing high-density lipoprotein cholesterol levels with low to very low evidence certainty (SUCRAs:93.7% and 94.6%, respectively). Vitamin E supplements ranked best in reducing low-density lipoprotein cholesterol levels with very low evidence certainty (SUCRAs:80.0%). Our analyses indicated that micronutrient supplements, especially chromium, vitamin E, vitamin K, vanadium, and niacin supplements, may be more efficacious in managing T2DM than other micronutrients. Considering the clinical importance of these findings, new research is needed to get better insight into this issue.
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Polyphenols as potential metabolism mechanisms regulators in liver protection and liver cancer prevention.
Li, S, Yin, S, Ding, H, Shao, Y, Zhou, S, Pu, W, Han, L, Wang, T, Yu, H
Cell proliferation. 2023;56(1):e13346
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Multiple risk factors could lead to the development of liver cancer, one of the most common malignant tumours in the world. These risk factors include hepatitis infection, non-alcoholic fatty liver disease and excessive alcohol consumption. Polyphenols are bioactive compounds with antioxidant, anti-inflammatory, anti-mutagenic, anti-viral, hypoglycaemic, anti-hypertensive, antibacterial and anti-proliferative properties. Polyphenols may be effective in reducing the risk of developing liver cancer by altering the metabolism. This review evaluated the effectiveness of polyphenols in protecting the liver and inhibiting hepatocarcinoma development. In addition, the review evaluated several mechanisms by which polyphenols affect glucose and lipid metabolism and mitochondrial metabolism and reduce the effects of oxidative stress, inflammation and toxic metabolites. Further robust studies are required to assess the beneficial effects of polyphenols as a therapeutic agent, as the current knowledge is limited. However, healthcare professionals can use the results of this study to understand the protective effects of polyphenols against liver disease.
Abstract
BACKGROUND Liver cancer is one of the common malignancies. The dysregulation of metabolism is a driver of accelerated tumourigenesis. Metabolic changes are well documented to maintain tumour growth, proliferation and survival. Recently, a variety of polyphenols have been shown to have a crucial role both in liver disease prevention and metabolism regulation. METHODS We conducted a literature search and combined recent data with systematic analysis to comprehensively describe the molecular mechanisms that link polyphenols to metabolic regulation and their contribution in liver protection and liver cancer prevention. RESULTS Targeting metabolic dysregulation in organisms prevents and resists the development of liver cancer, which has important implications for identifying new therapeutic strategies for the management and treatment of cancer. Polyphenols are a class of complex compounds composed of multiple phenolic hydroxyl groups and are the main active ingredients of many natural plants. They mediate a broad spectrum of biological and pharmacological functions containing complex lipid metabolism, glucose metabolism, iron metabolism, intestinal flora imbalance, as well as the direct interaction of their metabolites with key cell-signalling proteins. A large number of studies have found that polyphenols affect the metabolism of organisms by interfering with a variety of intracellular signals, thereby protecting the liver and reducing the risk of liver cancer. CONCLUSION This review systematically illustrates that various polyphenols, including resveratrol, chlorogenic acid, caffeic acid, dihydromyricetin, quercetin, catechins, curcumin, etc., improve metabolic disorders through direct or indirect pathways to protect the liver and fight liver cancer.
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The effects of dietary patterns and food groups on symptomatic osteoarthritis: A systematic review.
Zeng, J, Franklin, DK, Das, A, Hirani, V
Nutrition & dietetics: the journal of the Dietitians Association of Australia. 2023;80(1):21-43
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Plain language summary
Osteoarthritis is a chronic joint disease that can lead to disability, characterised by the deterioration and loss of joint cartilage, inflammation, pain, aches, and stiffness. Research has shown a positive association between osteoarthritis progression and pro-inflammatory diets, such as Western diets, and a negative association with anti-inflammatory diets, such as the DASH and Mediterranean diets. This systematic review evaluated the evidence from the literature to show the positive and negative associations between osteoarthritis and diet. The Prudent diet, Mediterranean diet, and increased fibre intake were effective in reducing the progression of osteoarthritis and alleviating its symptoms, while the Western diet increased the progression of symptomatic osteoarthritis. The Prudent diet was found to be particularly effective in alleviating symptomatic osteoarthritis. The beneficial effects of anti-inflammatory diets and increased fibre intake are thought to be due to the reduction and suppression of inflammatory cytokines, while inflammatory diets have the opposite effect. Although there is high heterogeneity between the studies, healthcare professionals can use the results of this systematic review to understand the therapeutic clinical utility of anti-inflammatory diets and high-fibre intake in reducing the progression of symptomatic osteoarthritis in people above the age of 45 years. Further robust studies are needed to evaluate the effectiveness of other therapeutic dietary strategies.
Abstract
AIM: To systematically review current literature to determine the association between symptomatic osteoarthritis and dietary patterns, diet quality and food groups in adults aged ≥45 years. METHODS The review was registered on PROSPERO (CRD42021270891). Cochrane Central Library, Cumulative Index of Nursing and Allied Health Literature, Embase, Medline and Web of Science databases were searched. A total of 3816 records were identified. Eligible articles involved populations aged ≥45 years with symptomatic osteoarthritis, assessing dietary patterns, diet quality or food groups, with pain in joints as outcomes. The Joanna Briggs Institute Critical Appraisal Checklists were used for quality assessment. Grading of Recommendations, Assessment, Development and Evaluation was used to assess the certainty of evidence. RESULTS Six cohort studies were included. The Prudent dietary pattern and the Mediterranean dietary pattern reduced the progression of osteoarthritis symptoms. The Western dietary pattern increased symptomatic osteoarthritis progression. Increased total fibre consumption reduced symptomatic osteoarthritis progression and pain worsening, but the effects of fibre from each food group were inconclusive. Diet with high inflammatory potential increased risk of new onset symptomatic osteoarthritis, but the effects of overall diet quality were inconclusive. CONCLUSIONS The Prudent dietary pattern showed the highest protection on symptomatic osteoarthritis in adults aged 45 years and over. The body of evidence is limited, suggesting that further research is needed to corroborate the estimated effect at a high certainty of evidence, and to incorporate previously unstudied dietary patterns and food groups. Identifying the most beneficial dietary pattern may inform future guidelines for reducing symptomatic osteoarthritis in middle aged and older adults.