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Consumption of ultra-processed foods and health outcomes: a systematic review of epidemiological studies.
Chen, X, Zhang, Z, Yang, H, Qiu, P, Wang, H, Wang, F, Zhao, Q, Fang, J, Nie, J
Nutrition journal. 2020;19(1):86
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Unhealthy diets are recognized as a major determinant of the occurrence of non-communicable diseases (NCDs). The aim of this study was to summarize the evidence for the association between ultra-processed food (UPFs) consumption and health outcomes. This study is a systemic review of 20 published epidemiological studies (12 cohort and 8 cross-sectional studies), with a total of 334,114 participants and 10 diseases. Results indicate a positive association between UPFs consumption and risk of all-cause mortality, overall cardiovascular diseases, coronary heart diseases, cerebrovascular diseases, hypertension, metabolic syndrome, overweight and obesity, depression, irritable bowel syndrome, overall cancer, postmenopausal breast cancer, gestational obesity, adolescent asthma and wheezing, and frailty. However, on the contrary, there was not an obvious association with cardiovascular disease mortality, prostate and colorectal cancer, gestational diabetes mellitus and gestational overweight. Authors conclude that their findings encouraged a decrease in UPFs consumption and an increase in the proportion of unprocessed or minimally processed foods, such as fruits and vegetables.
Abstract
BACKGROUND Consumption of ultra-processed foods (UPFs) plays a potential role in the development of obesity and other diet-related noncommunicable diseases (NCDs), but no studies have systematically focused on this. This study aimed to summarize the evidence for the association between UPFs consumption and health outcomes. METHODS A comprehensive search was conducted in PubMed, Embase, and Web of Science to identify all relevant studies. Epidemiological studies were included, and identified studies were evaluated for risk of bias.A narrative review of the synthesized findings was provided to assess the association between UPFs consumption and health outcomes. RESULTS 20 studies (12 cohort and 8 cross-sectional studies) were included in the analysis, with a total of 334,114 participants and 10 health outcomes. In a narrative review, high UPFs consumption was obviously associated with an increased risk of all-cause mortality, overall cardiovascular diseases, coronary heart diseases, cerebrovascular diseases, hypertension, metabolic syndrome, overweight and obesity, depression, irritable bowel syndrome, overall cancer, postmenopausal breast cancer, gestational obesity, adolescent asthma and wheezing, and frailty. It showed no significant association with cardiovascular disease mortality, prostate and colorectal cancers, gestational diabetes mellitus and gestational overweight. CONCLUSIONS This study indicated a positive association between UPFs consumption and risk of several health outcomes. Large-scale prospective designed studies are needed to confirm our findings.
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Food processing and cardiometabolic risk factors: a systematic review.
Santos, FSD, Dias, MDS, Mintem, GC, Oliveira, IO, Gigante, DP
Revista de saude publica. 2020;54:70
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Cardiovascular diseases (CVD) comprise the main cause of mortality in the world and approximately three quarters of deaths occur in low- and middle-income countries. The aim of this study was to assess the association between food consumption according to processing and cardiometabolic factors in adults and/or the elderly. This study is a systematic review of eleven studies. Five studies (46%) had a sample size greater than 10,000 participants and the smallest sample identified evaluated 302 individuals. Results indicate that the consumption of UPF can have an unfavourable impact on the health of individuals, especially contributing to increase the body mass index. The cardiometabolic risk factors identified were overweight or obesity, arterial hypertension and metabolic syndrome. Authors conclude that their findings may contribute to strengthening scientific evidence that underlies public policies related to the area of food and nutrition and the coping with cardiovascular diseases.
Abstract
OBJECTIVE To systematically review the evidence for the association between food consumption according to processing and cardiometabolic factors in adults and/or the elderly. METHOD Two independent evaluators analyzed the electronic databases PubMed, Web of Science and Lilacs until December 2018. We used the following terms: (convenience foods OR food processing OR highly-processed OR industrialized foods OR minimally-processed OR prepared foods OR processed foods OR ultra-processed OR ultraprocessed OR ultra processed OR unprocessed) AND (metabolic syndrome OR hypertension OR blood pressure OR diabetes mellitus OR glucose OR glycaemia OR insulin OR cholesterol OR triglycerides OR blood lipids OR overweight OR obesity) AND (adult OR adults OR adulthood OR aged OR elderly OR old). We assessed methodological and evidence qualities, and also extracted information for the qualitative synthesis from the selected studies. RESULTS Of the 6,423 studies identified after removing duplicates, eleven met the eligibility criteria. The main food classification we used was Nova. The consumption of ultra-processed foods was positively associated with overweight and obesity, high blood pressure and metabolic syndrome. All articles included met more than 50% of the methodological quality criteria. The quality of evidence was considered moderate for the outcome overweight and obesity and weak for hypertension and metabolic syndrome. CONCLUSIONS The Nova food classification stands out in the area of nutritional epidemiology when assessing the effects of food processing on health outcomes. Although caution is required in the interpretation, the results indicated that the consumption of ultra-processed foods can have an unfavorable impact in the health of individuals.
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Exercise Training Modulates Gut Microbiota Profile and Improves Endotoxemia.
Motiani, KK, Collado, MC, Eskelinen, JJ, Virtanen, KA, Löyttyniemi, E, Salminen, S, Nuutila, P, Kalliokoski, KK, Hannukainen, JC
Medicine and science in sports and exercise. 2020;52(1):94-104
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The gut microbiome differs between healthy people and those with metabolic diseases, including metabolic syndrome and type 2 diabetes (T2D) and it is suggested that this association is mediated by endotoxemia, the release of toxins, in particular lipopolysaccharides (LPS), from the gut bacteria. The aim of this study was to investigate the effects of exercise on gut microbiota composition and metabolic endotoxemia in people with prediabetes and T2D. 26 sedentary participants with either prediabetes or T2D took part in either a sprint interval training (SIT) or moderate-intensity continuous training (MICT) three times per week for two weeks. Both training types induced fat loss and improved the gut microbiota, HbA1C (a marker for whole body insulin sensitivity) as well as some markers of systemic and intestinal inflammation, although there were differences in the way the two types of exercise altered the gut bacterial composition. Only SIT improved aerobic capacity. The authors concluded that exercise training improves the gut microbiota and reduces endotoxemia.
Abstract
INTRODUCTION Intestinal metabolism and microbiota profiles are impaired in obesity and insulin resistance. Moreover, dysbiotic gut microbiota has been suggested to promote systemic low-grade inflammation and insulin resistance through the release of endotoxins particularly lipopolysaccharides. We have previously shown that exercise training improves intestinal metabolism in healthy men. To understand whether changes in intestinal metabolism interact with gut microbiota and its release of inflammatory markers, we studied the effects of sprint interval (SIT) and moderate-intensity continuous training (MICT) on intestinal metabolism and microbiota in subjects with insulin resistance. METHODS Twenty-six, sedentary subjects (prediabetic, n = 9; type 2 diabetes, n = 17; age, 49 [SD, 4] yr; body mass index, 30.5 [SD, 3]) were randomized into SIT or MICT. Intestinal insulin-stimulated glucose uptake (GU) and fatty acid uptake (FAU) from circulation were measured using positron emission tomography. Gut microbiota composition was analyzed by 16S rRNA gene sequencing and serum inflammatory markers with multiplex assays and enzyme-linked immunoassay kit. RESULTS V˙O2peak improved only after SIT (P = 0.01). Both training modes reduced systematic and intestinal inflammatory markers (tumor necrosis factor-α, lipopolysaccharide binding protein) (time P < 0.05). Training modified microbiota profile by increasing Bacteroidetes phylum (time P = 0.03) and decreasing Firmicutes/Bacteroidetes ratio (time P = 0.04). Moreover, there was a decrease in Clostridium genus (time P = 0.04) and Blautia (time P = 0.051). Only MICT decreased jejunal FAU (P = 0.02). Training had no significant effect on intestinal GU. Colonic GU associated positively with Bacteroidetes and inversely with Firmicutes phylum, ratio Firmicutes/Bacteroidetes and Blautia genus. CONCLUSIONS Intestinal substrate uptake associates with gut microbiota composition and whole-body insulin sensitivity. Exercise training improves gut microbiota profiles and reduces endotoxemia.
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Fasting blood glucose at admission is an independent predictor for 28-day mortality in patients with COVID-19 without previous diagnosis of diabetes: a multi-centre retrospective study.
Wang, S, Ma, P, Zhang, S, Song, S, Wang, Z, Ma, Y, Xu, J, Wu, F, Duan, L, Yin, Z, et al
Diabetologia. 2020;63(10):2102-2111
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Hyperglycaemia was a risk factor for mortality from severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) and is an independent risk factor for lower respiratory tract infection and poor prognosis. The aim of this retrospective study of 605 patients without previously diagnosed diabetes was to examine the association between fasting blood glucose (FBG) on admission and the 28-day in hospital mortality of COVID-19 patients. Patients with a FBG level of 7.0mmol/l or over had more than double the risk of dying than those with a level of 6.0mmol/l or less. Other risk factors for mortality included age, being male, and severity of pneumonia at admission. Compared with patients whose FBG was 6.0mmol/l or lower at admission, patients with FBG of 7.0 mmol/l and above had a 3.99 times higher risk of in-hospital complications, whilst those with FBG of 6.1–6.9 mmol/l had a 2.61 times higher risk of complications. The authors conclude that glycaemic testing and control are important to all COVID-19 patients even where they have no pre-existing diabetes.
Abstract
AIMS/HYPOTHESIS Hyperglycaemia is associated with an elevated risk of mortality in community-acquired pneumonia, stroke, acute myocardial infarction, trauma and surgery, among other conditions. In this study, we examined the relationship between fasting blood glucose (FBG) and 28-day mortality in coronavirus disease 2019 (COVID-19) patients not previously diagnosed as having diabetes. METHODS We conducted a retrospective study involving all consecutive COVID-19 patients with a definitive 28-day outcome and FBG measurement at admission from 24 January 2020 to 10 February 2020 in two hospitals based in Wuhan, China. Demographic and clinical data, 28-day outcomes, in-hospital complications and CRB-65 scores of COVID-19 patients in the two hospitals were analysed. CRB-65 is an effective measure for assessing the severity of pneumonia and is based on four indicators, i.e. confusion, respiratory rate (>30/min), systolic blood pressure (≤90 mmHg) or diastolic blood pressure (≤60 mmHg), and age (≥65 years). RESULTS Six hundred and five COVID-19 patients were enrolled, including 114 who died in hospital. Multivariable Cox regression analysis showed that age (HR 1.02 [95% CI 1.00, 1.04]), male sex (HR 1.75 [95% CI 1.17, 2.60]), CRB-65 score 1-2 (HR 2.68 [95% CI 1.56, 4.59]), CRB-65 score 3-4 (HR 5.25 [95% CI 2.05, 13.43]) and FBG ≥7.0 mmol/l (HR 2.30 [95% CI 1.49, 3.55]) were independent predictors for 28-day mortality. The OR for 28-day in-hospital complications in those with FBG ≥7.0 mmol/l and 6.1-6.9 mmol/l vs <6.1 mmol/l was 3.99 (95% CI 2.71, 5.88) or 2.61 (95% CI 1.64, 4.41), respectively. CONCLUSIONS/INTERPRETATION FBG ≥7.0 mmol/l at admission is an independent predictor for 28-day mortality in patients with COVID-19 without previous diagnosis of diabetes. Glycaemic testing and control are important to all COVID-19 patients even where they have no pre-existing diabetes, as most COVID-19 patients are prone to glucose metabolic disorders. Graphical abstract.
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Clinical Impact of Supplementation of Vitamins B1 and C on Patients with Sepsis-Related Acute Respiratory Distress Syndrome.
Yoo, JW, Kim, RB, Ju, S, Lee, SJ, Cho, YJ, Jeong, YY, Lee, JD, Kim, HC
Tuberculosis and respiratory diseases. 2020;83(3):248-254
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Acute respiratory distress syndrome (ARDS) is a life-threatening condition that commonly develops in patients with sepsis. Patients with ARDS require admission to intensive care and invasive mechanical ventilation. Vitamin B1 and C deficiencies have been reported in critically ill patients with sepsis. Vitamin B1 is involved in aerobic metabolism, and vitamin C has anti-inflammatory and anti-oxidative effects. The aim of this Korean retrospective cohort study was to evaluate the clinical impact of vitamin B1 and C supplementation in patients with sepsis-related ARDS. Patients with ARDS requiring invasive mechanical ventilation, admitted to an intensive care unit (ICU) were included in this study. Clinical outcomes were compared between patients administered with vitamin B1 (200 mg/day) and C (2 g/day) between June 2018-May 2019 (the supplementation group) and those who did not receive vitamin B1 and C administration between June 2017-May 2018 (the control group). Seventy-nine patients were included. Thirty-three patients received vitamin B1 and C, and 46 patients did not. There were no significant differences in the number of deaths between the patients who received vitamin B1 and C and those who did not. The mean number of days not requiring ICU admission or ventilation was greater in patients supplemented with vitamin B1 and C than that in the control patients, but the difference was not statistically significant. Steroid administration was more frequent in patients receiving vitamin B1 and C supplementation than in those without it. The authors concluded that Vitamin B1 and C supplementation at the doses used in this study did not reduce the death rates in ARDS patients.
Abstract
BACKGROUND Although few studies have reported improved clinical outcomes with the administration of vitamin B1 and C in critically ill patients with septic shock or severe pneumonia, its clinical impact on patients with sepsis-related acute respiratory distress syndrome (ARDS) remains unclear. The purpose of this study was to evaluate the association with vitamin B and C supplementation and clinical outcomes in patients with ARDS. METHODS Patients with ARDS requiring invasive mechanical ventilation, admitted to the medical intensive care unit (ICU) were included in this study. Clinical outcomes were compared between patients administered with vitamin B1 (200 mg/day) and C (2 g/day) June 2018-May 2019 (the supplementation group) and those who did not receive vitamin B1 and C administration June 2017-May 2018 (the control group). RESULTS Seventy-nine patients were included. Thirty-three patients received vitamin B1 and C whereas 46 patients did not. Steroid administration was more frequent in patients receiving vitamin B1 and C supplementation than in those without it. There were no significant differences in the mortality between the patients who received vitamin B1 and C and those who did not. There were not significant differences in ventilator and ICU-free days between each of the 21 matched patients. CONCLUSION Vitamin B1 and C supplementation was not associated with reduced mortality rates, and ventilator and ICU-free days in patients with sepsis-related ARDS requiring invasive mechanical ventilation.
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Endocrine and metabolic aspects of the COVID-19 pandemic.
Marazuela, M, Giustina, A, Puig-Domingo, M
Reviews in endocrine & metabolic disorders. 2020;21(4):495-507
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Endocrine and metabolic related diseases such as diabetes and obesity may increase the risk of developing severe Covid-19 and as a result these diseases could be severely affected by Covid-19 infection. This very large review paper looked at over 100 studies and outlined the interrelationship between Covid-19 infection and several endocrine diseases. Diabetes, obesity, pituitary-hypothalamic function, thyroid function, Cushing's syndrome and adrenal function were all reviewed. No aim was stated. Data on individuals with obesity and diabetes indicated an increased risk for severe Covid-19 infection, hospitalisation and mortality. Data surrounding pituitary-hypothalamic function, thyroid function, Cushing's syndrome and adrenal function was less abundant, however neurological issues in Covid-19 patients suggested an involvement of the pituitary and hypothalamus. In lieu of sufficient data the author commented on the possible similarities between severe acute respiratory syndrome coronavirus with the Covid-19 virus. A number of management strategies were discussed such as the use of vitamin D, oxytocin and melatonin, however the authors commented on the lack of data regarding oxytocin and melatonin in Covid-19 patients, but mechanistic data suggested they might be of use. No overall conclusions were drawn on the findings. Clinicians could use this paper to understand how patients with pre-existing endocrine and metabolic conditions may be at a higher risk of more severe Covid-19 and if contracted could exacerbate their pre-existing condition. These patients could require constant monitoring and additional measures to avoid contracting Covid-19. Supplements such as vitamin D, oxytocin or melatonin could be therapeutic, however more data needs to be reviewed.
Abstract
COVID-19 infection has tremendously impacted our daily clinical practice as well as our social living organization. Virtually all organs and biological systems suffer from this new coronavirus infection, either because the virus targets directly specific tissues or because of indirect effects. Endocrine diseases are not an exception and some of endocrine organs are at risk of direct or indirect lesion by COVID-19. Although there is still no evidence of higher predisposition to contract the infection in patients with diabetes and/or obesity, the coexistence of these conditions contributes to a worse prognosis because both conditions confer an impaired immunologic system. Cytokines storm can be amplified by these two latter conditions thereby leading to multisystemic failure and death. Glycaemic control has been demonstrated to be crucial to avoiding long hospital stays, ICU requirement and also prevention of excessive mortality. Endocrine treatment modifications as a consequence of COVID-19 infection are required in a proactive manner, in order to avoid decompensation and eventual hospital admission. This is the case of diabetes and adrenal insufficiency in which prompt increase of insulin dosage and substitutive adrenal steroids through adoption of the sick day's rules should be warranted, as well as easy contact with the health care provider through telematic different modalities. New possible endocrinological targets of COVID-19 have been recently described and warrant a full study in the next future.
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The Effect of Moderate Weight Loss on a Non-Invasive Biomarker of Liver Fibrosis: A Randomised Controlled Trial.
Koutoukidis, DA, Jebb, SA, Aveyard, P, Astbury, NM
Obesity facts. 2020;13(2):144-151
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Non-alcoholic fatty liver disease covers a range of conditions from excess fat in the liver through inflammation and fibrosis, to advanced fibrosis, and cirrhosis. The Enhanced Liver Fibrosis (ELF) score is emerging as a promising blood biomarker for fibrosis. The aim of this study was to examine whether a community weight loss programme reduces ELF score over 12 months compared with a weight-loss intervention which is less effective. This study is a secondary analysis of a published randomised controlled trial. Participants (n=73) were equally randomised to a community weight loss programme (WeightWatchers) or usual care. Results indicate that there was no evidence of an effect of a community weight loss programme on changes in the ELF score and no association between weight loss and the ELF score in people who had, on average, an ELF score compatible with moderate fibrosis. Authors conclude that using the ELF test to assess weight loss treatment efficacy in improving liver fibrosis may be of limited value, thus biopsy remains the gold-standard assessment for liver fibrosis.
Abstract
BACKGROUND Referral to weight loss programmes is the only effective treatment for non-alcoholic fatty liver disease (NAFLD). Clinicians should advise weight loss and screen for liver fibrosis using the Enhanced Liver Fibrosis (ELF) score. AIM: To examine if the ELF score changes with weight loss. DESIGN AND SETTING Randomised controlled trial (ISRCTN85485463) in UK primary care during 2007-2008. METHOD Adults with a BMI of 27-35 kg/m2 and ≥1 risk factor for obesity-related disease were randomised to attend a community weight loss programme (n = 45) or receive usual weight loss advice from a practice nurse (n = 28). Weight and the ELF score were measured at baseline and 1 year. Analysis of covariance examined mean changes in the ELF score between groups and its relationship with weight loss. RESULTS Mean (SD) BMI was 31.10 kg/m2 (2.55) with evidence of moderate levels of liver fibrosis at baseline (mean ELF score: 8.93 [0.99]). There was no evidence that the community weight loss programme reduced the ELF score compared with usual care (difference +0.13 points, 95% CI: -0.25 to 0.52) despite greater weight loss (difference: -2.66 kg, 95% CI: -5.02 to -0.30). Mean weight loss in the whole cohort was 7.8% (5.9). There was no evidence of an association between weight change and change in ELF; the coefficient for a 5% weight loss was -0.15 (95% CI: -0.30 to 0.0002). CONCLUSION We found no evidence that the ELF score changed meaningfully following moderate weight loss. Clinicians should not use the ELF score to measure improvements in NAFLD fibrosis following weight loss programmes.
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Effect of Smartphone-Based Lifestyle Coaching App on Community-Dwelling Population With Moderate Metabolic Abnormalities: Randomized Controlled Trial.
Cho, SMJ, Lee, JH, Shim, JS, Yeom, H, Lee, SJ, Jeon, YW, Kim, HC
Journal of medical Internet research. 2020;22(10):e17435
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Metabolic disorders are established precursors to cardiovascular disease. The aim of the study was to evaluate the longitudinal effect of smartphone-based health care app on metabolic parameters in a sample of the general population with moderate metabolic abnormalities. The study is a single-blind 3-arm parallel-design randomized controlled trial delivering a 6-month primary prevention program via mobile app. One hundred twenty-nine smartphone users, aged between 30-59 years with at least 2 metabolic abnormalities, have been recruited. Results showed that the simultaneous diet/exercise logging and lifestyle coaching yielded greater body weight reduction, specifically via body fat mass reduction. On the other hand, the systolic blood pressure did not change notably between the 3 groups at any follow-up examinations. Authors conclude that future studies focusing on comparative effectiveness using alternative study designs are needed to integrate these apps in everyday lives and clinic practice.
Abstract
BACKGROUND Metabolic disorders are established precursors to cardiovascular diseases, yet they can be readily prevented with sustained lifestyle modifications. OBJECTIVE We assessed the effectiveness of a smartphone-based weight management app on metabolic parameters in adults at high-risk, yet without physician diagnosis nor pharmacological treatment for metabolic syndrome, in a community setting. METHODS In this 3-arm parallel-group, single-blind, randomized controlled trial, we recruited participants aged 30 to 59 years with at least 2 conditions defined by the Third Report of the National Cholesterol Education Program expert panel (abdominal obesity, high blood pressure, high triglycerides, low high-density lipoprotein cholesterol, and high fasting glucose level). Participants were randomly assigned (1:1:1) by block randomization to either the nonuser group (control), the app-based diet and exercise self-logging group (app only), or the app-based self-logging and personalized coaching from professional dieticians and exercise coordinators group (app with personalized coaching). Assessments were performed at baseline, week 6, week 12, and week 24. The primary outcome was change in systolic blood pressure (between baseline and follow-up assessments). Secondary outcomes were changes in diastolic blood pressure, body weight, body fat mass, waist circumference, homeostatic model of assessment of insulin resistance, triglyceride level, and high-density lipoprotein cholesterol level between baseline and follow-up assessments. Analysis was performed using intention-to-treat. RESULTS Between October 28, 2017 and May 28, 2018, 160 participants participated in the baseline screening examination. Participants (129/160, 80.6%) who satisfied the eligibility criteria were assigned to control (n=41), app only (n=45), or app with personalized coaching (n=43) group. In each group, systolic blood pressure showed decreasing trends from baseline (control: mean -10.95, SD 2.09 mmHg; app only: mean -7.29, SD 1.83 mmHg; app with personalized coaching: mean -7.19, SD 1.66 mmHg), yet without significant difference among the groups (app only: P=.19; app with personalized coaching: P=.16). Instead, those in the app with personalized coaching group had greater body weight reductions (control: mean -0.12, SD 0.30 kg; app only: mean -0.35, SD 0.36 kg, P=.67; app with personalized coaching: mean -0.96, SD 0.37 kg; P=.08), specifically by body fat mass reduction (control: mean -0.13, SD 0.34 kg; app only: mean -0.64, SD 0.38 kg, P=.22; app with personalized coaching: mean -0.79, SD 0.38 kg; P=.08). CONCLUSIONS Simultaneous diet and exercise self-logging and persistent lifestyle modification coaching were ineffective in lowering systolic blood pressure but effective in losing weight and reducing body fat mass. These results warrant future implementation studies of similar models of care on a broader scale in the context of primary prevention. TRIAL REGISTRATION ClinicalTrials.gov NCT03300271; http://clinicaltrials.gov/ct2/show/NCT03300271.
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Stratifying cellular metabolism during weight loss: an interplay of metabolism, metabolic flexibility and inflammation.
Tareen, SHK, Kutmon, M, de Kok, TM, Mariman, ECM, van Baak, MA, Evelo, CT, Adriaens, ME, Arts, ICW
Scientific reports. 2020;10(1):1651
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Obesity is a public health concern as it has been linked to cardiovascular diseases, type 2 diabetes and metabolic syndrome. The aim of this study was to identify and analyse expression profiles of individuals clustered by cellular metabolism centring on metabolic flexibility. This study clustered gene expression samples from a weight loss study (Yoyo study’ - Clinical Trial ID: NCT01559415) into two clusters, based on 291 genes associated with cellular metabolic fexibility. The study covers two diets: a low-calorie diet (LCD) and a very low-calorie diet (VLCD). All the participants of the study were Caucasian with a BMI between 28kg/m2 and 35 kg/m2, aged between 32 and 67 years old. Findings showed that the majority of the individuals had their metabolism associated genes downregulated after weight loss and weight maintenance, but also had an upregulation of immune system associated genes. Furthermore, individuals who had changed their metabolic profiles in response to caloric restriction had a significant retention of lost weight compared to individuals which had not changed their cluster membership. Authors conclude that their findings indicate possible cross-talk between cellular metabolism and inflammation.
Abstract
Obesity is a global epidemic, contributing significantly to chronic non-communicable diseases, such as type 2 diabetes mellitus, cardiovascular diseases and metabolic syndrome. Metabolic flexibility, the ability of organisms to switch between metabolic substrates, is found to be impaired in obesity, possibly contributing to the development of chronic illnesses. Several studies have shown the improvement of metabolic flexibility after weight loss. In this study, we have mapped the cellular metabolism of the adipose tissue from a weight loss study to stratify the cellular metabolic processes and metabolic flexibility during weight loss. We have found that for a majority of the individuals, cellular metabolism was downregulated during weight loss, with gene expression of all major cellular metabolic processes (such as glycolysis, fatty acid β-oxidation etc.) being lowered during weight loss and weight maintenance. Parallel to this, the gene expression of immune system related processes involving interferons and interleukins increased. Previously, studies have indicated both negative and positive effects of post-weight loss inflammation in the adipose tissue with regards to weight loss or obesity and its co-morbidities; however, mechanistic links need to be constructed in order to determine the effects further. Our study contributes towards this goal by mapping the changes in gene expression across the weight loss study and indicates possible cross-talk between cellular metabolism and inflammation.
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Effects of Synbiotic Supplement on Human Gut Microbiota, Body Composition and Weight Loss in Obesity.
Sergeev, IN, Aljutaily, T, Walton, G, Huarte, E
Nutrients. 2020;12(1)
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The gut microbiota plays a role in the development of obesity and associated diseases. Whilst energy-restricted, low-carbohydrate, high-protein diets can facilitate substantial weight-loss, they also have been linked to ill-effects and unfavourable changes in the gut microbiota from excess protein fermentation. Pro-and prebiotics (synbiotics) have become a promising intervention in the management of obesity. This small placebo-controlled clinical trial involved 20 obese adults following an energy-restricted (approx.950 kcal/day) low-carbohydrate, high-protein diet. The study examined whether a supplementary synbiotic contributed to additional changes in body composition and metabolic biomarkers. The synbiotic contained Lactobacilli spp. and Bifidobacteria spp. and a prebiotic mixture of galactooligosaccharides. Overall, at the end of the 3-month trial, there was no remarkable difference between the groups. Both experienced a significant and decreasing trend in body mass, waist circumference, body mass index, fat mass, fat percentage, and glucose level, affirming the known benefits of the described weight-loss diet. However, the synbiotic supplementation group had a greater decrease in HbA1C and significant alterations in gut microbiota, showing an increased abundance of gut bacteria associated with positive health effects. Due to the complexity of microbial species and host interactions, the authors advocate for more research to identify their significance and shed light on contradictory findings. This study identified that synbiotics may not contribute to additional changes in body composition when combined with an energy-restricted, low-carbohydrate, high-protein diet but they can offer additional health benefits by inducing favourable changes to the gut microbiota.
Abstract
Targeting gut microbiota with synbiotics (probiotic supplements containing prebiotic components) is emerging as a promising intervention in the comprehensive nutritional approach to reducing obesity. Weight loss resulting from low-carbohydrate high-protein diets can be significant but has also been linked to potentially negative health effects due to increased bacterial fermentation of undigested protein within the colon and subsequent changes in gut microbiota composition. Correcting obesity-induced disruption of gut microbiota with synbiotics can be more effective than supplementation with probiotics alone because prebiotic components of synbiotics support the growth and survival of positive bacteria therein. The purpose of this placebo-controlled intervention clinical trial was to evaluate the effects of a synbiotic supplement on the composition, richness and diversity of gut microbiota and associations of microbial species with body composition parameters and biomarkers of obesity in human subjects participating in a weight loss program. The probiotic component of the synbiotic used in the study contained Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium longum, and Bifidobacterium bifidum and the prebiotic component was a galactooligosaccharide mixture. The results showed no statistically significant differences in body composition (body mass, BMI, body fat mass, body fat percentage, body lean mass, and bone mineral content) between the placebo and synbiotic groups at the end of the clinical trial (3-month intervention, 20 human subjects participating in weight loss intervention based on a low-carbohydrate, high-protein, reduced energy diet). Synbiotic supplementation increased the abundance of gut bacteria associated with positive health effects, especially Bifidobacterium and Lactobacillus, and it also appeared to increase the gut microbiota richness. A decreasing trend in the gut microbiota diversity in the placebo and synbiotic groups was observed at the end of trial, which may imply the effect of the high-protein low-carbohydrate diet used in the weight loss program. Regression analysis performed to correlate abundance of species following supplementation with body composition parameters and biomarkers of obesity found an association between a decrease over time in blood glucose and an increase in Lactobacillus abundance, particularly in the synbiotic group. However, the decrease over time in body mass, BMI, waist circumstance, and body fat mass was associated with a decrease in Bifidobacterium abundance. The results obtained support the conclusion that synbiotic supplement used in this clinical trial modulates human gut microbiota by increasing abundance of potentially beneficial microbial species.