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A plant-based diet in overweight individuals in a 16-week randomized clinical trial: metabolic benefits of plant protein.
Kahleova, H, Fleeman, R, Hlozkova, A, Holubkov, R, Barnard, ND
Nutrition & diabetes. 2018;8(1):58
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Suboptimal nutrition is a major cause of obesity, chronic disease, and premature death across the nation and worldwide. The aim of this study was to explore the effects of plant protein, as part of a plant-based diet, on weight control, body composition, and insulin resistance in overweight individuals. This study is a secondary analysis of data from a 16-week randomized clinical trial. Participants were randomly assigned in a 1:1 ratio to a vegan or a control group. Results indicate that: - the quality and quantity of dietary protein from a plant-based vegan diet are associated with improvements in body composition, body weight, and insulin resistance in overweight individuals. - decreased intake of animal protein and an increased intake of plant protein were associated with a decrease in fat mass. - decreased histidine [amino acid] intake was associated with a decrease in insulin resistance. - decreased intake of the amino acids threonine, leucine, lysine, methionine, and tyrosine were each associated with a decrease in insulin resistance (mainly driven by weight loss). Authors conclude that there is the need for additional research to explore the mechanisms explaining the beneficial role of plant protein and specific amino acids in regulating body weight, body composition, and insulin resistance.
Abstract
BACKGROUND AND OBJECTIVES A plant-based diet is an effective strategy in the treatment of obesity. In this 16-week randomized clinical trial, we tested the effect of a plant-based diet on body composition and insulin resistance. As a part of this trial, we investigated the role of plant protein on these outcomes. SUBJECTS AND METHODS Overweight participants (n = 75) were randomized to follow a plant-based (n = 38) or a control diet (n = 37). Dual X-ray Absorptiometry assessed body composition, Homeostasis Model Assessment (HOMA-IR) assessed insulin resistance, and a linear regression model was used to test the relationship between protein intake, body composition, and insulin resistance. RESULTS The plant-based vegan diet proved to be superior to the control diet in improving body weight, fat mass, and insulin resistance markers. Only the vegan group showed significant reductions in body weight (treatment effect -6.5 [95% CI -8.9 to -4.1] kg; Gxt, p < 0.001), fat mass (treatment effect -4.3 [95% CI -5.4 to -3.2] kg; Gxt, p < 0.001), and HOMA-IR (treatment effect -1.0 [95% CI -1.2 to -0.8]; Gxt, p = 0.004). The decrease in fat mass was associated with an increased intake of plant protein and decreased intake of animal protein (r = -0.30, p = 0.011; and r = +0.39, p = 0.001, respectively). In particular, decreased % leucine intake was associated with a decrease in fat mass (r = +0.40; p < 0.001), in both unadjusted and adjusted models for changes in BMI and energy intake. In addition, decreased % histidine intake was associated with a decrease in insulin resistance (r = +0.38; p = 0.003), also independent of changes in BMI and energy intake. CONCLUSIONS These findings provide evidence that plant protein, as a part of a plant-based diet, and the resulting limitation of leucine and histidine intake are associated with improvements in body composition and reductions in both body weight and insulin resistance.
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A 12-Month Lifestyle Intervention Program Improves Body Composition and Reduces the Prevalence of Prediabetes in Obese Patients.
König, D, Hörmann, J, Predel, HG, Berg, A
Obesity facts. 2018;11(5):393-399
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Obesity and its impact on the prevalence of diabetes and subsequent cardiovascular disease is one of the major health burdens in Western societies. Lifestyle intervention studies have shown that weight loss combined with increased physical activity can improve metabolic risk factors. The aim of this study was to evaluate the effect of a comprehensive lifestyle intervention programme on weight and metabolic risk factors in 5884 obese individuals. The programme included 61 sessions over 12 months, including 41 exercise sessions, 12 psychological/self-management sessions and 8 nutritional counselling sessions (based on a low glycaemic index, low fat diet). After 12 months there was a significant reduction in weight (average 6%), waist circumference, physical fitness and all metabolic parameters (including blood sugar and fat metabolism). Overall, in 839 (38%) of the 2,227 participants who were pre-diabetic before intervention, the criteria of pre-diabetes were no longer detectable after 12 months, whilst only 66 (3%) progressed to type 2 diabetes mellitus. 46.7% of the 1,641 participants fulfilling the criteria of metabolic syndrome before the intervention, did not show any signs of this syndrome after the intervention; whilst only 120 participants (+7.3%) newly developed metabolic syndrome. The authors concluded that the intensive lifestyle intervention programme was successful, even in obese people with pre-diabetes.
Abstract
BACKGROUND The present study investigated the effects of a 12-month interdisciplinary standardized lifestyle program addressing physical activity and changes in dietary and lifestyle behavior in 2,227 obese prediabetic participants. METHODS Measures of obesity (BMI, waist circumference), cardiopulmonary fitness, and metabolic parameters were determined before and after the intervention period. RESULTS From the 2,227 participants who were initially prediabetic, 839 participants (-37.7%) did no longer show the criteria of prediabetes after the intervention and had normal HbA1c levels. CONCLUSION The clinical effects are substantial, and it is likely that the applied intense and multidisciplinary lifestyle interventions could reduce the risk of developing diabetes and the prevalence of a full-blown metabolic syndrome in obese and prediabetic patients.
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Regaining body weight after weight reduction further increases pulse wave velocity in obese men with metabolic syndrome.
Liang, KW, Lee, WJ, Lee, IT, Lin, SY, Wang, JS, Lee, WL, Sheu, WH
Medicine. 2018;97(40):e12730
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Atherosclerosis can increase stiffness of the aorta and, therefore, increased pulse wave velocity (PWV), which is a predictor for cardiovascular disease and mortality. Metabolic syndrome (MetS), diabetes and obesity increase the risk of aortic stiffness and higher PWV. Weight loss may reduce arterial stiffness but mechanisms are not known. The aim this study was to investigate changes over time of PWV, ankle-brachial index (ABI, a marker for arterial disease of the leg), insulin resistance and inflammatory markers after weight loss and regained weight in obese non-diabetic men with MetS compared to lean controls. Obese participants followed a three months weight loss programme based on diet and exercise during which they lost an average of 8.6kg and saw statistically significant improvements in blood pressure and many biochemical markers but not in PWV or ABI. At the second follow-up visit, at 60 months, they had regained their weight, blood pressure and most biochemical markers were back to baseline whilst PWV and adiponectin were worse than before weight loss. Increases in blood pressure but not weight, hs-CRP (an inflammatory marker) or insulin resistance correlated with the increase in PWV after weight regain. Although healthy controls also gained weight over the 60 months study duration, their increase in PWV was significantly lower than in obese participants. Their PWV was also lower at baseline.
Abstract
Subjects with metabolic syndrome (MetS) or obesity have worse arterial stiffness. However, there have been no studies addressing time-sequential changes in pulse wave velocity (PWV) after weight loss and then regaining weight in obese non-diabetic men with MetS.We prospectively enrolled 40 obese, non-diabetic men with MetS undergoing a 3-month weight reduction program. Another 26 lean and healthy men were recruited for comparisons. Oral glucose tolerance test and brachial ankle (ba) PWV were assessed in study subjects. Eighteen obese non-diabetic MetS and 15 lean control subjects had follow-ups at the 60th month.The body weight of obese MetS decreased from 94.8 ± 7.6 to 86.1 ± 9.0 (N = 18, P < .001) after a 3-month weight reduction program but regained gradually thereafter to 93.6 ± 11.6 kg at the 60th month (P < .001 versus 3rd month). baPWV decreased after weight loss slightly (P = .240) while weight regain significantly increased the baPWV (from 3rd month, 1358 ± 168 to 60th month 1539 ± 264 cm/sec, P < .001). Systolic and diastolic blood pressure increments correlated with the increment of baPWV after weight regain. At the 60th month, lean controls (N = 15) had increases in body weight while their baPWV increased non-significantly. The increments of baPWV after weight regain in obese MetS were significantly higher than the increment of baPWV in lean controls after weight gain.In conclusion, regaining body weight after weight reduction worsened arterial stiffness with significant increase of baPWV in obese non-diabetic MetS.
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Evaluation of a 12-week lifestyle education intervention with or without partial meal replacement in Thai adults with obesity and metabolic syndrome: a randomised trial.
Chaiyasoot, K, Sarasak, R, Pheungruang, B, Dawilai, S, Pramyothin, P, Boonyasiri, A, Supapueng, O, Jassil, FC, Yamwong, P, Batterham, RL
Nutrition & diabetes. 2018;8(1):23
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Obesity and metabolic syndrome (MetS) have markedly increased in many low- and middle-income countries, such as Thailand, as a consequence of economic growth, increased urbanisation and adoption of a ‘western’ lifestyle. Weight-loss interventions by reducing energy intake and increasing physical activity through behavioural modification are the mainstay of the treatment of obesity and MetS, but poor compliance is a problem. The aim of this randomised study was to evaluate the effect of a low-cost lifestyle education intervention (LEI) alone or a LEI with meal replacements (LEI + MR) in Thai adults with obesity and MetS for 12 weeks. The lifestyle education was delivered by a dietitian and comprised a group session at baseline with advice on diet and physical activity, followed by four individual sessions at weeks 2, 4, 8 and 12. In addition, the LEI + MR group also received two meal replacement formula meals per day. The LEI+MR group lost more weight than the LEI group, 2.86% versus 1.53%. Weight loss was maintained at 26 weeks after the end of the intervention, but had gone back to baseline after another 26 weeks. Overall, the LEI+MR group had better outcomes in blood sugar control and metabolic syndrome scores. The authors conclude that both LEI and LEI + MR are acceptable for Thai patients with obesity and MetS and lead to modest weight loss and improvement in MetS and blood sugar control, with the LEI + MR group showing greater benefits at 12 weeks
Abstract
BACKGROUND/OBJECTIVES There have been no studies examining the efficacy of meal replacement (MR) on weight loss and metabolic syndrome (MS) improvement in Southeast Asians. Thus, we undertook a 12-week randomised trial to evaluate the effect of a lifestyle education intervention alone (LEI) or with partial MR (LEI + MR) in obese Thai adults with MS. SUBJECTS/METHODS A total of 110 patients were randomised to receive either LEI or LEI + MR. Both groups received LEI to achieve weight loss. LEI + MR group additionally received two MR daily to replace either breakfast, lunch or dinner. Mean ± SE body mass index of all participants was 34.6 ± 0.6 kg/m2, mean ± SE age was 42.5 ± 1.1 years and 83% of patients were female. Both groups were compared for anthropometric and cardiometabolic indices at 12-week. Body weight was also compared at weeks 38 and 64. RESULTS At 12 weeks, both groups exhibited statistically significant percentage weight loss (%WL) compared to initial weight but greater %WL was observed in LEI + MR compared to LEI, 2.9% vs. 1.5%, respectively (p < 0.05). MS criteria such as waist circumference and blood pressure improved significantly in both groups compared to baseline. However, improvement in fasting plasma glucose (FPG) was only significant in LEI + MR, and more participants with impaired FPG at baseline in LEI + MR (42.9%) than LEI (19%) returned to normal FPG at 12 weeks (p < 0.05). HbA1c, fasting insulin and HOMA-IR in LEI + MR were significantly lower than with LEI. At the end of the 12-week intervention period, 16% of participants no longer fulfilled MS criteria. A statistically significant weight loss from baseline persisted until 38 weeks but no longer reached statistically significant difference between groups CONCLUSIONS LEI and LEI + MR were acceptable and led to improvement in weight and MS. LEI + MR group exhibited additional weight reduction and glycemic benefits at 12 weeks.
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Predictors of completing a primary health care diabetes prevention intervention programme in people at high risk of type 2 diabetes: Experiences of the DE-PLAN project.
Gilis-Januszewska, A, Lindström, J, Barengo, NC, Tuomilehto, J, Schwarz, PE, Wójtowicz, E, Piwońska-Solska, B, Szybiński, Z, Windak, A, Hubalewska-Dydejczyk, A
Medicine. 2018;97(5):e9790
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As the prevalence of type 2 diabetes (T2D) begins to grow, the spotlight is on successful, cost-effective lifestyle interventions to help prevent it. Real-life implementation studies in various settings and with various people have shown than lower cost, less intensive interventions can help prevent T2D. The DE-PLAN (Diabetes in Europe: Prevention Using Lifestyle, Physical Activity and Nutritional Intervention) was implemented across 17 European countries, where it aimed to assess its application but also to create a network of trained professionals to deliver T2D prevention. This study aimed to explore the factors associated with completing the programme in primary healthcare in Poland. The study included nine GP practices in Krakow with 262 people at high risk of T2D (according to the Finnish Diabetes Risk Score). The prevention programme included 11 lifestyle counselling sessions, physical activity sessions and motivational phone calls/letters. Measurements including fasting glucose, body mass index and blood pressure were taken at baseline and 1 year after the programme. People who completed the whole programme were less likely to be employed, less likely to have high blood pressure and ate more fruits and vegetables each day. The authors concluded that people who healthier behaviours were more likely to complete the programme, whereas men and people who work were less likely to complete the programme. More strategies are needed to increase completion with these individuals.
Abstract
It has been shown that real-life implementation studies for the prevention of type 2 diabetes (DM2) performed in different settings and populations can be effective. However, not enough information is available on factors influencing the reach of DM2 prevention programmes. This study examines the predictors of completing an intervention programme targeted at people at high risk of DM2 in Krakow, Poland as part of the DE-PLAN project.A total of 262 middle-aged people, everyday patients of 9 general practitioners' (GP) practices, at high risk of DM2 (Finnish Diabetes Risk Score (FINDRISK) >14) agreed to participate in the lifestyle intervention to prevent DM2. Intervention consisted of 11 lifestyle counseling sessions, organized physical activity sessions followed by motivational phone calls and letters. Measurements were performed at baseline and 1 year after the initiation of the intervention.Seventy percent of the study participants enrolled completed the core curriculum (n = 184), 22% were men. When compared to noncompleters, completers had a healthier baseline diabetes risk profile (P <.05). People who completed the intervention were less frequently employed versus noncompleters (P = .037), less often had hypertension (P = .043), and more frequently consumed vegetables and fruit daily (P = .055).In multiple logistic regression model, employment reduced the likelihood of completing the intervention 2 times (odds ratio [OR] 0.45, 95% confidence interval [CI] 0.25-0.81). Higher glucose 2 hours after glucose load and hypertension were the independent factors decreasing the chance to participate in the intervention (OR 0.79, 95% 0.69-0.92 and OR 0.52, 95% CI 0.27-0.99, respectively). Daily consumption of vegetables and fruits increased the likelihood of completing the intervention (OR 1.86, 95% 1.01-3.41).In conclusion, people with healthier behavior and risk profile are more predisposed to complete diabetes prevention interventions. Male, those who work and those with a worse health profile, are less likely to participate and complete interventions. Targeted strategies are needed in real-life diabetes prevention interventions to improve male participation and to reach those who are working as well as people with a higher risk profile.
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Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis.
Grgic, J, Trexler, ET, Lazinica, B, Pedisic, Z
Journal of the International Society of Sports Nutrition. 2018;15:11
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The possible physical performance enhancing (or 'ergogenic) effects of caffeine have been extensively studied since the early 1900s. Recent focus has shifted to its impact on anaerobic physical performance outcomes such as muscular strength, endurance and jumping tasks that require power. Although it has been found to enhance muscle endurance, less is known about its impact on strength and power. This is the first meta-analysis on caffeine and muscle power, and includes 20 studies - ten on muscle strength outcomes and ten on muscle power. The analysis found that caffeine significantly improves muscle strength (SMD = 0.20; 95% confidence interval [CI]: 0.03, 0.36; p = 0.023) but only for upper and not lower body strength. These results were found for men but more robust studies are needed to examine the impact for women (although the limited research suggests there may be a positive impact). This is in contrast to a previous meta-analysis that found no impact of caffeine on muscle strength (Polito, Souza, Casonatto & Farinatti, 2016). It was also found to significantly improve muscle power (SMD = 0.17; 95% CI: 0.00, 0.34; p = 0.047). Although the pooled effect of caffeine on performance outcomes was small to medium, even small improvements can make a big difference competitively. Future research is needed to identify the best dosage and form of caffeine to maximise its performance enhancing effects. Additionally, more robust research is needed to reduce bias, and studies including women. It is important to recognise that individual physical performance changes as a result of caffeine are variable, so these findings must be applied on a case-by-case basis. * Polito MD, Souza DB, Casonatto J, Farinatti P. Acute effect of caffeine consumption on isotonic muscular strength and endurance: a systematic review and meta-analysis. Sci Sports. 2016;31:119–28.
Abstract
BACKGROUND Caffeine is commonly used as an ergogenic aid. Literature about the effects of caffeine ingestion on muscle strength and power is equivocal. The aim of this systematic review and meta-analysis was to summarize results from individual studies on the effects of caffeine intake on muscle strength and power. METHODS A search through eight databases was performed to find studies on the effects of caffeine on: (i) maximal muscle strength measured using 1 repetition maximum tests; and (ii) muscle power assessed by tests of vertical jump. Meta-analyses of standardized mean differences (SMD) between placebo and caffeine trials from individual studies were conducted using the random effects model. RESULTS Ten studies on the strength outcome and ten studies on the power outcome met the inclusion criteria for the meta-analyses. Caffeine ingestion improved both strength (SMD = 0.20; 95% confidence interval [CI]: 0.03, 0.36; p = 0.023) and power (SMD = 0.17; 95% CI: 0.00, 0.34; p = 0.047). A subgroup analysis indicated that caffeine significantly improves upper (SMD = 0.21; 95% CI: 0.02, 0.39; p = 0.026) but not lower body strength (SMD = 0.15; 95% CI: -0.05, 0.34; p = 0.147). CONCLUSION The meta-analyses showed significant ergogenic effects of caffeine ingestion on maximal muscle strength of upper body and muscle power. Future studies should more rigorously control the effectiveness of blinding. Due to the paucity of evidence, additional findings are needed in the female population and using different forms of caffeine, such as gum and gel.
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Effect of weight loss on circulating fatty acid profiles in overweight subjects with high visceral fat area: a 12-week randomized controlled trial.
Lee, YJ, Lee, A, Yoo, HJ, Kim, M, Kim, M, Jee, SH, Shin, DY, Lee, JH
Nutrition journal. 2018;17(1):28
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Compared with abdominal subcutaneous fat, the amount of visceral fat a person stores, the more at risk they are for certain health complications. Numerous studies have shown a correlation between visceral fat amount and alteration in serum fatty acids. Henceforth the objective of this study was to investigate the effect of weight loss by calorie restricting on nondiabetic overweight individuals with high visceral fat. A 12-week, placebo-controlled, randomised study was conducted with 80 high visceral fatty acid, nondiabetic overweight subjects in Korea. A significant reduction in total saturated fatty acids was observed in subjects who lost weight and henceforth, the authors concluded that mild calorie restriction has potential health benefits.
Abstract
BACKGROUND Significant associations between visceral fat and alterations in plasma fatty acids have been identified in overweight individuals. However, there are scant data regarding the relationships of the visceral fat area (VFA) with the plasma fatty acid profiles and desaturase activities following weight loss. We investigated the effect of weight loss with mild calorie restriction on the circulating fatty acid profiles and desaturase activities in nondiabetic overweight subjects with high VFA. METHODS Eighty overweight subjects with high VFA (L4 VFA ≥100 cm2) were randomized into the 12-week mild-calorie-restriction (300 kcal/day) or control groups. RESULTS Comparison of the percent of body weight changes between groups revealed that the weight-loss group had greater reductions in body weight. The VFA decreased by 17.7 cm2 from baseline in the weight-loss group (P < 0.001). At follow-up, the weight-loss group showed greater reductions in serum triglycerides, insulin, and HOMA-IR than the control group. Significantly greater reductions in total saturated fatty acids, palmitic acid, stearic acid, total monounsaturated fatty acids, palmitoleic acid, oleic acid, eicosadienoic acid, and dihomo-γ-linolenic acid levels were detected in the weight-loss group compared with the control group after adjusting for baseline values. Following weight loss, C16 Δ9-desaturase activity was significantly decreased and Δ5-desaturase activity was significantly increased, and the changes were greater in the weight-loss group than in the control group. CONCLUSIONS The results suggest that mild weight loss improves abdominal obesity, overall fatty acid profiles, and desaturase activities; therefore, mild calorie restriction has potential health benefits related to obesity-related diseases in overweight subjects with high VFA. TRIAL REGISTRATION NCT02992639. Retrospectively registered 11 December 2016.
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Association between muscle strength and type 2 diabetes mellitus in adults in Korea: Data from the Korea national health and nutrition examination survey (KNHANES) VI.
Lee, MR, Jung, SM, Bang, H, Kim, HS, Kim, YB
Medicine. 2018;97(23):e10984
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The incidence of type 2 diabetes is increasing worldwide. This study aimed to identify the association between muscle strength and type 2 diabetes in Korean adults. The researchers measured handgrip strength along with markers of glucose sensitivity, insulin sensitivity and inflammation in each of the participants. People with type 2 diabetes and those with insulin resistance had a significantly lower handgrip strength than those without type 2 diabetes or insulin resistance. The authors concluded that further studies should be carried out to determine whether improving muscle strength might help to prevent type 2 diabetes.
Abstract
Diabetes mellitus (DM) is a significant chronic disease, and health burden from DM is increasing. Recently, studies on the relationship between handgrip strength, which is a measuring tool for muscle strength, and type 2 DM were published. However, the results have been conflicting. In addition, few studies that used data from adults in Korea have been conducted. Thus, this study aimed to identify the association between handgrip strength as well as type 2 DM and insulin resistance in adults using data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2014 to 2015. Inflammation is a condition affecting the muscle strength of individuals with type 2 DM; therefore, its mediating effects were also examined.We included 8208 participants aged between 19 and 80 years who had undergone a handgrip test and had received information about type 2 DM. General linear and binary logistic regression models were used to examine the association between handgrip strength and type 2 DM variables. In addition, mediation analysis was conducted to estimate the role of inflammation in the relationship between handgrip strength and type 2 DM.After adjusting for age, sex, education, alcohol consumption, lifetime smoking, obesity, and aerobic physical activity, handgrip strength was inversely associated with fasting glucose, HbA1c, and fasting insulin levels as well as the homeostasis model assessment of insulin resistance (HOMA-IR) score. Multivariable logistic regression analyses showed that handgrip strength was significantly inversely associated with type 2 DM and insulin resistance. The high-sensitivity C-reactive protein (hs-CRP), an inflammation-related biomarker, mediated approximately 10% of the association between handgrip strength and type 2 DM.Using large, well-defined, nationally representative cross-sectional data on adults in Korea, we found that handgrip strength, which is an indicator of muscle strength, was associated with type 2 DM.
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The effect of a short-term low-carbohydrate, high-fat diet with or without postmeal walks on glycemic control and inflammation in type 2 diabetes: a randomized trial.
Myette-Côté, É, Durrer, C, Neudorf, H, Bammert, TD, Botezelli, JD, Johnson, JD, DeSouza, CA, Little, JP
American journal of physiology. Regulatory, integrative and comparative physiology. 2018;315(6):R1210-R1219
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Inflammation is associated with the pathogenesis of insulin resistance, type 2 diabetes (T2D), and related complications. Lifestyle therapy is a frontline treatment for improving glucose control in people with T2D. The main aim of this study was to determine whether reducing hyperglycaemia with a low-carbohydrate high-fat (LC) diet could lower markers of innate immune cell activation and systemic inflammation in people with T2D. A secondary aim was to examine if the combination of an LCHF diet with strategically timed postmeal walking was superior to an LCHF diet alone. The study is a randomised cross over study which enrolled Individuals with physician-diagnosed T2D to complete three short-term controlled-intervention periods. Sixteen participants were enrolled (men = 8 and women = 8) who were aged between 48 and 72 years. Results indicate that while LC and LC together with exercise (LC+Ex) led to superior improvements in glucose control and fasting proinsulin (the pro-hormone precursor to insulin) levels as compared with low-fat low glycaemic index diet (GL), all three diets (GL, LC and LC+Ex), appeared to lower a particular marker of cellular inflammation over the short-term. Authors conclude that an LCHF diet with or without daily postmeal walks improved four-day glycaemic control and fasting proinsulin levels compared with a GL diet.
Abstract
Lowering carbohydrate consumption effectively lowers glucose, but impacts on inflammation are unclear. The objectives of this study were to: 1) determine whether reducing hyperglycemia by following a low-carbohydrate, high-fat (LC) diet could lower markers of innate immune cell activation in type 2 diabetes (T2D) and 2) examine if the combination of an LC diet with strategically timed postmeal walking was superior to an LC diet alone. Participants with T2D ( n = 11) completed a randomized crossover study involving three 4-day diet interventions: 1) low-fat low-glycemic index (GL), 2) and 3) LC with 15-min postmeal walks (LC+Ex). Four-day mean glucose was significantly lower in the LC+Ex group as compared with LC (-5%, P < 0.05), whereas both LC+Ex (-16%, P < 0.001) and LC (-12%, P < 0.001) conditions were lower than GL. A significant main effect of time was observed for peripheral blood mononuclear cells phosphorylated c-Jun N-terminal kinase ( P < 0.001), with decreases in all three conditions (GL: -32%, LC: -45%, and LC+Ex: -44%). A significant condition by time interaction was observed for monocyte microparticles ( P = 0.040) with a significant decrease in GL (-76%, P = 0.035) and a tendency for a reduction in LC (-70%, P = 0.064), whereas there was no significant change in LC+Ex (0.5%, P = 0.990). Both LC (-27%, P = 0.001) and LC+Ex (-35%, P = 0.005) also led to significant reductions in circulating proinsulin. An LC diet improved 4-day glycemic control and fasting proinsulin levels when compared with GL, with added glucose-lowering benefits when LC was combined with postmeal walking.
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Combining Short-Term Interval Training with Caloric Restriction Improves ß-Cell Function in Obese Adults.
Francois, ME, Gilbertson, NM, Eichner, NZM, Heiston, EM, Fabris, C, Breton, M, Mehaffey, JH, Hassinger, T, Hallowell, PT, Malin, SK
Nutrients. 2018;10(6)
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The development of type 2 diabetes is characterised by insulin resistance and dysfunction of the pancreas. Over time, loss of function of the ß-cells of the pancreas leads to impaired tolerance of blood sugar and type 2 diabetes. Low-calorie diets have been shown to improve blood sugar regulation, but it is unclear what impact interval exercise has in addition to a low-calorie diet. This study tested the hypothesis that combining interval exercise with a low-calorie diet would enhance pancreatic function compared to a low calorie diet alone in adults with obesity. Twenty-six obese adults were assigned to 2 weeks of a LCD (1200 kcal/day), using meal replacement shakes for breakfast and lunch. Half the group also underwent 60 minutes of interval training a day; after each session they received a 350 kcal shake to compensate for the calories burned during training. A series of blood tests was carried out to measure glucose tolerance and insulin secretion rates. Combining a low calorie diet with interval training reduced glucose and insulin secretion rates, whereas the low calorie diet alone did not. Both interventions improved insulin sensitivity. The authors concluded that the data supports combining low calorie diets with interval training to preserve pancreatic function and prevent type 2 diabetes.
Abstract
Although low-calorie diets (LCD) improve glucose regulation, it is unclear if interval exercise (INT) is additive. We examined the impact of an LCD versus LCD + INT training on ß-cell function in relation to glucose tolerance in obese adults. Twenty-six adults (Age: 46 ± 12 year; BMI 38 ± 6 kg/m²) were randomized to 2-week of LCD (~1200 kcal/day) or energy-matched LCD + INT (60 min/day alternating 3 min at 90 and 50% HRpeak). A 2 h 75 g oral glucose tolerance test (OGTT) was performed. Insulin secretion rates (ISR) were determined by deconvolution modeling to assess glucose-stimulated insulin secretion ([GSIS: ISR/glucose total area under the curve (tAUC)]) and ß-cell function (Disposition Index [DI: GSIS/IR]) relative to skeletal muscle (Matsuda Index), hepatic (HOMA-IR) and adipose (Adipose-IRfasting) insulin resistance (IR). LCD + INT, but not LCD alone, reduced glucose and total-phase ISR tAUC (Interactions: p = 0.04 and p = 0.05, respectively). Both interventions improved skeletal muscle IR by 16% (p = 0.04) and skeletal muscle and hepatic DI (Time: p < 0.05). Improved skeletal muscle DI was associated with lower glucose tAUC (r = -0.57, p < 0.01). Thus, LCD + INT improved glucose tolerance more than LCD in obese adults, and these findings relate to ß-cell function. These data support LCD + INT for preserving pancreatic function for type 2 diabetes prevention.