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Effects of probiotic administration on overweight or obese children: a meta-analysis and systematic review.
Li, Y, Liu, T, Qin, L, Wu, L
Journal of translational medicine. 2023;21(1):525
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The prevalence of overweight or obesity in children is increasing due to changes in dietary structure and exercise habits, as determined by the body mass index (BMI) calculated from height and weight. Childhood obesity can cause some clinical complications such as hypertension, nonalcoholic fatty liver disease (NAFLD), and cardiovascular disease. The aim of this study was to examine the effects of probiotics on eight factors in children with overweight or obesity. This study was a systematic review and meta-analysis of four studies with a total of 206 overweight or obesity children. Among them, 105 were in the probiotic group, and 101 were in the placebo group. Results showed that probiotics can improve high- and low-density lipoprotein cholesterol, adiponectin, leptin, and TNF-α in overweight or obese children. The systematic review showed that probiotics work mainly by reshaping disturbed intestinal microbiota, regulating lipid metabolism, reducing inflammation and immune response, playing a positive effect of short-chain fatty acids produced, alleviating oxidative stress and endoplasmic reticulum stress, and inhibiting the growth and reproduction of pathogens in the gut. Authors concluded that probiotics could regulate lipid metabolism and immune response to some degree in children with overweight or obesity.
Abstract
BACKGROUND This paper aimed to examine the effects of probiotics on eight factors in overweight or obese children by meta-analysis, namely, body mass index (BMI), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), adiponectin, leptin and tumor necrosis factor-α (TNF-α) and summarize the mechanisms of action of probiotics based on the existing researches. METHODS Six databases (PubMed, Web of Science, Embase, Cochrane Library, SinoMed and CNKI) were searched until March 2023. Review Manager 5.4 was used for meta-analysis. The data were analysed using weighted mean differences (WMDs) or standardized mean differences (SMDs) under a fixed effect model or random effect model to observe the effects of probiotic administration on the included indicators. RESULTS Four publications with a total of 206 overweight or obesity children were included. According to the meta-analysis, probiotics were able to significantly decrease the levels of HDL-C (MD, 0.06; 95% CI 0.03, 0.09; P = 0.0001), LDL-C (MD, - 0.06; 95% CI - 0.12, - 0.00; P = 0.04), adiponectin (MD, 1.39; 95% CI 1.19, 1.59; P < 0.00001), leptin (MD, - 2.72; 95% CI - 2.9, - 2.54; P < 0.00001) and TNF-α (MD, - 4.91; 95% CI - 7.15, - 2.67; P < 0.0001) compared to those in the placebo group. Still, for BMI, the palcebo group seemed to be better than the probiotic group (MD, 0.85; 95% CI 0.04, 1.66; P = 0.04). TC (MD, - 0.05; 95% CI - 0.12, 0.02; P = 0.14) and TG (MD, - 0.16; 95% CI - 0.36, 0.05; P = 0.14) were not different between two groups. CONCLUSIONS This review drew that probiotics might act as a role in regulating HDL-C, LDL-C, adiponectin, leptin and TNF-α in overweight or obesity children. Additionally, our systematic review yielded that probiotics might regulate lipid metabolism and improve obese associated symptoms by some paths. This meta-analysis has been registered at PROSPERO with ID: CRD42023408359.
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The effects of time-restricted eating and weight loss on bone metabolism and health: a 6-month randomized controlled trial.
Papageorgiou, M, Biver, E, Mareschal, J, Phillips, NE, Hemmer, A, Biolley, E, Schwab, N, Manoogian, ENC, Gonzalez Rodriguez, E, Aeberli, D, et al
Obesity (Silver Spring, Md.). 2023;31 Suppl 1:85-95
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Intermittent fasting (IF) involves an alternation of abstinence and consumption of food and caloric beverages over a cycle of hours to days. Time-restricted feeding (in animals) or eating (TRE in humans) is a form of IF that entails restricting eating within a window of 4 to 12 hours per 24-hour cycle and prolonging the time spent in the fasted state to realign eating-fasting patterns with circadian rhythms. The aim of this study was to explore the impact of a 6-month randomised controlled trial of TRE versus standard dietary advice (SDA, active control arm) on bone metabolism and health in a population with at least one component of the metabolic syndrome. This study is a secondary analysis of an open-label 6-month randomised controlled trial in which participants who ate within a time interval > 14 hours per 24-hour cycle (n=54) were randomised to TRE or SDA (active control) with a 1:1 allocation ratio. A total of 42 participants (76% women) with available bone turnover markers and/or bone mass measurements were included in this study. Results show that there weren’t any detrimental effects on bone health outcomes i.e. bone metabolism or bone loss after 6 months of TRE. Additionally, weight loss following a period of TRE might be associated with small bone-sparing effects compared with SDA. Authors conclude that future studies of longer duration (>6 months) assessing multiple bone phenotypes are required in order to confirm the study’s findings and explore the effects of various TRE regimens particularly among individuals at risk for bone fragility such as postmenopausal women and the elderly.
Abstract
OBJECTIVE This study explored the impact of time-restricted eating (TRE) versus standard dietary advice (SDA) on bone health. METHODS Adults with ≥1 component of metabolic syndrome were randomized to TRE (ad libitum eating within 12 hours) or SDA (food pyramid brochure). Bone turnover markers and bone mineral content/density by dual energy x-ray absorptiometry were assessed at baseline and 6-month follow-up. Statistical analyses were performed in the total population and by weight loss response. RESULTS In the total population (n = 42, 76% women, median age 47 years [IQR: 31-52]), there were no between-group differences (TRE vs. SDA) in any bone parameter. Among weight loss responders (≥0.6 kg weight loss), the bone resorption marker β-carboxyterminal telopeptide of type I collagen tended to decrease after TRE but increase after SDA (between-group differences p = 0.041), whereas changes in the bone formation marker procollagen type I N-propeptide did not differ between groups. Total body bone mineral content decreased after SDA (p = 0.028) but remained unchanged after TRE (p = 0.31) in weight loss responders (between-group differences p = 0.028). Among nonresponders (<0.6 kg weight loss), there were no between-group differences in bone outcomes. CONCLUSIONS TRE had no detrimental impact on bone health, whereas, when weight loss occurred, it was associated with some bone-sparing effects compared with SDA.
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Gut microbiota in nonalcoholic fatty liver disease: a PREDIMED-Plus trial sub analysis.
Gómez-Pérez, AM, Ruiz-Limón, P, Salas-Salvadó, J, Vioque, J, Corella, D, Fitó, M, Vidal, J, Atzeni, A, Torres-Collado, L, Álvarez-Sala, A, et al
Gut microbes. 2023;15(1):2223339
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Nonalcoholic fatty liver disease (NAFLD) is the main cause of chronic liver disease. The aim of this study was to evaluate the changes in the microbiota associated with changes in biochemical markers of NAFLD/NASH after an intervention. This substudy was conducted in the frame of the PREDIMED-Plus study, a 6-year, multicentre, randomised clinical trial for primary prevention of cardiovascular disease (CVD) conducted in men aged 55–75 years and women aged 60–75 years with overweight or obesity and metabolic syndrome. Results showed a relationship between liver disease biochemical indexes changes and gut microbiota changes within a context of a Mediterranean lifestyle. In fact, two noninvasive scores for liver steatosis and liver fibrosis, usually used in clinical practice, could differentiate gut microbiota populations. Authors conclude that their findings highlight the importance of lifestyle intervention in the modulation of gut microbiota and the management of metabolic syndrome and its hepatic manifestations.
Abstract
To evaluate the changes in the gut microbiota associated with changes in the biochemical markers of nonalcoholic fatty liver disease (NAFLD) after a lifestyle intervention with the Mediterranean diet. Participants (n = 297) from two centers of PREDIMED-Plus trial (Prevención con Dieta Mediterránea) were divided into three different groups based on the change tertile in the Hepatic Steatosis Index (HSI) or the Fibrosis-4 score (FIB-4) between baseline and one year of intervention. One-year changes in HSI were: tertile 1 (T1) (-24.9 to -7.51), T2 (-7.5 to -1.86), T3 (-1.85 to 13.64). The most significant differences in gut microbiota within the year of intervention were observed in the T1 and T3. According to the FIB-4, participants were categorized in non-suspected fibrosis (NSF) and with indeterminate or suspected fibrosis (SF). NSF participants showed higher abundances of Alcaligenaceae, Bacteroidaceae, Bifidobacteriaceae, Clostridiaceae, Enterobacteriaceae, Peptostreptococcaceae, Verrucomicrobiaceae compared to those with SF. Then, participants were divided depending on the FIB-4 tertile of change: T1 (-89.60 to -5.57), T2 (-5.56 to 11.4), and T3 (11.41 to 206.24). FIB-4 T1 showed a decrease in Akkermansia and an increase in Desulfovibrio. T2 had an increase in Victivallaceae, Clostridiaceae, and Desulfovibrio. T3 showed a decrease in Enterobacteriaceae, and an increase in Sutterella, Faecalibacterium, and Blautia. A relation between biochemical index changes of NAFLD/NASH (HSI and FIB-4) and gut microbiota changes were found. These observations highlight the importance of lifestyle intervention in the modulation of gut microbiota and the management of metabolic syndrome and its hepatic manifestations. What You Need to KnowWhat is the context:Obesity and metabolic syndrome have been associated with nonalcoholic fatty liver disease (NAFLD). Gut microbiota and its interaction with the environment may play a key role in NAFLD.What is new:Mediterranean diet and physical activity can modify the scores for liver steatosis (HSI) and liver fibrosis (FIB−4) in only one year. A relation between the changes in these scores and gut microbiota changes was found.What is the impact:The discovery of microbiota-based biomarkers for NAFLD and the development of strategies to modulate gut microbiota in the treatment of NAFLD.
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Time-restricted feeding's effect on overweight and obese patients with chronic kidney disease stages 3-4: A prospective non-randomized control pilot study.
Lao, BN, Luo, JH, Xu, XY, Fu, LZ, Tang, F, Ouyang, WW, Xu, XZ, Wei, MT, Xiao, BJ, Chen, LY, et al
Frontiers in endocrinology. 2023;14:1096093
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Obesity is a chronic metabolic disease caused by multiple factors. It is an independent risk factor for the development and progression of chronic kidney disease (CKD). The aim of this study was to explore the efficacy and safety of TRF in overweight and obese patients with moderate-to-severe stage CKD. This study was a prospective, non-randomised, controlled exploratory intervention study. Twenty-eight participants were included in the study, and were assigned to either the time-restricted feeding (TRF) group or the control diet (CD) group according to their preferences. Results showed that: - TRF helped improve renal function in overweight and obese moderate-to-severe CKD patients. - the TRF group experienced some hunger, but within tolerable range, and stated that TRF adherence was good. - the TRF group experienced a decrease in serum phosphate and uric acid, maintenance of total protein and albumin. - TRF shifted the gut microbiota in a positive direction. Authors concluded that TRF may be a safe and effective dietary intervention for overweight and obese CKD patients.
Abstract
BACKGROUND Time-restricted feeding (TRF) has become a popular weight loss method in recent years. It is widely used in the nutritional treatment of normal obese people and obese people with chronic diseases such as diabetes mellitus and hypertension, and has shown many benefits. However, most TRF studies have excluded chronic kidney disease (CKD) patients, resulting in a lack of sufficient evidence-based practice for the efficacy and safety of TRF therapy for CKD. Therefore, we explore the efficacy and safety of TRF in overweight and obese patients with moderate-to-severe stage CKD through this pilot study, and observe patient compliance to assess the feasibility of the therapy. METHODS This is a prospective, non-randomized controlled short-term clinical trial. We recruited overweight and obese patients with CKD stages 3-4 from an outpatient clinic and assigned them to either a TRF group or a control diet (CD) group according to their preferences. Changes in renal function, other biochemical data, anthropometric parameters, gut microbiota, and adverse events were measured before the intervention and after 12 weeks. RESULTS The change in estimated glomerular filtration rate (eGFR) before and after intervention in the TRF group (Δ = 3.1 ± 5.3 ml/min/1.73m2) showed significant improvement compared with the CD group (Δ = -0.8 ± 4.4 ml/min/1.73m2). Furthermore, the TRF group had a significant decrease in uric acid (Δ = -70.8 ± 124.2 μmol/L), but an increase in total protein (Δ = 1.7 ± 2.5 g/L), while the changes were inconsistent for inflammatory factors. In addition, the TRF group showed a significant decrease in body weight (Δ = -2.8 ± 2.9 kg) compared to the CD group, and body composition indicated the same decrease in body fat mass, fat free mass and body water. Additionally, TRF shifted the gut microbiota in a positive direction. CONCLUSION Preliminary studies suggest that overweight and obese patients with moderate-to-severe CKD with weight loss needs, and who were under strict medical supervision by healthcare professionals, performed TRF with good compliance. They did so without apparent adverse events, and showed efficacy in protecting renal function. These results may be due to changes in body composition and alterations in gut microbiota.
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The effectiveness of interventions during the first 1,000 days to improve energy balance-related behaviors or prevent overweight/obesity in children from socio-economically disadvantaged families of high-income countries: a systematic review.
Lioret, S, Harrar, F, Boccia, D, Hesketh, KD, Kuswara, K, Van Baaren, C, Maritano, S, Charles, MA, Heude, B, Laws, R
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2023;24(1):e13524
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The first 1,000 days is an opportune time to support parents, as primary caregivers and role model, to promote a healthy lifestyle and prevent obesity for their children. The aim of this study was to update the current evidence on the effectiveness of family-based interventions implemented during pregnancy and up to 2 years of age to improve energy balance-related behaviours and growth, or prevent overweight (OW)/ obesity (OB), in children growing up in families experiencing socio-economic disadvantage. This study is a systematic review of thirty-three studies which corresponded to 24 distinct interventions. Of the 24 interventions, nearly all were (cluster) randomised controlled trials; three had a quasi-experimental design. Results show that there is some effectiveness on behavioural and anthropometric outcomes in young children when programmes target and are tailored to families experiencing socioeconomic disadvantage. Authors conclude that a holistic, multilevel and proportionate interventions are likely to more effective and sustainably address the issue of social inequalities and inequities. Additionally, more thorough process evaluation of such complex interventions using mixed methods is needed to better understand why interventions worked or not, by which mechanisms of action (if any), for whom and in which context.
Abstract
This narrative systematic review examined effectiveness of interventions during pregnancy and up to 2 years of age in improving energy balance-related behaviors or prevent overweight/obesity in children from families experiencing socio-economic disadvantage. We identified 24 interventions, from 33 articles, since 1990. Overall, despite their heterogeneity and variability in internal and external validity, there was some evidence of beneficial impact of interventions on obesity risk (4/15), and associated behaviors, e.g.: breastfeeding (9/18), responsive feeding (11/16), diet (7/8), sedentary (1/3) and movement (4/7) behaviors, and sleep (1/2). The most effective interventions aimed at promoting breastfeeding commenced antenatally; this was similar for the prevention of obesity, provided the intervention continued for at least 2 years postnatally and was multi-behavioral. Effective interventions were more likely to target first-time mothers and involve professional delivery agents, multidisciplinary teams and peer groups. Among ethnic/racial minorities, interventions delivered by lay agents had some impact on dietary behavior but not weight outcomes. Co-creation with stakeholders, including parents, and adherence to theoretical frameworks were additional ingredients for more pragmatic, inclusive, non-judgmental, and effective programs. The growing body of evidence on obesity prevention interventions targeting families experiencing socio-economic disadvantage is promising for reducing early inequalities in obesity risk.
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Distribution of energy intake across the day and weight loss: A systematic review and meta-analysis.
Young, IE, Poobalan, A, Steinbeck, K, O'Connor, HT, Parker, HM
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2023;24(3):e13537
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Obesity increases an individual's risk of metabolic disease, such as diabetes and cardiovascular disease, musculoskeletal disorders such as osteoarthritis, and some cancers. “Chrononutrition” relates to the timing of meals and distribution of total energy intake across the day. Evidence is building chrononutrition as a potential target in both weight loss and metabolic disease interventions. The aim of this study was to examine the impact of earlier versus later distribution of total daily energy intake on weight loss, and to evaluate the potential for utilizing altered energy distribution as a tool in weight loss interventions. This study is a systematic review and meta-analysis of nine clinical studies. Total number of participants was 485 (earlier distributed total energy intakes: n = 244, later distributed total energy intakes; n = 241). Results show that energy intakes with a focus on earlier distribution resulted in significantly greater weight loss when compared with similarly energy-restricted diets with individuals consuming a larger proportion of their total energy intake later in the day and into the evening. Authors conclude that earlier energy intakes may be a promising tool to be used in conjunction with other weight loss strategies such as energy restriction to enhance weight loss. However, further research is required to elucidate the additional positive impacts that earlier distributed total energy intakes may have on weight and metabolic health.
Expert Review
Conflicts of interest:
None
Take Home Message:
Implementing a dietary strategy where a higher proportion of energy is consumed earlier in the day may offer additional benefits to an energy restricted diet for weight loss, blood glucose, improve markers of insulin resistance, increase satiety and improve hunger management. Based on the findings, earlier distribution of energy intake may serve as an effective component of a weight loss protocol.
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:
Background
Chrononutrition refers to the timing and distribution of total daily energy intake across the day. It has been proposed that consuming a greater proportion of total daily energy intake earlier in the day as opposed to the evening may be beneficial for weight loss and metabolic health.
Aims
This systematic review and meta-analysis aimed to assess the impact of earlier versus later distribution of total daily energy intake on weight loss.
Results
A total of 9 randomised controlled trials involving 485 participants were included in this analysis. The study durations ranged from 5-16 weeks. All of the studies included in this analysis applied energy-restricted diets to both intervention arms. The mean percentages of energy intake in 8 of the 9 studies per meal were:
- Earlier distributed intakes: breakfast: 34% ± 16%, lunch: 38% ± 7%, dinner: 20% ± 6%.
- Later distributed intakes: breakfast: 19% ± 6%, lunch: 30% ± 10%, dinner; 40% ± 11%.
One of the studies advised percentage of energy intakes as either:
- Earlier: 70% for breakfast, morning tea and lunch and 30% for afternoon tea and dinner
- Late: 55% for breakfast, morning tea and lunch and 45% for afternoon tea and dinner.
The earlier distributed energy intake groups demonstrated significantly greater weight loss when compared with later distributed energy intake groups ( Mean Difference (MD) −1.23 kg; 95% CI −2.40, −0.06, p = 0.04;
I2 = 98%).
The earlier energy intake groups also displayed lower fasting and bedtime glucose levels (fasting: −0.83 vs. −0.27 mmol/L, p = 0.001; before sleep: −1.70 vs. −0.28 mmol/L, p = 0.009).
A random-effects model demonstrated that the earlier intake groups displayed greater reductions in LDL (MD: −0.11 mmol/L; 95% CI −0.14, −0.07, p < 0.01), fasting glucose (MD: 0.15 mmol/L, 95% CI −0.23, −0.06, p < 0.001) and HOMA-IR (MD: −0.38; 95% CI −0.64, −0.11, p = 0.005).
One study reported that earlier distribution energy intake also led to a greater reduction in medications following the intervention for type 2 diabetics (31% vs. 0%, P=0.002).
Two of the studies assessed both appetite and hunger and identified that earlier distribution of energy led to improvements in their urge to eat, preoccupation with food and cravings for sweets and fats.
Clinical practice applications:
Earlier distribution of energy intake may be beneficial for:
- Weight loss
- Improve fasting insulin, HOMA-IR, fasting glucose and HbA1c
- Reducing LDL
- Improving satiety and hunger management
- Supporting the reduction of medications for individuals with type 2 diabetes
- Improving regularity of sleep and waking times
Considerations for future research:
As the included studies only ranged from 5-16 weeks, longer duration studies would be useful to identify the effect of earlier distribution of energy intake on body weight, metabolic health and appetite over a longer period of time. There was a high degree of heterogeneity between the studies and a lack of uniformity in the distributions of energy intake across the day. Further studies with more uniformity of energy distribution would be needed to identify the optimal distribution of energy across the day to improve body weight and metabolic health.
Abstract
Consuming a greater proportion of total energy intake earlier in the day rather than in the evening is proposed to positively influence weight loss and health, potentially due to greater synchronization of human body circadian rhythms. This systematic review provides an update on existing evidence regarding earlier distributed eating patterns in weight loss interventions. Using a robust search strategy in five electronic databases, nine randomized controlled trials investigating the impact of energy intake distribution on weight loss were identified. Following critical appraisal, a random-effects meta-analyses found that, in the context of an energy-reduced diet, distributing energy intake with a focus on earlier intake resulted in significantly greater weight loss (-1.23 kg; 95% CI 2.40, -0.06, p = 0.04). Improvements in HOMA-IR, fasting glucose, and LDL cholesterol were also seen. The current study provides a timely update on the evidence linking distribution of total daily energy intake and health, showing that a focus on earlier intakes can result in greater short-term weight loss compared with later intakes. Future studies are needed to elucidate the impact that earlier intakes may have on weight management and metabolic health.
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The Effect of Regular Consumption of Reformulated Breads on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.
Schadow, AM, Revheim, I, Spielau, U, Dierkes, J, Schwingshackl, L, Frank, J, Hodgson, JM, Moreira-Rosário, A, Seal, CJ, Buyken, AE, et al
Advances in nutrition (Bethesda, Md.). 2023;14(1):30-43
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The metabolic effect of bread depends on several qualitative aspects ranging from the type of grain, the amount of carbohydrates, levels of other nutrients, as well as the chemical structure and processing. The aim of this study was to assess the certainty of the evidence and to investigate the overall effect of regular consumption of reformulated breads on glycaemic control in the following groups: a) healthy adults; b) those at risk of developing cardiometabolic disease (e.g., having hypertension, hyperglycaemia, hypercholesterolemia and/or overweight/obesity); and c) those with manifest type 2 diabetes mellitus (T2DM). This study is a systematic review and meta-analysis of 22 studies and 23 distinct study populations. All studies were randomised controlled trials, 12 of which had a crossover design and 10 had a parallel design. In total, 1037 participants were included. These provided 669 and 595 data points for intervention and control comparisons, respectively. Results show a beneficial effect of reformulated bread variants on fasting blood glucose concentrations. This benefit may be more pronounced among people with manifest T2DM (low certainty of evidence). Authors conclude that bread quality is relevant for metabolic health among adults and that future studies should address its relevance among people at risk of T2DM.
Expert Review
Conflicts of interest:
None
Take Home Message:
This study’s findings suggest the effect of reformulated breads high in dietary fibre, whole grains, and/or functional ingredients may be more beneficial than regular breads on fasting blood glucose concentrations in adults, primarily among those with T2DM. Reformulated breads however, did not lower fasting insulin concentrations, HOMA-IR and HbA1C when compared to regular bread.
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:
Overview
This study evaluated the effect of regular consumption of “reformulated breads” on glycemic control among healthy adults, adults at cardiometabolic risk or with manifest T2DM in 22 RCTs with 1037 participants. Compared with “regular” or comparator bread, consumption of reformulated intervention breads yielded lower fasting blood glucose concentrations only among people with T2DM (low certainty of evidence), yet no differences in fasting insulin, HOMA-IR, HbA1c, or postprandial glucose response were identified.
[*’reformulated bread’ as defined by the World Health Organisation of altering the processing or composition of a food to improve its nutritional profile, and contained whole-grains and dietary fibre]
Results
Sub group analysis revealed that the effect of reformulated breads high in dietary fibre, whole grains, and/or functional ingredients on lowering fasting blood glucose was confined to participants with T2DM, with no significant effect among participants without T2DM (0.68 mmol/L; 95% CI: 1.11, 0.36; I2 1⁄4 57% and 0.04 mmol/L; 95% CI: 0.13, 0.05; I2 1⁄4 25%, respectively; P < 0.001).
Subgroup analyses by continent revealed a more pronounced effect on fasting blood glucose concentrations in studies conducted in Asia and the Middle East compared with studies conducted in Europe, North America, and Oceania (MD: 0.84 mmol/L; 95% CI: 1.35, 0.33; I2 1⁄4 52% and MD: 0.04 mmol/L; 95% CI: 0.10, 0.03; I2 1⁄4 0%, respectively; P < 0.001)
Additional subgroup analyses found that the type of control bread, but not the type of intervention bread, affected the pooled effect estimate of fasting blood glucose concentration (P 1⁄4 0.03), with the largest difference reported in studies not describing the control bread used.
Limitations
Publication bias was considered negligible for the studies included in this meta-analysis, and the risk of bias assessment revealed that most of the studies had some concerns of risk of bias. One author is a member of the International Carbohydrate Quality Consortium and another is a member of the GRADE working group.
Strengths
This systematic review and meta-analysis include the focus on high-quality intervention studies (i.e., RCTs using either crossover or parallel design) and the inclusion of longer-term studies (>2 wk) to address the effectiveness of regular bread replacement for glycemic control in everyday life.
Clinical practice applications:
- This data suggests that bread quality is relevant for metabolic health among adults at risk of T2DM. In particular, reformulated breads were found to have a more beneficial impact than regular breads on fasting blood glucose concentrations in adults with TsDM. However, consumption of the reformulated bread (enriched with dietary fiber, whole grains, or functional ingredients) did not lower fasting insulin concentrations compared with the control breads (MD: 1.59 pmol/L; 95% CI: 5.78, 2.59; moderate certainty of evidence)
- Consumption of the reformulated bread did not lower HOMA-IR compared with the control breads (MD: 0.09; 95% CI: 0.35, 0.22; moderate certainty of evidence)
- Consumption of the reformulated bread did not lower HbA1c concentrations compared with the control bread (0.14; 95% CI: 0.39, 0.10; P 1⁄4 0.195; very low certainty of evidence).
Considerations for future research:
- Longer intervention periods may be required to determine the beneficial effects on the HbA1c concentrations and to elicit changes in markers of insulin resistance
- Future studies should use the 2022 WHO standardised HbA1c diagnostic reference criterion for diabetes mellitus
- Improvements in specific outcomes may also be linked to defined groups within populations such as persons with manifest T2DM.
- The type of reformulation of the bread may be an important factor but differ considerably around the world
Abstract
Bread is a major source of grain-derived carbohydrates worldwide. High intakes of refined grains, low in dietary fiber and high in glycemic index, are linked with increased risk for type 2 diabetes mellitus (T2DM) and other chronic diseases. Hence, improvements in the composition of bread could influence population health. This systematic review evaluated the effect of regular consumption of reformulated breads on glycemic control among healthy adults, adults at cardiometabolic risk or with manifest T2DM. A literature search was performed using MEDLINE, Embase, Web of Science and the Cochrane Central Register of Controlled Trials. Eligible studies employed a bread intervention (≥2 wk) in adults (healthy, at cardiometabolic risk or manifest T2DM) and reported glycemic outcomes (fasting blood glucose, fasting insulin, HOMA-IR, HbA1c, and postprandial glucose responses). Data were pooled using generic inverse variance with random-effects model and presented as mean difference (MD) or standardized MD between treatments with 95% CIs. Twenty-two studies met the inclusion criteria (n = 1037 participants). Compared with "regular" or comparator bread, consumption of reformulated intervention breads yielded lower fasting blood glucose concentrations (MD: -0.21 mmol/L; 95% CI: -0.38, -0.03; I2 = 88%, moderate certainty of evidence), yet no differences in fasting insulin (MD: -1.59 pmol/L; 95% CI: -5.78, 2.59; I2 = 38%, moderate certainty of evidence), HOMA-IR (MD: -0.09; 95% CI: -0.35, 0.23; I2 = 60%, moderate certainty of evidence), HbA1c (MD: -0.14; 95% CI: -0.39, 0.10; I2 = 56%, very low certainty of evidence), or postprandial glucose response (SMD: -0.46; 95% CI: -1.28, 0.36; I2 = 74%, low certainty of evidence). Subgroup analyses revealed a beneficial effect for fasting blood glucose only among people with T2DM (low certainty of evidence). Our findings suggest a beneficial effect of reformulated breads high in dietary fiber, whole grains, and/or functional ingredients on fasting blood glucose concentrations in adults, primarily among those with T2DM. This trial was registered at PROSPERO as CRD42020205458.
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The efficacy of morning versus evening exercise for weight loss: A randomized controlled trial.
Brooker, PG, Gomersall, SR, King, NA, Leveritt, MD
Obesity (Silver Spring, Md.). 2023;31(1):83-95
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Despite considerable efforts to promote a healthy lifestyle, rates of overweight and obesity are continuing to rise worldwide, and obesity is now considered a pandemic. Although dietary intervention is the most effective lifestyle intervention for weight loss, exercise plays an important role in weight management. The aim of this study was to investigate the influence of a 12-week exercise programme, performed in either the morning or evening, on weight loss, cardiometabolic health risk factors, and components of energy balance in inactive adults with overweight and obesity. This study is a three-armed randomised controlled trial. Participants allocated to the two intervention conditions were prescribed 250 minutes per week of self-paced aerobic (treadmill-based) exercise for 12 weeks. Results show that there was no compelling evidence to support or encourage exercise exclusively at a particular time of day for weight loss. However, there were improvements in cardiometabolic health, such as weight reduction and increased cardiorespiratory fitness, increased levels of physical activity, and positive changes to dietary intake in both intervention groups. Following the intervention, both exercise groups continued to lose weight, and the improvements in cardiorespiratory fitness were sustained. Authors conclude that consistent reporting of time of day of exercise interventions among high-quality studies would significantly contribute to the literature and provide critical insight into the relative importance (or lack thereof) of prescribing exercise at a particular time of day.
Abstract
OBJECTIVE The aim of this study was to investigate the influence of morning versus evening exercise on weight loss, cardiometabolic health, and components of energy balance. METHODS A total of 100 inactive adults with overweight or obesity were randomized to morning exercise (AMEx; 06:00-09:00), evening exercise (PMEx; 16:00-19:00), or wait-list control (CON). AMEx and PMEx were prescribed 250 min·wk-1 of self-paced aerobic exercise for 12 weeks. Anthropometry and body composition, physical activity, and dietary intake were assessed at baseline, 6 weeks, and 12 weeks. Cardiorespiratory fitness (V̇O2 peak), resting metabolic rate, and blood markers were assessed at baseline and 12 weeks. Body composition and V̇O2 peak were also measured at 3- and 6-month follow-up. RESULTS AMEx and PMEx lost weight during the intervention (mean [SD], AMEx, -2.7 [2.5] kg, p < 0.001; PMEx, -3.1 [3.4] kg, p < 0.001). V̇O2 peak significantly increased in both intervention groups, and these changes were different from CON (AMEx, +4.7 mL·kg-1 ·min-1 , p = 0.034; PMEx, +4.2 mL·kg-1 ·min-1 , p = 0.045). There were no between-group differences for resting metabolic rate or physical activity. At 12 weeks, total energy intake was significantly reduced in both AMEx and PMEx versus CON (AMEx, -3974 kJ, p < 0.001; PMEx, -3165 kJ, p = 0.001). CONCLUSIONS Adults with overweight and obesity experience modest weight loss in response to an exercise program, but there does not appear to be an optimal time to exercise.
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Macronutrient composition and its effect on body composition changes during weight loss therapy in patients with non-alcoholic fatty liver disease: Secondary analysis of a randomized controlled trial.
Lindqvist, C, Holmer, M, Hagström, H, Petersson, S, Tillander, V, Brismar, TB, Stål, P
Nutrition (Burbank, Los Angeles County, Calif.). 2023;110:111982
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Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide and it is closely linked to overweight and obesity. Weight loss leads to an amelioration of NAFLD, which preferably should lead to loss of fat mass while maintaining lean body mass. The aim of this study was to examine if different diet compositions during weight loss therapy were associated with different reductions in abdominal fat mass compared with standard weight loss advice given by a physician. This study was a secondary analysis of data collected in an open-label, randomised controlled trial. The trial examined the effect of two popular weight loss diets, calorie-restricted intermittent fasting (5:2) and a calorie-restricted low-carbohydrate high-fat (LCHF) diet, compared with standard of care (SOC) on reduction in liver fat in 74 persons with NAFLD. Results show that a dietitian-led nutrition counselling treatment with an LCHF or 5:2 diet reduced weight to a higher extent than physician-supported SOC during a 12-wk treatment. Improvements in most of the variables related to body composition parameters and metabolic function were found, independent of dietary composition. Furthermore, during weight loss, visceral fat was mobilized to a greater extent than subcutaneous fat. Authors conclude that further studies are needed with a focus on the effect of diet composition on body composition changes during weight loss.
Abstract
OBJECTIVES Dietary composition may affect body composition during weight loss therapy. We tested the hypothesis of whether dietary macronutrient composition influences the reduction of total abdominal adipose tissue, subcutaneous adipose tissue (SAT), or visceral adipose tissue (VAT) during weight loss. METHODS Dietary macronutrient composition and body composition were analyzed as a secondary outcome of a randomized controlled trial of 62 participants with non-alcoholic fatty liver disease. Patients were randomly assigned to a calorie-restricted intermittent fasting (5:2), calorie-restricted low-carbohydrate high-fat (LCHF), or healthy lifestyle advice (standard-of-care) diet in a 12-wk intervention phase. Dietary intake was assessed by self-reported 3-d food diaries and by characterization of total plasma fatty acid profile. Percentage of energy intake (E%) from different macronutrients was calculated. Body composition was assessed by magnetic resonance imaging and anthropometric measurements. RESULTS The macronutrient composition differed significantly between the 5:2 (fat 36 E% and carbohydrates 43 E%) and the LCHF (fat 69 E% and carbohydrates 9 E%) groups (P < 0.001). Weight loss was similar in the 5:2 and LCHF groups (-7.2 [SD = 3.4] kg versus 8.0 [SD = 4.8] kg; P = 0.44) and significantly larger than for standard of care (-2.5 kg [SD = 2.3]; P < 0.001). The volume of total abdominal fat, adjusted for height, decreased on average by 4.7% (standard of care), 14.3% (5:2), and 17.7% (LCHF), with no significant differences between the 5:2 and LHCF groups (P = 0.32). VAT and SAT, adjusted for height, decreased on average by 17.1% and 12.7% for 5:2, respectively, and by 21.2% and 17.9% for LCHF, with no significant group differences (VAT [P = 0.16] and SAT [P = 0.10]). VAT was mobilized to a greater extent than SAT in all diets. CONCLUSIONS The 5:2 and LCHF diets had similar effects on changes in intraabdominal fat mass and anthropometrics during weight loss. This might indicate that overall weight loss is more important than diet composition to achieve changes in total abdominal adipose tissue, VAT, or SAT. The results of the present study suggest that there is a need for further studies on the effect of diet composition on body composition changes during weight loss therapy.
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Nutrition and Exercise Interventions to Improve Body Composition for Persons with Overweight or Obesity Near Retirement Age: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials.
Eglseer, D, Traxler, M, Embacher, S, Reiter, L, Schoufour, JD, Weijs, PJM, Voortman, T, Boirie, Y, Cruz-Jentoft, A, Bauer, S
Advances in nutrition (Bethesda, Md.). 2023;14(3):516-538
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Obesity is characterised by excessive fat accumulation that often occurs during the process of aging. Aging is accompanied not only by a gradual increase in body fat stores but also a decrease in muscle mass, muscle function, and water retention. The aim of this study was to assess which nutrition and exercise interventions are most effective for improving the body composition (fat mass and muscle mass), body mass index, and waist circumference in persons with overweight or obesity near retirement age (55 to 70 years of age). This study was a systematic review and network meta-analysis (NMA) of randomised controlled trials of sixty-six studies. Results of the NMA showed that the most effective strategy to improve body composition, i.e., losing fat without increasing risk of sarcopenia in persons with obesity around retirement age, was combining energy restriction with resistance training or with mixed exercise (resistance combined with aerobic exercise) and/or high-protein intake. In fact, without training, an energy-restricted diet with or without added protein helped individuals lose fat mass but also tended to result in losses of muscle mass. Authors conclude that an energy-restricted diet alone probably contributes to the development of sarcopenic obesity in persons of retirement age. Thus, to simultaneously lose weight and maintain muscle mass, authors recommend a combination of energy restriction and resistance training.
Abstract
The retirement phase is an opportunity to integrate healthy (nutrition/exercise) habits into daily life. We conducted this systematic review to assess which nutrition and exercise interventions most effectively improve body composition (fat/muscle mass), body mass index (BMI), and waist circumference (WC) in persons with obesity/overweight near retirement age (ages 55-70 y). We conducted a systematic review and network meta-analysis (NMA) of randomized controlled trials, searching 4 databases from their inception up to July 12, 2022. The NMA was based on a random effects model, pooled mean differences, standardized mean differences, their 95% confidence intervals, and correlations with multi-arm studies. Subgroup and sensitivity analyses were also conducted. Ninety-two studies were included, 66 of which with 4957 participants could be used for the NMA. Identified interventions were clustered into 12 groups: no intervention, energy restriction (i.e., 500-1000 kcal), energy restriction plus high-protein intake (1.1-1.7 g/kg/body weight), intermittent fasting, mixed exercise (aerobic and resistance), resistance training, aerobic training, high protein plus resistance training, energy restriction plus high protein plus exercise, energy restriction plus resistance training, energy restriction plus aerobic training, and energy restriction plus mixed exercise. Intervention durations ranged from 8 wk to 6 mo. Body fat was reduced with energy restriction plus any exercise or plus high-protein intake. Energy restriction alone was less effective and tended to decrease muscle mass. Muscle mass was only significantly increased with mixed exercise. All other interventions including exercise effectively preserved muscle mass. A BMI and/or WC decrease was achieved with all interventions except aerobic training/resistance training alone or resistance training plus high protein. Overall, the most effective strategy for nearly all outcomes was combining energy restriction with resistance training or mixed exercise and high protein. Health care professionals involved in the management of persons with obesity need to be aware that an energy-restricted diet alone may contribute to sarcopenic obesity in persons near retirement age. This network meta-analysis is registered at https://www.crd.york.ac.uk/prospero/ as CRD42021276465.