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Metabolic, hormonal and performance effects of isomaltulose ingestion before prolonged aerobic exercise: a double-blind, randomised, cross-over trial.
Notbohm, HL, Feuerbacher, JF, Papendorf, F, Friese, N, Jacobs, MW, Predel, HG, Zacher, J, Bloch, W, Schumann, M
Journal of the International Society of Sports Nutrition. 2021;18(1):38
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Isomaltulose is a low-glycaemic index carbohydrate that lowers insulin and glucose levels postprandially. The benefits of taking Isomaltulose in an exercise setting are not well studied. This double-blinded, randomised, crossover study evaluated the effects of Isomaltulose intake on metabolic responses, hormonal responses, exercise performance and gastrointestinal disturbances in runners. Twenty-one male recreational endurance runners took part in four separate experimental sessions to compare Isomaltulose to maltodextrin and glucose. Fat and carbohydrate oxidation rates were not different among groups. This might be because the lower dose of Isomaltulose (50g) was used in this trial. Compared to glucose and maltodextrin, isomaltulose lowered metabolic and hormonal responses to exercise. In the study, Isomaltulose, glucose, and maltodextrin did not differ in exercise performance or gastrointestinal disturbances. A higher dose may be needed in order to demonstrate exercise performance, but caution should be exercised since a higher dose may cause gastrointestinal upset. A robust investigation of Isomalulose dose and its effects on glucose, insulin, and glucose-dependent insulinotropic polypeptides is required to determine if exercise leads to hypoglycaemia in the clinical population. Healthcare practitioners can use the findings of this study to understand the advantageous effects of 50g Isomaltulose in regulating glucose, insulin and glucose-dependent insulinotropic polypeptide during aerobic exercise.
Abstract
BACKGROUND Isomaltulose has been discussed as a low glycaemic carbohydrate but evidence concerning performance benefits and physiological responses has produced varying results. Therefore, we primarily aimed to investigate the effects of isomaltulose ingestion compared to glucose and maltodextrin on fat and carbohydrate oxidation rates, blood glucose levels and serum hormone concentrations of insulin and glucose-dependent insulinotropic polypeptide (GIP). As secondary aims, we assessed running performance and gastrointestinal discomfort. METHODS Twenty-one male recreational endurance runners performed a 70-min constant load trial at 70% maximal running speed (Vmax), followed by a time to exhaustion (TTE) test at 85% Vmax after ingesting either 50 g isomaltulose, maltodextrin or glucose. Fat and carbohydrate oxidation rates were calculated from spiroergometric data. Venous blood samples for measurement of GIP and insulin were drawn before, after the constant load trial and after the TTE. Capillary blood samples for glucose concentrations and subjective feeling of gastrointestinal discomfort were collected every 10 min during the constant load trial. RESULTS No between-condition differences were observed in the area under the curve analysis of fat (p = 0.576) and carbohydrate oxidation rates (p = 0.887). Isomaltulose ingestion led to lower baseline postprandial concentrations of blood glucose compared to maltodextrin (percent change [95% confidence interval], - 16.7% [- 21.8,-11.6], p < 0.001) and glucose (- 11.5% [- 17.3,-5.7], p = 0.001). Similarly, insulin and GIP concentrations were also lower following isomaltulose ingestion compared to maltodextrin (- 40.3% [- 50.5,-30.0], p = 0.001 and - 69.1% [- 74.3,-63.8], p < 0.001, respectively) and glucose (- 32.6% [- 43.9,-21.2], p = 0.012 and - 55.8% [- 70.7,-40.9], p < 0.001, respectively). Furthermore, glucose fluctuation was lower after isomaltulose ingestion compared to maltodextrin (- 26.0% [- 34.2,-17.8], p < 0.001) and glucose (- 17.4% [- 29.1,-5.6], p < 0.001). However, during and after exercise, no between-condition differences for glucose (p = 0.872), insulin (p = 0.503) and GIP (p = 0.244) were observed. No between-condition differences were found for TTE (p = 0.876) or gastrointestinal discomfort (p = 0.119). CONCLUSION Isomaltulose ingestion led to lower baseline postprandial concentrations of glucose, insulin and GIP compared to maltodextrin and glucose. Consequently, blood glucose fluctuations were lower during treadmill running after isomaltulose ingestion, while no between-condition differences were observed for CHO and fat oxidation rates, treadmill running performance and gastrointestinal discomfort. Further research is required to provide specific guidelines on supplementing isomaltulose in performance and health settings.
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Gut microbiota plasticity is correlated with sustained weight loss on a low-carb or low-fat dietary intervention.
Grembi, JA, Nguyen, LH, Haggerty, TD, Gardner, CD, Holmes, SP, Parsonnet, J
Scientific reports. 2020;10(1):1405
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Obesity is responsible for a substantial number of deaths and is associated with considerable economic costs. Dietary intervention can help with weight loss; however, success varies between individuals. Gut microbiota could influence weight loss as they have been shown in previous studies to affect feelings of hunger. This cohort study taken from an RCT of 161 obese adults aimed to determine if differing gut microbiota communities could be involved in determining weight loss success when on a low-carbohydrate or a low-fat diet over 12 months. The results showed that specific gut microbiota did not predict weight loss success. However, having a diverse gut microbiota prior to starting a low-fat diet, predicted higher weight loss. This was only observed in those on a low-carbohydrate diet after 10 weeks of dieting. Interestingly individuals that reported better dietary adherence weren’t necessarily more successful with weight loss. It was concluded that gut microbiota diversity is important in sustained weight loss, especially if on a low-fat diet. This study could be used by healthcare professionals to understand that microbial diversity may determine the success of a diet regime and the importance of personalising recommendations.
Abstract
While low-carbohydrate and low-fat diets can both lead to weight-loss, a substantial variability in achieved long-term outcomes exists among obese but otherwise healthy adults. We examined the hypothesis that structural differences in the gut microbiota explain a portion of variability in weight-loss using two cohorts of obese adults enrolled in the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) study. A total of 161 pre-diet fecal samples were sequenced from a discovery cohort (n = 66) and 106 from a validation cohort (n = 56). An additional 157 fecal samples were sequenced from the discovery cohort after 10 weeks of dietary intervention. We found no specific bacterial signatures associated with weight loss that were consistent across both cohorts. However, the gut microbiota plasticity (i.e. variability), was correlated with long-term (12-month) weight loss in a diet-dependent manner; on the low-fat diet subjects with higher pre-diet daily plasticity had higher sustained weight loss, whereas on the low-carbohydrate diet those with higher plasticity over 10 weeks of dieting had higher 12-month weight loss. Our findings suggest the potential importance of gut microbiota plasticity for sustained weight-loss. We highlight the advantages of evaluating kinetic trends and assessing reproducibility in studies of the gut microbiota.
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Non-Systematic Review of Diet and Nutritional Risk Factors of Cardiovascular Disease in Obesity.
Rychter, AM, Ratajczak, AE, Zawada, A, Dobrowolska, A, Krela-Kaźmierczak, I
Nutrients. 2020;12(3)
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Nutrition is a major factor influencing obesity associated heart disease risk, however many people with this disease do not follow nutritional recommendations. This review of 155 studies aimed to summarise dietary aspects of heart disease prevention. The paper began by outlining the role of obesity through the development of other disorders that contribute to heart disease, such as type 2 diabetes, high blood pressure and blood sugar imbalance. The quantity and distribution of fat tissue also can contribute to heart disease risk, especially if it is located within the heart or around the major organs of the body. Dietary factors which can increase heart disease risk were described as an increased intake of processed foods, sugar, salt and certain fats and low intakes of fruit, vegetables, fibre, whole grains, beans and nuts. The Mediterranean diet, the dietary approaches to stop hypertension (DASH) diet, plant-based diets, the portfolio dietary pattern and low carbohydrate diets were all reviewed and although mixed results were stated for low carbohydrate diets, most of the diets reviewed reported improved heart disease outcomes. The role of intestinal microbiota in heart disease were also reviewed and the influence of a poor diet was implicated in imbalanced gut microbiota and the development of heart disease. It was concluded that an unhealthy diet can contribute to heart disease and that dietary patterns such as the Mediterranean diet and plant-based diets may be favourable for its management. This study could be used by healthcare professionals to individualise dietary recommendations for patients with heart disease or who are at risk of it.
Abstract
Although cardiovascular disease and its risk factors have been widely studied and new methods of diagnosis and treatment have been developed and implemented, the morbidity and mortality levels are still rising-cardiovascular disease is responsible for more than four million deaths each year in Europe alone. Even though nutrition is classified as one of the main and changeable risk factors, the quality of the diet in the majority of people does not follow the recommendations essential for prevention of obesity and cardiovascular disease. It demonstrates the need for better nutritional education in cardiovascular disease prevention and treatment, and the need to emphasize dietary components most relevant in cardiovascular disease. In our non-systematic review, we summarize the most recent knowledge about nutritional risk and prevention in cardiovascular disease and obesity.
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An Almond-Based Low Carbohydrate Diet Improves Depression and Glycometabolism in Patients with Type 2 Diabetes through Modulating Gut Microbiota and GLP-1: A Randomized Controlled Trial.
Ren, M, Zhang, H, Qi, J, Hu, A, Jiang, Q, Hou, Y, Feng, Q, Ojo, O, Wang, X
Nutrients. 2020;12(10)
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Associations between type 2 diabetes (T2D) and depression may exist, with depression increasing the risk of T2D and T2D increasing risk of depression. Nutritional changes such as a low carbohydrate diet (LCD) are a large part of T2D management, however the effects on depression remain controversial. Almonds as part of a LCD may have additional benefits to individuals with T2D and those with depression, potentially through its ability to modify gut microbiota. This three-month randomised control trial of 50 individuals with T2D aimed to determine if an almond based LCD (a-LCD) would affect depression and T2D through modulation of gut microbiota and associated gut-brain signalling molecules compared to a low-fat diet (LFD). The results showed that although measures of blood glucose control improved in both groups, those on the a-LCD had better blood glucose control. Symptoms of depression were reduced in participants on the a-LCD compared to the LFD. Gut-brain signalling molecules were maintained in the a-LCD but decreased in the LFD after three months. Several species of gut bacteria were changed by a-LCD. It was concluded that an a-LCD diet may improve symptoms of depression in individuals with T2D through the modulation of gut bacteria and maintenance of gut-brain signalling molecules. This study could be used by healthcare professionals to recommend a low carbohydrate diet rich in almonds for the improvement of symptoms of depression and blood glucose control in individuals with T2D. Low fat diets may also be of benefit to blood glucose control individuals with T2D.
Abstract
BACKGROUND Alow carbohydrate diet (LCD) is more beneficial for the glycometabolism in type 2 diabetes (T2DM) and may be effective in reducing depression. Almond, which is a common nut, has been shown to effectively improve hyperglycemia and depression symptoms. This study aimed to determine the effect of an almond-based LCD (a-LCD) on depression and glycometabolism, as well as gut microbiota and fasting glucagon-like peptide 1 (GLP-1) in patients with T2DM. METHODS This was a randomized controlled trial which compared an a-LCD with a low-fat diet (LFD). Forty-five participants with T2DM at a diabetes club and the Endocrine Division of the First and Second Affiliated Hospital of Soochow University between December 2018 to December 2019 completed each dietary intervention for 3 months, including 22 in the a-LCD group and 23 in the LFD group. The indicators for depression and biochemical indicators including glycosylated hemoglobin (HbA1c), gut microbiota, and GLP-1 concentration were assessed at the baseline and third month and compared between the two groups. RESULTS A-LCD significantly improved depression and HbA1c (p <0.01). Meanwhile, a-LCD significantly increased the short chain fatty acid (SCFAs)-producing bacteria Roseburia, Ruminococcus and Eubacterium. The GLP-1 concentration in the a-LCD group was higher than that in the LFD group (p <0.05). CONCLUSIONS A-LCD could exert a beneficial effect on depression and glycometabolism in patients with T2DM. We speculate that the role of a-LCD in improving depression in patients with T2DM may be associated with it stimulating the growth of SCFAs-producing bacteria, increasing SCFAs production and GPR43 activation, and further maintaining GLP-1 secretion. In future studies, the SCFAs and GPR43 activation should be further examined.
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Chronic Ketogenic Low Carbohydrate High Fat Diet Has Minimal Effects on Acid-Base Status in Elite Athletes.
Carr, AJ, Sharma, AP, Ross, ML, Welvaert, M, Slater, GJ, Burke, LM
Nutrients. 2018;10(2)
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The low-fat, high-carbohydrate ketogenic diet has recently been applied to the context of elite athletes to observe potential impact on performance and metabolism during exercise and rest. The aim to this study was to assess the effect of a long-term ketogenic diet on the acid-base status in elite athletes, particularly investigating whether sustained diet change caused alterations in overall acid production. Twenty-one athletes were assigned to a high carbohydrate diet, low carbohydrate diet and periodised carbohydrate availability diet for three sustained weeks. Acid-base balance was measured via blood samples at baseline and post-intervention. The main finding of this study was that a sustained ketogenic diet had no influence of acid-base status. Based on these results, the authors conclude that long-term manipulation of macronutrient intake is unlikely to influence acid-base status in this population. It is also noted that elite athletes may have an increased buffering capacity compared with the general population, and that further research should be done in different participant populations.
Abstract
Although short (up to 3 days) exposure to major shifts in macronutrient intake appears to alter acid-base status, the effects of sustained (>1 week) interventions in elite athletes has not been determined. Using a non-randomized, parallel design, we examined the effect of adaptations to 21 days of a ketogenic low carbohydrate high fat (LCHF) or periodized carbohydrate (PCHO) diet on pre- and post-exercise blood pH, and concentrations of bicarbonate (HCO₃-) and lactate (La-) in comparison to a high carbohydrate (HCHO) control. Twenty-four (17 male and 7 female) elite-level race walkers completed 21 days of either LCHF (n = 9), PCHO (n = 7), or HCHO (n = 8) under controlled diet and training conditions. At baseline and post-intervention, blood pH, blood [HCO₃-], and blood [La-] were measured before and after a graded exercise test. Net endogenous acid production (NEAP) over the previous 48-72 h was also calculated from monitored dietary intake. LCHF was not associated with significant differences in blood pH, [HCO₃-], or [La-], compared with the HCHO diet pre- or post-exercise, despite a significantly higher NEAP (mEq·day-1) (95% CI = [10.44; 36.04]). Our results indicate that chronic dietary interventions are unlikely to influence acid-base status in elite athletes, which may be due to pre-existing training adaptations, such as an enhanced buffering capacity, or the actions of respiratory and renal pathways, which have a greater influence on regulation of acid-base status than nutritional intake.
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Does high-carbohydrate intake lead to increased risk of obesity? A systematic review and meta-analysis.
Sartorius, K, Sartorius, B, Madiba, TE, Stefan, C
BMJ open. 2018;8(2):e018449
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As overweight and obesity is rising globally, better understanding its cause is important to help with prevention and management of disease. The objective of this meta-analysis is to investigate the relationship between carbohydrate intake and obesity, particularly at the differences between low and high carbohydrate diets. Based on 22 articles that met the inclusion criteria, a high-carbohydrate diet, or increased proportion of energy intake in the form of carbohydrates, does not increase the risk of being obese. Based on these results, the authors iterate further studies are required to better understand obesity risk with regards different carbohydrate groups including refined versus unrefined carbohydrates.
Abstract
OBJECTIVES The present study aimed to test the association between high and low carbohydrate diets and obesity, and second, to test the link between total carbohydrate intake (as a percentage of total energy intake) and obesity. SETTING, PARTICIPANTS AND OUTCOME MEASURES We sought MEDLINE, PubMed and Google Scholar for observation studies published between January 1990 and December 2016 assessing an association between obesity and high-carbohydrate intake. Two independent reviewers selected candidate studies, extracted data and assessed study quality. RESULTS The study identified 22 articles that fulfilled the inclusion and exclusion criteria and quantified an association between carbohydrate intake and obesity. The first pooled strata (high-carbohydrate versus low-carbohydrate intake) suggested a weak increased risk of obesity. The second pooled strata (increasing percentage of total carbohydrate intake in daily diet) showed a weak decreased risk of obesity. Both these pooled strata estimates were, however, not statistically significant. CONCLUSIONS On the basis of the current study, it cannot be concluded that a high-carbohydrate diet or increased percentage of total energy intake in the form of carbohydrates increases the odds of obesity. A central limitation of the study was the non-standard classification of dietary intake across the studies, as well as confounders like total energy intake, activity levels, age and gender. Further studies are needed that specifically classify refined versus unrefined carbohydrate intake, as well as studies that investigate the relationship between high fat, high unrefined carbohydrate-sugar diets. PROSPERO REGISTRATION NUMBER CRD42015023257.
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Effects of Popular Diets without Specific Calorie Targets on Weight Loss Outcomes: Systematic Review of Findings from Clinical Trials.
Anton, SD, Hida, A, Heekin, K, Sowalsky, K, Karabetian, C, Mutchie, H, Leeuwenburgh, C, Manini, TM, Barnett, TE
Nutrients. 2017;9(8)
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Calorie-restricted diets have not been highly successful in reducing obesity levels. This has led to an increased interest in alternative dietary approaches to achieve sustained weight loss. The purpose of this systematic review was to analyse the most popular diets of 2016 for short- and long-term weight loss outcomes based on findings from clinical trials that do not include calorie restriction or increased physical activity levels. Of all existing literature, only 16 articles met the inclusion criteria covering 7 popular diets, indicating the lack of clinical trials and high-quality evidence. The Atkins diet is the most well-researched popular diet and demonstrates substantial long-term weight loss. The Paleolithic diet has also been found to produce sustained weight loss according to the one study included on this diet. Based to these findings, the authors conclude that of the popular diets, those with a low carbohydrate component seem to be effective, though the safety of these diets has not been critically examined. Further evidence is needed to provide a more comprehensive evaluation of the efficacy of each of these popular diets.
Abstract
The present review examined the evidence base for current popular diets, as listed in the 2016 U.S. News & World Report, on short-term (≤six months) and long-term (≥one year) weight loss outcomes in overweight and obese adults. For the present review, all diets in the 2016 U.S. News & World Report Rankings for "Best Weight-Loss Diets", which did not involve specific calorie targets, meal replacements, supplementation with commercial products, and/or were not categorized as "low-calorie" diets were examined. Of the 38 popular diets listed in the U.S. News & World Report, 20 met our pre-defined criteria. Literature searches were conducted through PubMed, Cochrane Library, and Web of Science using preset key terms to identify all relevant clinical trials for these 20 diets. A total of 16 articles were identified which reported findings of clinical trials for seven of these 20 diets: (1) Atkins; (2) Dietary Approaches to Stop Hypertension (DASH); (3) Glycemic-Index; (4) Mediterranean; (5) Ornish; (6) Paleolithic; and (7) Zone. Of the diets evaluated, the Atkins Diet showed the most evidence in producing clinically meaningful short-term (≤six months) and long-term (≥one-year) weight loss. Other popular diets may be equally or even more effective at producing weight loss, but this is unknown at the present time since there is a paucity of studies on these diets.
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Diets that differ in their FODMAP content alter the colonic luminal microenvironment.
Halmos, EP, Christophersen, CT, Bird, AR, Shepherd, SJ, Gibson, PR, Muir, JG
Gut. 2015;64(1):93-100
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A low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols) diet is being increasingly recommended for the management of IBS. However, the FODMAP diet can be low in potential prebiotic and fermentable fibre which may have an adverse effect on gut bacteria diversity and other colonic health biomarkers. This study set out to identify how a low FODMAP diet affected the pH, short-chain fatty acid concentrations and bacterial abundance and diversity in comparison to a typical Australian diet. The randomised cross over study consisted of 27 IBS and 6 healthy subjects who were blinded to 21 days of a low FODMAP diet and then, following a washout period of 21 days following their usual diet they were crossed over to the typical Australian diet for 21 days. The study found increased faecal pH, similar short chain fatty acid concentrations, a greater microbial diversity and reduced bacterial abundancy in faecal samples whilst following the low FODMAP diet. It was concluded that caution should be used when reducing FODMAP intake in the long term and that a low FODMAP diet should not be recommended for asymptomatic populations.
Abstract
OBJECTIVE A low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) diet reduces symptoms of IBS, but reduction of potential prebiotic and fermentative effects might adversely affect the colonic microenvironment. The effects of a low FODMAP diet with a typical Australian diet on biomarkers of colonic health were compared in a single-blinded, randomised, cross-over trial. DESIGN Twenty-seven IBS and six healthy subjects were randomly allocated one of two 21-day provided diets, differing only in FODMAP content (mean (95% CI) low 3.05 (1.86 to 4.25) g/day vs Australian 23.7 (16.9 to 30.6) g/day), and then crossed over to the other diet with ≥21-day washout period. Faeces passed over a 5-day run-in on their habitual diet and from day 17 to day 21 of the interventional diets were pooled, and pH, short-chain fatty acid concentrations and bacterial abundance and diversity were assessed. RESULTS Faecal indices were similar in IBS and healthy subjects during habitual diets. The low FODMAP diet was associated with higher faecal pH (7.37 (7.23 to 7.51) vs. 7.16 (7.02 to 7.30); p=0.001), similar short-chain fatty acid concentrations, greater microbial diversity and reduced total bacterial abundance (9.63 (9.53 to 9.73) vs. 9.83 (9.72 to 9.93) log10 copies/g; p<0.001) compared with the Australian diet. To indicate direction of change, in comparison with the habitual diet the low FODMAP diet reduced total bacterial abundance and the typical Australian diet increased relative abundance for butyrate-producing Clostridium cluster XIVa (median ratio 6.62; p<0.001) and mucus-associated Akkermansia muciniphila (19.3; p<0.001), and reduced Ruminococcus torques. CONCLUSIONS Diets differing in FODMAP content have marked effects on gut microbiota composition. The implications of long-term reduction of intake of FODMAPs require elucidation. TRIAL REGISTRATION NUMBER ACTRN12612001185853.