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Vegetarian and Vegan Diet in Fibromyalgia: A Systematic Review.
Nadal-Nicolás, Y, Miralles-Amorós, L, Martínez-Olcina, M, Sánchez-Ortega, M, Mora, J, Martínez-Rodríguez, A
International journal of environmental research and public health. 2021;18(9)
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Fibromyalgia (FM) is a chronic non-degenerative disease of unknown etiology without effective medical treatment that mostly affects women. The aim of this study was to evaluate the efficacy of mainly plant-based diets in patients with FM compared to omnivorous diets. A secondary aim was to examine the main effects of these diets on patients’ symptoms and the improvement in their quality of life. This study is a systemic review of six studies (n = 4 clinical trials and n = 2 observational cohort studies). The selected studies included 157 FM patients in both the intervention and control groups, and more than 117 were women. Results indicate that a mainly plant-based diet improves biochemical parameters and body inflammation; body weight, sleep quality, quality of life, pain at rest as well as other symptoms of FM and their impact on health. Authors conclude that even though their findings are promising further well-designed clinical trials are needed to consolidate these dietary recommendations in FM patient.
Abstract
Fibromyalgia (FM) is a chronic non-degenerative disease characterized by the presence of multiple symptoms such as chronic pain, which negatively influence the quality of life of sufferers, most of whom are women. Currently, there is no effective treatment to limit the impact of these symptoms. The aim of this research is to review the scientific evidence on the effect of following a vegetarian or vegan diet on fibromyalgia patients. A systematic review included the original articles that answered the research question. These articles were in 2021 in the PubMed, Web of Science and Scopus databases. The research used the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. No time restriction was applied, and grey literature was not included. The evaluation of the methodological quality of the articles was carried out using the following different scales: STROBE (strengthening the reporting of observational studies in epidemiology), PEDro (Physiotherapy Evidence Database), and MMAT (Mixed Methods Appraisal Tool) scales. A total of 88 studies were analyzed, of which 6 investigations were included in this systematic review (n = 4 clinical trials and n = 2 cohort studies). These investigations show significant improvements in biochemical parameters, quality of life, quality of sleep, pain at rest and general health status when following mainly plant-based dietary patterns. In conclusion, these findings are promising but interpretation of the findings is limited due to the methodological quality of the studies. Well-designed clinical trials are needed to consolidate these dietary recommendations in FM patients.
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A Systematic Review of the Association Between Vegan Diets and Risk of Cardiovascular Disease.
Kaiser, J, van Daalen, KR, Thayyil, A, Cocco, MTARR, Caputo, D, Oliver-Williams, C
The Journal of nutrition. 2021;151(6):1539-1552
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Plant-based diets have increased in popularity due to concerns for the environment and animal welfare and due to perceived health benefits. The aim of this study was to assess the association between vegan diets and risks of primary, intermediate, and recurrent cardiovascular disease (CVD). This study is a systemic review of 7 epidemiological studies comprising over 73,000 participants, of whom at least 7661 were vegans. Results indicate that there was no significant evidence of an association between adherence to a vegan diet and risks of primary CVD or a coronary heart disease event. Authors conclude that further experimental evidence and research in large diverse cohorts is required in order to better understand the clinical relevance and public health implications of the vegan diet.
Abstract
BACKGROUND Plant-based diets are gaining attention globally due to their environmental benefits and perceived health-protective role. A vegan diet may have cardiovascular benefits; however, evidence remains conflicting and insufficiently assessed. OBJECTIVES We evaluated the utility of the vegan diet in cardiovascular disease (CVD) prevention. METHODS We conducted a systematic review of studies evaluating the association between vegan diets and cardiovascular outcomes. We searched 5 databases (Ovid MEDLINE, EMBASE, Web of Science, Scopus, and OpenGrey) through 31 October 2020. Four investigators independently screened the full texts for inclusion, assessed quality, and extracted data from published reports. RESULTS Out of the 5729 identified records, 7 were included, comprising over 73,000 participants, of whom at least 7661 were vegans. Three studies, with at least 73,426 individuals (including at least 7380 vegans), examined risks of primary cardiovascular events (total CVD, coronary heart disease, acute myocardial infarction, total stroke, hemorrhagic stroke, and ischemic stroke) in individuals who followed a vegan diet compared to those who did not. None of the studies reported a significantly increased or decreased risk of any cardiovascular outcome. One study suggested that vegans were at greater risk of ischemic stroke compared to individuals who consumed animal products (HR, 1.54; 95% CI, 0.95-2.48). Yet in another study, vegans showed lower common carotid artery intima-media thickness (0.56 ± 0.1 mm vs. 0.74 ± 0.1 mm in controls; P < 0.001), and in 3 studies of recurrent CVD events, vegans had 0-52% lower rates. Furthermore, endothelial function did not differ between vegans and nonvegans. Using the Grading of Recommendations Assessment, Development and Evaluation approach, evidence was deemed to be of low to very low strength/quality. CONCLUSIONS Among the Western populations studied, evidence weakly demonstrates associations between vegan diets and risk of CVDs, with the direction of associations varying with the specific CVD outcome tested. However, more high-quality research on this topic is needed. This study was registered at PROSPERO as CRD42019146835.
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Evolution of the Human Diet and Its Impact on Gut Microbiota, Immune Responses, and Brain Health.
González Olmo, BM, Butler, MJ, Barrientos, RM
Nutrients. 2021;13(1)
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One explanation for the increased prevalence in chronic disease and mental illness is from the evolutionary perspective. This suggests the rapid shift in diet towards processed foods in the past 200 years has not allowed for sufficient adaptation of the gut microbiome. The gut microbiome plays an important role in the digestive, immune and nervous systems via the gut-brain axis, and may be a key factor in modulating inflammation and disease. The aim of this review is to discuss how what we eat affects the immune system and impacts our brain health. The literature currently shows significant associations between the Western diet and its impact on the health of the gut microbiome and the brain. Increased intake of saturated fats, refined carbohydrates and sugar, coupled with a reduction in fiber, negatively impacts the digestive system and elicits an immune response. This response can lead to neuroinflammation, which is now found to be associated with deficits in learning and memory, as well as increased rates of neurodegenerative disease and depression. Based on the existing literature, the authors conclude the human gut microbiome has not had sufficient time to adapt to many modern foods, thus leading to inflammation and disease. The authors recommend that a diet composed of natural whole foods with minimal processing can help prevent and alleviate some of the burden caused by chronic disease, and suggest future studies focus on improving techniques to evaluate neuroinflammation in humans.
Abstract
The relatively rapid shift from consuming preagricultural wild foods for thousands of years, to consuming postindustrial semi-processed and ultra-processed foods endemic of the Western world less than 200 years ago did not allow for evolutionary adaptation of the commensal microbial species that inhabit the human gastrointestinal (GI) tract, and this has significantly impacted gut health. The human gut microbiota, the diverse and dynamic population of microbes, has been demonstrated to have extensive and important interactions with the digestive, immune, and nervous systems. Western diet-induced dysbiosis of the gut microbiota has been shown to negatively impact human digestive physiology, to have pathogenic effects on the immune system, and, in turn, cause exaggerated neuroinflammation. Given the tremendous amount of evidence linking neuroinflammation with neural dysfunction, it is no surprise that the Western diet has been implicated in the development of many diseases and disorders of the brain, including memory impairments, neurodegenerative disorders, and depression. In this review, we discuss each of these concepts to understand how what we eat can lead to cognitive and psychiatric diseases.
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Augmenting Clinical Interventions in Psychiatric Disorders: Systematic Review and Update on Nutrition.
Offor, SJ, Orish, CN, Frazzoli, C, Orisakwe, OE
Frontiers in psychiatry. 2021;12:565583
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Mental disorders are widespread and impact significantly on health. “Nutritional psychiatry” pivots on the impact of nutrition (food) on the state of mind and mood. The aim of this study was to justify the inclusion and recognition of nutrition in the management of psychiatric illnesses. This study is a systemic review which included 97 studies. The literature shows that several foods and food compounds modulate biomarkers and molecular mechanisms involved in the aetiogenesis [the origin and development of a pathological condition] of several mental disorders. Furthermore, the evidence-based approach warrants the inclusion and co-recognition of nutrition in the management of psychiatric illnesses. Authors conclude that there is a need to advocate for policies aimed at bridging the knowledge gap and encourage the utilization and integration of nutrition in addition to contemporary therapies in clinical settings.
Abstract
There is a strong relationship between a healthy diet and mental well-being. Several foods and food compounds are known to modulate biomarkers and molecular mechanisms involved in the aetiogenesis of several mental disorders, and this can be useful in containing the disease progression, including its prophylaxis. This is an updated systematic review of the literature to justify the inclusion and recognition of nutrition in the management of psychiatric illnesses. Such foods and their compounds include dietary flavanols from fruits and vegetables, notable antioxidant and anti-inflammatory agents, probiotics (fermented foods) known to protect good gut bacteria, foods rich in polyunsaturated fatty acids (e.g., Omega-3), and avoiding diets high in saturated fats and refined sugars among others. While the exact mechanism(s) of mitigation of many nutritional interventions are yet to be fully understood, the evidence-based approach warrants the inclusion and co-recognition of nutrition in the management of psychiatric illnesses. For the greater public health benefit, there is a need for policy advocacy aimed at bridging the knowledge gap and encouraging the integration of nutritional intervention with contemporary therapies in clinical settings, as deficiencies of certain nutrients make therapy difficult even with appropriate medication.
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Igg Food Antibody Guided Elimination-Rotation Diet Was More Effective than FODMAP Diet and Control Diet in the Treatment of Women with Mixed IBS-Results from an Open Label Study.
Ostrowska, L, Wasiluk, D, Lieners, CFJ, Gałęcka, M, Bartnicka, A, Tveiten, D
Journal of clinical medicine. 2021;10(19)
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IBS, also known as irritable bowel syndrome, is a debilitating condition characterised by abdominal pain, irregular bowel movements, and changes in the consistency of stool. Symptoms of IBS may appear shortly after eating a meal. Excluding foods high in FODMAP carbohydrates, such as fermentable oligo- and di-saccharides, mono- and disaccharides, and polyols, or following an elimination rotation diet to reduce IgG-dependent food hypersensitivity, which has been shown to improve IBS symptoms previously. The purpose of this open-label study is to investigate the effectiveness of a low-FODMAPS diet and an elimination rotation diet based on IgG as well as a control diet in reducing symptoms of IBS. During the eight-week study, 73 female subjects with a mix of IBS were assigned to either of the three dietary treatments. Compared to the other diet groups, the IgG based elimination rotation diet group showed a significant improvement in the IBS symptoms and comorbid symptoms after the intervention period. In order to determine whether IgG-mediated food hypersensitivity plays a role in IBS and the efficacy of an IgG-dependent elimination rotation diet in the general population, further robust research is required. Healthcare professionals, however, can make use of these results to gain a better understanding of how an IgG based elimination diet tailored to each individual can improve IBS symptoms.
Expert Review
Conflicts of interest:
None
Take Home Message:
- After implementing the three diets, among patients with IBS-M, a statistically significant reduction of the frequency of the idiopathic abdominal pain, abdominal pain after a meal, abdominal pain during defecation, and sensation of incomplete defecation before and after the diet plans, were only found in Group 2.
- Significantly, only in the Group 2 IgG based elimination-rotation-diet was there a high decrease or complete disappearance of dyspeptic IBS symptoms and co-morbidities together with IBS symptoms.
- This study shows that a personalised dietary approach is more effective in treating IBS than generalised diet recommendations, with elimination diets focused on IgG antibodies providing the best results.
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:
Science supports the use of a low-FODMAP diet for symptom relief of IBS. However, more recently evidence suggests that IBS is a low-grade inflammatory disease that may result from or lead to IgG-dependent food hyper-sensitivities.
This study compared the effectiveness of three dietary treatment plans in 73 female patients diagnosed with mixed-form IBS based on Rome III criteria and no other gastrointestinal condition over 8 weeks.
The 3 dietary groups were:
- Group 1-low FODMAP diet
- Group 2- IgG based elimination-rotation-diet
- Group 3-control diet (control group)
Diets of G1 and G2 were determined individually by a dietitian, based on low-FODMAP dietary information and results from IgG food sensitivity testing respectively. Group 3 received nutrition advice from a gastroenterologist.
In G1, some of the IBS symptoms significantly improved (mucus in stool, p = 0.031; bloating, p < 0.001). Gurgling sensation and gastric fullness also reach statistical significance in G1.
IBS symptoms as well as co-morbid symptoms significantly improved or disappeared completely in G2 (idiopathic abdominal pain, p < 0.001; abdominal pain after a meal, p < 0.001; abdominal pain during defecation, p = 0.008; sensation of incomplete defecation p = 0.001; difficulty to defecate (constipation) p = 0.002; bloating p = < 0.001; gurgling sensation < 0.001; gastric fullness p = < 0.001. However, blood and mucus in the stool were impossible to test because the symptoms were not reported by any patient during the 2nd examination). (p-values less than 0.05 were considered statistically significant).
In group G3 no statistically significant improvements were seen in any measure.
Based on the results of this open-label study, it was concluded that personalised dietary interventions were more effective in the treatment of IBS-M patients than generalised diet recommendations. Dietary elimination based on IgG food sensitivity test results had the greatest impact on IBS and related symptoms.This study supports results from other studies showing an IgG-guided diet as an effective strategy in co-morbid conditions such as fatigue, headache/migraine, and skin conditions.
Conflicts of Interest
C.F.J.L., M.G. and A.B. are employees of the Institute of Microecology in Poznan ,where the ImuPro tests were determined. D.T. is the Head of Laboratory and shareholder of Lab1, offering ImuPro tests in Norway.
Clinical practice applications:
- Low FODMAP diets studies (NICE) showed GI improvements for abdominal pain, abdominal cramps, diarrhoea, gas, and bloating, largely because FODMAPs mainly cause an excessive production of gas, leading to discomfort and pain and an increased osmotic effect leading to increased bowel movement and diarrhoea. However 30% of patients still suffered from bloating on the FODMAP diet. Gurgling sensation decreased from 65% to 15%, and gastric fullness decreased from 58% to 11% in the patients on the low FODMAP diet.
- A potential new approach to resolve functional symptoms of gastrointestinal conditions could be to start with an IgG-guided elimination diet, as it was proven to be the more effective diet in this open study, and in cases of persistent symptoms, it could be combined with a low-FODMAP diet.
- Calprotectin is currently one of the best-known diagnostic markers indicating mucosa inflammation and changes in the inflammation intensity. In this study serious intestinal inflammation was diagnosed at the faecal calprotectin concentration of >50 mg/kg of stool. During the first examination, no statistically significant differences were found in calprotectin concentrations between the compared groups of patients, and the values were low, suggesting that the included patients suffered from low-grade inflammation and were suitable for diet alteration as the best choice of treatment.
Limitations:
- The main limitations of this study are the open-labeled nature, the low number of participants and the bias of only including female participants with only the patients in the G2 group tested for IgG food antibodies.
- Foods consumed by the patients before they entered the study were not ascertained.
Considerations for future research:
- Claims that IgG food antibodies only reveal exposure to food and not intolerance should be reinvestigated in larger double-blinded studies.
Abstract
Irritable bowel syndrome (IBS) is a chronic disease with recurrent abdominal pain, disturbed bowel emptying, and changes in stool consistency. We compared the effectiveness of three different dietary treatment plans (G1-FM-low FODMAP diet, G2-IP IgG based elimination-rotation-diet, and as control group, the G3-K control diet recommended by an attending gastroenterologist) in treating patients diagnosed with mixed irritable bowel syndrome. A total of seventy-three female patients diagnosed with a mixed form of irritable bowel syndrome (IBS-M) were enrolled in the study. The diet of each patient in Group 1 (G1-FM) and 2 (G2-IP) was determined individually during a meeting with a dietitian. Patients from Group 3 (G3-K) received nutrition advice from a gastroenterologist. Significant differences in the reduction of IBS symptoms were found between the groups. IBS symptoms as well as comorbid symptoms significantly improved or disappeared completely in the G2-IP group (idiopathic abdominal pain, p < 0.001; abdominal pain after a meal, p < 0.001; abdominal pain during defecation, p = 0.008), while in the G1-FM group, some of the IBS symptoms significantly improved (mucus in stool, p = 0.031; bloating, p < 0.001). In group G3-K no significant improvement was seen. Based on the results of this open-label study, it was concluded that various dietary interventions in the treatment of IBS-M patients do not uniformly affect the course and outcomes of disease management. Rotation diets based on IgG show significantly better results compared to other diets.
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A Low-Carbohydrate Diet Realizes Medication Withdrawal: A Possible Opportunity for Effective Glycemic Control.
Han, Y, Cheng, B, Guo, Y, Wang, Q, Yang, N, Lin, P
Frontiers in endocrinology. 2021;12:779636
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Many studies have shown that diet restrictions can help glycemic control and reduce metabolic risks in patients with type 2 diabetes mellitus (T2DM). The aim of this study was to look at the efficacy of two diets, the LCD and the low-fat diet (LFD), on glycemic control and clinical treatment. The study was a prospective, open-label, double-arm, randomized controlled trial conducted from March 2019 to December 2020 in China. 134 T2DM participants took part and they were randomly assigned to the LCD group or the low -fat diet (LFD) group. The following were measured at the beginning and end of each intervention: weight, fasting blood glucose (FBG), postprandial 2-h blood glucose (PPG), glycosylated haemoglobin (HbA1c), antiglycemic medications, and medications for other diseases and emerging diseases. The effect of decreasing blood glucose control with the LCD is superior to that of the LFD for Chinese patients with T2DM. It also led to a lower medication effects score (MES). It can reduce body weight, BMI, and lipid-lowering agents. Strict diet control and monitoring are the keys to managing diabetes. Further larger scale studies are needed to obtain more evidence.
Abstract
Objective: Multiple studies have confirmed that diet restrictions can effectively realize glycemic control and reduce metabolic risks in patients with type 2 diabetes mellitus (T2DM). In 2018, the American Diabetes Association (ADA) and European Association for the Study of Diabetes (EASD) stated that individuals can select a low-carbohydrate diet (LCD) according to their needs and preferences. Owing to the influence of Chinese traditional eating habits, only a small portion of patients in China have achieved their blood glucose goals. As a result, the Chinese government will incur huge expenditures. Method: This study recruited 134 T2DM participants and randomly assigned them to the LCD group (n = 67) or the low-fat diet (LFD) group (n = 67). All of the patients had a fixed amount of exercise and were guided by clinicians. After a period of dietary washout, all of the patients received corresponding dietary education according to group. The follow-up time was 6 months. The indicators for anthropometry, glycemic control, and medication application parameters were collected and compared between the two groups. Results: There were 121 participants who finally entered the study. The proportions of calories from three major nutrients the participants consumed met the requirements of LCD and LFD. Compared with baseline, the pre-postdifferences of body weight, BMI, and several other indicators were significant except for dosages of insulin used in the LCD group and MES in the LFD group. After the intervention, body weight, body weight index (BMI), fasting blood glucose (FBG), postprandial 2-h blood glucose (PPG), and glycosylated hemoglobin (HbA1c) levels in the LCD group decreased significantly (p < 0.05) compared with the LFD group. The number of patients using lipid-lowering agents was significant higher in the LCD group and lower in the LFD group. However, there was no significant difference between the two groups for antihypertensive, hormone-replacement, and other agents. Conclusions: The LCD diet can decrease body weight, glycemic levels, MES, and lipid-lowering agents more than the LFD diet, thus decreasing cost burden in Chinese patients with T2DM. Strict diet control and monitoring are the keys to managing diabetes.
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Effects of Low-Carbohydrate versus Mediterranean Diets on Weight Loss, Glucose Metabolism, Insulin Kinetics and β-Cell Function in Morbidly Obese Individuals.
Tricò, D, Moriconi, D, Berta, R, Baldi, S, Quinones-Galvan, A, Guiducci, L, Taddei, S, Mari, A, Nannipieri, M
Nutrients. 2021;13(4)
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Both low-carbohydrate and Mediterranean style diets are used to prevent lifestyle associated diseases such as obesity and type 2 diabetes. However, which diet is more effective is unclear. The aim of this randomised control trial of 36 morbidly obese individuals was to compare the effectiveness of Mediterranean diets and low-carbohydrate diets to improve metabolic measures such as blood sugar levels, pre-diabetes, and the body’s ability to use sugar. The results showed that in the short-term both diets were equally effective at improving biochemical dysfunctions that contribute to type 2 diabetes. The low-carbohydrate diet did result in higher weight loss than the Mediterranean diet. Studies on long-term effects are warranted. It was concluded that a low-carbohydrate diet is in the short-term a feasible alternative to the Mediterranean diet for improved weight loss and biological contributors to type 2 diabetes. This study could be used by healthcare professionals to understand that the Mediterranean diet and low-carbohydrate diet are both effective in the short-term for improvements to contributors to type 2 diabetes, however the low-carbohydrate diet may be superior if weight loss is required.
Abstract
Low-calorie Mediterranean-style or low-carbohydrate dietary regimens are widely used nutritional strategies against obesity and associated metabolic diseases, including type 2 diabetes. The aim of this study was to compare the effectiveness of a balanced Mediterranean diet with a low-carbohydrate diet on weight loss and glucose homeostasis in morbidly obese individuals at high risk to develop diabetes. Insulin secretion, insulin clearance, and different β-cell function components were estimated by modeling plasma glucose, insulin and C-peptide profiles during 75-g oral glucose tolerance tests (OGTTs) performed at baseline and after 4 weeks of each dietary intervention. The average weight loss was 5%, being 58% greater in the low-carbohydrate-group than Mediterranean-group. Fasting plasma glucose and glucose tolerance were not affected by the diets. The two dietary regimens proved similarly effective in improving insulin resistance and fasting hyperinsulinemia, while enhancing endogenous insulin clearance and β-cell glucose sensitivity. In summary, we demonstrated that a low-carbohydrate diet is a successful short-term approach for weight loss in morbidly obese patients and a feasible alternative to the Mediterranean diet for its glucometabolic benefits, including improvements in insulin resistance, insulin clearance and β-cell function. Further studies are needed to compare the long-term efficacy and safety of the two diets.
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The PREVIEW intervention study: Results from a 3-year randomized 2 x 2 factorial multinational trial investigating the role of protein, glycaemic index and physical activity for prevention of type 2 diabetes.
Raben, A, Vestentoft, PS, Brand-Miller, J, Jalo, E, Drummen, M, Simpson, L, Martinez, JA, Handjieva-Darlenska, T, Stratton, G, Huttunen-Lenz, M, et al
Diabetes, obesity & metabolism. 2021;23(2):324-337
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The main risk for the development of type 2 diabetes is being overweight or obese. Strategies to decrease weight are important to prevent its development or reverse disease. This long-term, randomised control trial of 2326 adults with prediabetes, aimed to compare the effectiveness of different maintenance diets, after initial weight loss; one which was high protein and low glycaemic index, and the other which was moderate protein and moderate glycaemic index. These diets were then combined with either moderate intensity or high intensity exercise. The results showed that after 3 years, the incidence of type 2 diabetes was low and did not differ between the diet and exercise groups. However, more individuals achieved normal blood sugar levels when on a moderate protein diet combined with moderate exercise and when on a high protein diet combined with moderate exercise. The high protein diet with high intensity exercise was the least effective at maintaining normal blood sugar levels. The amount of weight lost was the same no matter what combination of diet and exercise. It was concluded that the incidence of type 2 diabetes was lower than expected with the diet and exercise regimes and did not differ between the diets. This study could be used by healthcare professionals to introduce a long-term protocol combining weight loss, healthy eating, and physical activity to pre diabetic individuals who want to reduce their chance of developing type 2 diabetes.
Abstract
AIM: To compare the impact of two long-term weight-maintenance diets, a high protein (HP) and low glycaemic index (GI) diet versus a moderate protein (MP) and moderate GI diet, combined with either high intensity (HI) or moderate intensity physical activity (PA), on the incidence of type 2 diabetes (T2D) after rapid weight loss. MATERIALS AND METHODS A 3-year multicentre randomized trial in eight countries using a 2 x 2 diet-by-PA factorial design was conducted. Eight-week weight reduction was followed by a 3-year randomized weight-maintenance phase. In total, 2326 adults (age 25-70 years, body mass index ≥ 25 kg/m2 ) with prediabetes were enrolled. The primary endpoint was 3-year incidence of T2D analysed by diet treatment. Secondary outcomes included glucose, insulin, HbA1c and body weight. RESULTS The total number of T2D cases was 62 and the cumulative incidence rate was 3.1%, with no significant differences between the two diets, PA or their combination. T2D incidence was similar across intervention centres, irrespective of attrition. Significantly fewer participants achieved normoglycaemia in the HP compared with the MP group (P < .0001). At 3 years, normoglycaemia was lowest in HP-HI (11.9%) compared with the other three groups (20.0%-21.0%, P < .05). There were no group differences in body weight change (-11% after 8-week weight reduction; -5% after 3-year weight maintenance) or in other secondary outcomes. CONCLUSIONS Three-year incidence of T2D was much lower than predicted and did not differ between diets, PA or their combination. Maintaining the target intakes of protein and GI over 3 years was difficult, but the overall protocol combining weight loss, healthy eating and PA was successful in markedly reducing the risk of T2D. This is an important clinically relevant outcome.
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Type 2 diabetes preventive effects with a 12-months sardine-enriched diet in elderly population with prediabetes: An interventional, randomized and controlled trial.
Díaz-Rizzolo, DA, Serra, A, Colungo, C, Sala-Vila, A, Sisó-Almirall, A, Gomis, R
Clinical nutrition (Edinburgh, Scotland). 2021;40(5):2587-2598
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Older people have a higher risk of developing Type 2 diabetes (T2D) due to the possibility of β-cell dysfunction due to ageing. Sardines are believed to be protective against the development of T2D. Therefore, this randomised controlled trial evaluated the preventative effects of a sardine-rich diet in elderly prediabetic patients. For one year, both the sardine group (SG) and control group (CG) followed a T2D prevention diet, with the SG consuming 200 g of sardines each week. Both groups improved body weight, BMI, waist and hip circumference, and body composition. Taurine, EPA, DHA, omega-3 fatty acid, calcium, iodine, zinc, phosphorous and fluoride, vitamin B12 and D, and lycopene and tocopherols were found to be higher in the SG than the CG, indicating the sardines were protective against T2D. In SG, HDL cholesterol and adiponectin levels were significantly increased, and blood pressure and triglycerides were decreased, signalling a reduced risk of T2D and cardiovascular disease. In addition, SG showed a reduction in HOMA-IR and an Omega-3 fatty acid was substituted for Omega-6 fatty acids in the erythrocyte membrane, suggesting a reduced risk of T2D. Further robust research is required to confirm the protective effect of a sardine-enriched diet against T2D. It may be useful to healthcare providers to comprehend how a sardine-enriched diet could improve obesity, T2D and CVD markers in pre-diabetic elderly patients.
Abstract
BACKGROUND Fish could play a role in preventing type 2 diabetes (T2D) but there has been little specification about the type of fish and the preventive mechanism involved in its health claim. The sardine is a source of omega-3 and taurine that, in isolation or in synergy, would produce T2D-delaying through different molecular mechanism. HYPOTHESIS The consumption of twice a week of sardine, during one year would reduce T2D-developing risk in a population with prediabetes (preDM) and old age. DESIGN 152 subjects with fasting glucose between 100-124 mg/dL aged ≥65 yo were recruited from three primary care centers in Barcelona and were randomly distributed among two interventional groups: control group (CG) and sardine group (SG). Both groups received same T2D-prevention nutritional during a year but only SG had to add 200 g of sardine per week. All variables were collected before to start and at the end of the diet. (ClinicalTrials.gov: NCT03557541). RESULTS 152 people were randomized into CG (n=77) and SG (n=75) with 18 and 12 drop outs respectively. Subjects in SG, significantly compared to CG, decreased percentage classified-individuals in a very high risk group to develop T2D according to FINDRISC (p=0.035). In addition to increasing HDL-cholesterol and adiponectin and decreasing triglycerides (p<0.05) and blood pressure (<0.05), SG showed a lower HOMA-IR (p=0.032). The consumption of sardine characteristics nutrients as omega-3, EPA and DHA, vitamin D, fluorine and taurine were higher for SG (p<0.05). These results agreed with the increased of taurine, fatty acid (FA) omega-3 and bile acids circulating metabolites (p<0.05). Changes erythrocyte membrane FA were detected only in SG with a decrease of 5 omega-6 FA (p<0.001) and an increase of 3 omega-3 FA types (p<0.001). CONCLUSION We conclude that a year T2D-prevention diet with sardine supplementation has a greater protective effect against developing T2D and CV events.
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Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta-analysis of published and unpublished randomized trial data.
Goldenberg, JZ, Day, A, Brinkworth, GD, Sato, J, Yamada, S, Jönsson, T, Beardsley, J, Johnson, JA, Thabane, L, Johnston, BC
BMJ (Clinical research ed.). 2021;372:m4743
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Diet modification has long been recognised as a component for the treatment of diabetes. Diets low in carbohydrates have been extensively researched, as a diet for those with Type 2 Diabetes (T2D). This systematic review and meta-analysis aimed to determine the effect of low carbohydrate diets on T2D. The systematic review found 23 studies, including 1357 individuals, investigating the role of low carbohydrate diets on T2D outcomes. Low carbohydrate diet was defined as less than 130g of carbohydrate (less than 26% of calories from carbohydrate) for at least 12 weeks. Results reported at 6 months, found low carbohydrate diets were more effective than a normal diet at achieving diabetes remission. However, this effect diminished at 12 months, although longer term improvements were seen in blood lipids, weight loss and measures of prediabetes. It was concluded that individuals with T2D, eating a low carbohydrate diet for 6 months may reverse the disease. This study could be used by healthcare professionals to recommend a short-term low carbohydrate diet to individuals with T2D, to improve their chance of going into remission.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Type 2 diabetes remains a significant and worsening problem worldwide, despite many pharmaceutical developments and a global emphasis on glycemic control.
- This review highlights structured LCDs as a worthwhile option for the management and treatment of diabetes, providing an opportunity for Nutritional Therapy Practitioners to support clients in adopting evidence-informed, modifiable dietary and lifestyle changes for Type Two Diabetes.
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:
- Type 2 diabetes is the most common form of diabetes, accounting for 90-95% of cases.
- Previous randomised trials assessed low carbohydrate diets (LCDs) (<26-45% of daily calories from carbohydrate) as encouraging to improve blood glucose control and outcomes of type 2 diabetes but did not systematically assessed remission of diabetes using low carbohydrate diets (LCDs) and very low carbohydrate diets (VLCDs) for people with type 2 diabetes.
- Systematic reviews (SR) and meta-analyses represent the most valuable, reliable, and objective tool to summarise evidence from primary studies.
- This SR assessed 23 randomised controlled trials comparing LCDs with mostly low fat control diets in individuals / subjects / participants with type 2 diabetes. LCDs were defined as diets with less than 130 g/day or less than 26% of calories from carbohydrates, based on 2000 kcal/day. The authors used the Cochrane Risk of Bias tool 2.0 (RoB 2) to assess methodological quality of evidence, GRADE to assess the certainty of evidence
- On the basis of assessment of moderate to low certainty evidence, individuals / subjects / participants adhering to a LCD for six months may experience remission of type 2 diabetes without adverse consequences.
- Primary outcomes of interest were remission of type 2 diabetes (dichotomously defined as HbA1c <6.5% or fasting glucose <7.0 mmol/L), with or without the use of diabetes medication.
- Eight studies reported on remission of diabetes at six months. Pooled analysis showed that when remission was defined by an HbA1c level below 6.5% independent of medication use, LCDs increased remissions by an additional 32 per 100 patients followed (risk difference 0.32, 95% confidence interval 0.17 to 0.47; 8 studies, n=264; GRADE=moderate)
- When remission was defined by an HbA1c level below 6.5% and the absence of diabetes medication, LCDs increased remissions at a lower rate (risk difference 0.05, –0.05 to 0.14; 5 studies, n=199; GRADE=low)
- Additional primary outcomes were weight loss, HbA1c:
- 18 studies reported on Weight loss results (mean difference –3.46, 95% confidence interval –5.25 to –1.67; n=882 (note that positive results not sustained at 12 mo)
- Seventeen studies reported on HbA1c levels at six months, LCDs achieved greater reductions in HbA1c than did control diets (mean difference –0.47%, –0.60 to –0.34; n=747
- Limitations of study: 1) the definition of remission of diabetes, 2) Self-reported dietary intake data are prone to measurement error, particularly in dietary trials in which participants are not blinded
- This SR was funded in part by Texas A&M University.
- The authors declared no conflicts of interest.
Clinical practice applications:
The Authors highlight LCD diets incorporating carbohydrate of less than 130 g/day or less than 26% of calories (based on 2000 kcal/day) may be a safe strategy to help individuals with type 2 diabetes achieve weight loss and better blood glucose control over a six-month period. Results may not be sustained at 12 months.
Considerations for future research:
- The definition of diabetes remission needs clarification, especially with regard to threshold concentrations of Hb1Ac or fasting glucose and the use of diabetes medication.
- Safety concerns have been raised with LCDs. Although no significant or clinically important increase in total or serious adverse events was identified in this SR, these outcomes should be reported in future trials to confirm the certainty of evidence for safety.
- The Authors suggest long term, well designed, calorie controlled randomised trials are needed to determine the effects of LCD on sustained weight loss and remission of diabetes.
- Larger treatment effects for LCDs in shorter term trials (3 to <6 months), may be trialed as an effect modifier
Abstract
OBJECTIVE To determine the efficacy and safety of low carbohydrate diets (LCDs) and very low carbohydrate diets (VLCDs) for people with type 2 diabetes. DESIGN Systematic review and meta-analysis. DATA SOURCES Searches of CENTRAL, Medline, Embase, CINAHL, CAB, and grey literature sources from inception to 25 August 2020. STUDY SELECTION Randomized clinical trials evaluating LCDs (<130 g/day or <26% of a 2000 kcal/day diet) and VLCDs (<10% calories from carbohydrates) for at least 12 weeks in adults with type 2 diabetes were eligible. DATA EXTRACTION Primary outcomes were remission of diabetes (HbA1c <6.5% or fasting glucose <7.0 mmol/L, with or without the use of diabetes medication), weight loss, HbA1c, fasting glucose, and adverse events. Secondary outcomes included health related quality of life and biochemical laboratory data. All articles and outcomes were independently screened, extracted, and assessed for risk of bias and GRADE certainty of evidence at six and 12 month follow-up. Risk estimates and 95% confidence intervals were calculated using random effects meta-analysis. Outcomes were assessed according to a priori determined minimal important differences to determine clinical importance, and heterogeneity was investigated on the basis of risk of bias and seven a priori subgroups. Any subgroup effects with a statistically significant test of interaction were subjected to a five point credibility checklist. RESULTS Searches identified 14 759 citations yielding 23 trials (1357 participants), and 40.6% of outcomes were judged to be at low risk of bias. At six months, compared with control diets, LCDs achieved higher rates of diabetes remission (defined as HbA1c <6.5%) (76/133 (57%) v 41/131 (31%); risk difference 0.32, 95% confidence interval 0.17 to 0.47; 8 studies, n=264, I2=58%). Conversely, smaller, non-significant effect sizes occurred when a remission definition of HbA1c <6.5% without medication was used. Subgroup assessments determined as meeting credibility criteria indicated that remission with LCDs markedly decreased in studies that included patients using insulin. At 12 months, data on remission were sparse, ranging from a small effect to a trivial increased risk of diabetes. Large clinically important improvements were seen in weight loss, triglycerides, and insulin sensitivity at six months, which diminished at 12 months. On the basis of subgroup assessments deemed credible, VLCDs were less effective than less restrictive LCDs for weight loss at six months. However, this effect was explained by diet adherence. That is, among highly adherent patients on VLCDs, a clinically important reduction in weight was seen compared with studies with less adherent patients on VLCDs. Participants experienced no significant difference in quality of life at six months but did experience clinically important, but not statistically significant, worsening of quality of life and low density lipoprotein cholesterol at 12 months. Otherwise, no significant or clinically important between group differences were found in terms of adverse events or blood lipids at six and 12 months. CONCLUSIONS On the basis of moderate to low certainty evidence, patients adhering to an LCD for six months may experience remission of diabetes without adverse consequences. Limitations include continued debate around what constitutes remission of diabetes, as well as the efficacy, safety, and dietary satisfaction of longer term LCDs. SYSTEMATIC REVIEW REGISTRATION PROSPERO CRD42020161795.