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Effects of Intermittent Energy Restriction Compared with Those of Continuous Energy Restriction on Body Composition and Cardiometabolic Risk Markers - A Systematic Review and Meta-Analysis of Randomized Controlled Trials in Adults.
Schroor, MM, Joris, PJ, Plat, J, Mensink, RP
Advances in nutrition (Bethesda, Md.). 2024;15(1):100130
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Intermittent energy restriction (IER) diets, such as the 5:2 diet, time-restricted eating (TRE), and alternate-day fasting (ADF), are gaining popularity. According to previous research, IER protocols effectively manage obesity and may have many other health benefits, including improving metabolic health. This systematic review and meta-analysis of twenty-eight parallel-design randomised controlled trials looked at the benefits of IER protocols, such as ADF, TRE, and the 5:2 diet, and the effects of continuous energy restriction (CER) on anthropometric and cardiometabolic outcomes. The results of this systematic review and meta-analysis showed that both the IER and CER are equally beneficial. However, IER protocols showed greater but clinically insignificant improvements in fat-free mass and waist circumference in healthy adults. IER and CER protocols were not different in improving the lipid profile, glucose and insulin levels and blood pressure. Different IER diets showed different positive effects on metabolic parameters. Future robust studies are required to assess the effects of these energy-restriction diets on metabolic and anthropometric parameters because of the high variability in the included studies. However, healthcare professionals can use the results of this review to understand the potential clinical utility of various energy-restriction diets.
Abstract
The interest in intermittent energy restriction (IER) diets as a weight-loss approach is increasing. Different IER protocols exist, including time-restricted eating (TRE), alternate-day fasting (ADF), and the 5:2 diet. This meta-analysis compared the effects of these IER diets with continuous energy restriction (CER) on anthropometrics and cardiometabolic risk markers in healthy adults. Twenty-eight trials were identified that studied TRE (k = 7), ADF (k = 10), or the 5:2 diet (k = 11) for 2-52 wk. Energy intakes between intervention groups within a study were comparable (17 trials), lower in IER (5 trials), or not reported (6 trials). Weighted mean differences (WMDs) were calculated using fixed- or random-effects models. Changes in body weight [WMD: -0.42 kg; 95% confidence interval (CI): -0.96 to 0.13; P = 0.132] and fat mass (FM) (WMD: -0.31 kg; 95% CI: -0.98 to 0.36; P = 0.362) were comparable when results of the 3 IER diets were combined and compared with those of CER. All IER diets combined reduced fat-free mass (WMD: -0.20 kg; 95% CI: -0.39 to -0.01; P = 0.044) and waist circumference (WMD: -0.91 cm; 95% CI: -1.76 to -0.06; P = 0.036) more than CER. Effects on body mass index [BMI (kg/m2)], glucose, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), serum lipid and lipoprotein concentrations, and blood pressure did not differ. Further, TRE reduced body weight, FM, and fat-free mass more than CER, whereas ADF improved HOMA-IR more. BMI was reduced less in the 5:2 diet compared with CER. In conclusion, the 3 IER diets combined did not lead to superior improvements in anthropometrics and cardiometabolic risk markers compared with CER diets. Slightly greater reductions were, however, observed in fat-free mass and waist circumference. To what extent differences in energy intakes between groups within studies may have influenced these outcomes should be addressed in future studies.
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Reducing meat and/or dairy consumption in adults: a systematic review and meta-analysis of effects on protein intake, anthropometric values, and body composition.
Habumugisha, T, Engebretsen, IMS, Måren, IE, Kaiser, CWM, Dierkes, J
Nutrition reviews. 2024;82(3):277-301
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Reduced consumption of meat and dairy is being encouraged over climate change fears, and health implications. However, meat and dairy provide high quality protein and nutrients and concerns have grown over nutrient deficiencies in people on plant-based diets. This systematic review and meta-analysis of 19 randomised control trials (RCTs) aimed to determine the effect of a reduced meat/dairy diet in protein intake, and body shape and composition. The results showed that the RCTs included ran for a median duration of 12 weeks. Participants on a reduced meat/dairy diet had lower protein intakes, and reduced meat/dairy diet had no effect on body weight, body mass index, waist circumference, body fat, or muscle mass. It was concluded that a low meat/dairy diet decreases protein intake, however it does not affect body shape, or composition. It was also concluded that studies of longer duration are warranted to determine long-term effects. This study could be used by healthcare professionals to understand that reduced meat/dairy intake over a moderate period of time may have no effect on body shape or composition but will result in lower protein intakes.
Abstract
CONTEXT Consumers are increasingly encouraged to reduce meat and dairy consumption. However, few meta-analyses of randomized controlled trials (RCTs) on the effect of reducing meat and/or dairy on (absolute) protein intake, anthropometric values, and body composition are available. OBJECTIVE The aim of this systematic review and meta-analysis was to evaluate the effect of reducing meat and/or dairy consumption on (absolute) protein intake, anthropometric values, and body composition in adults aged ≥ 45 years. DATA SOURCES The MEDLINE, Cochrane CENTRAL, Embase, ClinicalTrials.gov, and International Clinical Trials Registry Platform databases were searched up to November 24, 2021. DATA EXTRACTION Randomized controlled trials reporting protein intake, anthropometric values, and body composition were included. DATA ANALYSIS Data were pooled using random-effects models and expressed as the mean difference (MD) with 95%CI. Heterogeneity was assessed and quantified using Cochran's Q and I2 statistics. In total, 19 RCTs with a median duration of 12 weeks (range, 4-24 weeks) and a total enrollment of 1475 participants were included. Participants who consumed meat- and/or dairy-reduced diets had a significantly lower protein intake than those who consumed control diets (9 RCTs; MD, -14 g/d; 95%CI, -20 to -8; I2 = 81%). Reducing meat and/or dairy consumption had no significant effect on body weight (14 RCTs; MD, -1.2 kg; 95%CI, -3 to 0.7; I2 = 12%), body mass index (13 RCTs; MD, -0.3 kg/m2; 95%CI, -1 to 0.4; I2 = 34%), waist circumference (9 RCTs; MD, -0.5 cm; 95%CI, -2.1 to 1.1; I2 = 26%), amount of body fat (8 RCTs; MD, -1.0 kg; 95%CI, -3.0 to 1.0; I2 = 48%), or lean body mass (9 RCTs; MD, -0.4 kg; 95%CI, -1.5 to 0.7; I2 = 0%). CONCLUSION Reduction of meat and/or dairy appears to reduce protein intake. There is no evidence of a significant impact on anthropometric values or body composition. More long-term intervention studies with defined amounts of meat and dairy are needed to investigate the long-term effects on nutrient intakes and health outcomes. SYSTEMATIC REVIEW REGISTRATION PROSPERO registration no. CRD42020207325.
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A starch- and sucrose-reduced diet may lead to improvement of intestinal and extraintestinal symptoms in more conditions than irritable bowel syndrome and congenital sucrase-isomaltase deficiency.
Roth, B, Ohlsson, B
Nutrition (Burbank, Los Angeles County, Calif.). 2024;117:112254
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Studies have shown that a starch and sucrose-reduced diet (SSRD) leads to considerable improvements of gastrointestinal and extraintestinal symptoms in patients with irritable bowel syndrome (IBS). The purpose of this pilot study was to see if a SSRD would be beneficial in other conditions with similar symptoms. Two people took part in the study. A man with functional diarrhoea and a woman with microscopic colitis. The SSRD consists of low intakes of sugar-rich products, but continued or increased intakes of all meats and fish, fat, natural dairy products, eggs, berries, fruits, nuts, seeds, and vegetables low in starch. Fiber-rich bread and pasta and raw or wild rice were recommended instead of white bread and more processed rice and pasta. During the 4-week intervention, the participants lost weight and waist circumference reduced. The degree of satiety after a meal was increased and the sweet cravings were strongly reduced. The gastrointestinal symptoms improved in the participant with diarrhoea but was unaffected in the participant with microscopic colitis. Reductions of diarrhoea and of bloating and flatulence were most pronounced in both patients. The psychological well-being was improved during the intervention. Extraintestinal symptoms were also reduced during the SSRD, especially urinary urgency and belching. This is a small intervention study and therefore not possible to make generalised claims or recommendations. However, healthcare practitioners could look at SSRD when working with IBS patients as a therapeutic dietary option.
Abstract
OBJECTIVES A starch- and sucrose-reduced diet has been found to improve gastrointestinal and extraintestinal symptoms in irritable bowel syndrome, as well as reduce weight and improve psychological well-being. Our hypothesis was that a starch- and sucrose-reduced diet would also be beneficial in other conditions with similar symptoms. The aim of the present research letter was to describe the role of a starch- and sucrose-reduced diet in a pilot project in patients with diarrhea having varying causes. METHODS One man, age 36 y, suffering from functional diarrhea and one woman, 56 y, suffering from microscopic colitis, were randomized to a starch- and sucrose-reduced diet for 4 wk. At baseline, dietary information was given, and blood samples collected. Weight and waist circumference were measured. The participants completed the irritable bowel syndrome severity scoring system for evaluating specific gastrointestinal and extraintestinal symptoms and visual analog scale for irritable bowel syndrome for evaluation of specific gastrointestinal symptoms and psychological well-being. The degrees of satiety and sweet craving were measured on visual analog scales. After 4 wk, all procedures were repeated. RESULTS Weight, body mass index, and waist circumference were decreased during the intervention. The total amount of gastrointestinal symptoms was decreased in the participants with functional diarrhea, and diarrhea and bloating were decreased in both participants. Both had reduced extraintestinal symptoms and improved psychological well-being. Blood levels had mainly unchanged or slightly increased values of measurements reflecting nutrient intake. CONCLUSIONS A starch- and sucrose-reduced diet may lead to weight reduction, reduced symptoms, and improved well-being in several patient categories, not only in patients suffering from irritable bowel syndrome. Future randomized trials should be done.
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Examining the Association between Coffee Intake and the Risk of Developing Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis.
Lee, JY, Yau, CY, Loh, CYL, Lim, WS, Teoh, SE, Yau, CE, Ong, C, Thumboo, J, Namasivayam, VSO, Ng, QX
Nutrients. 2023;15(22)
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Irritable bowel syndrome (IBS) is a highly prevalent disorder of brain–gut interaction with a significant impact on quality of life and social functioning. Diet has been implicated in the pathophysiology of IBS as well as disease flares. A significant proportion of IBS patients experience food-related symptoms associated with consuming or eliminating certain foods. This study's aim was to determine if there is an association between coffee intake and the likelihood of developing IBS. This study was a systematic review and meta-analysis of eight studies with 432,022 participants. Results showed that coffee drinkers (any intake) may have a decreased risk of developing IBS compared to controls. However, these findings must be interpreted in light of several shortcomings. Authors concluded that future studies should (1) prioritise high-quality prospective cohort studies with well-documented coffee consumption (and exposure) and track the development of incident IBS in previously healthy individuals over time, and (2) investigate biological mechanisms.
Abstract
Irritable bowel syndrome (IBS) is a highly prevalent disorder of brain-gut interaction with a significant impact on quality of life. Coffee is a widely consumed beverage with numerous bioactive compounds that have potential effects on human health and disease states. Current studies on the effect of regular coffee consumption on the risk of developing IBS symptoms have yielded conflicting results. This systematic review and meta-analysis aimed to determine whether coffee intake is associated with developing IBS. A systematic literature search was performed in three electronic databases, namely PubMed, EMBASE, and The Cochrane Library, from inception until 31 March 2023. All original studies reporting associations between coffee intake and IBS were considered for inclusion. Odds ratios (ORs) were calculated for each study, and estimates were pooled, and where appropriate, 95% confidence intervals (95% CI) and p-values were calculated. Eight studies comprising 432,022 patients were included in the final meta-analysis. Using a fixed-effects model, coffee drinkers (any intake) had a reduced likelihood of developing IBS compared to controls, with a pooled OR of 0.84 (95% CI: 0.80 to 0.84). Sensitivity analysis confirmed the stability of the estimates. Future research should prioritise prospective cohort studies that are robust and closely track the development of incident IBS in previously healthy individuals.
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Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons.
Barnes, LL, Dhana, K, Liu, X, Carey, VJ, Ventrelle, J, Johnson, K, Hollings, CS, Bishop, L, Laranjo, N, Stubbs, BJ, et al
The New England journal of medicine. 2023;389(7):602-611
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Lifestyle interventions targeting diet are a possible approach that could affect public health. Most clinical trials have investigated comprehensive diets, in contrast to dietary manipulation of single foods or nutrients. The aim of this study was to evaluate the effects of a 3-year dietary intervention on cognitive decline and brain-imaging markers of dementia and Alzheimer’s disease in older, cognitively unimpaired adults at risk for dementia because of family history. This study was a 3-year, two-site, randomised, controlled trial. The participants were randomly assigned to follow the MIND diet with mild caloric restriction for weight loss or their usual diet with the same mild caloric restriction for weight loss (control diet). Participants were randomly assigned in a 1:1 ratio. Results showed that the participants who followed the MIND diet had small improvements in a global measure of cognition that were similar to those who followed a control diet with mild caloric restriction. Authors concluded that brain health, cognitive function and brain imaging outcomes (after 3 years) did not differ significantly between participants who followed the MIND diet and those who followed a control diet with a mild caloric restriction.
Abstract
BACKGROUND Findings from observational studies suggest that dietary patterns may offer protective benefits against cognitive decline, but data from clinical trials are limited. The Mediterranean-DASH Intervention for Neurodegenerative Delay, known as the MIND diet, is a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet, with modifications to include foods that have been putatively associated with a decreased risk of dementia. METHODS We performed a two-site, randomized, controlled trial involving older adults without cognitive impairment but with a family history of dementia, a body-mass index (the weight in kilograms divided by the square of the height in meters) greater than 25, and a suboptimal diet, as determined by means of a 14-item questionnaire, to test the cognitive effects of the MIND diet with mild caloric restriction as compared with a control diet with mild caloric restriction. We assigned the participants in a 1:1 ratio to follow the intervention or the control diet for 3 years. All the participants received counseling regarding adherence to their assigned diet plus support to promote weight loss. The primary end point was the change from baseline in a global cognition score and four cognitive domain scores, all of which were derived from a 12-test battery. The raw scores from each test were converted to z scores, which were averaged across all tests to create the global cognition score and across component tests to create the four domain scores; higher scores indicate better cognitive performance. The secondary outcome was the change from baseline in magnetic resonance imaging (MRI)-derived measures of brain characteristics in a nonrandom sample of participants. RESULTS A total of 1929 persons underwent screening, and 604 were enrolled; 301 were assigned to the MIND-diet group and 303 to the control-diet group. The trial was completed by 93.4% of the participants. From baseline to year 3, improvements in global cognition scores were observed in both groups, with increases of 0.205 standardized units in the MIND-diet group and 0.170 standardized units in the control-diet group (mean difference, 0.035 standardized units; 95% confidence interval, -0.022 to 0.092; P = 0.23). Changes in white-matter hyperintensities, hippocampal volumes, and total gray- and white-matter volumes on MRI were similar in the two groups. CONCLUSIONS Among cognitively unimpaired participants with a family history of dementia, changes in cognition and brain MRI outcomes from baseline to year 3 did not differ significantly between those who followed the MIND diet and those who followed the control diet with mild caloric restriction. (Funded by the National Institute on Aging; ClinicalTrials.gov number, NCT02817074.).
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Effects of a low-protein nutritional formula with dietary counseling in older adults with chronic kidney disease stages 3-5: a randomized controlled trial.
Yang, WC, Hsieh, HM, Chen, JP, Liu, LC, Chen, CH
BMC nephrology. 2023;24(1):372
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Chronic kidney disease (CKD) is a prevalent clinical issue often observed in older adults. Nutritional management has become essential for older adults with CKD. Recent nutritional guidelines have suggested that a low-protein diet (LPD) can be prescribed. The aim of this study was to compare the effects of a regular LPD alone or a 6% LPF combined with a regular LPD prescription on nutrition status, physical performance, and clinical parameter changes in older adults with CKD stages 3–5. This study was a single-centre, two-armed, open-label, parallel, randomised controlled clinical trial. Participants were allocated at a 1:1 ratio - (1) the control group, patients received a regular LPD prescription; (2) the intervention group, patients received a regular LPD prescription with 6% LPF. Results showed that an LPD plus a 6% LPF provided no changes in energy and protein intake while increasing fatty acid and specific micronutrient intake during the 3-month follow-up period. Furthermore, blood urea nitrogen (clinical parameter) was significantly reduced in the intervention group over three months. Authors concluded that an LPD prescription with a 6% LPF can delay physical performance deterioration and increase micronutrient intake in three months compared to LPD education alone in older adults with CKD stages 3–5.
Abstract
BACKGROUND Although combining a low-protein diet (LPD) with oral nutritional supplements increases treatment adherence and nutritional status in patients with chronic kidney disease (CKD), the effect of this combination approach in older adults remains unclear. This study examined the impact of a 6% low-protein formula (6% LPF) with diet counseling in older adults with stage 3-5 CKD. METHODS In this three-month randomized controlled study, 66 patients (eGFR < 60 mL/min/1.73 m2, non-dialysis, over 65 years of age) were randomly assigned to an intervention group (LPD plus a 6% LPF) or control group (LPD alone). The 6% LPF comprised 400 kcal, 6 g of protein, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and various micronutrients. All data were collected at baseline and after three months, including physical performance based on hand grip strength (HGS) and gait speed, nutritional status using Mini Nutritional Assessment-Short Form (MNA-SF) scores, body composition through bioelectrical impedance analysis, and dietary intake from 24-h dietary records. RESULTS This study incorporated 47 participants (median age, 73; median eGFR, 36 ml/min/1.73 m2; intervention group: 24; control group: 23). The intervention group exhibited significant differences in HGS and gait speed, and micronutrient analysis revealed significantly higher monounsaturated fatty acids (MUFA), EPA, DHA, calcium, iron, zinc, copper, thiamine, riboflavin, niacin, B6, B12, and folic acid intake than the control group. MNA-SF scores, macronutrient intake, and body composition did not differ significantly between the two groups. CONCLUSIONS Compared to LPD counseling alone, an LPD prescription with 6% LPF in older adults with CKD stages 3-5 helped relieve physical deterioration and increased micronutrient intake after three months. TRIAL REGISTRATION ClinicalTrials.gov NCT05318014 (retrospectively registered on 08/04/2022).
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Modulating the Gut Microbiome in Multiple Sclerosis Management: A Systematic Review of Current Interventions.
Tsogka, A, Kitsos, DK, Stavrogianni, K, Giannopapas, V, Chasiotis, A, Christouli, N, Tsivgoulis, G, Tzartos, JS, Giannopoulos, S
Journal of clinical medicine. 2023;12(24)
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Multiple sclerosis (MS) is an autoimmune disease caused by the altered immune system mistakenly attacking the central nervous system. While genetics play a leading causative role in the manifestation of this disease, other contributing environmental factors can also exist, such as a disruption in the intestinal microbial composition. Previous research has shown that the bidirectional communication between the brain's and gut's health, also known as the gut-brain axis, may contribute to the prognosis of MS. Modulating gut microbial composition can be a therapeutic strategy in MS patients to manage symptoms and prevent disease progression. This systematic review assessed different protocols for modulating gut microbial composition, including dietary modifications, probiotic use, intermittent fasting, and faecal microbial transplantation. The review included thirteen studies that compared the effects of the above gut microbial modulation intervention protocols in MS patients with healthy participants. While different dietary modification strategies improved MS symptoms, probiotic supplementations and intermittent fasting reduced inflammation, and faecal microbial transplantation showed promising positive effects in a few reports. Due to the methodological limitations of the included studies, further robust studies are required to evaluate the beneficial effects of gut microbial modulation strategies in reducing the symptoms of MS patients. However, healthcare professionals can use the results of this study to understand the benefits of gut microbial modulation in MS patients.
Abstract
This review attempted to explore all recent clinical studies that have investigated the clinical and autoimmune impact of gut microbiota interventions in multiple sclerosis (MS), including dietary protocols, probiotics, fecal microbiota transplantation (FMT), and intermittent fasting (IF). Methods: Thirteen studies were held between 2011 and 2023 this demonstrated interventions in gut microbiome among patients with MS and their impact the clinical parameters of the disease. These included specialized dietary interventions, the supply of probiotic mixtures, FMT, and IF. Results: Dietary interventions positively affected various aspects of MS, including relapse rates, EDSS disability scores, MS-related fatigue, and metabolic features. Probiotic mixtures showed promising results on MS-related fatigue, EDSS parameters, inflammation; meanwhile, FMT-though a limited number of studies was included-indicated some clinical improvement in similar variables. IF showed reductions in EDSS scores and significant improvement in patients' emotional statuses. Conclusions: In dietary protocols, clinical MS parameters, including relapse rate, EDSS, MFIS, FSS, and MSQoL54 scales, were significantly improved through the application of a specific diet each time. Probiotic nutritional mixtures promote a shift in inflammation towards an anti-inflammatory cytokine profile in patients with MS. The administration of such mixtures affected disability, mood levels, and quality of life among patients with MS. FMT protocols possibly demonstrate a therapeutic effect in some case reports. IF protocols were found to ameliorate EDSS and FAMS scores. All interventional means of gut microbiome modulation provided significant conclusions on several clinical aspects of MS and highlight the complexity in the relationship between MS and the gut microbiome.
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Advancements in Nutritional Strategies for Gestational Diabetes Management: A Systematic Review of Recent Evidence.
Sánchez-García, JC, Saraceno López-Palop, I, Piqueras-Sola, B, Cortés-Martín, J, Mellado-García, E, Muñóz Sánchez, I, Rodríguez-Blanque, R
Journal of clinical medicine. 2023;13(1)
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Gestational Diabetes Mellitus (GDM) causes hyperglycaemia due to the deficit of insulin during pregnancy. Dietary and lifestyle management plays a vital role in maintaining glycaemic control in women with GDM to avoid health risks to the mother and baby. Therefore, this systematic review of fourteen randomised controlled trials evaluated the latest research advancements to identify effective nutritional strategies for managing hyperglycaemia in women with GDM. Among all the dietary strategies implemented in the included randomised controlled trials, probiotic supplementation and supplementation of probiotics and vitamin D were most effective in GDM. Further robust studies are required to evaluate the potential effectiveness of different nutritional strategies for managing GDM. Healthcare professionals can use the results of this systematic review to understand the latest evidence supporting nutritional strategy for women with GDM and the need for personalised support for managing hyperglycaemia in GDM.
Abstract
Gestational diabetes mellitus (GDM) is defined as hyperglycaemia first detected at any time during pregnancy with values lower than those determined by the WHO for diabetes diagnosis in adults. This pathology, with a worldwide prevalence of 13.4%, causes significant maternal and foetal risks. The first line of treatment consists of maintaining normo-glycaemia through an adequate diet and lifestyle changes. The aim is to synthesize the scientific evidence updating the nutritional recommendations for the effective management of GDM. A systematic review of the scientific literature was conducted following the PRISMA guidelines. Randomized clinical trials published within the last five years and providing information on nutritional recommendations to achieve an effective management of gestational diabetes were selected. The databases searched were PubMed, the WOS Core Collection, SCOPUS, and CINAHL, using the MeSH terms: "Diabetes, Gestational"; "Nutrition Assessment (nutrition*)"; "Diet"; "Eating"; and "Food"; with the Boolean operators "AND" and "OR". The PEDro scale (Physiotherapy Evidence Database) was used to assess the scientific quality of the studies, with a mean score of 8.9, indicating an average good scientific quality. Results: A total of 809 papers were collected, of which, after applying the inclusion and exclusion criteria, 14 randomized clinical trials were selected. Probiotic supplementation and co-supplementation with vitamin D have been found to be the most beneficial options for both mothers with GDM and neonates, but the most effective regimens are not known. Diets enriched with extra virgin olive oil (EVOO) and oat bran, as well as some recommendations focused on carbohydrates also seem effective, as well as diets designed for this group of women with GDM such as "CHOICE". Conclusions: Although there are numerous proposals that have been published in recent years focused on the diet of women with GDM in order to improve their results and those of their children, it is the supplementation with probiotics and the co-supplementation with vitamin D that is most agreed upon as beneficial; however, more research is needed into which protocols are most effective. Other proposals that could also be beneficial should be further studied.
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Life expectancy can increase by up to 10 years following sustained shifts towards healthier diets in the United Kingdom.
Fadnes, LT, Celis-Morales, C, Økland, JM, Parra-Soto, S, Livingstone, KM, Ho, FK, Pell, JP, Balakrishna, R, Javadi Arjmand, E, Johansson, KA, et al
Nature food. 2023;4(11):961-965
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The mortality rate is rising in the United Kingdom (UK) due to the poor quality dietary patterns among the general population. Public Health England and the UK government recommend the population eat a healthy balanced diet based on the Eatwell Guide. Adherence to the Eatwell Guide dietary pattern could reduce the mortality rate among the general population in the UK. This research estimated the benefits of sustainably changing the unhealthy dietary pattern to the Eatwell Guide or longevity-associated dietary pattern on life expectancy in the UK. Longevity-associated dietary pattern is based on a moderate consumption of whole grains, fruit, fish and white meat; a substantial consumption of dairy, vegetables, nuts and legumes; a comparatively low consumption of eggs, red meat and sugar-sweetened beverages; and a low consumption of refined grains and processed meat. The unhealthy dietary pattern included limited amounts of whole grains, vegetables, fruits, nuts, legumes, fish, milk and dairy, and white meat and high consumption of processed meat, eggs, refined grains and sugar-sweetened beverages. This peer-reviewed review used prospective population-based cohort data from the UK Biobank. In UK adults aged 40 years, the change from an unhealthy dietary pattern to the Eatwell guide added 8.9 years in males and 8.6 years in females to their life expectancy. Furthermore, sustained adherence to the Eatwell guide increased life expectancy up to 10.8 years in males and 10.4 years in females. Further robust studies are required to evaluate the correlation between life expectancy and different food groups due to the limitations of the current research. However, healthcare professionals can use the results of this research to develop health policies and to understand the beneficial effect of following the Eatwell Guide or longevity dietary pattern in increasing life expectancy in middle-aged men and women in the UK.
Abstract
Adherence to healthy dietary patterns can prevent the development of non-communicable diseases and affect life expectancy. Here, using a prospective population-based cohort data from the UK Biobank, we show that sustained dietary change from unhealthy dietary patterns to the Eatwell Guide dietary recommendations is associated with 8.9 and 8.6 years gain in life expectancy for 40-year-old males and females, respectively. In the same population, sustained dietary change from unhealthy to longevity-associated dietary patterns is associated with 10.8 and 10.4 years gain in life expectancy in males and females, respectively. The largest gains are obtained from consuming more whole grains, nuts and fruits and less sugar-sweetened beverages and processed meats. Understanding the contribution of sustained dietary changes to life expectancy can provide guidance for the development of health policies.
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Mediterranean diet and structural neuroimaging biomarkers of Alzheimer's and cerebrovascular disease: A systematic review.
Gregory, S, Pullen, H, Ritchie, CW, Shannon, OM, Stevenson, EJ, Muniz-Terrera, G
Experimental gerontology. 2023;172:112065
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Nearly a million people in the UK have Alzheimer's disease, the most common type of dementia. Mediterranean diet (MedDiet) adherence is associated with healthy brain ageing, a reduced stroke risk, and a lower incidence of dementia. Seven studies were included in this review to evaluate the effects of MedDiet on hippocampal volume and white matter hyperintensity volume, predictors of stroke and dementia. This systematic review did not reveal any associations between MedDiet adherence and hippocampal volume. However, there was a significant negative relationship between MedDiet adherence and white matter hyperintensity volume in two of the studies included. It is necessary to conduct more robust studies to investigate the associations between MedDiet adherence and structural brain imaging findings and understand the mechanisms behind dementia and other cerebrovascular diseases. This study could provide healthcare professionals with valuable information about the effects of increased MedDiet adherence on brain health, including its potential to delay neurodegenerative disease progression.
Expert Review
Conflicts of interest:
None
Take Home Message:
Due to inconclusive results on the associations between MedDiet adherence and AD and cerebrovascular related structural neuroimaging findings, specific recommendations for the MedDiet cannot be made on the basis of this study until further research has been completed.
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:
Changes in hippocampal volume (HV) and white matter intensity volume (WMIV) have been identified as structural neuroimaging biomarkers of neurodegenerative disease such as Alzheimer’s Disease (AD) and Cerebrovascular disease (CVD) respectively. Evidence has shown adherence to the Mediterranean Diet (MedDiet) has been associated with reduced risk for strokes. This review evaluated the MedDiet in relation to HV and WMIV.
Methods:
The review followed PRISMA guidelines and was registered on PROSPERO. Literature searching resulted in seven studies published between 2012 and 2022, which met the inclusion criteria. Six studies analysed cross-sectional data and one analysed longitudinal data. The NIH Quality Assessment Tool for Observational and Cross-Sectional Studies was used to assess risk of bias.
Overall, the studies were rated as low-risk of bias with details of the research question, participant group exposure and outcome variables included. Due to moderate to high heterogeneity in some studies, a meta-analysis was deemed unsuitable and narrative synthesis was conducted to present the results.
Results:
Mean participant age ranged from 53.19 to 80.3 years and volunteers were healthy or had subjective cognitive decline and a few participants had dementia (n=46).
Hippocampal Volume:
Four studies included 20,077 participants and found no significant associations between MedDiet adherence and hippocampal volume. All four studies were cross-sectional from larger cohort studies. To establish causative relationships longitudinal and RCT trials are required.
White Matter Hyperintensity Volumes:
Four studies included 1938 participants. Two studies found a significant negative association between MedDiet and WMHV, demonstrating higher Mediterranean Scores were associated with lower level of WHMV. The other two studies found no significant associations.
Although the review methodology with a piloted search strategy was considered a key strength, the lack of meta-analysis as planned in the a priori protocol, due to minimal eligible studies and high heterogeneity was a limitation as well as the restriction of brain imaging outcomes.
Conclusion:
Overall, these results are inconclusive on the associations between the MedDiet and HV and WMHV, and identify a gap in the knowledge, therefore further research such as RCT’s remains a priority to further understand the impact diet may have on neuroimaging markers of AD and CVD.
Clinical practice applications:
There were no significant associations between MedDiet adherence and HV, which was surprising given the evidence stating adherence to the MedDiet is associated with a lower incidence of dementia and stroke. However all four studies were cross-sectional studies and in order to detect causal associations, longitudinal and RCT’s are needed. Two studies did show a significant association between higher MedDiet adherence and lower WMHV, whereas two studies reported no significant associations.
Caution needs to be taken when recommending the MedDiet specifically for a reduction in HV and WMHV until further research has been undertaken.
Considerations for future research:
Future research should consider:
- larger cohorts and participants from the Mediterranean region where lifelong adherence to the MedDiet is more likely.
- looking at other risk factors to include obesity, lack of activity, poor sleep quality and stress.
- evaluating different socio-economic status, which has been shown to impact dietary behaviour.
- alternative imaging outcomes such as cortical thinning, PET amyloid and tau.
- . gold standard for methodology in particular dietary analysis and scanning and outcome derivation.
Abstract
Previous studies have demonstrated an association between adherence to the Mediterranean diet (MedDiet) and better cognitive performance, lower incidence of dementia and lower Alzheimer's disease biomarker burden. The aim of this systematic review was to evaluate the evidence base for MedDiet associations with hippocampal volume and white matter hyperintensity volume (WMHV). We searched systematically for studies reporting on MedDiet and hippocampal volume or WMHV in MedLine, EMBASE, CINAHL and PsycInfo. Searches were initially carried out on 21st July 2021 with final searches run on 23rd November 2022. Risk of bias was assessed using the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Of an initial 112 papers identified, seven papers were eligible for inclusion in the review reporting on 21,933 participants. Four studies reported on hippocampal volume, with inconclusive or no associations seen with MedDiet adherence. Two studies found a significant association between higher MedDiet adherence and lower WMHV, while two other studies found no significant associations. Overall these results highlight a gap in our knowledge about the associations between the MedDiet and AD and cerebrovascular related structural neuroimaging findings.