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The Effects of Dairy Product and Dairy Protein Intake on Inflammation: A Systematic Review of the Literature.
Nieman, KM, Anderson, BD, Cifelli, CJ
Journal of the American College of Nutrition. 2021;40(6):571-582
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Systemic inflammation contributes to the risk and progression of chronic disease, which is in turn influenced by several factors including diet. The aim of this study was to conduct a systematic review to evaluate the effect of dairy products and dairy protein on markers of inflammation in adults that do not have inflammatory-related disorders. The authors analysed 27 previous randomised controlled trial, of which 19 looked at dairy products, and eight looked at dairy protein (casein or whey). In the trials which evaluated dairy products, 10 reported no effect of the intervention, while eight reported a reduction in at least one biomarker of inflammation. All eight trials that investigated dairy protein intake on markers of inflammation reported no effect. The researchers concluded that the available literature suggests that dairy products and dairy proteins have neutral to beneficial effects on biomarkers of inflammation. Additional clinical studies designed using inflammatory biomarkers as the primary outcome are needed to fully understand the effects of dairy intake on inflammation.
Abstract
Systemic inflammation is associated with obesity and chronic disease risk. Intake of dairy foods is associated with reduced risk of type 2 diabetes and cardiovascular disease; however, the impact of dairy foods on inflammation is not well-established. The objective of this study was to conduct a systematic review to evaluate the effect of dairy product (milk, cheese, and yogurt) and dairy protein consumption on low-grade systemic inflammation in adults without severe inflammatory disorders. A literature search was completed in September 2019 using PubMed and CENTRAL as well as inspection of reference lists from relevant review articles. The search resulted in the identification of 27 randomized controlled trials which were included in this analysis. In the 19 trials which evaluated dairy products, 10 reported no effect of the intervention, while 8 reported a reduction in at least one biomarker of inflammation. All 8 trials that investigated dairy protein intake on markers of inflammation reported no effect of the intervention. The available literature suggests that dairy products and dairy proteins have neutral to beneficial effects on biomarkers of inflammation. Additional clinical studies designed using inflammatory biomarkers as the primary outcome are needed to fully elucidate the effects of dairy intake on inflammation.
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Coping Strategies Influence Cardiometabolic Risk Factors in Chronic Psychological Stress: A Post Hoc Analysis of A Randomized Pilot Study.
Armborst, D, Bitterlich, N, Alteheld, B, Rösler, D, Metzner, C, Siener, R
Nutrients. 2021;14(1)
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Chronic psychological stress is increasingly recognized as a significant contributor to mental and physiological disorders in modern societies. The individual response to chronic stressors and resulting disorders depends on numerous factors. The aim of this study was to investigate the cardiometabolic risk profile in participants with ‘high’ and ‘very high’ chronic stress loads and the impact of positive and negative coping factors used. This study is a post hoc analysis of a randomised pilot study. For this analysis, baseline data were available for 62 chronic psychologically stressed participants, of whom 61 participants (43 women and 18 men) were included in the intention-to-treat (ITT) population. Results indicate that: - perceiving high chronic stress is significantly associated with the criteria of the metabolic syndrome. - on the contrary, a very high perceived chronic stress load seemed to be rather associated with mental health risk than with cardiometabolic risk. - inflammation and oxidative stress markers significantly correlated with cardiometabolic risk parameters. - stress load can be coped with in diverse ways and that the coping strategy is crucial for cardiometabolic risk. Authors conclude that long-term studies are necessary to examine further adaptations to chronic stress and to evaluate individual stress-management strategies.
Abstract
Chronic psychological stress can result in physiological and mental health risks via the activation of the hypothalamic-pituitary-adrenal (HPA) axis, sympathoadrenal activity and emotion-focused coping strategies. The impact of different stress loads on cardiometabolic risk is poorly understood. This post hoc analysis of a randomized pilot study was conducted on 61 participants (18-65 years of age) with perceived chronic stress. The Perceived Stress Questionnaire (PSQ30), Psychological Neurological Questionnaire (PNF), anthropometric, clinical and blood parameters were assessed. Subjects were assigned to 'high stress' (HS; PSQ30 score: 0.573 ± 0.057) and 'very high stress' (VHS; PSQ30 score: 0.771 ± 0.069) groups based on the PSQ30. Morning salivary cortisol and CRP were elevated in both groups. Visceral adiposity, elevated blood pressure and metabolic syndrome were significantly more frequent in the HS group vs. the VHS group. The fatty liver index (FLI) was higher (p = 0.045), while the PNF score was lower (p < 0.001) in the HS group. The HS group was comprised of more smokers (p = 0.016). Energy intake and physical activity levels were similar in both groups. Thus, high chronic stress was related to visceral adiposity, FLI, elevated blood pressure and metabolic syndrome in the HS group, while very high chronic stress was associated with psychological-neurological symptoms and a lower cardiometabolic risk in the VHS group, probably due to different coping strategies.
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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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Eight-hour time-restricted feeding improves endocrine and metabolic profiles in women with anovulatory polycystic ovary syndrome.
Li, C, Xing, C, Zhang, J, Zhao, H, Shi, W, He, B
Journal of translational medicine. 2021;19(1):148
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Polycystic ovary syndrome (PCOS) is one of the most common reproductive endocrine and metabolic disorders that affects up to 10% women of childbearing age. The aim of this study was to explore the effects of time-restricted feeding (TRF) on menstruation, gonadal and metabolic parameters in women with anovulatory PCOS and propose a basis for its inclusion in the treatment of PCOS. This study is a 6-week trial with 2 consecutive periods: (1) 1-week baseline weight stabilization period; and (2) 5-week TRF period. Fifteen subjects were included in the study whose age varied between 18 and 31 years. Results show that five weeks of TRF improved menstruation, gonadal profiles, body weight, body mass index, body composition profiles, hyperinsulinemia and insulin resistance profiles, decreasing chronic inflammation markers and increasing insulin growth factor –1 [hormone]. Authors conclude that TRF may be suitable for PCOS women with appropriate counselling and patient management.
Abstract
BACKGROUND Time-restricted feeding (TRF) is a form of intermittent fasting, which is beneficial for weight loss and cardiometabolic health. Polycystic ovary syndrome (PCOS) is one of the most common reproductive endocrine and metabolic diseases affecting women of childbearing age. It is associated with an increased prevalence of metabolic syndrome, cardiovascular diseases and type 2 diabetes. The effects of TRF on PCOS patients remains undefined, here we investigated the impact of TRF on women with anovulatory PCOS. METHODS Eighteen PCOS women aged between 18 and 31 with anovulation participated in a 6-week trial which were divided into two consecutive periods: (1) 1-week baseline weight stabilization period and (2) 5-week TRF period. Fifteen participants completed the study. Changes in body weight, body mass index (BMI), Waist-to-Hip Ratio, skeletal muscle mass, body fat mass (BFM), body fat percentage (BF%), visceral fat area (VFA), luteinizing hormone (LH), follicle-stimulating hormone (FSH), LH/FSH, total testosterone (TT), sex hormone-binding globulin (SHBG), free androgen index (FAI), fasting glucose, fasting insulin (FINS), homeostasis model assessment-insulin resistance (HOMA-IR), area under the curve (AUC) for insulin (AUCIns), area under the curve (AUC) for glucose (AUCGlu), AUCIns/AUCGlu Ratio, lipids, uric acid, alanine aminotransferase (ALT), aspartate aminotransferase, high-sensitivity C-reactive protein (hsCRP), insulin-like growth factor (IGF-1), menstrual cycle and eating behaviors were evaluated. RESULTS Significant changes in body weight, BMI, BFM, BF%, VFA, TT, SHBG, FAI, FINS, HOMA-IR, AUCIns, AUCIns/AUCGlu Ratio, ALT, hsCRP and IGF-1 were found after the TRF period. An improvement in menstrual cycle irregularity was detected in 73.3% (11/15) patients. CONCLUSION The diet of TRF may be beneficial to anovulatory PCOS on weight loss especially reducing body fat, improving menstruation, hyperandrogenemia, insulin resistance and chronic inflammation. Trial registration Clinicaltrial.gov, NCT04580433, registered October 8, 2020, https://clinicaltrials.gov/ct2/show/NCT04580433.
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Randomized crossover trial of a modified ketogenic diet in Alzheimer's disease.
Phillips, MCL, Deprez, LM, Mortimer, GMN, Murtagh, DKJ, McCoy, S, Mylchreest, R, Gilbertson, LJ, Clark, KM, Simpson, PV, McManus, EJ, et al
Alzheimer's research & therapy. 2021;13(1):51
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Most people with dementia have Alzheimer’s disease (AD), a disorder that characteristically results in progressive cognitive and functional decline. Brain energy metabolism is impaired in AD. Ketogenic diets can theoretically mitigate impaired brain energy metabolism in AD, leading to improved cognition, daily function, or quality of life. Ketogenic diets are high-fat, low-carbohydrate diets that shift the body towards fat metabolism. The aim of this study was to determine whether a 12-week modified ketogenic diet was well-tolerated and improved cognition, daily function, or quality of life in a hospital clinic of AD patients. This study is a single-phase, assessor-blinded, two-period randomised crossover trial. Participants (n=26) were randomised (1:1 allocation) to a modified ketogenic diet (intervention diet) or their usual diet supplemented with low-fat healthy-eating guidelines and optional recipes (control diet). Results show that high rates of retention and adherence are achievable by following a 12-week modified ketogenic diet to AD patients. Compared with a usual diet supplemented with low-fat healthy-eating guidelines, patients on the ketogenic diet improved in daily function and quality of life. Furthermore, changes in cardiovascular risk factors were mostly favourable and adverse effects were mild. Authors conclude that ketogenic diets may hold promise as viable and effective treatment strategies in AD, but larger and longer studies are needed in order to draw definitive conclusions.
Abstract
BACKGROUND Brain energy metabolism is impaired in Alzheimer's disease (AD), which may be mitigated by a ketogenic diet. We conducted a randomized crossover trial to determine whether a 12-week modified ketogenic diet improved cognition, daily function, or quality of life in a hospital clinic of AD patients. METHODS We randomly assigned patients with clinically confirmed diagnoses of AD to a modified ketogenic diet or usual diet supplemented with low-fat healthy-eating guidelines and enrolled them in a single-phase, assessor-blinded, two-period crossover trial (two 12-week treatment periods, separated by a 10-week washout period). Primary outcomes were mean within-individual changes in the Addenbrookes Cognitive Examination - III (ACE-III) scale, AD Cooperative Study - Activities of Daily Living (ADCS-ADL) inventory, and Quality of Life in AD (QOL-AD) questionnaire over 12 weeks. Secondary outcomes considered changes in cardiovascular risk factors and adverse effects. RESULTS We randomized 26 patients, of whom 21 (81%) completed the ketogenic diet; only one withdrawal was attributed to the ketogenic diet. While on the ketogenic diet, patients achieved sustained physiological ketosis (12-week mean beta-hydroxybutyrate level: 0.95 ± 0.34 mmol/L). Compared with usual diet, patients on the ketogenic diet increased their mean within-individual ADCS-ADL (+ 3.13 ± 5.01 points, P = 0.0067) and QOL-AD (+ 3.37 ± 6.86 points, P = 0.023) scores; the ACE-III also increased, but not significantly (+ 2.12 ± 8.70 points, P = 0.24). Changes in cardiovascular risk factors were mostly favourable, and adverse effects were mild. CONCLUSIONS This is the first randomized trial to investigate the impact of a ketogenic diet in patients with uniform diagnoses of AD. High rates of retention, adherence, and safety appear to be achievable in applying a 12-week modified ketogenic diet to AD patients. Compared with a usual diet supplemented with low-fat healthy-eating guidelines, patients on the ketogenic diet improved in daily function and quality of life, two factors of great importance to people living with dementia. TRIAL REGISTRATION This trial is registered on the Australia New Zealand Clinical Trials Registry, number ACTRN12618001450202 . The trial was registered on August 28, 2018.
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Effects of DHA-Rich n-3 Fatty Acid Supplementation and/or Resistance Training on Body Composition and Cardiometabolic Biomarkers in Overweight and Obese Post-Menopausal Women.
Félix-Soriano, E, Martínez-Gayo, A, Cobo, MJ, Pérez-Chávez, A, Ibáñez-Santos, J, Palacios Samper, N, Goikoetxea Galarza, I, Cuervo, M, García-Unciti, M, González-Muniesa, P, et al
Nutrients. 2021;13(7)
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Menopause may increase risk for chronic diseases such as obesity, osteoporosis and type 2 diabetes. Interventions to limit menopausal changes such as diet and exercise may improve outcomes. Resistance training and polyunsaturated fats may increase muscle production, however previous studies in postmenopausal women have had mixed outcomes. Therefore this randomised placebo control trial of 124 postmenopausal women aimed to determine if a polyunsaturated fat rich fish oil in combination with resistance training or alone for 16 weeks could affect overweight and obese postmenopausal women. The results showed no combined effect of resistance training and fish oil on body composition, muscle strength, blood pressure, lipids, or blood sugar balance. The resistance training group maintained bone density, increased muscle mass, decreased fat mass and increased blood sugar balance. The fish oil group showed lower blood pressure, lowered triglycerides, and improved muscle quality in lower limbs. It was concluded that resistance training improved body composition, bone density and blood sugar balance and fish oil improved heart health in postmenopausal women. This study could be used by healthcare professionals to recommend fish oil and resistance training to improve all aspects of physiological changes associated with menopause.
Abstract
Resistance training (RT) and n-3 polyunsaturated fatty acids (n-3 PUFA) supplementation have emerged as strategies to improve muscle function in older adults. Overweight/obese postmenopausal women (55-70 years) were randomly allocated to one of four experimental groups, receiving placebo (olive oil) or docosahexaenoic acid (DHA)-rich n-3 PUFA supplementation alone or in combination with a supervised RT-program for 16 weeks. At baseline and at end of the trial, body composition, anthropometrical measures, blood pressure and serum glucose and lipid biomarkers were analyzed. Oral glucose tolerance tests (OGTT) and strength tests were also performed. All groups exhibit a similar moderate reduction in body weight and fat mass, but the RT-groups maintained bone mineral content, increased upper limbs lean mass, decreased lower limbs fat mass, and increased muscle strength and quality compared to untrained-groups. The RT-program also improved glucose tolerance (lowering the OGTT incremental area under the curve). The DHA-rich supplementation lowered diastolic blood pressure and circulating triglycerides and increased muscle quality in lower limbs. In conclusion, 16-week RT-program improved segmented body composition, bone mineral content, and glucose tolerance, while the DHA-rich supplement had beneficial effects on cardiovascular health markers in overweight/obese postmenopausal women. No synergistic effects were observed for DHA supplementation and RT-program combination.
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A Single Bout of Premeal Resistance Exercise Improves Postprandial Glucose Metabolism in Obese Men with Prediabetes.
Bittel, AJ, Bittel, DC, Mittendorfer, B, Patterson, BW, Okunade, AL, Abumrad, NA, Reeds, DN, Cade, WT
Medicine and science in sports and exercise. 2021;53(4):694-703
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Prediabetes is a metabolic condition defined by elevated fasting (impaired fasting glucose) and/or postprandial (impaired glucose tolerance) plasma glucose. The aim of this study was to determine the effects of a single bout of resistance exercise on postprandial glucose metabolism following a mixed meal in obese, sedentary men with prediabetes. This study is a randomised, cross-over study design which enrolled ten participants. Participants were aged 39-62 years, obese, and demonstrated insulin resistance with compensatory increases in beta cell function. Results show that a single bout of resistance exercise performed 4.5 hours before a mixed meal (as opposed to an oral glucose tolerance test) reduced total postprandial glucose appearance, increased insulin sensitivity, and reduced the glycaemic response to a mixed meal. However, it did not have effect on glucose oxidation in obese men with prediabetes. Improvements in insulin sensitivity were complemented by reduced postprandial insulin concentration. Authors conclude that further investigation is needed to elucidate how resistance exercise affects exogenous (meal) vs endogenous postprandial glucose metabolism, and if additional bouts of exercise (i.e. training) produce superior outcomes for this population.
Abstract
INTRODUCTION Prediabetes is a major risk factor for type 2 diabetes and cardiovascular diseases. Although resistance exercise (RE) is recommended for individuals with prediabetes, the effects of RE on postprandial glucose metabolism in this population are poorly understood. Therefore, the purpose of this study was to elucidate how RE affects postprandial glucose kinetics, insulin sensitivity, beta cell function, and glucose oxidation during the subsequent meal in sedentary men with obesity and prediabetes. METHODS We studied 10 sedentary men with obesity (body mass index, 33 ± 3 kg·m-2) and prediabetes by using a randomized, cross-over study design. After an overnight fast, participants completed either a single bout of whole-body RE (seven exercises, 3 sets of 10-12 repetitions at 80% one-repetition maximum each) or an equivalent period of rest. Participants subsequently completed a mixed meal test in conjunction with an intravenous [6,6-2H2]glucose infusion to determine basal and postprandial glucose rate of appearance (Ra) and disappearance (Rd) from plasma, insulin sensitivity, and the insulinogenic index (a measure of beta cell function). Skeletal muscle biopsies were obtained 90 min postmeal to evaluate pyruvate-supported and maximal mitochondrial respiration. Whole-body carbohydrate oxidation was assessed using indirect calorimetry. RESULTS RE significantly reduced the postprandial rise in glucose Ra and plasma glucose concentration. Postprandial insulin sensitivity was significantly greater after RE, whereas postprandial plasma insulin concentration was significantly reduced. RE had no effect on the insulinogenic index, postprandial pyruvate respiration, or carbohydrate oxidation. CONCLUSION/INTERPRETATION A single bout of RE has beneficial effects on postprandial glucose metabolism in men with obesity and prediabetes by increasing postprandial insulin sensitivity, reducing the postprandial rise in glucose Ra, and reducing postprandial plasma insulin concentration.
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Assessment of causal association between thyroid function and lipid metabolism: a Mendelian randomization study.
Wang, JJ, Zhuang, ZH, Shao, CL, Yu, CQ, Wang, WY, Zhang, K, Meng, XB, Gao, J, Tian, J, Zheng, JL, et al
Chinese medical journal. 2021;134(9):1064-1069
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Obesity, dyslipidaemia, and metabolic syndrome are major risk factors for cardiovascular disease, however, effect of thyroid dysfunction on dyslipidaemia and cardiovascular disease is largely unknown. This study used mendelian randomisation (MR), where a genetic variant is used as an instrumental variable to detect the causal effects of exposure to disease. This study used two sample MR analyses to find out whether clinical thyroid function measures show a causal relationship with the changes in lipid levels. The results showed a significant association between the elevated thyrotropin (TSH) level and increased total cholesterol. Also, there was a significant correlation between the free triiodothyronine (FT3): free thyroxine (FT4) ratio and total cholesterol and low-density lipoprotein (LDL). Further robust studies are required to confirm the results and investigate the causal effect of thyroid hormone dysregulation and cardiometabolic diseases due to the limitations of this study. However, healthcare professionals can use the results of this study to understand the importance of the pituitary-thyroid-cardiac axis in lipid metabolism and its impact on cardiometabolic health.
Abstract
BACKGROUND Thyroid dysfunction is associated with cardiovascular diseases. However, the role of thyroid function in lipid metabolism remains partly unknown. The present study aimed to investigate the causal association between thyroid function and serum lipid metabolism via a genetic analysis termed Mendelian randomization (MR). METHODS The MR approach uses a genetic variant as the instrumental variable in epidemiological studies to mimic a randomized controlled trial. A two-sample MR was performed to assess the causal association, using summary statistics from the Atrial Fibrillation Genetics Consortium (n = 537,409) and the Global Lipids Genetics Consortium (n = 188,577). The clinical measures of thyroid function include thyrotropin (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) levels, FT3:FT4 ratio and concentration of thyroid peroxidase antibodies (TPOAb). The serum lipid metabolism traits include total cholesterol (TC) and triglycerides, high-density lipoprotein, and low-density lipoprotein (LDL) levels. The MR estimate and MR inverse variance-weighted method were used to assess the association between thyroid function and serum lipid metabolism. RESULTS The results demonstrated that increased TSH levels were significantly associated with higher TC (β = 0.052, P = 0.002) and LDL (β = 0.041, P = 0.018) levels. In addition, the FT3:FT4 ratio was significantly associated with TC (β = 0.240, P = 0.033) and LDL (β = 0.025, P = 0.027) levels. However, no significant differences were observed between genetically predicted FT4 and TPOAb and serum lipids. CONCLUSION Taken together, the results of the present study suggest an association between thyroid function and serum lipid metabolism, highlighting the importance of the pituitary-thyroid-cardiac axis in dyslipidemia susceptibility.
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Effect of sleep duration on dietary intake, desire to eat, measures of food intake and metabolic hormones: A systematic review of clinical trials.
Soltanieh, S, Solgi, S, Ansari, M, Santos, HO, Abbasi, B
Clinical nutrition ESPEN. 2021;45:55-65
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Adequate sleep is crucial to health. Yet, sleep disturbances have become very common in modern societies. A lack of sleep is linked to increased risk for several chronic diseases such as diabetes, high blood pressure, metabolic syndrome and cardiovascular disease. Furthermore, appetite-regulating hormones can be disrupted by sleep shortages, which is thought to drive chronic overeating, leading to weight gain, obesity and its associated health consequences. This review examined the relationship between sleep duration and food consumption and energy intake, whilst also monitoring changes in body weight and appetite-regulating hormones. The review encompassed 50 randomized controlled trials (RCTs) with 3387 participants, including 1079 children and adolescents and 2308 adults. The findings suggested that sleep shortages contribute to significant increases in calorie intake, fat intake, increased body weight, appetite, hunger, more frequent eating and bigger portion sizes. In this review lack of sleep did not change protein and carbohydrate intake. Nor did lack of sleep make people exert more or less energy overall, however, a variance amongst ethnic groups was observed here. There was not enough evidence for changes in metabolic rate, so the review assumed no significant effect. When viewed collectively, the appetite-regulating hormones of leptin and ghrelin, the stress hormone cortisol and the sugar-regulating hormone insulin were not significantly influenced by sleep duration. However, there seemed to be a wide variance of outcomes when looking at individual studies' results. In conclusion, the authors reiterated the importance of sleep for health maintenance, advocating for a minimum of 7 hours of sleep per day for adults and that, despite busy modern lifestyles, sleep optimisation strategies should be prioritised. Less than 6 hours of sleep per day increases the risk of health consequences, like weight gain and metabolic disorders and sleep management should be considered part of their treatment protocols.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Reduced sleep duration may serve as a mediator for weight gain in part due to increased appetite, increased fat intake and disruptions to energy balance.
- Enhancing sleep quality may serve to support weight loss protocols.
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:
Introduction
Short sleep duration and disruptions to circadian rhythm have been associated with being overweight and obese. It has been suggested that sleep restriction may interfere with appetite regulating hormones leading to increased appetite and disrupted energy balance.
This study aimed to systematically review studies exploring the relationship between sleep duration and food consumption, energy intake, anthropometric characteristics and appetite-regulating hormones.
Methods
This systematic review included 50 randomised controlled trials including 3,387 participants.
Results
Energy intake
- 13 out of 30 the included studies found that short sleep conditions led to higher energy intake.
- 1 study identified that sleep restriction resulted in a 15.3% and 9.2% increase in energy intake in both women and men.
- 3 studies noted that prolonging sleep duration led to a reduction in energy intake.
- 1 study reported a reduction in energy intake after sleep restriction (P=0.031).
Fat consumption
- 9 studies out of 22 identified a significant association between short sleep and increased fat consumption.
- 7 studies did not identify a difference between groups.
- 3 studies noted a decrease in fat consumption following prolonged sleep (P<0.001, P<0.05, P=0.04).
Hunger and appetite
- 11 studies out of 17 observed that sleep restriction resulted in increased hunger ratings.
- 3 studies found an increase in appetite following sleep restriction (P<0.01) with 3 finding no difference..
- 1 study reported a decrease in appetite following sleep restriction.
- 2 studies noted that portion sizes increased as a result of sleep restriction (P<0.01).
- 1 study reported an increase in eating occasions following restricted sleep compared to habitual sleep (6.08 vs 4.96).
Body weight
- 6 studies out of 14 found no effect of sleep loss on body weight.
- 4 studies identified that sleep restriction led to weight gain (P<0.001, P<0.05, P=0.14, P=0.031).
- 2 studies reported weight loss following increased sleep duration (P<0.001).
Ghrelin and leptin
- Leptin and ghrelin levels were generally not found to be influenced by sleep duration, with the exception of a few studies.
Clinical practice applications:
Reduced sleep duration may promote weight gain by:
- Increasing energy intake.
- Increasing fat consumption.
- Increasing hunger and appetite.
- Increasing portion sizes and eating occasions.
Prolonging sleep duration may support weight loss by:
- Reducing energy intake.
- Reducing fat intake.
Considerations for future research:
- Mixed results on the influence of sleep restriction on appetite regulating hormones, leptin and ghrelin.
- Some studies noted the negative impact of sleep restriction on leptin and ghrelin concentrations, collectively shortened sleep duration did not appear to influence these hormones.
- Further sleep restriction studies exploring additional appetite regulating hormones and neuropeptides and the reward system may provide a more definitive understanding of the underlying mechanism for reduced sleep duration to disrupt the appetite and energy balance and promote weight gain.
Abstract
BACKGROUND AND AIMS Sleep, as well as diet and physical activity, plays a significant role in growth, maturation, health, and regulation of energy homeostasis. Recently, there is increasing evidence indicating a possible causal association between sleep duration and energy balance. We aimed to examine the relationship between sleep duration and food consumption, energy intake, anthropometric characteristics, and appetite-regulating hormones by randomized controlled trials (RCTs). METHODS Electronic literature searches were conducted on Medline, Web of Science, and Google Scholar until July 2020. The search was conducted with the following words: "Sleep Duration", "Circadian Rhythm", "Sleep Disorders" in combination with "Obesity", "Overweight", "Abdominal Obesity", "Physical Activity", "Energy Intake", "Body Mass Index", "Lipid Metabolism", "Caloric Restriction", Leptin, "Weight Gain", and "Appetite Regulation" using human studies.methods RESULTS After screening 708 abstracts, 50 RCTs (7 on children or adolescents and 43 on adults) were identified and met the inclusion criteria. In general, the findings suggested that sleep restriction may leads to a significant increment in energy intake, fat intake, body weight, appetite, hunger, eating occasions, and portion size, while protein and carbohydrate consumption, total energy expenditure, and respiratory quotient remained unaffected as a result of sleep restriction. Serum leptin, ghrelin, and cortisol concentrations were not influenced by sleep duration as well. CONCLUSION Insufficient sleep can be considered as a contributing factor for energy imbalance, weight gain, and metabolic disorders and it is suggested that to tackle disordered eating it may be necessary to pay more attention to sleep duration.
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Impact of dietary anthocyanins on systemic and vascular inflammation: Systematic review and meta-analysis on randomised clinical trials.
Fallah, AA, Sarmast, E, Fatehi, P, Jafari, T
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. 2020;135:110922
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Low-grade chronic inflammation contributes to the development of various chronic conditions like diabetes mellitus type2, chronic kidney disease, stroke, atherosclerosis, cardiovascular diseases, and cancer. Anthocyanins, a member of the flavonoid family, are water-soluble pigments that give plants their red-orange to blue-violet colours and have been shown to have antioxidant properties. The aim of this review and meta-analysis of 32 randomised controlled trials was to evaluate the impact of pure anthocyanins or anthocyanin-rich extracts/powders on inflammatory markers. The quality of studies for the meta-analysis was high for the inflammatory markers CRP (C-reactive protein), IL-6, TNF-alpha, adiponectin, and VCAM-1. There was a significant reduction in the pro-inflammatory CRP, IL-6, TNF-alpha and VCAM-1, and a significant increase in the anti-inflammatory adinopectin. Quality of studies was poor for other inflammatory markers evaluated. Higher doses tended to have a bigger positive effect. The authors conclude that anthocyanins may reduce inflammation.
Abstract
Anthocyanins are natural bioactive compounds that have several health benefits. This systematic review and meta-analysis assessed the impact of dietary anthocyanins on markers of systemic and vascular inflammation. Meta-analysis of 32 randomised controlled trials indicated that dietary anthocyanins significantly decreased levels of C-reactive protein (CRP; -0.33 mg/l, 95% CI: -0.55 to -0.11, P = 0.003), interleukin-6 (IL-6; -0.41 ρg/ml, 95% CI: -0.70 to -0.13, P = 0.004), tumor necrosis factor-alpha (TNF-α; -0.64 ρg/ml, 95% CI: -1.18 to -0.09, P = 0.023), intercellular adhesion molecule-1 (-52.4 ng/ml, 95% CI: -85.7 to -19.1, P = 0.002), and vascular adhesion molecule-1 (VCAM-1; -49.6 ng/ml, 95% CI: -72.7 to -26.5, P < 0.001) while adiponectin level was significantly increased (0.75 μg/ml, 95% CI: 0.23 to 1.26, P = 0.004). The levels of interleukin-1β (IL-1β; -0.45 ρg/ml, 95% CI: -3.77 to 2.88, P = 0.793) and P-selectin (-6.98 ng/ml, 95% CI: -18.1 to 4.15, P = 0.219) did not significantly change. Subgroup analyses showed that administration of higher doses of anthocyanins (>300 mg/day) significantly decreased levels of CRP, IL-6, TNF-α, and VCAM-1. The results indicate that dietary anthocyanins reduce the levels of systemic and vascular inflammation in the subjects.
keywords:"Cardiovascular Diseases" OR (Cardiovascular AND Diseases) OR "Cardiovascular Diseases" OR (cardiovascular AND disease) OR "cardiovascular disease"