Short sleep duration is associated with higher risk of central obesity in adults: A systematic review and meta-analysis of prospective cohort studies.

Background and Objective: The relationship between sleep duration and obesity has been the focus of numerous investigations. This systematic review and meta-analysis of prospective cohort studies aimed to assess the relationship between sleep duration, abdominal obesity, and body composition. Methods: PubMed, Scopus, and Web of Science were searched until February 2024. Cohort studies that assessed the relationship between sleep duration at night and central obesity measures or body composition indices in adults were included. The quality of studies was assessed using the Newcastle-Ottawa scale. Random-effects meta-analysis was conducted on studies that reported risk ratio (RR) and 95% confidence intervals (CIs). Results: Eighteen studies were eligible to be included. Eleven out of the 18 studies were not included in the analysis as 10 studies did not report RR, and in one study, the definition of short and normal sleep duration was different from others. The results of the meta-analysis indicated that short sleep duration was significantly associated with abdominal obesity (RR = 1.08; 95% CI: 1.04-1.12; I 2 = 49.1%, n = 7), but long sleep duration was not (RR = 1.02; 95% CI: 0.83-1.24; I 2 = 98.2%, n = 6). Conclusions: Short sleep duration was associated with a slightly higher risk of central obesity, while long sleep duration was not.

Gender-specific link between sleep quality and body composition components: a cross-sectional study on the elderly.

Sleep duration has been associated with overweight/obesity. Since sleep quality and body composition alter during aging, we conducted this study to determine if sleep quality is linked to body composition components in elderly people. This is a cross-sectional study conducted on 305 Iranian community-dwelling elderly aged ≥ 65 years. Sleep quality and body composition components were evaluated using Pittsburgh sleep quality index and bioelectric impedance analysis, respectively. The association of sleep quality and body composition components was examined using linear regression analysis. The prevalence of poor sleep quality and overweight/obesity was 48.9% and 54.4% in men and 77.0% and 79.3% in women, respectively. Women had significantly higher scores in most PSQI items than men, indicating their worse sleep quality compared to men. Women also had significantly higher body mass index (BMI), body fat percentage, and visceral adipose tissue and lower skeletal muscle and fat-free mass percentages than men. In the adjusted regression model, men showed positive associations between the third tertile of poor sleep quality and BMI (B = 1.35; 95% CI 0.08-2.61) and waist circumference (B = 4.14; 95% CI 0.39-7.89), but they did not demonstrate an association between sleep quality and body composition components. In the adjusted regression model for women, there were positive associations for BMI (B = 1.21; 95% CI 0.34-2.07), waist circumference (B = 2.95; 95% CI 0.99-4.91), body fat percentage (B = 2.75; 95% CI 1.06-4.45), and visceral adipose tissue (B = 7.80; 95% CI 1.73-13.87); also there were negative associations for skeletal muscle (B = - 1.40; 95% CI - 2.39 - - 0.41) and fat-free mass (B = - 2.76; 95% CI - 4.46 - -1.07) percentages. Except for waist circumference, other variables differed between men and women (P < 0.001). Weight management, prevention of muscle wasting, and improvement of sleep quality should be considered in a consortium when designing healthcare strategies for the elderly.

Food insecurity is associated with low diet quality and unhealthy cooking and eating habits in Iranian women.

BACKGROUND: Food insecurity affects diet and nutrition intakes. We explored the relationship between food insecurity and dietary intakes in a group of Iranian women. METHODS: The cross-sectional study was performed on 190 healthy females aged 20-55 years attending primary healthcare centers in Shiraz. Food insecurity was evaluated by Household Food Insecurity Access Scale, which is a validated tool for assessing food insecurity in developing countries. Diet was assessed using a food frequency questionnaire. The association of dietary patterns and food insecurity was assessed by linear regression. RESULTS: Assessment of dietary intakes revealed that consumption of red meat, poultry, fish, dairy, fruits, non-starchy vegetables, and nuts decreased whereas that of grains, processed meats, potato, and sugary foods increased with increasing food insecurity. Among nutrients, carbohydrates, fiber, vitamin A, vitamin C, folic acid, potassium, calcium, and magnesium decreased while fat and sodium increased as food insecurity increased. Three major dietary patterns were detected. Healthy dietary patterns showed inverse associations with food insecurity in the crude (ß = -0.422 and - 0.435, P < 0.001) and adjusted (adjusted for age, marital status, and educational level) (ß = -0.475 and - 0.341, P < 0.001) models of regression analysis but unhealthy pattern did not show an association with food insecurity. Compared to food secure participants, a higher percentage of food insecure individuals indicated unhealthy eating habits, such as skipping breakfast, lower snack ingestion, more fast and fried food consumption, and using unhealthy cooking methods. CONCLUSION: Overall, this study showed that food insecurity was associated with less healthy diet and unhealthy cooking and eating habits.

Sleep deprivation in development of obesity, effects on appetite regulation, energy metabolism, and dietary choices.

Sleep deprivation, which is a decrease in duration and quality of sleep, is a common problem in today's life. Epidemiological and interventional investigations have suggested a link between sleep deprivation and overweight/obesity. Sleep deprivation affects homeostatic and non-homoeostatic regulation of appetite, with the food reward system playing a dominant role. Factors such as sex and weight status affect this regulation; men and individuals with excess weight seem to be more sensitive to reward-driven and hedonistic regulation of food intake. Sleep deprivation may also affect weight through affecting physical activity and energy expenditure. In addition, sleep deprivation influences food selection and eating behaviours, which are mainly managed by the food reward system. Sleep-deprived individuals mostly crave for palatable energy-dense foods and have low desire for fruit and vegetables. Consumption of meals may not change but energy intake from snacks increases. The individuals have more desire for snacks with high sugar and saturated fat content. The relationship between sleep and the diet is mutual, implying that diet and eating behaviours also affect sleep duration and quality. Consuming healthy diets containing fruit and vegetables and food sources of protein and unsaturated fats and low quantities of saturated fat and sugar may be used as a diet strategy to improve sleep. Since the effects of sleep deficiency differ between animals and humans, only evidence from human subject studies has been included, controversies are discussed and the need for future investigations is highlighted.

Effect of short- and long-term protein consumption on appetite and appetite-regulating gastrointestinal hormones, a systematic review and meta-analysis of randomized controlled trials.

AIM: High-protein diets are considered as useful diets for weight loss programs. We collected randomized controlled trials that evaluated the effect of protein on appetite and gastrointestinal hormones involved in appetite regulation. METHODS: Trials were included if participants were healthy adults and isocaloric treatments were used in control and treatment arms. Random-effects model was used to calculate mean difference and 95% confidence intervals. RESULTS: In total, 49 publications for acute and 19 articles for long-term effect of protein were included. In acute interventions, protein decreased hunger (-7 mm visual analogue scale (VAS), P<0.001), desire to eat (-5 mm, P = 0.045), and prospective food consumption (-5 mm, P = 0.001) and increased fullness (10 mm, P<0.001) and satiety (4 mm, P<0.001). There was also a decrease in ghrelin (-20 pg/ml, P<0.001) and increase in cholecystokinin (30 pg/ml, P<0.001) and glucagon-like peptide-1 (GLP-1) (21 ng/ml, P<0.001), but no change in gastric inhibitory polypeptide and peptide YY was observed. Appetite markers were affected by protein doses < 35 g but ghrelin, cholecystokinin, and GLP-1 changed significantly after doses ≥ 35 g. Long-term ingestion of protein did not affect these outcomes, except for GLP-1 which showed a significant decrease. CONCLUSION: Results of this meta-analysis showed that acute ingestion of protein suppresses appetite, decreases ghrelin, and augments cholecystokinin and GLP-1. Results of long-term trials are inconclusive and further trials are required before a clear and sound conclusion on these trials could be made.

Flaxseed oil in the context of a weight loss programme ameliorates fatty liver grade in patients with non-alcoholic fatty liver disease: a randomised double-blind controlled trial.

Long-chain n-3 fatty acids have been shown to regulate lipid metabolism and reduce fat accumulation in the liver. This trial investigated the effect of flaxseed oil, as a rich source of α-linolenic acid, on fatty liver and cardiometabolic risk factors in patients with non-alcoholic fatty liver disease (NAFLD). The randomised, double-blind, controlled trial was performed on sixty-eight NAFLD patients who were divided into flaxseed (n 34) and sunflower (n 34) oil groups. Patients were given a hypoenergetic diet (-2092 kJ/d) and 20 g/d of the corresponding oil for 12 weeks. Fatty liver grade, liver enzymes and cardiometabolic parameters were determined. The intention-to-treat approach was used for data analysis. Fatty liver grade significantly decreased in both groups (-0·68 in flaxseed v. -0·29 in sunflower, P = 0·002). Alanine aminotransferase and aspartate aminotransferase decreased in both groups (P < 0·01). Also, significant reduction was observed in blood glucose (P = 0·005) and fat mass (P = 0·01) in the flaxseed and muscle mass (P = 0·01) in the sunflower group. However, none of these alterations was significantly different between the groups. Weight, waist circumference and blood pressure were significantly decreased in both groups but only weight change was significantly different between the groups (P = 0·01). IL-6 did not significantly change in either group but showed a significant between-group difference (P = 0·03). Overall, the results showed that in the context of a low-energy diet and moderate physical activity, flaxseed oil may benefit NAFLD patients to improve fatty liver grade, weight and IL-6 compared with sunflower oil.

Effect of Natural Honey on Glycemic Control and Anthropometric Measures of Patients with Type 2 Diabetes: A Randomized Controlled Crossover Trial.

BACKGROUND: Due to high content of fructose, honey has been introduced as a suitable natural sweetener for patients with type 2 diabetes. We investigated the effect of honey consumption on glycemic control and anthropometric measures of patients with type 2 diabetes. METHODS: This randomized controlled crossover clinical trial was conducted on 53 patients with type 2 diabetes. The participants were randomly divided into groups of control (weight maintenance diet) or treatment (weight maintenance diet +50 g/day honey) for 8 weeks. After a 4-week washout, the second phase began, in which the role of the groups was interchanged. Blood glycated hemoglobin (HbA1c), glucose, insulin, and anthropometric characteristics were measured. Statistical analysis was performed with SPSS. Repeated measures of ANOVA were used to test differences within- and between the two conditions. RESULTS: Forty-two patients completed the study. HbA1c significantly decreased in control (-0.22%, P = 0.03) and nonsignificantly increased in honey condition (+0.17%, P = 0.22). There was a significant difference between the two conditions (P = 0.02). Fasting glucose did not significantly change in either honey or control condition but insulin concentrations (-0.85 µU/ml, P = 0.01) and insulin secretion (-10.7%, P = 0.01) decreased significantly in the control condition. There was no significant difference in any of these parameters between the two conditions. Waist circumference decreased by honey treatment with a significant difference between the two conditions (P = 0.02). CONCLUSIONS: Eight weeks consumption of 50 g/day honey increased HbA1c and decreased waist circumference of patients with type 2 diabetes.