Effects of pre-sleep protein consumption on muscle-related outcomes - A systematic review.

OBJECTIVES: The timing of protein intake over the day on muscle mass and strength gains have received interest in the literature. Thus, the aim of this systematic review is to analyze clinical studies that evaluated the acute effects of pre-sleep protein consumption on overnight muscle protein synthesis and the chronic effects on muscle mass and strength. DESIGNS: Systematic review. METHODS: A literature search was conducted up to June 2020 according to PRISMA statement and nine articles were included to analyze. RESULTS: The consumption of 20-40 g of casein approximately 30 min before sleep stimulates whole-body protein synthesis rates over a subsequent overnight period in young and elderly men (preceded or not by resistance exercise, respectively). In addition, pre-sleep protein consumption can augment the muscle adaptive response (muscle fiber cross-sectional area, strength and muscle mass) during 10-12 weeks of resistance exercise in young, but not in elderly men. CONCLUSIONS: Based on current evidence, the consumption of 20-40 g of casein approximately 30 min before sleep improves protein synthetic response during an overnight recovery period in healthy young adult men, with possible positive effects on muscle mass and strength following prolonged resistance exercise. In elderly, despite the initial evidence regarding the pre-sleep protein enhances overnight muscle protein synthesis rates, the current available evidence is limited precluding to conclude about the chronic effects on skeletal muscle mass or strength. These conclusions need to be taken with caution due to uneven protein intakes between experimental groups. Therefore, more data are needed before further considering pre-sleep protein as an effective nutritional intervention.

Effects of coffee consumption on glucose metabolism: A systematic review of clinical trials.

Epidemiological studies indicate an inverse association of coffee consumption with risk of type 2 diabetes mellitus. However, studies to determine the clinical effects of coffee consumption on the glucose metabolism biomarkers remain uncertain. The aim of this systematic review was to evaluate the effects of coffee consumption on glucose metabolism. A search of electronic databases (PubMed and Web of Science) was performed identifying studies published until September 2017. Eight clinical trials (n = 247 subjects) were identified for analyses. Participants and studies characteristics, main findings, and study quality (Jadad Score) were reported. Short-term (1-3 h) and long-term (2-16 weeks) studies were summarized separately. Short-term studies showed that consumption of caffeinated coffee may increase the area under the curve for glucose response, while for long-term studies, caffeinated coffee may improve the glycaemic metabolism by reducing the glucose curve and increasing the insulin response. The findings suggest that consumption of caffeinated coffee may lead to unfavourable acute effects; however, an improvement on glucose metabolism was found on long-term follow-up.

Decaffeinated coffee improves insulin sensitivity in healthy men.

Epidemiological studies have found coffee consumption is associated with a lower risk for type 2 diabetes mellitus, but the underlying mechanisms remain unclear. Thus, the aim of this randomised, cross-over single-blind study was to investigate the effects of regular coffee, regular coffee with sugar and decaffeinated coffee consumption on glucose metabolism and incretin hormones. Seventeen healthy men participated in five trials each, during which they consumed coffee (decaffeinated, regular (containing caffeine) or regular with sugar) or water (with or without sugar). After 1 h of each intervention, they received an oral glucose tolerance test with one intravenous dose of [1-13C]glucose. The Oral Dose Intravenous Label Experiment was applied and glucose and insulin levels were interpreted using a stable isotope two-compartment minimal model. A mixed-model procedure (PROC MIXED), with subject as random effect and time as repeated measure, was used to compare the effects of the beverages on glucose metabolism and incretin parameters (glucose-dependent insulinotropic peptide (GIP)) and glucagon-like peptide-1 (GLP-1)). Insulin sensitivity was higher with decaffeinated coffee than with water (P<0·05). Regular coffee with sugar did not significantly affect glucose, insulin, C-peptide and incretin hormones, compared with water with sugar. Glucose, insulin, C-peptide, GLP-1 and GIP levels were not statistically different after regular and decaffeinated coffee compared with water. Our findings demonstrated that the consumption of decaffeinated coffee improves insulin sensitivity without changing incretin hormones levels. There was no short-term adverse effect on glucose homoeostasis, after an oral glucose challenge, attributable to the consumption of regular coffee with sugar.

Improvement in metabolic parameters in obese subjects after 16 weeks on a Brazilian-staple calorie-restricted diet.

BACKGROUND/OBJECTIVES: The standard pattern of Brazilian food consumption is based on the combination of rice and beans served together in the main meals. This study assessed the effects of Brazilian-staple calorie-restricted (BS-diet) dietary advice, with brown rice and beans, on metabolic parameters, body composition, and food intake in overweight/obese subjects. SUBJECTS/METHODS: Twentyseven subjects were randomly assigned to a conventional-type calorie-restricted diet (CT-diet) (n = 13) or a BS-diet (n = 14). Glucose metabolism, lipid profile, anthropometric and body composition parameters, and food intake were measured before and after 16 weeks. Paired t-tests/Wilcoxon tests were used for comparison of differences from baseline and unpaired t-tests/Mann-Whitney tests were used for comparison of differences between the groups. RESULTS: After 16 weeks, both groups showed reductions in weight and waist circumference (P < 0.02), and the BS-diet group showed a decrease in body fat (P = 0.0001), and significant improvement in glucose metabolism (fasting plasma glucose, glucose and insulin areas under the curve, Cederholm index, and HOMA2-%ß) (P ≤ 0.04) and lipid profile (cholesterol, triacylglycerol, LDL-c, VLDL-c, and cholesterol/HDL-c ratio) (P ≤ 0.05). In addition, the BS-diet group showed significant improvement in HOMA2-%ß, compared to the CT-diet group (P = 0.03). The BS-diet group also showed a significant reduction in energy, lipids, carbohydrate, and cholesterol intake (P ≤ 0.04) and an increase in fiber intake (P ≤ 0.001), while the CT-diet group showed a significant reduction in intake of energy, macronutrients, PUFA, and cholesterol (P ≤ 0.002). CONCLUSIONS: These results demonstrate the benefits of the BS-diet on metabolic parameters in obese subjects.

Acute and second-meal effects of peanuts on glycaemic response and appetite in obese women with high type 2 diabetes risk: a randomised cross-over clinical trial.

Nut consumption is associated with a reduced risk of type 2 diabetes mellitus (T2DM). The aim of the present study was to assess the effects of adding peanuts (whole or peanut butter) on first (0-240 min)- and second (240-490 min)-meal glucose metabolism and selected gut satiety hormone responses, appetite ratings and food intake in obese women with high T2DM risk. A group of fifteen women participated in a randomised cross-over clinical trial in which 42·5 g of whole peanuts without skins (WP), peanut butter (PB) or no peanuts (control) were added to a 75 g available carbohydrate-matched breakfast meal. Postprandial concentrations (0-490 min) of glucose, insulin, NEFA, glucagon-like peptide-1 (GLP-1), peptide YY (PYY), cholecystokinin (CCK), appetitive sensations and food intake were assessed after breakfast treatments and a standard lunch. Postprandial NEFA incremental AUC (IAUC) (0-240 min) and glucose IAUC (240-490 min) responses were lower for the PB breakfast compared with the control breakfast. Insulin concentrations were higher at 120 and 370 min after the PB consumption than after the control consumption. Desire-to-eat ratings were lower, while PYY, GLP-1 and CCK concentrations were higher after the PB intake compared with the control intake. WP led to similar but non-significant effects. The addition of PB to breakfast moderated postprandial glucose and NEFA concentrations, enhanced gut satiety hormone secretion and reduced the desire to eat. The greater bioaccessibility of the lipid component in PB is probably responsible for the observed incremental post-ingestive responses between the nut forms. Inclusion of PB, and probably WP, to breakfast may help to moderate glucose concentrations and appetite in obese women.

Role of bariatric-metabolic surgery in the treatment of obese type 2 diabetes with body mass index <35 kg/m2: a literature review.

Bariatric surgery has been used to treat type 2 diabetes mellitus (T2DM); however, its efficacy is still debatable. This literature review analyzed articles that evaluated the effects of bariatric surgery in treatment of T2DM in obese patients with a body mass index (BMI) of <35 kg/m(2). A paired t test was applied for the analysis of pre- and postintervention mean BMI, fasting plasma glucose (FPG), and glycosylated hemoglobin (A1c) values. A significant (P<0.001) reduction in BMI (from 29.95±0.51 kg/m(2) to 24.83±0.44 kg/m(2)), FPG (from 207.86±8.51 mg/dL to 113.54±4.93 mg/dL), and A1c (from 8.89±0.15% to 6.35±0.18%) was observed in 29 articles (n=675). T2DM resolution (A1c <7% without antidiabetes medication) was achieved in 84.0% (n=567) of the subjects. T2DM remission, control, and improvement were observed in 55.41%, 28.59%, and 14.37%, respectively. Only 1.63% (n=11) of the subjects presented similar or worse glycemic control after the surgery. T2DM remission (A1c <6% without antidiabetes medication) was higher after mini-gastric bypass (72.22%) and laparoscopic/Roux-en-Y gastric bypass (70.43%). According to the Foregut and Hindgut Hypotheses, T2DM results from the imbalance between the incretins and diabetogenic signals. The procedures that remove the proximal intestine and do ileal transposition contribute to the increase of glucagon-like peptide-1 levels and improvement of insulin sensitivity. These findings provide preliminary evidence of the benefits of bariatric-metabolic surgery on glycemic control of T2DM obese subjects with a BMI of <35 kg/m(2). However, more clinical trials are needed to investigate the metabolic effects of bariatric surgery in T2DM remission on pre-obese and obese class I patients.