0
selected
-
1.
Morphological Adaptation in the Jejunal Mucosa after Iso-Caloric High-Fat versus High-Carbohydrate Diets in Healthy Volunteers: Data from a Randomized Crossover Study.
Casselbrant, A, Wallenius, V, Elebring, E, Marschall, HU, Johansson, BR, Helander, HF, Fändriks, L
Nutrients. 2022;14(19)
-
-
-
Free full text
Plain language summary
The small intestinal mucosa is a large organ which acts as an intestinal barrier. The jejunal mucosa is the largest part of the small intestinal mucosa, and its functions include digestion and absorption of food. Epithelium cells on the surface of the small intestine renew every few days. Therefore, this single-centre, randomised, unblinded, crossover study looked at how jejunal mucosal cells change after two weeks of an isocaloric high-fat diet (HFD) and high-carbohydrate diet (HCD) in fifteen healthy people. The study also measured ketogenesis rate-limiting enzyme 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) and mitochondria following the isocaloric HFD and HCD. Neither HFD nor HCD changes the mucosal surface enlargement factor. However, at the ultrastructural level, there was a significant surface enlargement in the bases of the villi after following HCD than HFD. In addition, HFD increased the number of mitochondrial cristae in the erythrocytes than HCD. The increased number of mitochondrial cristae in the erythrocytes was associated with the increased expression of HMGCS2. Healthcare professionals can use the results of this study to understand how short-term implementation of different diets affects jejunal mucosal morphology at the ultrastructural level. Further robust studies are required to evaluate the long-term effects of HFD and HCD in jejunal mucosa and how the morphological adaptations impact people with obesity.
Abstract
BACKGROUND AND AIMS The conditions for jejunal glucose absorption in healthy subjects have not been thoroughly studied. In this study we investigated differences in the jejunal villi enlargement factor, as well as ultrastructural aspects of the surface enterocytes and mitochondria, comparing 2 weeks of high-carbohydrate (HCD) versus high-fat diets (HFD). We also measured the ketogenesis rate-limiting enzyme 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) in relation to jejunal mitochondria. METHODS A single-centre, randomized, unblinded crossover study in 15 healthy volunteers ingesting strictly controlled equicaloric diets (either HCD or HFD), with 60% energy from the respective source. An enteroscopy was carried out after 2 weeks of each diet and jejunal mucosal biopsies were acquired. Conventional histology, immunofluorescent staining, transmission electron microscopy and confocal microscopy were used. RESULTS The villi did not demonstrate any change in the epithelial enlargement factor. Despite an increased mitosis, there were no changes in apoptotic indices. However, the ultrastructural analysis demonstrated a significant increase in the enlargement factor at the bases of the villi. The mitochondria demonstrated increased amounts of cristae after the HFD. The confocal microscopy revealed increased HMGCS2 per mitochondrial marker at the top of the villi after the HFD compared to the HCD. CONCLUSION There is a morphometric adaption in the jejunal mucosa following the 2-week diets, not only on a histological level, but rather on the ultrastructural level. This study supports the notion that mitochondrial HMGCS2 is regulated by the fat content of the diet and is involved in the expression of monosaccharide transporters.
-
2.
Prolonged Collagen Peptide Supplementation and Resistance Exercise Training Affects Body Composition in Recreationally Active Men.
Kirmse, M, Oertzen-Hagemann, V, de Marées, M, Bloch, W, Platen, P
Nutrients. 2019;11(5)
-
-
-
Free full text
Plain language summary
Currently little is known concerning collagen protein supplementation combined with a prolonged resistance exercising training (RET) programme. The aim of this study was to determine the effects of long-term collagen peptide supplementation and RET on body composition, strength and muscle fibre cross-sectional surface area (fCSA) in 57 recreationally active men. In this double-blind, placebo-controlled study, participants were randomly allocated to receive either collagen peptides or placebo for 12 weeks. Both groups trained three times a week. Strength testing, bioimedance analysis and muscle biopsies were taken at baseline and post-intervention. Most notably the collagen group experienced a significant increase in fat-free mass while body fat mass remained unchanged, compared to the placebo group. Both groups showed significant increases in strength tests and the fCSA increased significantly without differences. Based on these results, the authors conclude collagen protein supplementation have positive impact on body composition however suggest further study include connective tissue in addition to muscle tissue to better understand the mechanisms underlying these changes.
Abstract
We aimed to determine the effects of long-term collagen peptide (CP) supplementation and resistance exercise training (RET) on body composition, strength, and muscle fiber cross-sectional area (fCSA) in recreationally active men. Fifty-seven young men were randomly and double-blinded divided into a group receiving either collagen peptides (COL, 15 g/day) or a placebo (PLA). Strength testing, bioimpedance analysis, and muscle biopsies were used prior to and after an RET intervention. Food record protocols were performed during the RET intervention. The groups trained three times a week for 12 weeks. Baseline parameters showed no differences between groups, and the external training load and dietary food intake were also similar. COL showed a significant increase in fat-free mass (FFM) compared with the placebo group (p < 0.05). Body fat mass (BFM) was unchanged in COL, whereas a significant increase in BFM was observed in PLA. Both groups showed significant increases in all strength tests, with a trend for a slightly more pronounced effect in COL. The fCSA of type II muscle fibers increased significantly in both groups without differences between the two groups. We firstly demonstrated improved body composition in healthy, recreationally active men subsequent to prolonged CP supplementation in combination with RET. As the observed increase in FFM was not reflected in differences in fCSA hypertrophy between groups, we assume enhanced passive connective tissue adaptations in COL due to CP intake.
-
3.
Adipose Tissue Meal-Derived Fatty Acid Uptake Before and After Diet-Induced Weight Loss in Adults with Overweight and Obesity.
Vink, RG, Roumans, NJ, van der Kolk, BW, Fazelzadeh, P, Boekschoten, MV, Mariman, EC, van Baak, MA
Obesity (Silver Spring, Md.). 2017;25(8):1391-1399
-
-
-
Plain language summary
Weight loss among the obese population is difficult to sustain and there is substantial evidence arising that biological and metabolic mechanisms are a crucial factor. In obese people, the ability of adipose tissue to remove fatty acids from circulation is impaired, and it is hypothesised that reducing the size of adipose cells through weight loss will increase the storage capacity in adipose tissue, leading to greater uptake for circulating fatty acids. Therefore the aim of this study was to investigate whether diet-induced weight loss alters fat uptake in adipose tissue. In this randomised controlled trial, 16 individuals were assigned to either a low-calorie diet for 12-weeks or very low calorie diet for 5-weeks, both followed by a 4-week weight stable period and a 9-month follow up. Blood samples, adipose tissue biopsies and anthropometric measurements were taken at baseline, after weight loss, after weight stable period and at follow-up. Contrary to hypothesis, this study found that fatty acid uptake dynamics and expression of genes involved in fat metabolism were not significantly changed during the intervention period. Based on these results, the authors did not detect dietary weight loss-induced changes in gene expression involved in fat metabolism.
Abstract
OBJECTIVE This study investigated whether diet-induced weight loss alters indices of in vivo postprandial fat uptake in adipose tissue (AT) and whether these changes are associated with weight regain in adults with overweight and obesity. METHODS In this randomized controlled trial, 16 (6 male) individuals (BMI: 28-35 kg/m2 ) were randomized to either a low-calorie diet (1,250 kcal/d) for 12 weeks or a very-low-calorie diet (500 kcal/d) for 5 weeks (weight loss [WL] period) followed by a 4-week weight-stable (WS) period (together, the dietary intervention [DI] period) and a 9-month follow-up period. Arteriovenous difference measurements combined with stable isotope labeling ([U-13 C] palmitate) of a mixed meal were used to determine postprandial fatty acid uptake in AT. RESULTS Body weight was significantly reduced during the WL period (-8.2 ± 0.6 kg, P < 0.001), remained stable during the WS period (0.4 ± 0.3 kg, P = 0.150), and increased during follow-up (3.5 ± 0.8 kg, P = 0.001). Meal-derived in vivo fatty acid uptake dynamics across AT and expression of genes important for fatty acid uptake, storage, and release were not significantly changed during the DI period. CONCLUSIONS Subcutaneous AT does not appear prone to enhanced meal-derived fatty acid uptake after weight loss, nor were fatty acid uptake dynamics detected as related to weight regain.
-
4.
Dairy proteins, dairy lipids, and postprandial lipemia in persons with abdominal obesity (DairyHealth): a 12-wk, randomized, parallel-controlled, double-blinded, diet intervention study.
Bohl, M, Bjørnshave, A, Rasmussen, KV, Schioldan, AG, Amer, B, Larsen, MK, Dalsgaard, TK, Holst, JJ, Herrmann, A, O'Neill, S, et al
The American journal of clinical nutrition. 2015;101(4):870-8
-
-
-
Free full text
-
Plain language summary
The health effects of dairy products on cardiovascular disease (CVD), diabetes, obesity and total mortality may depend on their varying composition. This study aims to examine the long-term effects of milk proteins (whey and casein) and milk with a high or low content of medium-chain saturated fatty acids (MC-SFAs) on postprandial lipid metabolism. In this randomised, parallel-controlled, double-blinded, 12-week intervention study, 63 abdominally obese individuals were randomised to one of four diets, containing different compositions of whey, casein and MC-SFAs. Results showed that whey compared to casein significantly decreased postprandial apoB-48, independently of the fatty acid composition. Fasting and postprandial triacylglycerol and FFA responses were independent of protein or fatty acids composition. Authors conclude that 12-week supplementation with whey protein reduces postprandial apoB-48 compared to casein, indicating a beneficial effect on CVD risk.
Abstract
BACKGROUND Abdominal obesity and exaggerated postprandial lipemia are independent risk factors for cardiovascular disease (CVD) and mortality, and both are affected by dietary behavior. OBJECTIVE We investigated whether dietary supplementation with whey protein and medium-chain saturated fatty acids (MC-SFAs) improved postprandial lipid metabolism in humans with abdominal obesity. DESIGN We conducted a 12-wk, randomized, double-blinded, diet intervention study. Sixty-three adults were randomly allocated to one of 4 diets in a 2 × 2 factorial design. Participants consumed 60 g milk protein (whey or casein) and 63 g milk fat (with high or low MC-SFA content) daily. Before and after the intervention, a high-fat meal test was performed. We measured changes from baseline in fasting and postprandial triacylglycerol, apolipoprotein B-48 (apoB-48; reflecting chylomicrons of intestinal origin), free fatty acids (FFAs), insulin, glucose, glucagon, glucagon-like peptide 1 (GLP-1), and gastric inhibitory polypeptide (GIP). Furthermore, changes in the expression of adipose tissue genes involved in lipid metabolism were investigated. Two-factor ANOVA was used to examine the difference between protein types and fatty acid compositions, as well as any interaction between the two. RESULTS Fifty-two participants completed the study. We found that the postprandial apoB-48 response decreased significantly after whey compared with casein (P = 0.025) independently of fatty acid composition. Furthermore, supplementation with casein resulted in a significant increase in the postprandial GLP-1 response compared with whey (P = 0.003). We found no difference in postprandial triacylglycerol, FFA, insulin, glucose, glucagon, or GIP related to protein type or MC-SFA content. We observed no interaction between milk protein and milk fat on postprandial lipemia. CONCLUSION We found that a whey protein supplement decreased the postprandial chylomicron response compared with casein in persons with abdominal obesity, thereby indicating a beneficial impact on CVD risk. This trial was registered at clinicaltrials.gov as NCT01472666.
-
5.
Enhanced cortisol production rates, free cortisol, and 11beta-HSD-1 expression correlate with visceral fat and insulin resistance in men: effect of weight loss.
Purnell, JQ, Kahn, SE, Samuels, MH, Brandon, D, Loriaux, DL, Brunzell, JD
American journal of physiology. Endocrinology and metabolism. 2009;296(2):E351-7
-
-
-
Free full text
Plain language summary
Excess abdominal fat in men is a risk factor for both type 2 diabetes and cardiovascular disease. The aim of this study was to test the hypothesis that increased cortisol levels contribute to increased abdominal fat and insulin resistance in men. Twenty-four healthy men aged 18-70 took part in the study. Eight of the participants, who were obese, were put on a calorie-controlled weight loss diet. Cortisol production rate (CPR) and free cortisol (FC) were correlated with increased intra-abdominal fat (IAF) and decreased insulin sensitivity (Si). Cortisol levels were not correlated with subcutaneous fat (SQF). CPR and FC did not change with weight loss, suggesting that cortisol levels could influence the distribution of body fat upon weight regain. The authors concluded that their findings support a role for activation of the HPA axis and abnormal cortisol secretion in determining body fat distribution and predisposing these men to type 2 diabetes.
Abstract
Controversy exists as to whether endogenous cortisol production is associated with visceral obesity and insulin resistance in humans. We therefore quantified cortisol production and clearance rates, abdominal fat depots, insulin sensitivity, and adipocyte gene expression in a cohort of 24 men. To test whether the relationships found are a consequence rather than a cause of obesity, eight men from this larger group were studied before and after weight loss. Daily cortisol production rates (CPR), free cortisol levels (FC), and metabolic clearance rates (MCR) were measured by stable isotope methodology and 24-h sampling; intra-abdominal fat (IAF) and subcutaneous fat (SQF) by computed tomography; insulin sensitivity (S(I)) by frequently sampled intravenous glucose tolerance test; and adipocyte 11beta-hydroxysteroid dehydrogenase-1 (11beta-HSD-1) gene expression by quantitative RT-PCR from subcutaneous biopsies. Increased CPR and FC correlated with increased IAF, but not SQF, and with decreased S(I). Increased 11beta-HSD-1 gene expression correlated with both IAF and SQF and with decreased S(I). With weight loss, CPR, FC, and MCR did not change compared with baseline; however, with greater loss in body fat than lean mass during weight loss, both CPR and FC increased proportionally to final fat mass and IAF and 11beta-HSD-1 decreased compared with baseline. These data support a model in which increased hypothalamic-pituitary-adrenal activity in men promotes selective visceral fat accumulation and insulin resistance and may promote weight regain after diet-induced weight loss, whereas 11beta-HSD-1 gene expression in SQF is a consequence rather than cause of adiposity.