[Show abstract][Hide abstract] ABSTRACT: Evidence supports that a high proportion of calories from protein increases weight loss and prevents weight (re)gain. Proteins are known to induce satiety, increase secretion of gastrointestinal hormones, and increase diet-induced thermogenesis, but less is known about whether various types of proteins exert different metabolic effects. In the Western world, dairy protein, which consists of 80% casein and 20% whey, is a large contributor to our daily protein intake. Casein and whey differ in absorption and digestion rates, with casein being a "slow" protein and whey being a "fast" protein. In addition, they differ in amino acid composition. This review examines whether casein, whey, and other protein sources exert different metabolic effects and targets to clarify the underlying mechanisms. Data indicate that whey is more satiating in the short term, whereas casein is more satiating in the long term. In addition, some studies indicate that whey stimulates the secretion of the incretin hormones glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide more than other proteins. However, for the satiety (cholecystokinin and peptide YY) and hunger-stimulating (ghrelin) hormones, no clear evidence exists that 1 protein source has a greater stimulating effect compared with others. Likewise, no clear evidence exists that 1 protein source results in higher diet-induced thermogenesis and promotes more beneficial changes in body weight and composition compared with other protein sources. However, data indicate that amino acid composition, rate of absorption, and protein/food texture may be important factors for protein-stimulated metabolic effects.
Advances in Nutrition 07/2013; 4(4):418-38. · 3.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A systematic review was conducted to assess the evidence linking beer consumption to abdominal and general obesity. Following a systematic search strategy, 35 eligible observational studies and 12 experimental studies were identified. Regarding abdominal obesity, most observational data pointed towards a positive association or no association between beer intake and waist circumference or waist-to-hip ratio in men, whereas results for women were inconsistent. Data from a subset of studies indicated that beer intake > 500 mL/day may be positively associated with abdominal obesity. Regarding general obesity, most observational studies pointed towards an inverse association or no association between beer intake and body weight in women and a positive association or no association in men. Data from six experimental studies in men, in which alcoholic beer was compared with low-alcoholic beer, suggested that consumption of alcoholic beer (for 21-126 days) results in weight gain (0.73 kg; P < 0.0001), but data from four studies comparing intake of alcoholic beer with intake of no alcohol did not support this finding. Generally, experimental studies had low-quality data. In conclusion, the available data provide inadequate scientific evidence to assess whether beer intake at moderate levels (<500 mL/day) is associated with general or abdominal obesity. Higher intake, however, may be positively associated with abdominal obesity.
[Show abstract][Hide abstract] ABSTRACT: The consumption of high levels of industrial trans fatty acids (TFA) has been related to cardiovascular disease, diabetes and sudden cardiac death but the causal mechanisms are not well known. In this study, NMR and LC-MS untargeted metabolomics has been used as an approach to explore the impact of TFA intake on plasma metabolites.
In a double-blinded randomized controlled parallel-group study, 52 overweight postmenopausal women received either partially hydrogenated soybean oil, providing 15.7 g/day of TFA (trans18:1) or control oil with mainly oleic acid for 16 weeks. Subsequent to the intervention period, the subjects participated in a 12-week dietary weight loss program. Before and after the TFA intervention and after the weight loss programme, volunteers participated in an oral glucose tolerance test. PLSDA revealed elevated lipid profiles with TFA intake. NMR indicated up-regulated LDL cholesterol levels and unsaturation. LC-MS profiles demonstrated elevated levels of specific polyunsaturated (PUFA) long-chain phosphatidylcholines (PCs) and a sphingomyelin (SM) which were confirmed with a lipidomics based method. Plasma levels of these markers of TFA intake declined to their low baseline levels after the weight loss program for the TFA group and did not fluctuate for the control group. The marker levels were unaffected by OGTT.
This study demonstrates that intake of TFA affects phospholipid metabolism. The preferential integration of trans18:1 into the sn-1 position of PCs, all containing PUFA in the sn-2 position, could be explained by a general up-regulation in the formation of long-chain PUFAs after TFA intake and/or by specific mobilisation of these fats into PCs. NMR supported these findings by revealing increased unsaturation of plasma lipids in the TFA group. These specific changes in membrane lipid species may be related to the mechanisms of TFA-induced disease but need further validation as risk markers.
Registered at clinicaltrials.gov as NCT00655902.
PLoS ONE 01/2013; 8(7):e69589. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose: To evaluate the effects of weight loss on heart rate (HR) and heart rate variability (HRV) parameters in overweight postmenopausal women.Design and Methods: Forty-nine overweight postmenopausal women with an average body mass index of 28.8 ± 1.9 kg/m(2) underwent a 12-week dietary weight-loss programme. Accepted variables for characterization of HRV were analysed before and after the weight loss by 24-h ambulatory ECG monitoring; mean and standard deviation for the time between normal-to-normal complexes (MeanNN and SDNN, respectively), and the mean of standard deviations of normal-to-normal intervals for each 5-min period (SDNNindex). Baseline body fat mass (FM%) and changes in body composition was determined by dual X-ray absorptiometry. Before and after the weight-loss period, total abdominal fat, intra-abdominal fat (IAAT), and subcutaneous abdominal fat (SCAT) were measured by single-slice MRI at L3.Results: The weight loss of 3.9 ± 2.0 kg was accompanied by an improvement of HRV. SDNN increased by 9.2% (p = 0.003) and SDNNindex increased by 11.4% (p = 0.0003). MeanNN increased by 2.4%, reflecting a decrease in mean heart rate from 74.1 to 72.3 beats/min (p = 0.033). Systolic blood pressure (SBP) decreased by 2.7%, total cholesterol by 5.1% and high-sensitivity C-reactive protein (hsCRP) by 15.8% (p = 0.002). Improvements in SDNN and cholesterol were correlated with weight loss (r = -0.329, p = 0.024 and r = 0.327, p = 0.020, respectively) but changes in HR, SBP, and hsCRP were not. IAAT and the IAAT/SCAT-ratio were found to be negatively associated with HRV parameters but changes in body composition were not associated with changes in HRV.Conclusions: The observed improvement of HRV seems to be facilitated by weight loss. IAAT and the IAAT/SCAT ratio were found to be associated with low HRV.
European journal of preventive cardiology. 03/2012;
[Show abstract][Hide abstract] ABSTRACT: Consumption of industrially produced trans fatty acids (IP-TFA) has been positively associated with systemic markers of low-grade inflammation and endothelial dysfunction in cross-sectional studies, but results from intervention studies are inconclusive. Therefore, we conducted a 16 week double-blind parallel intervention study with the objective to examine the effect of IP-TFA intake on biomarkers of inflammation, oxidative stress, and endothelial dysfunction. Fifty-two healthy overweight postmenopausal women (49 completers) were randomly assigned to receive either partially hydrogenated soybean oil (15.7 g/day IP-TFA) or control oil without IP-TFA. After 16 weeks, IP-TFA intake increased baseline-adjusted serum tumor necrosis factor (TNF) α by 12% [95% confidence interval (CI): 5-20; P = 0.002] more in the IP-TFA group compared with controls. Plasma soluble TNF receptors 1 and 2 were also increased by IP-TFA [155 pg/ml (CI: 63-247); P < 0.001 and 480 pg/ml (CI: 72-887); P = 0.02, respectively]. Serum C-reactive protein, interleukin (IL) 6 and adiponectin and subcutaneous abdominal adipose tissue mRNA expression of IL6, IL8, TNFα, and adiponectin as well as ceramide content were not affected by IP-TFA, nor was urinary 8-iso-prostaglandin-F(2α). In conclusion, this dietary trial indicates that the mechanisms linking dietary IP-TFA to cardiovascular disease may involve activation of the TNFα system.
The Journal of Lipid Research 07/2011; 52(10):1821-8. · 4.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Intake of trans-fatty acids (TFA), especially industrially produced TFA (I-TFA), has been associated with the risk of CHD through influence on serum lipid levels. Other causal pathways remain less investigated. In the present cross-sectional study of middle-aged men representing a broad range of BMI, the association between intake of TFA, I-TFA and ruminant TFA (R-TFA) and obesity-associated risk markers of CHD was assessed. The study comprised 393 Danish men (median age 49 years) with a median BMI of 28·4 kg/m(2). Intake of TFA was estimated based on 7 d dietary records, whereas outcomes of interest (waist circumference, sagittal abdominal diameter, percentage of truncal fat, C-reactive protein, IL-6, blood lipids, blood pressure, HbA1c and insulin sensitivity index) were obtained through clinical examination. The associations were assessed by linear regression analysis. The median intake of total TFA among the 393 men was 1·3 g/d, covering a daily I-TFA intake of 0·4 g (10-90th percentile 0·0-1·0) and R-TFA intake of 0·9 g (10-90th percentile 0·4-1·8). Intake of these amounts of TFA showed no significant associations with abdominal fatness, inflammatory markers, blood lipids, blood pressure and insulin homeostasis. Among middle-aged men with a generally low intake of TFA, neither I-TFA nor R-TFA was significantly related to obesity-associated risk markers of CHD. The decreased average intake of I-TFA in Denmark since 1995 is suggested to effectively prevent occurrence of the adverse metabolic changes and health consequences, which have formerly been observed in relation to, especially, I-TFA intake.
The British journal of nutrition 05/2011; 106(8):1245-52. · 3.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: High-protein diets have beneficial effects on body fat regulation, but the difference in effect of various types of protein is not known. Thus, this review examines whether proteins from different sources have similar effects on body composition and energy balance. Animal proteins, especially those from dairy, seem to support better muscle protein synthesis than plant proteins. This could potentially enhance energy expenditure, but no conclusion can be drawn from the scant evidence. Some studies, but not all, demonstrate the higher satiating effect of whey and fish proteins than other protein sources. The evidence from intervention studies comparing the effects of different protein sources on body weight is inconclusive. However, body composition was not evaluated precisely in these studies and the literature is still incomplete (e.g. comparative data are missing for legumes and nuts). Protein intake enhances energy expenditure, satiety and fat loss, but there is no clear evidence to indicate whether there is a difference in the effect dependent on the source of the protein, i.e. from animal or plant-based foods.
[Show abstract][Hide abstract] ABSTRACT: Intake of industrially produced trans-fatty acids (TFA) has been linked to increased risk of type 2 diabetes mellitus in observational studies. We investigated the causality of this association by examining if a high intake of TFA impairs measures of glucose homeostasis and induces intramuscular lipid deposition in abdominally obese women. In a double-blind, parallel dietary intervention study, 52 healthy but overweight postmenopausal women were randomized to receive either partially hydrogenated soybean oil (15 g/d TFA) or a control oil (mainly oleic and palmitic acid) for 16 weeks. Three markers of glucose homeostasis and 4 markers of lipolysis were derived from glucose, insulin, C-peptide, nonesterified fatty acid, and glycerol concentrations during a 3-hour frequent sampling oral glucose tolerance test. Intramuscular lipids were assessed by magnetic resonance spectroscopy. Forty-nine women completed the study. Insulin sensitivity (assessed by ISI(composite)), β-cell function (the disposition index), and the metabolic clearance rate of insulin were not significantly affected by the dietary intervention. Neither was the ability of insulin to suppress plasma nonesterified fatty acid and glycerol during oral glucose ingestion nor the intramuscular lipid deposition. In conclusion, high TFA intake did not affect glucose metabolism over 16 weeks in postmenopausal overweight women. A study population with a stronger predisposition to insulin resistance and/or a longer duration of exposure may be required for insulin sensitivity to be affected by intake of industrial TFA.
Metabolism: clinical and experimental 03/2011; 60(7):906-13. · 3.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this systematic review and meta-analysis was to summarize the evidence from observational studies assessing the association between intake of trans fatty acids (TFA) and the risk of coronary heart disease (CHD), with a specific emphasis on distinguishing between TFA of industrial and ruminant origin. By searching five bibliographic databases, analyses from six published and two unpublished prospective cohort studies, assessing the association of intake of TFA with fatal and/or non-fatal CHD, were identified. Four and three studies reported separate associations for intake of ruminant or industrial-TFA, respectively. The pooled relative risk estimates for comparison of extreme quintiles of total-TFA intake (corresponding to intake increments ranging from 2.8 to ∼10 g/day) were 1.22 (95% confidence interval: 1.08-1.38; P=0.002) for CHD events and 1.24 (1.07-1.43; P=0.003) for fatal CHD. Ruminant-TFA intake (increments ranging from 0.5 to 1.9 g/day) was not significantly associated with risk of CHD (risk ratio (RR)=0.92 (0.76-1.11); P=0.36), and neither was industrial-TFA intake, although there was a trend towards a positive association (RR=1.21 (0.97-1.50); P=0.09). In conclusion, our analysis suggests that industrial-TFA may be positively related to CHD, whereas ruminant-TFA is not, but the limited number of available studies prohibits any firm conclusions concerning whether the source of TFA is important. The null association of ruminant-TFA with CHD risk may be due to lower intake levels.
European journal of clinical nutrition 03/2011; 65(7):773-83. · 3.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:Intake of industrially produced trans fatty acids (TFAs) is, according to observational studies, associated with an increased risk of cardiovascular disease, but the causal mechanisms have not been fully elucidated. Besides inducing dyslipidemia, TFA intake is suspected to promote abdominal and liver fat deposition.Objective:We examined the effect of a high intake of TFA as part of an isocaloric diet on whole-body, abdominal and hepatic fat deposition, and blood lipids in postmenopausal women.Methods:In a 16-week double-blind parallel intervention study, 52 healthy overweight postmenopausal women were randomized to receive either partially hydrogenated soybean oil providing 15.7 g day(-1) of TFA or a control oil with mainly oleic and palmitic acid. Before and after the intervention, body composition was assessed by dual-energy X-ray absorptiometry, abdominal fat by magnetic resonance (MR) imaging, and liver fat by (1)H MR spectroscopy.Results:Compared with the control fat, TFA intake decreased plasma high-density lipoprotein (HDL)-cholesterol by 10%, increased low-density lipoprotein (LDL)-cholesterol by 18% and resulted in an increased LDL/HDL-cholesterol ratio (baseline adjusted mean (95% CI) difference between diet groups 0.41 (0.22; 0.60); P<0.001). TFA tended to increase the body fat (0.46 (-0.20; 1.17) kg; P=0.16) and waist circumference (1.1 (-0.1; 2.4) cm; P=0.08) more than the control fat, whereas neither abdominal nor liver fat deposition was affected by TFA.Conclusion:The adverse effect of dietary TFA on cardiovascular disease risk involves induction of dyslipidemia, and perhaps body fat, whereas weight gain-independent accumulation of ectopic fat could not be identified as a contributory factor during short-term intake.
[Show abstract][Hide abstract] ABSTRACT: Evidence suggests that dietary calcium intake may be inversely related to body weight. One explanatory mechanism is that dietary calcium increases fecal fat excretion, due to either calcium soap formation and/or binding of bile acids (BAs) in the intestine.
To examine the effect of calcium from low-fat dairy products on fecal fat excretion.
A randomized crossover study with 11 subjects, comparing two 7-d diets: one high in calcium from low-fat dairy products (high-Ca; 2300 mg Ca per d) and one low in calcium (low-Ca; 700 mg Ca per d).
All feces were collected during the last 5 days of each diet period and analyzed for fat, energy and calcium content and fatty acid (FA) and BA composition.
Dairy calcium significantly increased the total fecal fat excretion from 5.4+/-0.5 g d(-1) on the low-Ca diet to 11.5+/-1.4 g d(-1) on the high-Ca diet (P<0.001). The fecal energy excretion increased almost correspondingly. Saturated, monounsaturated and polyunsaturated FAs were all excreted in larger amounts on the high-Ca diet (P<0.001 for all), with the effect of calcium being greater for monounsaturated than for saturated FAs. The fecal excretion of BAs was unaffected of calcium intakes.Conclusions:Increasing the intake of calcium from low-fat dairy products by 1600 mg d(-1) for 7 days doubled total fecal fat excretion, but did not affect the excretion of BAs. The results may partially explain why a high-calcium diet can produce weight loss.
International journal of obesity (2005) 10/2008; 32(12):1816-24. · 5.22 Impact Factor