1.
Plasma lipid profiling of tissue-specific insulin resistance in human obesity.
van der Kolk, BW, Vogelzangs, N, Jocken, JWE, Valsesia, A, Hankemeier, T, Astrup, A, Saris, WHM, Arts, ICW, van Greevenbroek, MMJ, Blaak, EE, et al
International journal of obesity (2005). 2019;(5):989-998
Abstract
BACKGROUND/OBJECTIVES Obesity-associated insulin resistance (IR) may develop in multiple organs, representing different aetiologies towards cardiometabolic diseases. This study aimed to identify distinct plasma lipid profiles in overweight/obese individuals who show muscle-IR and/or liver-IR. SUBJECTS/METHODS Baseline data of the European multicenter DiOGenes project were used (n = 640; 401 women, nondiabetic BMI: 27-45 kg/m2). Muscle insulin sensitivity index (MISI) and hepatic insulin resistance index (HIRI) were derived from a 5-point oral glucose tolerance test. The 140 plasma lipids were quantified by liquid chromatography-mass spectrometry. Linear mixed models were used to evaluate associations between MISI, HIRI and plasma lipids. RESULTS MISI was comparable between sexes while HIRI and triacylglycerol (TAG) levels were lower in women than in men. MISI was associated with higher lysophosphatidylcholine (LPC) levels (standardized (std)β = 0.126; FDR-p = 0.032). Sex interactions were observed for associations between HIRI, TAG and diacylglycerol (DAG) lipid classes. In women, but not in men, HIRI was associated with higher levels of TAG (44 out of 55 species) and both DAG species (stdβ: 0.139-0.313; FDR-p < 0.05), a lower odd-chain/even-chain TAG ratio (stdβ = -0.182; FDR-p = 0.005) and a lower very-long-chain/long-chain TAG ratio (stdβ = -0.156; FDR-p = 0.037). CONCLUSIONS In overweight/obese individuals, muscle insulin sensitivity is associated with higher plasma LPC concentrations. Women have less hepatic IR and lower TAG than men. Nevertheless, hepatic IR is associated with higher plasma TAG and DAG concentrations and a lower abundance of odd-chain and very-long-chain TAG in women, but not in men. This suggests a more pronounced worsening of plasma lipid profile in women with the progression of hepatic IR.
2.
Increased nocturnal fat oxidation in young healthy men with low birth weight: results from 24-h whole-body respiratory chamber measurements.
Brøns, C, Lilleøre, SK, Jensen, CB, Toubro, S, Vaag, A, Astrup, A
Metabolism: clinical and experimental. 2013;(5):709-16
Abstract
OBJECTIVE Low birth weight (LBW), a marker of disturbed fetal growth, is associated with adiposity and increased risk of type 2 diabetes (T2D). The aim of the study was to investigate whether LBW is associated with changes in 24-h energy expenditure (EE) and/or substrate utilization rates, potentially contributing to the development of adiposity and/or T2D compared to matched control subjects. MATERIALS/METHODS Forty-six young, healthy men were included in the study; 20 with LBW (≤ 10th percentile) and 26 control subjects with normal birth weight (NBW) (50th-90th percentile). The subjects were fed a weight maintenance diet and 24-h energy expenditure (EE), respiratory quotient (RQ), and substrate oxidation were assessed in a respiratory chamber. RESULTS No differences in 24-h EE, RQ or substrate oxidation were observed between LBW and controls. Interestingly, the LBW group exhibited lower nocturnal RQ compared to controls (0.81 ± 0.01 vs. 0.85 ± 0.01 (mean ± SE), P = 0.01), and hence higher nocturnal fat oxidation (2.55 ± 0.13 vs. 2.09 ± 0.12 kJ/min (mean ± SE), P = 0.02). CONCLUSIONS Young LBW men do not exhibit reductions in 24-h EE. However, LBW subjects display increased nocturnal fat oxidation at the expense of reduced glucose oxidation. We speculate that this may be associated with insufficient capability to retain fat in subcutaneous adipose tissue after meals during day time, with an increased rate of nocturnal and morning lipolysis, and potentially with subtle elevations of gluconeogenesis and of fasting glucose levels in the LBW subjects.
3.
Dairy calcium intake modifies responsiveness of fat metabolism and blood lipids to a high-fat diet.
Lorenzen, JK, Astrup, A
The British journal of nutrition. 2011;(12):1823-31
Abstract
Intervention studies have demonstrated that saturated fat increases total and LDL-cholesterol concentrations, and it is therefore recommended that the intake of high-fat dairy products be limited. However, observational studies have found an inverse relationship between the intake of dairy products and incidence of CVD. We aimed to study whether the Ca content of dairy products influences the effect of dairy fat on the lipid profile. The study had a randomised cross-over design. Subjects (n 9) were randomised to one of the sequence of four isoenergetic 10 d diets: low Ca and low fat (LC/LF: approximately 700 mg Ca/d, 25 % of energy (fat); high Ca and LF (HC/LF: approximately 2800 mg Ca/d, 25 % of energy fat); LC and high fat (LC/HF: approximately 700 mg Ca/d, 49 E% fat); or HC and HF (approximately 2800 mg Ca/d, 49 E% fat). Blood variables were measured before and after each diet period, and faeces and urine were collected at the end of each diet period. A two-way ANOVA was used to examine the effect of Ca and fat intake. Independent of Ca intake, the HF diet increased the concentrations of total (9 %; P < 0·0001), LDL (14 %; P < 0·0001)- and HDL (13 %; P = 0·0002)-cholesterol compared with the LF diet. However, independent of fat intake, the HC diet decreased the concentrations of total (4 %; P = 0·0051) and LDL-cholesterol (10 %; P < 0·0001) but not HDL-cholesterol compared with the LC diet. In addition, total:HDL-cholesterol was decreased (5 %; P = 0·0299), and HDL:LDL was increased (12 %; P = 0·0097) by the HC diet compared with the LC diet. Faecal fat excretion was increased by both the HC (P < 0·0001) and HF (P = 0·0052) diets. In conclusion, we observed that dairy Ca seems to partly counteract the raising effect of dairy fat on total and LDL-cholesterol, without reducing HDL-cholesterol.
4.
Effect of calcium from dairy and dietary supplements on faecal fat excretion: a meta-analysis of randomized controlled trials.
Christensen, R, Lorenzen, JK, Svith, CR, Bartels, EM, Melanson, EL, Saris, WH, Tremblay, A, Astrup, A
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2009;(4):475-86
Abstract
Observational studies have found that dietary calcium intake is inversely related to body weight and body fat mass. One explanatory mechanism is that dietary calcium increases faecal fat excretion. To examine the effect of calcium from dietary supplements or dairy products on quantitative faecal fat excretion, we performed a systematic review with meta-analysis. We included randomized, controlled trials of calcium (supplements or dairy) in healthy subjects, where faecal fat excretion was measured. Meta-analyses used random-effects models with changes in faecal fat excreted expressed as standardized mean differences, as the studies assessed the same outcome but measured in different ways. An increased calcium intake resulted in increased excretion of faecal fat by a standardized mean difference of 0.99 (95% confidence intervals: 0.63-1.34; P < 0.0001; expected to correspond to approximately 2g day(-1)) with moderate heterogeneity (I(2) = 49.5%) indicating some inconsistency in trial outcomes. However, the dairy trials showed homogeneous outcomes (I(2)=0%) indicating consistency among these trials. We estimated that increasing the dairy calcium intake by 1241 mg day(-1) resulted in an increase in faecal fat of 5.2 (1.6-8.8) g day(-1). In conclusion, dietary calcium has the potential to increase faecal fat excretion to an extent that could be relevant for prevention of weight (re-)gain. Long-term studies are required to establish its potential contribution.