Postprandial metabolism of meal triglyceride in humans

Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX, USA.
Biochimica et Biophysica Acta (Impact Factor: 4.66). 05/2012; 1821(5):721-6. DOI: 10.1016/j.bbalip.2012.01.006
Source: PubMed


The intake of dietary fat above energy needs has contributed to the growing rates of obesity worldwide. The concept of disease development occurring in the fed state now has much support and dysregulation of substrate flux may occur due to poor handling of dietary fat in the immediate postprandial period. The present paper will review recent observations implicating cephalic phase events in the control of enterocyte lipid transport, the impact of varying the composition of meals on subsequent fat metabolism, and the means by which dietary lipid carried in chylomicrons can lead to elevated postprandial non-esterified fatty acid concentrations. This discussion is followed by an evaluation of the data on quantitative meal fat oxidation at the whole body level and an examination of dietary fat clearance to peripheral tissues - with particular attention paid to skeletal muscle and liver given the role of ectopic lipid deposition in insulin resistance. Estimates derived from data of dietary-TG clearance show good agreement with clearance to the liver equaling 8-12% of meal fat in lean subjects and this number appears higher (10-16%) in subjects with diabetes and fatty liver disease. Finally, we discuss new methods with which to study dietary fatty acid partitioning in vivo. Future research is needed to include a more comprehensive understanding of 1) the potential for differential oxidation of saturated versus unsaturated fatty acids which might lead to meaningful energy deficit and whether this parameter varies based on insulin sensitivity, 2) whether compartmentalization exists for diet-derived fatty acids within tissues vs. intracellular pools, and 3) the role of reduced peripheral fatty acid clearance in the development of fatty liver disease. Further advancements in the quantitation of dietary fat absorption and disposal will be central to the development of therapies designed to treat diet-induced obesity. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.

Download full-text


Available from: Elizabeth J Parks, Nov 21, 2014
  • Source
    • "However, difference in the ability to incorporate NEFA could cause the different NEFA levels between the control and active FM periods; thus we consider that the control FM period might less incorporate NEFA than the active FM period. Such NEFA which is not incorporated and remaining in the bloodstream is known to be crucial for the late postprandial rise in NEFA [23,24]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Lactobacillus gasseri SBT2055 (LG2055) inhibits dietary fat absorption in rats and exerts preventive effects on abdominal adiposity in rats and humans. The present study aimed to evaluate the effects of LG2055 on postprandial serum lipid responses in Japanese subjects with hypertriacylglycerolemia after the intake of oral fat-loading test (OFLT) meals. We conducted a single-blind, placebo-controlled, within-subject, repeated-measure intervention trial. Twenty subjects initially ingested the fermented milk (FM) without LG2055 for 4 weeks (control FM period), followed by a 4-week washout period, and then consumed FM containing LG2055 for 4 weeks (active FM period). The subjects were asked to consume FM at 200 g/day. At the end of each 4-week period, an 8-h OFLT was conducted. Blood samples were collected at fasting and every hour for 8 h after OFLT meal intake. Thereafter, postprandial serum non-esterified fatty acid (NEFA) and triacylglycerol (TAG) levels and fasting blood parameters were measured. The OFLT showed that the postprandial serum NEFA levels from 120 to 480 min and the postprandial serum TAG level at 120 min in the active FM period were significantly (P < 0.05) lower than those in the control FM period. The fasting serum NEFA level in the active FM period significantly (P < 0.001) decreased at week 4 from the initial period compared with the control FM period. The consumption of probiotic LG2055 reduced postprandial and fasting serum NEFA levels, suggesting its possible contribution to the reduction of the risk for obesity and type 2 diabetes mellitus. Trial registration: UMIN000011605.
    Full-text · Article · Feb 2014 · Lipids in Health and Disease
  • Source
    • "In addition, incretin-mediated changes in portal insulin and glucagon concentrations may have masked effects of oral lipid ingestion on liver glucose metabolism, which is sensitive to small changes in portal insulin and glucagon (30). Incretins can also increase lipoprotein lipase activity in adipose tissue (31), thereby further increasing the release and uptake of FA from chylomicrons and reducing the spillover (i.e., the release into the blood) (32), which is in line with the observation of elevated chylomicrons, but not FA, in the current study. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Several mechanisms, such as innate immune responses via toll-like receptor-4, accumulation of diacylglycerols (DAG)/ceramides and activation of protein kinase C (PKC), are considered to underlie skeletal muscle insulin resistance. Here, we examined initial events occurring during the onset of insulin resistance upon oral high-fat loading compared to lipid and low-dose endotoxin infusion.Sixteen lean insulin-sensitive volunteers received intravenous fat (iv fat), oral fat (po fat), intravenous endotoxin (LPS) and intravenous glycerol as control (con). After 6 hours, whole-body insulin sensitivity was reduced by iv fat, po fat and LPS to 60%, 67% and 48%, respectively (all P<0.01), which was due to decreased nonoxidative glucose utilization, while hepatic insulin sensitivity was unaffected. Muscle PKCθ activation increased by 50% after iv and po fat, membrane Di-C18:2 DAG species doubled after iv fat and correlated with PKCθ activation after po fat, whereas ceramides were unchanged. Only after LPS, circulating inflammatory markers (TNF-α, IL-6, IL-1ra), their mRNA expression in subcutaneous adipose tissue and circulating cortisol were elevated.Oral fat ingestion rapidly induces insulin resistance by reducing nonoxidative glucose disposal, which associates with PKCθ activation and a rise in distinct myocellular membrane DAG, while endotoxin-induced insulin resistance is exclusively associated with stimulation of inflammatory pathways.
    Full-text · Article · Mar 2013 · Diabetes
  • Source
    • "Another possible explanation relates to the TAG reservoirs that are known to exist in enterocytes [19]. It might be that the lipids of the DPA breakfast were stored in the enterocytes and released either over a longer time span than the 5 h that were followed in this study or after the following meal. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The study of the metabolism of docosapentaenoic acid (DPA, 22:5n-3) in humans has been limited by the unavailability of pure DPA and the fact that DPA is found in combination with eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) in natural products. In this double blind cross over study, pure DPA and EPA were incorporated in meals served to healthy female volunteers. Mass spectrometric methods were used to study the chylomicron lipidomics. Plasma chylomicronemia was significantly reduced after the meal containing DPA compared with the meal containing EPA or olive oil only. Both EPA and DPA were incorporated into chylomicron TAGs, while there was less incorporation into chylomicron phospholipids. Lipidomic analysis of the chylomicron TAGs revealed the dynamic nature of chylomicron TAGs. The main TAG species that EPA and DPA were incorporated into were EPA/18:1/18:1, DPA/18:1/16:0 and DPA/18:1/18:1. There was very limited conversion of DPA and EPA to DHA and there were no increases in EPA levels during the 5h postprandial period after the DPA meal. In conclusion, EPA and DPA showed different metabolic fates, and DPA hindered the digestion, ingestion or incorporation into chylomicrons of the olive oil present in the meal.
    Full-text · Article · Feb 2013 · Prostaglandins Leukotrienes and Essential Fatty Acids
Show more