1
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Srnic N, Dearlove D, Johnson E, MacLeod C, Krupa A, McGonnell A, Frazer-Morris C, O'Rourke P, Parry S, Hodson L. Greater oxidation of dietary linoleate compared to palmitate in humans following an acute high-carbohydrate diet. Clin Nutr 2024; 43:2305-2315. [PMID: 39226718 DOI: 10.1016/j.clnu.2024.08.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 08/14/2024] [Accepted: 08/23/2024] [Indexed: 09/05/2024]
Abstract
BACKGROUND We have previously demonstrated that dietary saturated fatty acids (SFA), when compared to polyunsaturated fatty acids (PUFA), are preferentially partitioned into oxidation pathways. However, it remains unclear if this preferential handling is maintained when hepatocellular metabolism is shifted toward fatty acid (FA) esterification and away from oxidation, such as when hepatic de novo lipogenesis (DNL) is upregulated. AIM To investigate whether an acute upregulation of hepatic DNL influences dietary FA partitioning into oxidation pathways. METHODS 20 healthy volunteers (11 females) underwent a fasting baseline visit followed by two study days, 2-weeks apart. Prior to each study day, participants consumed an isocaloric high-carbohydrate diet (to upregulate hepatic DNL) for 3-days. On the two study days, participants consumed an identical standardised test meal that contained either [U13C]palmitate or [U13C]linoleate, in random order, to trace the fate of dietary FA. Blood and breath samples were collected over a 6h postprandial period and 13C enrichment in breath CO2 and plasma lipid fractions were measured using gas-chromatography-combustion-isotope ratio mass spectrometry. RESULTS Compared to the baseline visit, fasting plasma triglyceride concentrations and markers of hepatic DNL, the lipogenic and stearyl-CoA desaturase indices, were significantly (p < 0.05) increased after consumption of the high-carbohydrate diet. Appearance of 13C in expired CO2 and tracer recovery were significantly (p < 0.05) higher after consumption of the meal containing [U13C]linoleate compared to [U13C]palmitate (5.1 ± 0.5% vs. 3.7 ± 0.4%), respectively. Incorporation of 13C into the plasma triglyceride and non-esterified fatty acid pool was significantly (p < 0.001) greater for [U13C]palmitate compared to [U13C]linoleate. CONCLUSION Dietary PUFA compared to SFA appear to be preferentially partitioned into oxidation pathways during an acute upregulation of hepatic DNL, thus consumption of a PUFA-enriched diet may help mitigate intrahepatic triglyceride accumulation in individuals at risk of cardiometabolic disease.
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Affiliation(s)
- Nikola Srnic
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - David Dearlove
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Elspeth Johnson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Cameron MacLeod
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Antoni Krupa
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Alice McGonnell
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Charlotte Frazer-Morris
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Paige O'Rourke
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Sion Parry
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK; Aston Medical School, Aston University, Birmingham B4 7ET, UK
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK; Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford, UK.
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2
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Liu Z, Yuan J, Wen P, Guo X, Wen H, Guo Y, Li D. Effect of lard plus soybean oil on blood pressure and other cardiometabolic risk factors in healthy subjects: a randomized controlled-feeding trial. Food Funct 2023; 14:7117-7129. [PMID: 37461334 DOI: 10.1039/d3fo01765f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
Lard has been consumed by humans for thousands of years, but its consumption has declined substantially in the last few decades, because of negative publicity about the consumption of animal-derived saturated fats. Emerging evidence highlights that lard plus soybean oil (blend oil) could be more beneficial for body weight and liver function than the individual use of the two oils. This study aimed to evaluate the effects of blend oil on cardiometabolic risk factors in healthy subjects. This was a parallel, three-arm, randomized controlled-feeding trial. 334 healthy subjects (mean age: 33.1 years, 60% women) were randomized into three isoenergetic diet groups with three different edible oils (30 g day-1) (soybean oil, lard, and blend oil [50% lard and 50% soybean oil]) for 12 weeks. 245 (73.4%) participants completed the study. After the 12-week intervention, reductions in both systolic blood pressure (SBP) and diastolic blood pressure (DBP) were greater in the blend oil group than in the other two groups (P = 0.023 and 0.008 for the interaction between the diet group and time, respectively). Reductions of SBP and DBP in the blend oil group were more significant than those in the soybean oil group with P = 0.008 and P = 0.026 and the lard group with P < 0.001 and P < 0.001. Changes in SBP/DBP at 12 weeks were -6.0 (95% CI: -8.6 to -3.4)/0.8 (95% CI: -1.7 to 3.2) mmHg in the blend oil group, -3.3 (95% CI: -5.7 to -0.9)/1.5 (95% CI: -1.0 to 4.0) mmHg in the soybean oil group and -1.2 (95% CI: -3.7 to 1.4)/3.3 (95% CI: 0.9 to 5.8) mmHg in the lard group. Subgroup analyses showed that blend oil significantly decreased SBP and DBP compared with the other two groups in participants with BP ≥ 130/80 mmHg and body mass index ≥25. There were no significant differences in the changes in body weight, waist circumference, serum lipids, or glucose between groups. In conclusion, our findings suggest that blend oil (lard plus soybean oil) reduces BP compared with soybean oil and lard in healthy subjects.
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Affiliation(s)
- Zhiyuan Liu
- Institute of Nutrition & Health, Qingdao University, Qingdao, China.
| | - Jihong Yuan
- Department of Nutrition, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Ping Wen
- Supply Department, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Xiaofei Guo
- Institute of Nutrition & Health, Qingdao University, Qingdao, China.
| | - Haichao Wen
- Institute of Nutrition & Health, Qingdao University, Qingdao, China.
| | - Yanjun Guo
- Institute of Nutrition & Health, Qingdao University, Qingdao, China.
| | - Duo Li
- Institute of Nutrition & Health, Qingdao University, Qingdao, China.
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
- Department of Nutrition, Dietetics and Food, Monash University, Melbourne, Australia
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3
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Basset-Sagarminaga J, Roumans KHM, Havekes B, Mensink RP, Peters HPF, Zock PL, de Mutsert R, Borén J, Lindeboom L, Schrauwen P, Schrauwen-Hinderling VB. Replacing Foods with a High-Glycemic Index and High in Saturated Fat by Alternatives with a Low Glycemic Index and Low Saturated Fat Reduces Hepatic Fat, Even in Isocaloric and Macronutrient Matched Conditions. Nutrients 2023; 15:nu15030735. [PMID: 36771441 PMCID: PMC9920748 DOI: 10.3390/nu15030735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/27/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Current guidelines aim to limit the dietary glycemic index (GI) and intake of saturated fatty acids (SFA). Several studies have shown favorable effects of low-GI or low-SFA diets on intrahepatic lipid content (IHL), but these studies were performed under overfeeding conditions or extreme differences in GI or SFA to maximize the contrast between diets. By combining changes in GI and SFA, we can mimic how people can improve their diet in a realistic setting. OBJECTIVES We investigated the effect on liver fat content and substrate metabolism of both reducing GI and replacing SFA with polyunsaturated fat in practically realistic amounts under isocaloric conditions. DESIGN AND METHODS In a randomized crossover study, thirteen overweight participants consumed two diets, one high in GI and SFA (high GI/SFA) and one low in GI and SFA (low GI/SFA) with identical macronutrient composition, for two weeks each. Diets were equal in caloric content, consisted of habitual food items, and had a macronutrient composition that can be easily achieved in daily life. At the end of each intervention, IHL content/composition and liver glycogen were measured by magnetic resonance spectroscopy. Additionally, fasted and postprandial hepatic de novo lipogenesis and glycemic and metabolic responses were investigated. RESULTS IHL was significantly lower (-28%) after the two-week low-GI/SFA diet (2.4 ± 0.5% 95% CI [1.4, 3.4]) than after the two-week high-GI/SFA diet (3.3 ± 0.6% 95% CI [1.9, 4.7], p < 0.05). Although hepatic glycogen content, hepatic de novo lipogenesis, hepatic lipid composition, and substrate oxidation during the night were similar between the two diets, the glycemic response to the low-GI/SFA diet was reduced (p < 0.05). CONCLUSIONS Changes in macronutrient quality can already have drastic effects on liver fat content and postprandial glycemia after two weeks and even when energy content and the percentage of total fat and carbohydrate remains unchanged.
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Affiliation(s)
- Jeremy Basset-Sagarminaga
- Department of Nutrition and Movement Sciences, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Kay H. M. Roumans
- Department of Nutrition and Movement Sciences, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Bas Havekes
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
| | - Ronald P. Mensink
- Department of Nutrition and Movement Sciences, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Harry P. F. Peters
- Unilever Food Innovation Center, Plantage 14, 6708 WJ Wageningen, The Netherlands
| | - Peter L. Zock
- Unilever Food Innovation Center, Plantage 14, 6708 WJ Wageningen, The Netherlands
| | - Renée de Mutsert
- Department of Clinical Epidemiology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands
| | - Jan Borén
- Department of Molecular and Clinical Medicine, University of Gothenburg, P.O. Box 428, 40530 Gothenburg, Sweden
| | - Lucas Lindeboom
- Department of Nutrition and Movement Sciences, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
| | - Patrick Schrauwen
- Department of Nutrition and Movement Sciences, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Vera B. Schrauwen-Hinderling
- Department of Nutrition and Movement Sciences, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich Heine University, 40225 Düsseldorf, Germany
- Correspondence:
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4
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Catherine Prater M, Scheurell AR, Paton CM, Cooper JA. Metabolic Responses to Eight Weeks of Consuming Cottonseed Oil v. Olive Oil in Adults with Dyslipidemia, a Randomized Trial. J Hum Nutr Diet 2022; 36:1079-1089. [PMID: 36056703 DOI: 10.1111/jhn.13085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 10/14/2022]
Abstract
BACKGROUND Differences in metabolic responses between diets rich in monounsaturated (MUFA) and polyunsaturated fats (PUFA) could affect energy balance and weight maintenance. The present study was a secondary analysis to investigate 8-week diet interventions rich in either PUFA (cottonseed oil (CSO)) or MUFA (olive oil (OO)) on metabolic responses in adults with dyslipidemia. METHODS Forty-one adults with dyslipidemia completed this randomized trial consisting of an 8-week partial-outpatient feeding trial. Provided foods accounted for ~60% of their daily energy needs, with ~30% of energy needs provided by CSO (n=20) or OO (n=21). At pre- and post-diet intervention visits, participants consumed a high saturated fat (SFA) meal (35% daily energy needs, 47.9% from SFA), and fasting and 3.5h postprandial indirect calorimetry was used to measure energy expenditure (EE) and substrate oxidation. RESULTS No changes were observed in fasting measures. The OO group had greater increases in postprandial EE (p=0.002); however, there were no differences in substrate oxidation between groups. A lack of metabolic flexibility was found in both groups, which was partially explained by changes in insulin sensitivity (homeostasis model assessment of insulin resistance (HOMA-IR)). CONCLUSIONS The results of the present study show OO, but not CSO, diet enrichment improves EE following the occasional high SFA meal, which may improve weight maintenance over time. Registered at clinicaltrials.gov (NCT04397055). This article is protected by copyright. All rights reserved.
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Affiliation(s)
- M Catherine Prater
- Department of Nutritional Sciences, University of Georgia, Athens, GA, USA
| | - Alexis R Scheurell
- Department of Nutritional Sciences, University of Georgia, Athens, GA, USA
| | - Chad M Paton
- Department of Nutritional Sciences, University of Georgia, Athens, GA, USA.,Department of Food Science and Technology, University of Georgia, Athens, GA, USA
| | - Jamie A Cooper
- Department of Nutritional Sciences, University of Georgia, Athens, GA, USA
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5
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Monnard CR, Dulloo AG. Polyunsaturated fatty acids as modulators of fat mass and lean mass in human body composition regulation and cardiometabolic health. Obes Rev 2021; 22 Suppl 2:e13197. [PMID: 33471425 DOI: 10.1111/obr.13197] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/22/2022]
Abstract
It is now recognized that the amount and type of dietary fat consumed play an important role in metabolic health. In humans, high intake of polyunsaturated fatty acids (PUFAs) has been associated with reductions in cardiovascular disease risk, improvements in glucose homeostasis, and changes in body composition that involve reductions in central adiposity and, more recently, increases in lean body mass. There is also emerging evidence, which suggests that high intakes of the plant-based essential fatty acids (ePUFAs)-n-6 linoleic acid (LA) and n-3 α-linolenic acid (ALA)-have a greater impact on body composition (fat mass and lean mass) and on glucose homeostasis than the marine-derived long-chain n-3 PUFA-eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In addition, high intake of both ePUFAs (LA and ALA) may also have anti-inflammatory effects in humans. The purpose of this review is to highlight the emerging evidence, from both epidemiological prospective studies and clinical intervention trials, of a role for PUFA, in particular ePUFA, in the long-term regulation of body weight and body composition, and their impact on cardiometabolic health. It also discusses current notions about the mechanisms by which PUFAs modulate fat mass and lean mass through altered control of energy intake, thermogenesis, or lean-fat partitioning.
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Affiliation(s)
- Cathriona R Monnard
- Faculty of Science and Medicine, Department of Endocrinology, Metabolism and Cardiovascular System, University of Fribourg, Fribourg, Switzerland
| | - Abdul G Dulloo
- Faculty of Science and Medicine, Department of Endocrinology, Metabolism and Cardiovascular System, University of Fribourg, Fribourg, Switzerland
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6
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Parry SA, Rosqvist F, Cornfield T, Barrett A, Hodson L. Oxidation of dietary linoleate occurs to a greater extent than dietary palmitate in vivo in humans. Clin Nutr 2021; 40:1108-1114. [DOI: 10.1016/j.clnu.2020.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/08/2020] [Accepted: 07/13/2020] [Indexed: 01/22/2023]
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7
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Fritzen AM, Lundsgaard AM, Kiens B. Tuning fatty acid oxidation in skeletal muscle with dietary fat and exercise. Nat Rev Endocrinol 2020; 16:683-696. [PMID: 32963340 DOI: 10.1038/s41574-020-0405-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/12/2020] [Indexed: 12/31/2022]
Abstract
Both the consumption of a diet rich in fatty acids and exercise training result in similar adaptations in several skeletal muscle proteins. These adaptations are involved in fatty acid uptake and activation within the myocyte, the mitochondrial import of fatty acids and further metabolism of fatty acids by β-oxidation. Fatty acid availability is repeatedly increased postprandially during the day, particularly during high dietary fat intake and also increases during, and after, aerobic exercise. As such, fatty acids are possible signalling candidates that regulate transcription of target genes encoding proteins involved in muscle lipid metabolism. The mechanism of signalling might be direct or indirect targeting of peroxisome proliferator-activated receptors by fatty acid ligands, by fatty acid-induced NAD+-stimulated activation of sirtuin 1 and/or fatty acid-mediated activation of AMP-activated protein kinase. Lactate might also have a role in lipid metabolic adaptations. Obesity is characterized by impairments in fatty acid oxidation capacity, and individuals with obesity show some rigidity in increasing fatty acid oxidation in response to high fat intake. However, individuals with obesity retain improvements in fatty acid oxidation capacity in response to exercise training, thereby highlighting exercise training as a potential method to improve lipid metabolic flexibility in obesity.
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Affiliation(s)
- Andreas Mæchel Fritzen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Anne-Marie Lundsgaard
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Bente Kiens
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
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8
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Tutunchi H, Ostadrahimi A, Saghafi-Asl M. The Effects of Diets Enriched in Monounsaturated Oleic Acid on the Management and Prevention of Obesity: a Systematic Review of Human Intervention Studies. Adv Nutr 2020; 11:864-877. [PMID: 32135008 PMCID: PMC7360458 DOI: 10.1093/advances/nmaa013] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/06/2020] [Accepted: 02/04/2020] [Indexed: 12/21/2022] Open
Abstract
Obesity is associated with an increased risk of several major noncommunicable diseases, and is an important public health concern globally. Dietary fat content is a major contributor to the increase in global obesity rates. Changes in dietary habits, such as the quality of fatty acids in the diet, are proposed to prevent obesity and its metabolic complications. In recent years, a number of studies have found that oleic acid (OA), the most common MUFA in daily nutrition, has protective effects against human disease. Importantly, there is emerging evidence indicating the beneficial effects of OA in regulating body weight. Accordingly, the objective of this systematic review was to investigate the effects of diets enriched in monounsaturated OA on the management and prevention of obesity, emphasizing possible mechanisms of action of OA in energy homeostasis. Searches were performed in PubMed/MEDLINE, ScienceDirect, Scopus, ProQuest, and Google Scholar databases for clinical trials that examined the effects of diets rich in OA on obesity. Of 821 full-text articles assessed, 28 clinical trials were included in the present study. According to the studies examined in this review, diets enriched in OA can influence fat balance, body weight, and possibly energy expenditure. Importantly, abdominal fat and central obesity can be reduced following consumption of high-OA-containing meals. Mechanistically, OA-rich diets can be involved in the regulation of food intake, body mass, and energy expenditure by stimulating AMP-activated protein kinase signaling. Other proposed mechanisms include the prevention of the nucleotide-binding oligomerization domain-like receptor 3/caspase-1 inflammasome pathway, the induction of oleoylethanolamide synthesis, and possibly the downregulation of stearoyl-CoA desaturase 1 activity. In summary, current findings lend support to advice not restricting consumption of OA-rich meals so as to maintain a healthy body weight.
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Affiliation(s)
- Helda Tutunchi
- Nutrition Research Center, Student Research Committee, School of Nutrition & Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran,Department of Clinical Nutrition, School of Nutrition & Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
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9
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Abstract
The effect of dietary fats on cardiometabolic diseases, including cardiovascular diseases and type 2 diabetes mellitus, has generated tremendous interest. Many earlier investigations focused on total fat and conventional fat classes (such as saturated and unsaturated fats) and their influence on a limited number of risk factors. However, dietary fats comprise heterogeneous molecules with diverse structures, and growing research in the past two decades supports correspondingly complex health effects of individual dietary fats. Moreover, health effects of dietary fats might be modified by additional factors, such as accompanying nutrients and food-processing methods, emphasizing the importance of the food sources. Accordingly, the rapidly increasing scientific findings on dietary fats and cardiometabolic diseases have generated debate among scientists, caused confusion for the general public and present challenges for translation into dietary advice and policies. This Review summarizes the evidence on the effects of different dietary fats and their food sources on cell function and on risk factors and clinical events of cardiometabolic diseases. The aim is not to provide an exhaustive review but rather to focus on the most important evidence from randomized controlled trials and prospective cohort studies and to highlight current areas of controversy and the most relevant future research directions for understanding how to improve the prevention and management of cardiometabolic diseases through optimization of dietary fat intake.
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10
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Hodson L, Gunn PJ. The regulation of hepatic fatty acid synthesis and partitioning: the effect of nutritional state. Nat Rev Endocrinol 2019; 15:689-700. [PMID: 31554932 DOI: 10.1038/s41574-019-0256-9] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is an increasing global public health burden. NAFLD is strongly associated with type 2 diabetes mellitus, obesity and cardiovascular disease and begins with intrahepatic triacylglycerol accumulation. Under healthy conditions, the liver regulates lipid metabolism to meet systemic energy needs in the fed and fasted states. The processes of fatty acid uptake, fatty acid synthesis and the intracellular partitioning of fatty acids into storage, oxidation and secretion pathways are tightly regulated. When one or more of these processes becomes dysregulated, excess lipid accumulation can occur. Although genetic and environmental factors have been implicated in the development of NAFLD, it remains unclear why an imbalance in these pathways begins. The regulation of fatty acid partitioning occurs at several points, including during triacylglycerol synthesis, lipid droplet formation and lipolysis. These processes are influenced by enzyme function, intake of dietary fats and sugars and whole-body metabolism, and are further affected by the presence of obesity or insulin resistance. Insight into how the liver controls fatty acid metabolism in health and how these processes might be affected in disease would offer the potential for new therapeutic treatments for NAFLD to be developed.
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Affiliation(s)
- Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Headington, Oxford, UK.
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Headington, Oxford, UK.
| | - Pippa J Gunn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Headington, Oxford, UK
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Headington, Oxford, UK
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11
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Najjar RS, Feresin RG. Plant-Based Diets in the Reduction of Body Fat: Physiological Effects and Biochemical Insights. Nutrients 2019; 11:nu11112712. [PMID: 31717463 PMCID: PMC6893503 DOI: 10.3390/nu11112712] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/30/2019] [Accepted: 11/05/2019] [Indexed: 02/07/2023] Open
Abstract
Obesity affects over one-third of Americans and increases the risk of cardiovascular disease and type II diabetes. Interventional trials have consistently demonstrated that consumption of plant-based diets reduces body fat in overweight and obese subjects, even when controlling for energy intake. Nonetheless, the mechanisms underlying this effect have not been well-defined. This review discusses six major dietary mechanisms that may lead to reduced body fat. These include (1) reduced caloric density, (2) improved gut microbiota symbiosis, (3) increased insulin sensitivity, (4) reduced trimethylamine-N-oxide (TMAO), (5) activation of peroxisome proliferator-activated receptors (PPARs), and (6) over-expression of mitochondrial uncoupling proteins. Collectively, these factors improve satiety and increase energy expenditure leading to reduced body weight.
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12
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Abstract
Non-alcoholic fatty liver disease encompasses a spectrum of conditions from hepatic steatosis through to cirrhosis; obesity is a known risk factor. The liver plays a major role in regulating fatty acid metabolism and perturbations in intrahepatic processes have potential to impact on metabolic health. It remains unclear why intra-hepatocellular fat starts to accumulate, but it likely involves an imbalance between fatty acid delivery to the liver, fatty acid synthesis and oxidation within the liver and TAG export from the liver. As man spends the majority of the day in a postprandial rather than postabsorptive state, dietary fatty acid intake should be taken into consideration when investigating why intra-hepatic fat starts to accumulate. This review will discuss the impact of the quantity and quality of dietary fatty acids on liver fat accumulation and metabolism, along with some of the potential mechanisms involved. Studies investigating the role of dietary fat in liver fat accumulation, although surprisingly limited, have clearly demonstrated that it is total energy intake, rather than fat intake per se, that is a key mediator of liver fat content; hyperenergetic diets increase liver fat whilst hypoenergetic diets decrease liver fat content irrespective of total fat content. Moreover, there is now, albeit limited evidence emerging to suggest the composition of dietary fat may also play a role in liver fat accumulation, with diets enriched in saturated fat appearing to increase liver fat content to a greater extent when compared with diets enriched in unsaturated fats.
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13
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Sihag J, Jones PJH. Oleoylethanolamide: The role of a bioactive lipid amide in modulating eating behaviour. Obes Rev 2018; 19:178-197. [PMID: 29124885 DOI: 10.1111/obr.12630] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/19/2017] [Accepted: 09/19/2017] [Indexed: 12/13/2022]
Abstract
Fatty acid ethanolamides are lipid mediators that regulate a plethora of physiological functions. One such bioactive lipid mediator, oleoylethanolamide (OEA), is a potent agonist of the peroxisome proliferator-activated receptor-alpha (PPAR-α), which modulates increased expression of the fatty acid translocase CD36 that enables the regulation of feeding behaviour. Consumption of dietary fat rich in oleic acid activates taste receptors in the gut activating specific enzymes that lead to the formation of OEA. OEA further combines with PPAR-α to enable fat oxidation in the liver, resulting in enhanced energy production. Evidence suggests that sustained ingestion of a high-fat diet abolishes the anorexic signal of OEA. Additionally, malfunction of the enterocyte that transforms oleic acid produced during fat digestion into OEA might be responsible for reduced satiety and hyperphagia, resulting in overweight and obesity. Thus, OEA anorectic signalling may be an essential element of the physiology and metabolic system regulating dietary fat intake and obesity. The evidence reviewed in this article indicates that intake of oleic acid, and thereby the resulting OEA imparting anorexic properties, is dependent on CD36, PPAR-α, enterocyte fat sensory receptors, histamine, oxytocin and dopamine; leading to increased fat oxidation and enhanced energy expenditure to induce satiety and increase feeding latency; and that a disruption in any of these systems will cease/curb fat-induced satiety.
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Affiliation(s)
- J Sihag
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.,Richardson Centre for Functional Foods and Nutraceuticals (RCFFN), University of Manitoba, Winnipeg, Manitoba, Canada
| | - P J H Jones
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.,Richardson Centre for Functional Foods and Nutraceuticals (RCFFN), University of Manitoba, Winnipeg, Manitoba, Canada
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Oleic acid-derived oleoylethanolamide: A nutritional science perspective. Prog Lipid Res 2017; 67:1-15. [PMID: 28389247 DOI: 10.1016/j.plipres.2017.04.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 03/17/2017] [Accepted: 04/03/2017] [Indexed: 01/11/2023]
Abstract
The fatty acid ethanolamide oleoylethanolamide (OEA) is an endogenous lipid mediator derived from the monounsaturated fatty acid, oleic acid. OEA is synthesized from membrane glycerophospholipids and is a high-affinity agonist of the nuclear transcription factor peroxisome proliferator-activated receptor α (PPAR-α). Dietary intake of oleic acid elevates circulating levels of OEA in humans by increasing substrate availability for OEA biosynthesis. Numerous clinical studies demonstrate a beneficial relationship between high-oleic acid diets and body composition, with emerging evidence to suggest OEA may mediate this response through modulation of lipid metabolism and energy intake. OEA exposure has been shown to stimulate fatty acid uptake, lipolysis, and β-oxidation, and also promote food intake control. Future research on high-oleic acid diets and body composition is warranted to confirm these outcomes and elucidate the underlying mechanisms by which oleic acid exerts its biological effects. These findings have significant practical implications, as the oleic acid-derived OEA molecule may be a promising therapeutic agent for weight management and obesity treatment.
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Liu X, Kris-Etherton PM, West SG, Lamarche B, Jenkins DJA, Fleming JA, McCrea CE, Pu S, Couture P, Connelly PW, Jones PJH. Effects of canola and high-oleic-acid canola oils on abdominal fat mass in individuals with central obesity. Obesity (Silver Spring) 2016; 24:2261-2268. [PMID: 27804268 PMCID: PMC5119743 DOI: 10.1002/oby.21584] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/09/2016] [Accepted: 05/17/2016] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To determine the effect of diets low in saturated fatty acids and high in monounsaturated fatty acids (MUFA) or polyunsaturated fatty acids on body composition in participants at risk for metabolic syndrome (MetS). METHODS This study was a randomized, crossover, controlled feeding study. Participants (n = 101, ages 49.5 ± 1.2, BMI 29.4 ± 0.4 kg/m2 ) were randomized to five isocaloric diets containing treatment oils: Canola, CanolaOleic, CanolaDHA, Corn/Safflower, and Flax/Safflower. Each diet period was 4 weeks followed by a 2- to 4-week washout period. RESULTS Canola (3.1 kg, P = 0.026) and CanolaOleic oil diets (3.09 kg, P = 0.03) reduced android fat mass compared with the Flax/Saff oil diet (3.2 kg), particularly in men. The decrease in abdominal fat mass was correlated with the reduction in blood pressure after the Canola (systolic blood pressure: r = 0.26, P = 0.062; diastolic blood pressure: r = 0.38, P = 0.0049) and CanolaOleic oil diets (systolic blood pressure: r = 0.39 P = 0.004; diastolic blood pressure: r = 0.45, P = 0.0006). The decrease in abdominal fat mass also was associated with a reduction in triglyceride levels after the CanolaOleic oil diet (r = 0.42, P = 0.002). CONCLUSIONS Diets high in MUFA (compared with PUFA) reduced central obesity with an accompanying improvement in MetS risk factors. Diets high in MUFA may be beneficial for treating and perhaps preventing MetS.
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Affiliation(s)
- Xiaoran Liu
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Penny M Kris-Etherton
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA.
| | - Sheila G West
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Benoît Lamarche
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Quebec, Canada
| | - David J A Jenkins
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Jennifer A Fleming
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Cindy E McCrea
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Shuaihua Pu
- Richardson Center for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Patrick Couture
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Quebec, Canada
| | - Philip W Connelly
- Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, Ontario, Canada
| | - Peter J H Jones
- Richardson Center for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, Manitoba, Canada
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Stevenson JL, Miller MK, Skillman HE, Paton CM, Cooper JA. A PUFA-rich diet improves fat oxidation following saturated fat-rich meal. Eur J Nutr 2016; 56:1845-1857. [PMID: 27193583 DOI: 10.1007/s00394-016-1226-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/08/2016] [Indexed: 01/22/2023]
Abstract
PURPOSE To determine substrate oxidation responses to saturated fatty acid (SFA)-rich meals before and after a 7-day polyunsaturated fatty acid (PUFA)-rich diet versus control diet. METHODS Twenty-six, normal-weight, adults were randomly assigned to either PUFA or control diet. Following a 3-day lead-in diet, participants completed the pre-diet visit where anthropometrics and resting metabolic rate (RMR) were measured, and two SFA-rich HF meals (breakfast and lunch) were consumed. Indirect calorimetry was used to determine fat oxidation (Fox) and energy expenditure (EE) for 4 h after each meal. Participants then consumed a PUFA-rich diet (50 % carbohydrate, 15 % protein, 35 % fat, of which 21 % of total energy was PUFA) or control diet (50 % carbohydrate, 15 % protein, 35 % fat, of which 7 % of total energy was PUFA) for the next 7 days. Following the 7-day diet, participants completed the post-diet visit. RESULTS From pre- to post-PUFA-rich diet, there was no change in RMR (16.3 ± 0.8 vs. 16.4 ± 0.8 kcal/20 min) or in incremental area under the curve for EE (118.9 ± 20.6-126.9 ± 14.1 kcal/8h, ns). Fasting respiratory exchange ratio increased from pre- to post-PUFA-rich diet only (0.83 ± 0.1-0.86 ± 0.1, p < 0.05). The postprandial change in Fox increased from pre- to post-visit in PUFA-rich diet (0.03 ± 0.1-0.23 ± 0.1 g/15 min for cumulative Fox; p < 0.05), whereas controls showed no change. CONCLUSIONS Adopting a PUFA-rich diet initiates greater fat oxidation after eating occasional high SFA meals compared to a control diet, an effect achieved in 7 days.
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Affiliation(s)
- Jada L Stevenson
- Department of Nutritional Sciences, Texas Christian University, Fort Worth, TX, USA.,Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
| | - Mary K Miller
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
| | - Hannah E Skillman
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
| | - Chad M Paton
- Department of Food Science and Technology, University of Georgia, Athens, GA, USA.,Department of Foods and Nutrition, University of Georgia, 305 Sanford Drive, Athens, GA, 30622, USA
| | - Jamie A Cooper
- Department of Foods and Nutrition, University of Georgia, 305 Sanford Drive, Athens, GA, 30622, USA.
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17
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Kien CL, Bunn JY, Fukagawa NK, Anathy V, Matthews DE, Crain KI, Ebenstein DB, Tarleton EK, Pratley RE, Poynter ME. Lipidomic evidence that lowering the typical dietary palmitate to oleate ratio in humans decreases the leukocyte production of proinflammatory cytokines and muscle expression of redox-sensitive genes. J Nutr Biochem 2015; 26:1599-606. [PMID: 26324406 DOI: 10.1016/j.jnutbio.2015.07.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 07/09/2015] [Accepted: 07/29/2015] [Indexed: 12/11/2022]
Abstract
We recently reported that lowering the high, habitual palmitic acid (PA) intake in ovulating women improved insulin sensitivity and both inflammatory and oxidative stress. In vitro studies indicate that PA can activate both cell membrane toll-like receptor-4 and the intracellular nucleotide oligomerization domain-like receptor protein (NLRP3). To gain further insight into the relevance to human metabolic disease of dietary PA, we studied healthy, lean and obese adults enrolled in a randomized, crossover trial comparing 3-week, high-PA (HPA) and low-PA/high-oleic-acid (HOA) diets. After each diet, both hepatic and peripheral insulin sensitivities were measured, and we assessed cytokine concentrations in plasma and in supernatants derived from lipopolysaccharide-stimulated peripheral blood mononuclear cells (PBMCs) as well as proinflammatory gene expression in skeletal muscle. Insulin sensitivity was unaffected by diet. Plasma concentration of tumor necrosis factor-α was higher during the HPA diet. Lowering the habitually high PA intake by feeding the HOA diet resulted in lower secretion of interleukin (IL)-1β, IL-18, IL-10, and tumor necrosis factor-α by PBMCs, as well as lower relative mRNA expression of cJun and NLRP3 in muscle. Principal components analysis of 156 total variables coupled to analysis of covariance indicated that the mechanistic pathway for the differential dietary effects on PBMCs involved changes in the PA/OA ratio of tissue lipids. Our results indicate that lowering the dietary and tissue lipid PA/OA ratio resulted in lower leukocyte production of proinflammatory cytokines and muscle expression of redox-sensitive genes, but the relevance to diabetes risk is uncertain.
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Affiliation(s)
- C Lawrence Kien
- Department of Pediatrics, University of Vermont, Burlington, VT; Department of Medicine, University of Vermont, Burlington, VT.
| | - Janice Y Bunn
- Department of Medical Biostatistics, University of Vermont, Burlington, VT
| | | | - Vikas Anathy
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, VT
| | - Dwight E Matthews
- Department of Medicine, University of Vermont, Burlington, VT; Department of Chemistry, University of Vermont, Burlington, VT
| | - Karen I Crain
- Department of Medicine, University of Vermont, Burlington, VT
| | | | - Emily K Tarleton
- College of Medicine Clinical Research Center, University of Vermont, Burlington, VT
| | - Richard E Pratley
- Translational Research Institute for Metabolism and Diabetes, Sanford-Burnham Medical Research Institute, Orlando, FL
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18
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Kien CL, Matthews DE, Poynter ME, Bunn JY, Fukagawa NK, Crain KI, Ebenstein DB, Tarleton EK, Stevens RD, Koves TR, Muoio DM. Increased palmitate intake: higher acylcarnitine concentrations without impaired progression of β-oxidation. J Lipid Res 2015; 56:1795-807. [PMID: 26156077 DOI: 10.1194/jlr.m060137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Indexed: 01/19/2023] Open
Abstract
Palmitic acid (PA) is associated with higher blood concentrations of medium-chain acylcarnitines (MCACs), and we hypothesized that PA may inhibit progression of FA β-oxidation. Using a cross-over design, 17 adults were fed high PA (HPA) and low PA/high oleic acid (HOA) diets, each for 3 weeks. The [1-(13)C]PA and [13-(13)C]PA tracers were administered with food in random order with each diet, and we assessed PA oxidation (PA OX) and serum AC concentration to determine whether a higher PA intake promoted incomplete PA OX. Dietary PA was completely oxidized during the HOA diet, but only about 40% was oxidized during the HPA diet. The [13-(13)C]PA/[1-(13)C]PA ratio of PA OX had an approximate value of 1.0 for either diet, but the ratio of the serum concentrations of MCACs to long-chain ACs (LCACs) was significantly higher during the HPA diet. Thus, direct measurement of PA OX did not confirm that the HPA diet caused incomplete PA OX, despite the modest, but statistically significant, increase in the ratio of MCACs to LCACs in blood.
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Affiliation(s)
- C Lawrence Kien
- Departments of Pediatrics, University of Vermont, Burlington, VT Medicine, University of Vermont, Burlington, VT
| | - Dwight E Matthews
- Medicine, University of Vermont, Burlington, VT Chemistry, University of Vermont, Burlington, VT
| | | | - Janice Y Bunn
- Medical Biostatistics, University of Vermont, Burlington, VT
| | | | | | | | - Emily K Tarleton
- College of Medicine Clinical Research Center, University of Vermont, Burlington, VT
| | - Robert D Stevens
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Timothy R Koves
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Deborah M Muoio
- Duke Molecular Physiology Institute, Duke University, Durham, NC
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19
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Krishnan S, Cooper JA. Effect of dietary fatty acid composition on substrate utilization and body weight maintenance in humans. Eur J Nutr 2013; 53:691-710. [PMID: 24363161 DOI: 10.1007/s00394-013-0638-z] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 11/30/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND/PURPOSE Dietary fat content is a primary factor associated with the increase in global obesity rates. There is a delay in achieving fat balance following exposure to a high-fat (HF) diet (≥ 40% of total energy from fat) and fat balance is closely linked to energy balance. Exercise has been shown to improve this rate of adaptation to a HF diet. Recently, however, the role of dietary fatty acid composition on energy and macronutrient balance has come into question. METHODS We chose studies that compared monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and saturated fatty acids (SFA). We have reviewed studies that measured diet-induced thermogenesis (DIT), energy expenditure (EE), or fat oxidation (FOx) in response to a HF meal challenge, or long-term dietary intervention comparing these fatty acids. RESULTS While single-meal studies show that SFA induce lower DIT and FOx compared to unsaturated fats, the effect of the degree of unsaturation (MUFA vs. PUFA) appears to yet be determined. Long-term dietary interventions also support the notion that unsaturated fats induce greater EE, DIT, and/or FOx versus SFA and that a high MUFA diet induces more weight loss compared to a high SFA diet. Sex and BMI status also affect the metabolic responses to different fatty acids; however, more research in these areas is warranted. CONCLUSION SFA are likely more obesigenic than MUFA, and PUFA. The unsaturated fats appear to be more metabolically beneficial, specifically MUFA ≥ PUFA > SFA, as evidenced by the higher DIT and FOx following HF meals or diets.
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Affiliation(s)
- Sridevi Krishnan
- Department of Nutrition, Hospitality, and Retailing, Texas Tech University, PO Box 41240, Lubbock, TX, 79409, USA,
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20
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Watt MJ, Hoy AJ, Muoio DM, Coleman RA. Distinct roles of specific fatty acids in cellular processes: implications for interpreting and reporting experiments. Am J Physiol Endocrinol Metab 2012; 302:E1-3. [PMID: 22180647 PMCID: PMC3774556 DOI: 10.1152/ajpendo.00418.2011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Plasma contains a variety of long-chain fatty acids (FAs), such that about 35% are saturated and 65% are unsaturated. There are countless examples that show how different FAs impart specific and unique effects, or even opposing actions, on cellular function. Despite these differing effects, palmitate (C16:0) is regularly used to represent "FAs" in cell based experiments. Although palmitate can be useful to induce and study stress effects in cultured cells, these effects in isolation are not physiologically relevant to dietary manipulations, obesity, or the consequences of physiological concentrations of FAs. Hence, authors should avoid conclusions that generalize about "FAs" or "saturated FAs" or "high-fat diet" effects if only a single FA was used in the reported experiments.
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Affiliation(s)
- Matthew J Watt
- Dept. of Physiology, Monash University, Clayton, VIC 3800, Australia.
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21
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Abstract
PURPOSE OF REVIEW A net retention of triacylglycerol within the liver is a prerequisite for the development of nonalcoholic fatty liver disease. The accumulation of liver fat reflects an imbalance between fatty acid input and disposal. Here we summarize recent research into understanding the fate of fatty acids within the hepatocyte. RECENT FINDINGS Several recent studies have elucidated the contribution of different sources of fatty acids to liver fat and to plasma triacylglycerol. Some recent studies have suggested that, contrary to expectations, hepatic fatty acid oxidation is upregulated in insulin-resistant individuals. A recent observation shows the potential importance of fatty acid transformation, especially desaturation, to determination of metabolic fate. These studies highlight our lack of understanding of the regulation of metabolic partitioning of fatty acids within the human liver. SUMMARY The regulation of hepatic fatty acid partitioning involves many factors; not least insulin. Insulin undoubtedly regulates the supply of fatty acids to the liver from adipose tissue; however, whether insulin has a direct intrahepatic effect on hepatic fatty acid partitioning, in humans, remains unclear. The transformation of fatty acids, by desaturases, may have an important role in aiding the disposal of saturated fatty acids via oxidative pathways. Factors that upregulate hepatic fatty acid oxidation need to be elucidated.
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Affiliation(s)
- Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK.
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22
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Kien CL, Everingham KI, D Stevens R, Fukagawa NK, Muoio DM. Short-term effects of dietary fatty acids on muscle lipid composition and serum acylcarnitine profile in human subjects. Obesity (Silver Spring) 2011; 19:305-11. [PMID: 20559306 PMCID: PMC3003742 DOI: 10.1038/oby.2010.135] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In cultured cells, palmitic acid (PA) and oleic acid (OA) confer distinct metabolic effects, yet, unclear, is whether changes in dietary fat intake impact cellular fatty acid (FA) composition. We hypothesized that short-term increases in dietary PA or OA would result in corresponding changes in the FA composition of skeletal muscle diacylglycerol (DAG) and triacylglycerol (TAG) and/or the specific FA selected for β-oxidation. Healthy males (N = 12) and females (N = 12) ingested a low-PA diet for 7 days. After fasting measurements of the serum acylcarnitine (AC) profile, subjects were randomized to either high-PA (HI PA) or low-PA/high-OA (HI OA) diets. After 7 days, the fasting AC measurement was repeated and a muscle/fat biopsy obtained. FA composition of intramyocellular DAG and TAG and serum AC was measured. HI PA increased, whereas HI OA decreased, serum concentration of 16:0 AC (P < 0.001). HI OA increased 18:1 AC (P = 0.005). HI PA was associated with a higher PA/OA ratio in muscle DAG and TAG (DAG: 1.03 ± 0.24 vs. 0.46 ± 0.08, P = 0.04; TAG: 0.63 ± 0.07 vs. 0.41 ± 0.03, P = 0.01). The PA concentration in the adipose tissue DAG (µg/mg adipose tissue) was 0.17 ± 0.02 in those receiving the HI PA diet (n = 6), compared to 0.11 ± 0.02 in the HI OA group (n = 4) (P = 0.067). The relative PA concentration in muscle DAG and TAG and the serum palmitoylcarnitine concentration was higher in those fed the high-PA diet.
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Affiliation(s)
- C Lawrence Kien
- Department of Pediatrics, University of Vermont, Burlington, Vermont, USA.
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23
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Even P, Mariotti F, Hermier D. Postprandial effects of a lipid-rich meal in the rat are modulated by the degree of unsaturation of 18C fatty acids. Metabolism 2010; 59:231-40. [PMID: 19775712 DOI: 10.1016/j.metabol.2009.07.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 07/16/2009] [Accepted: 07/16/2009] [Indexed: 10/20/2022]
Abstract
The fatty acid composition of high-fat diets is known to influence the magnitude of postprandial events that increase the risk of metabolic syndrome. These variations in magnitude may be directly ascribed to differences in the channeling of lipids toward oxidation or storage. A study was designed to compare the effects of 4 dietary fats on postprandial energy expenditure and on some risk factors of the metabolic syndrome. To avoid usual confounding factors due to simultaneous variations in chain length and double-bounds number of fatty acids, dietary fats were chosen to provide mainly 18-carbon fatty acids with 0 (stearic acid [SA]), 1 (oleic acid [OA]), 2 (linoleic acid [LA]), or 3 (alpha-linolenic acid [ALA]) double bounds. They were given as single high-fat test meals to 4 different groups of male rats. The resting metabolic rate and the lipid and carbohydrate oxidation were measured from oxygen consumption and carbon dioxide production using indirect calorimetry 2 hours before and 6.5 hours after the test meal. Plasma glucose, triglyceride, and chylomicron concentrations were determined at 0, 1.5, and 4 hours after the test meal. Postprandial concentration of glucose and triglyceride did not vary with the nature of the test meals, whereas that of chylomicrons was the highest after the LA test meal and the lowest after the SA test meal. Postprandial increase in resting metabolic rate was the highest after the LA and OA test meals, and the lowest after the SA and ALA test meals. Compared with the 3 other diets, the ALA test meal enhanced lipid oxidation and decreased glucose oxidation during the early postprandial period (0.25-3.25 hours). This suggests that stearic acid may not induce all the adverse effects classically described for other saturated fatty acids and that alpha-linolenic acid may beneficially influence energy partitioning, especially during the early postprandial state.
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Affiliation(s)
- Patrick Even
- INRA, UMR914 Nutrition Physiology and Ingestive Behavior, F-75005 Paris, France
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24
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Soares MJ. The Effect of Olive Oil on Postprandial Thermogenesis, Fat Oxidation and Satiety. OLIVES AND OLIVE OIL IN HEALTH AND DISEASE PREVENTION 2010:863-870. [DOI: 10.1016/b978-0-12-374420-3.00092-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Magkos F, Mittendorfer B. Stable isotope-labeled tracers for the investigation of fatty acid and triglyceride metabolism in humans in vivo. ACTA ACUST UNITED AC 2009; 4:215-230. [PMID: 20161007 DOI: 10.2217/clp.09.9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Understanding lipid metabolism and its regulation requires information on the rates at which lipids are produced within the body, absorbed (dietary lipids) into the body, transported within the body, and utilized by various tissues. This article focuses on the use of stable isotope-labeled tracers for the quantitative evaluation of major pathways of fatty acid and triglyceride metabolism in humans in vivo. Adipose tissue lipolysis and free fatty acid appearance in plasma, fatty acid tissue uptake and oxidation, and hepatic very low-density lipoprotein triglyceride secretion are among the metabolic pathways that can be studied by using stable isotope labeled tracers, and will be discussed in detail. The methodology has been in use for many years and is constantly being refined. A variety of tracers and analytical approaches are available and can be used; knowing the advantages, assumptions, and limitations of each is essential for the planning of studies and the interpretation of data, which can provide unique insights into human lipid metabolism.
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Affiliation(s)
- Faidon Magkos
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
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26
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Hodson L, McQuaid SE, Karpe F, Frayn KN, Fielding BA. Differences in partitioning of meal fatty acids into blood lipid fractions: a comparison of linoleate, oleate, and palmitate. Am J Physiol Endocrinol Metab 2009; 296:E64-71. [PMID: 18940935 PMCID: PMC2636984 DOI: 10.1152/ajpendo.90730.2008] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
There has been much interest in the health effects of dietary fat, but few studies have comprehensively compared the acute metabolic fate of specific fatty acids in vivo. We hypothesized that different classes of fatty acids would be variably partitioned in metabolic pathways and that this would become evident over 24 h. We traced the fate of fatty acids using equal amounts of [U-(13)C]linoleate, [U-(13)C]oleate, and [U-(13)C]palmitate given in a test breakfast meal in 12 healthy subjects. There was a tendency for differences in the concentrations of the tracers in plasma chylomicron-triacylglycerol (TG) (oleate > palmitate > linoleate). This pattern remained in plasma nonesterified fatty acid (NEFA) and very low-density lipoprotein (VLDL)-TG (P <or= 0.01 and P <or= 0.02 for [U-(13)C]oleate vs. both [U-(13)C]palmitate and [U-(13)C]linoleate for NEFA and VLDL-TG, respectively). There was significantly more [U-(13)C]linoleate than the other two tracers in plasma cholesteryl ester and phospholipid (PL). Using the values for isotopic enrichment in the different lipid fractions compared with the test meal, we calculated the contribution of meal fatty acids to the respective fractions. At 24 h, 10% of plasma PL-linoleate originated from the breakfast test meal. This was significantly greater than for oleate and palmitate (both 3 +/- 0.3%; P < 0.05). This pattern was also true for erythrocyte PL fatty acids. The marked rapid incorporation of linoleate from a single meal into blood PL fractions may have functional consequences such as maintenance of membrane fluidity and may explain why linoleate is a useful biomarker of dietary intake.
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Affiliation(s)
- Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Churchill Hospital, Oxford OX3 7LJ, UK.
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27
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Soares MJ, Piers LS, Walker KZ, O'Dea K. Is there a role for monounsaturated fat in the dietary management of obesity? Asia Pac J Public Health 2008; 15 Suppl:S18-21. [PMID: 18924536 DOI: 10.1177/101053950301500s06] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Animal and human studies indicate that high saturated fat (SFA) diets can be obesogenic. Monounsaturated fat (MUFA) has acute (meal related) effects that influence energy metabolism. These include increased postprandial fat oxidation and greater diet induced thermogenesis, factors that attenuate weight gain. Chronic (diet related) studies for 12 weeks or more, demonstrate that people following high MUFA diets do not gain excessive weight even when eating ad libitum. In fact, we have observed greater body weight and fat loss in men following an ad libitum MUFA diet, when compared to a SFA diet. High MUFA diets designed for weight loss should also incorporate a high vegetable intake according to traditional Mediterranean patterns. Such diets will promote the utilisation of fat and also have a low energy density. In our experience these diets are well accepted, and offer the prospect of greater long-term adherence to dietary advice.
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Affiliation(s)
- M J Soares
- Department of Nutrition Dietetics & Food Science School of Public Health, Curtin University, Perth, Australia
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28
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Kien CL, Bunn JY. Gender alters the effects of palmitate and oleate on fat oxidation and energy expenditure. Obesity (Silver Spring) 2008; 16:29-33. [PMID: 18223608 PMCID: PMC2263004 DOI: 10.1038/oby.2007.13] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Because estrogen and testosterone affect transcription factors regulating mitochondrial function, we assessed the effects of gender on the metabolic response to dietary palmitic acid (PA) vs. oleic acid (OA) in subjects participating in a previously described trial. METHODS AND PROCEDURES Adults (N = 43) were studied after following a baseline diet (PA = 8.4% kcal, OA = 13.1% kcal) and after undergoing one of two experimental diets: high PA (HI PA) (PA = 16.8%, OA = 16.4% kcal) (N = 21; 11 men) or high OA (HI OA) (PA = 1.7%, and OA = 31.4%) (N = 22; 11 men). RESULTS Relative to baseline, the rate of fatty acid (FA) oxidation (% resting energy expenditure(REE)) (mean +/- s.e.m.) increased in women on HI OA while decreasing on HI PA in the fed (+11.8 +/- 5.6% vs. -6.3 +/- 4.2%, P = 0.02) and fasting states (+13.4 +/- 4.2% vs. -12.7 +/- 6.9%, P = 0.047), but changes in men were not statistically significant. Daily energy expenditure changed only in men, increasing on HI OA and decreasing on HI PA (+66 +/- 61 kcal/day or 1.2 +/- 1.0 kcal/kg fat-free mass (FFM)/day vs. -266 +/- 78 kcal/day or -4.2 +/- 1.3 kcal/kg FFM/day, P = 0.004 and P = 0.007, respectively). DISCUSSION Increased dietary PA/OA caused decreased FA oxidation in women, in the fed and fasted states and decreased daily energy expenditure (DEE) in men.
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Affiliation(s)
- C Lawrence Kien
- Department of Pediatrics, University of Vermont, Burlington, Vermont, USA.
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Abstract
OBJECTIVE Using tracers, we showed, over 9 hours, that palmitic acid (PA) is oxidized at a lower rate than oleic acid (OA). Our subsequent clinical trial showed that enriching the diet for 28 days with PA, relative to OA, lowered fatty acid (FA) oxidation. However, because this conclusion was based on indirect calorimetry for 7 hours after a test meal, transient differences in the kinetics of oxidation of OA and PA could explain these results. Thus, we hypothesized that increasing PA vs. OA would decrease FA oxidation during the first day of feeding the diets. RESEARCH METHODS AND PROCEDURES A double-masked trial was conducted in 20 adults, who, after a baseline diet, were randomized to one of two experimental formula diets: high (HI) OA (PA=1.7% kcal, OA=31.4% kcal; N=11) or HI PA (PA=16.8% kcal, OA=16.4% kcal; N=9). Respiratory quotient (RQ) was measured over the first 14 hours of feeding the experimental diets (7:00 am to 9:00 pm). To determine whether these subjects were representative of the subjects in the previous trial, we assessed RQ 28 days after beginning either diet. RESULTS During the first 14 hours of feeding the diets, time (p=0.026) but not diet group had an effect on the difference between the RQ post-feeding and the fasting pre-value. However, RQ in the fed state was significantly higher in the HI PA group after 28 days of feeding. DISCUSSION Chronically increasing dietary PA for 28 days, but not acute meal feeding, lowers total FA oxidation.
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Affiliation(s)
- C Lawrence Kien
- Department of Pediatrics and Medicine, E203 Given Building, 89 Beaumont Avenue, University of Vermont College of Medicine, Burlington, VT 05405-0068, USA.
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30
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Abstract
Humans have a large variability in body fat distribution, which has tremendous implications for metabolic health. Obese individuals with an upper-body-fat distribution have increased health complications such as dyslipidemia, hypertension, insulin resistance, and type 2 diabetes in comparison with lower-body-obese individuals. Additionally, females have more body fat, a greater proportion of fat in their lower body, and much less visceral fat than do lean males at the same body mass index. The reasons for these differences in body fat distribution have not been clearly identified but could be important. Herein we review what has been learned about regional differences in triglyceride storage capacity and lipolysis as they relate to the causes and consequences of regional fat accumulation. Both sex and site differences in regional fat storage have been described. In contrast, with the exception of variations between men and women in the contribution of visceral adipose tissue to hepatic FFA delivery, most studies have failed to show important sex differences in regional lipolysis in vivo.
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Affiliation(s)
- Susanne B Votruba
- Endocrine Research Unit, Division of Endocrinology, Metabolism and Nutrition, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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31
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Heath RB, Karpe F, Milne RW, Burdge GC, Wootton SA, Frayn KN. Dietary fatty acids make a rapid and substantial contribution to VLDL-triacylglycerol in the fed state. Am J Physiol Endocrinol Metab 2007; 292:E732-9. [PMID: 17090753 DOI: 10.1152/ajpendo.00409.2006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Exaggerated postprandial lipemia is associated with coronary heart disease and type II diabetes, yet few studies have examined the effect of sequential meals on lipoprotein metabolism. We have used 13C-labeled fatty acids to trace the incorporation of fatty acid derived from a meal into apolipoprotein B-100 (apoB-100)-containing lipoproteins and plasma nonesterified fatty acids (NEFA) following two consecutive meals. Healthy volunteers (n=8) were given breakfast labeled with [1-(13)C]palmitic acid, eicosapentaenoic acid, and docosahexaenoic acid, followed 5 h later by lunch containing [1-(13)C]oleic acid. Blood samples were taken over a 9-h period. ApoB-100-containing lipoproteins were isolated by immunoaffinity chromatography. Chylomicron-triacylglycerol (TG) concentrations peaked at 195 min following breakfast but at 75 min following lunch (P<0.001). VLDL-TG concentrations, in contrast, rose to a broad peak after breakfast and then fell steadily after lunch. Breakfast markers followed chylomicron-TG concentrations and appeared in plasma NEFA with a similar profile, whereas [1-(13)C]oleic acid peaked 2 h after lunch in plasma TG and NEFA. Breakfast markers appeared steadily in VLDL, peaking 1-3 h after lunch, whereas [1-(13)C]oleic acid was still accumulating in VLDL at 9 h. Around 17% of VLDL-TG originated from recent dietary fat 5 h after breakfast, and around 40% at the end of the experiment. We conclude that there is rapid flux of fatty acids from the diet into endogenous pools. Further study of these processes may open up new targets for intervention to reduce VLDL-TG concentrations and postprandial lipemia.
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Affiliation(s)
- Richard B Heath
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, UK
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Vedala A, Wang W, Neese RA, Christiansen MP, Hellerstein MK. Delayed secretory pathway contributions to VLDL-triglycerides from plasma NEFA, diet, and de novo lipogenesis in humans. J Lipid Res 2006; 47:2562-74. [PMID: 16929033 DOI: 10.1194/jlr.m600200-jlr200] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Newly synthesized triglyceride (TG) may exit the liver immediately as VLDL-TG or be stored and secreted after a delay. We quantified the contributions from plasma NEFA, diet, and de novo lipogenesis (DNL) to VLDL-TG via immediate and delayed pathways in five lean, normolipidemic subjects; six obese, hypertriglyceridemic (HPTG) nondiabetics; and six obese, HPTG diabetics. Intravenous [(2)H(31)]palmitate and [1-(13)C(1)] acetate and oral [(2)H(35)]stearate were administered for 30 h preceding an overnight fast. [1,2,3,4-(13)C(4)]palmitate was infused during the subsequent 12 h fast. Contributions from plasma NEFA via the immediate pathway were 64 +/- 15, 33 +/- 6, and 58 +/- 2% in control, HPTG, and diabetic HPTG, respectively. Delayed pool fractional contributions were as follows: dietary FA, 2.0 +/- 0.9, 2.5 +/- 1, and 12 +/- 2%; DNL, 3 +/- 0.3, 14 +/- 3, and 13 +/- 4%; delayed NEFA, 15 +/- 4, 20 +/- 4, and 30 +/- 3%. VLDL-TG production rates and absolute input rates from the delayed pool were significantly higher in HPTG and diabetic HPTG than in controls. In conclusion, we provide direct kinetic evidence for a hepatic TG storage pool in humans and document its metabolic sources. The turnover time and sources of this pool differ in diabetic HPTG and nondiabetic HPTG, with potential therapeutic implications.
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Affiliation(s)
- Aruna Vedala
- Department of Nutritional Sciences and Toxicology, University of California at Berkeley, Berkeley, CA 94720, USA
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Kien CL, Bunn JY, Ugrasbul F. Increasing dietary palmitic acid decreases fat oxidation and daily energy expenditure. Am J Clin Nutr 2005. [DOI: 10.1093/ajcn/82.2.320] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- C Lawrence Kien
- From the Department of Pediatrics, University of Texas Medical Branch (CLK and FU) and Shriners Hospital for Children (CLK), Galveston, TX, and the Department of Medical Biostatistics, University of Vermont, Burlington, VT (JB)
| | - Janice Y Bunn
- From the Department of Pediatrics, University of Texas Medical Branch (CLK and FU) and Shriners Hospital for Children (CLK), Galveston, TX, and the Department of Medical Biostatistics, University of Vermont, Burlington, VT (JB)
| | - Figen Ugrasbul
- From the Department of Pediatrics, University of Texas Medical Branch (CLK and FU) and Shriners Hospital for Children (CLK), Galveston, TX, and the Department of Medical Biostatistics, University of Vermont, Burlington, VT (JB)
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Lisitsyn DM, Razumovskii SD, Tishenin MA, Titov VN. Kinetic parameters of oxidation of individual fatty acids with ozone. Bull Exp Biol Med 2005; 138:457-9. [PMID: 15723125 DOI: 10.1007/s10517-005-0069-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Using an original automated analyzer of double bonds we determined the rate constants for oxidation of saturated and unsaturated mono- and dienoic fatty acids (in vivo substrates for beta-oxidation in the mitochondria) by the ozone titration method. The rate constant for O(3) oxidation is maximum for oleic monoenoic acid, lower for dienoic linoleic, and very low for saturated palmitic acid. The rate constant for oxidation of oleic fatty acid, which by one order of magnitude surpasses that for oxidation of essential arachidonic acid, indicates that oleic acid is a leading in vivo acceptor of active O(2) species. By the rate of trapping active oxygen species and in the quantitative aspect, endogenously produced oleic acid can be regarded as the main biological antioxidant.
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Affiliation(s)
- D M Lisitsyn
- Laboratory of Clinical Biochemistry of Lipids and Lipoproteins, Institute of Clinical Cardiology, Cardiology Research Center, Ministry of Health of Russian Federation, Moscow, Russia
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Votruba SB, Atkinson RL, Schoeller DA. Sustained increase in dietary oleic acid oxidation following morning exercise. Int J Obes (Lond) 2004; 29:100-7. [PMID: 15505635 DOI: 10.1038/sj.ijo.0802779] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE We have previously reported that prior exercise increases the oxidation of dietary monounsaturated fat in comparison to rest when the fat is given in a mixed meal 30 min following the completion of exercise. In this study, we determined whether the increase in dietary fat oxidation after exercise persisted when the time between exercise and fatty acid administration was lengthened. DESIGN Six female subjects (age=24+/-0.1 y, BMI=21+/-1 kg/m2) were recruited for a total of six visits each. During three visits, a stationary cycle exercise session (1250 kJ) was performed at 65% VO2 peak in a whole-body calorimeter; while during three other visits, exercise was replaced with rest. Subjects received [1-13C]oleate and [d31]palmitate with a different meal at each visit: breakfast, lunch, and dinner. RESULTS Dietary oleate oxidation following prior rest did not differ between dose times and was 36+/-3, 42+/-5, and 42+/-3% for the 13 h following breakfast, lunch, and dinner. Prior exercise resulted in greater oleate oxidation following all dose times than prior rest (P<0.01) being 52+/-4, 64+/-3, and 53+/-3% for the breakfast, lunch, and dinner dose. The oxidation was significantly greater following lunch than the other dose times (P<0.05). Prior exercise (1250 kJ) did not result in greater oxidation of palmitate; however, oxidation following prior exercise increased with later dose times (13+/-2, 23+/-2, and 23+/-3% for breakfast, lunch, and dinner; P<0.05) and following rest (18+/-2, 22+/-2, and 27+/-2% for breakfast, lunch, and dinner; P<0.005). CONCLUSIONS The increase in oleate oxidation when administered after early morning exercise was found to persist for all three meals of the day, with the greatest effect occurring for the lunch meal. Palmitate oxidation, while apparently resistant to the effects of 1250 kJ of prior exercise, increases when administered later in the day, suggesting a diurnal variation in the oxidation of dietary fatty acids. These results demonstrate that prior exercise selectively alters the partitioning of dietary fatty acids. Furthermore, these findings demonstrate additional benefits of substituting monounsaturated for saturated fatty acids in the diet.
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Affiliation(s)
- S B Votruba
- Endocrine Research Unit, Mayo Clinic, Rochester, MN, USA
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Kien CL, Ugrasbul F. Prediction of daily energy expenditure during a feeding trial using measurements of resting energy expenditure, fat-free mass, or Harris-Benedict equations. Am J Clin Nutr 2004; 80:876-80. [PMID: 15447893 PMCID: PMC1409752 DOI: 10.1093/ajcn/80.4.876] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND During feeding trials, it is useful to predict daily energy expenditure (DEE) to estimate energy requirements and to assess subject compliance. OBJECTIVE We examined predictors of DEE during a feeding trial conducted in a clinical research center. DESIGN During a 28-d period, all food consumed by 26 healthy, nonobese, young adults was provided by the investigators. Energy intake was adjusted to maintain constant body weight. Before and after this period, fat-free mass (FFM) and fat mass were assessed by using dual-energy X-ray absorptiometry, and DEE was estimated from the change (after - before) in body energy (DeltaBE) and in observed energy intake (EI): DEE = EI - DeltaBE. We examined the relation of DEE to pretrial resting energy expenditure (REE), FFM, REE derived from the average of REE and calculated from FFM [REE = (21.2 x FFM) + 415], and an estimate of DEE based on the Harris-Benedict equation (HB estimate) (DEE = 1.6 REE). RESULTS DEE correlated (P < 0.001) with FFM (r = 0.78), REE (r = 0.73), average REE (r = 0.82), and the HB estimate (r = 0.81). In a multiple regression model containing all these variables, R(2) was 0.70. The mean (+/-SEM) ratios of DEE to REE, to average REE, and to the HB estimate were 1.86 +/- 0.06, 1.79 +/- 0.04, and 1.02 +/- 0.02, respectively. CONCLUSIONS Although a slightly improved prediction of DEE is possible with multiple measurements, each of these measurements suggests that DEE equals 1.60-1.86 x REE. The findings are similar to those of previous studies that describe the relation of REE to DEE measured directly.
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Affiliation(s)
- C Lawrence Kien
- Department of Pediatrics, University of Texas Medical Branch and the Shriners Hospital for Children, Galveston, TX, USA.
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Rodriguez M, Funke S, Fink M, Demmelmair H, Turini M, Crozier G, Koletzko B. Plasma fatty acids and [13C]linoleic acid metabolism in preterm infants fed a formula with medium-chain triglycerides. J Lipid Res 2003; 44:41-8. [PMID: 12518021 DOI: 10.1194/jlr.m200218-jlr200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Most preterm infant formulas contain medium-chain triacylglycerols (MCT), but the effects of MCT on polyunsaturated fatty acid status and metabolism are controversial. Thus, we studied the effects of MCT on linoleic acid metabolism using stable isotopes. Enterally fed preterm infants were randomized to receive for 7 days 40% of fat as MCT (n = 10) or a formula without MCT (n = 9). At study day 5, infants received orally 2 mg/kg body weight of (13)C-labeled linoleic acid. Fatty acids in plasma lipid classes and (13)C enrichment of phospholipid fatty acids were measured and tracer oxidation was monitored. Compared with the control group, the MCT group showed lower breath (13)CO(2) and higher plasma triacylglycerol contents of octanoic acid, of decanoic acid, and of total long-chain polyunsaturated fatty acids (57.1 +/- 4.4 micro mol/l vs. 37.9 +/- 4.8 micro mol/l, P < 0.01). Concentrations of several polyunsaturated fatty acids in plasma phospholipids and non esterified fatty acids were higher in the MCT group. (13)C concentrations in phospholipid n-6 fatty acids indicated no difference in the relative conversion of linoleic to arachidonic acid. We conclude that oral MCT effectively reduce polyunsaturated fatty acid and long chain polyunsaturated fatty acid oxidation in preterm infants without compromising endogenous n-6 long chain polyunsaturated fatty acid synthesis.
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Affiliation(s)
- Maria Rodriguez
- Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
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Emken EA. Stable isotope approaches, applications, and issues related to polyunsaturated fatty acid metabolism studies. Lipids 2001; 36:965-73. [PMID: 11724469 DOI: 10.1007/s11745-001-0807-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The use of stable isotope tracers for investigating fatty acid metabolism in human subjects has increased substantially over the last decade. Advances in analytical instrumentation, commercial availability of labeled substrates, and safety considerations are major reasons for this increased use of stable isotope tracers. Several experimental design options are available for using either deuterium or carbon-13 as tracers for fatty acid and lipid studies. Options include feeding a pulse dose of labeled fat or a mixture containing two or more labeled fats. Multiple doses of the labeled fat can be fed at timed intervals to increase enrichments. Administration by injection or continuous intravenous infusion is an alternative. Another option is to use diets containing foods from plants that have slightly higher natural carbon-13 enrichment. Each basic experimental design has its specific strengths, and the best choice of experimental design depends on the study objectives. Stable isotope studies have been used to address a variety of questions related to unsaturated fatty acid metabolism in humans. Examples are provided that illustrate the use of stable isotopes to investigate oxidation of docosahexaenoic acid, desaturation of linoleic and linolenic acids in infants and adults, incorporation of long-chain n-6 and n-3 fatty acids, bioequivalency of linolenic acid in primates, 13C nuclear magnetic resonance spectra of arachidonic acid in living rat brain, and effect of triacylglycerol structure on absorption. Radioisotope and stable isotope tracer studies in animals and humans are responsible for much of our understanding of fatty acid and lipid metabolism. However, tracer studies have limitations, and there are some unresolved issues associated with isotope studies. Examples of unresolved issues are quantification of isotope data, validity of in vivo fatty acid metabolite results, kinetic modeling, subject variability, and use of blood lipid data as a reflection of tissue lipid metabolism. Resolving these issues, developing novel methodology, and applying stable isotope tracer methods to questions related to PUFA metabolism are broad areas of interesting and challenging research opportunities.
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Affiliation(s)
- E A Emken
- Midwest Research Consultants, Princeville, Illinois 61559, USA.
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