Scientific Programme
Physiology & Nutrition
IS-PN06 - Omega-3 PUFA’s and metabolic health
Date: 04.07.2024, Time: 17:00 - 18:15, Lecture room: M1
Description
Omega-3 polyunsaturated fatty acids (n-3 PUFA) are bioactive long-chain fatty acids that have been researched for their potential benefit to human cardiovascular and metabolic health. Potential health benefits are thought to be driven primarily by: 1) n-3 PUFA incorporation into cell membranes which can subsequently alter responsiveness of cells to nutritional and/or contractile stimuli; and/or 2) anti-inflammatory effects of n-3 PUFA mediated through production of specialised pro-resolving mediators. These potential actions of n-3 PUFA on metabolic health outcomes in humans have been examined in a range of population samples from young active sport participants, through to inactive older adults or clinical populations. The most well-studied n-3 PUFA are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). There is growing evidence that these fatty acids can potentiate rates of muscle protein synthesis and suppress hepatic de novo lipogenesis, thus providing metabolic health benefits. However, effects of dose, ratios of fatty acids used, age and sex are all potential mediating factors in the outcomes of these studies. In this symposium we will provide an introduction to n-3 PUFA and explore the role of dose, age and sex effects on metabolic outcomes with a particular emphasis on skeletal muscle protein synthesis and hepatic lipid and glucose metabolism. We aim to provide an overview of current scientific research and to stimulate discussion of practical application.
Chair(s)
Stuart Galloway
University of Stirling, Faculty of Health Sciences and Sport
United Kingdom
Vassilis Mougios
Aristotle University of Thessaloniki, Physical Education and Sport Science at Thessaloniki
Greece
Speaker A
Stuart Galloway
University of Stirling, Faculty of Health Sciences and Sport
United Kingdom
Read CVECSS Glasgow 2024: IS-PN06
Omega-3 and metabolic health: dosing considerations
Omega-3 polyunsaturated fatty acids (n-3 PUFA) are bioactive long-chain fatty acids that have been implicated in human cardiovascular and metabolic health. The most widely studied bioactive n-3 PUFA are eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) which can be synthesised from alpha-linolenic acid (ALA). Common food sources rich in n-3 PUFA include linseed/flaxseed oil, chia seeds, walnuts, rapeseed/canola oil and soyabean oil which are good plant-based sources of ALA, whereas fatty fish such as mackerel, sardines, salmon, trout, and herring are good marine sources of EPA and DHA. Since ALA conversion to EPA and DHA is not particularly efficient in humans the ingestion of foods containing EPA and DHA is recommended. The European Food Safety Authority (EFSA, 2010) set an adequate intake (AI) for EPA and DHA for adults at 250mg/day, typically achieved through ingestion of one portion of fatty fish per week. However, research exploring the incorporation of n-3 PUFA into cell membranes to influence responsiveness to nutritional and/or contractile stimuli, as well studies exploring the role of n-3 PUFA in resolution of inflammation have typically used much higher doses. The dose of omega-3 administered in studies has varied from daily amounts of 4-5g/day over short (4-12 weeks) or long periods (6 months), to extremely high doses (up to 52g/day) over only a few days (3-6 days). This presentation will provide an introduction to n-3 PUFA metabolism and explore the incorporation of these lipids into tissues in human studies, in relation to dose administered and age of participants, with a focus on metabolic outcomes in response to contractile or nutritional stimuli.
Speaker B
Leanne Hodson
University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism
United Kingdom
Read CVECSS Glasgow 2024: IS-PN06
Omega-3 PUFA interactions with lipid and glucose metabolism
The liver is a key metabolic organ that undertakes a multitude of physiological processes. It serves as an intermediary organ between exogenous (dietary) and endogenous energy supply to extrahepatic organs, with hepatocytes rapidly transitioning back and forth between the metabolic tasks of energy storage and supply. Given its pivotal role in regulating systemic metabolism, perturbations in hepatic metabolism can impact on metabolic disease risk. Hepatic de novo lipogenesis (DNL) has been implicated in the development of fatty liver disease and supplementation with the omega-3 fatty acids (FA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has been demonstrated to decrease intrahepatic triacylglycerol (IHTAG) and plasma TAG concentrations. In vitro cellular and animal models have proposed the mechanisms by which this is achieved include down-regulation of lipogenic and up-regulation of β-oxidation pathways via hepatic transcriptions factors. The effects of omega-3 supplementation on markers of glycaemia are inconsistent, which may be due to the dose and duration of omega-3 supplementation, along with the clinical status of the individual studies. This talk will discuss how omega-3 fatty acids may alter synthesis and partitioning of fatty acids within the liver and the effects this may have on lipid and glucose metabolism, and the mechanisms that potentially underpin any alterations.
The effect of sex on changes in human skeletal muscle omega-3 fatty acid composition with fish oil supplementation
Omega-3 fatty acids play crucial roles in the formation of membranes, production of anti-inflammatory signalling molecules, and improved cardiovascular health. The two most well-characterised omega-3 fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In addition to the established effects on cardiovascular health there is growing evidence that EPA and DHA positively affect skeletal muscle. Indeed, there are reports that EPA+DHA intake potentiates rates of muscle protein synthesis in response to amino acid infusion, mitigates skeletal muscle disuse-atrophy following single-leg immobilization, and enhances skeletal muscle strength during resistance exercise training. Of particular interest is evidence that the effects of EPA+DHA intake are sex-dependent with females experiencing greater benefit from EPA+DHA supplementation compared to males. Although far from conclusive, these sex-dependent effects of EPA+DHA intake maybe related to differences in how EPA and DHA are metabolized in skeletal muscle. In this presentation, novel data related to changes in the content of skeletal muscle fatty acids in response to EPA+DHA intake in females and males will be shared. Data related to how changes in skeletal muscle fatty acid composition with EPA+DHA intake alter the expression of key genes involved in skeletal muscle metabolism will also be presented. Finally, we will discuss if existing fatty acid therapies used to treat cardiovascular disease can be leveraged to promote skeletal muscle heath and function.