FAT 6 pp - Essential Fatty Acids OmegaOmega-3 Fatty Acids...

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Unformatted text preview: Essential Fatty Acids OmegaOmega-3 Fatty Acids in Health Certain unsaturated fatty acids are essential Humans lack specific enzymes for synthesis – Unable to make a double bond before C9 Omega carbon Carbon 9 Acid end Methyl end Omega 3-6-9 Fatty Acids 3 1st double bond: 3rd C from methyl end – Linolenic, Eicosapentanoic, Docosahexanoic Eicosapentanoic, 1st double bond: 6th C from methyl end – Linoleic, Arachidonic 1st double bond: 9th C from methyl end – Oleic ~ NOT essential Fatty Acid Length Linolenic acid (omega 3) Linolenic used to make Eicosapentanoic acid (EPA) EPA used to make Docosahexanoic acid (DHA) Linoleic acid (omega 6) Linoleic used to make Arachidonic acid Fatty Acid Length Shorter chain EFA can be: – Lengthen at acid end Two carbons at a time – Desaturated (dehydrogenation) Add a double bond – May not be efficient in humans Acid end Methyl end 1 Fatty Acid Sources Essential Fatty Acid Function Structural role – Cell membrane components Essential Essential Fatty Acid Function Physiological roles – Neural development – Fetal development – High concentrations in Brain synapses Retina 2 Essential Fatty Acid Function Regulatory roles – Cell signaling and genetic control Immune system Cardiovascular system Metabolism Essential Fatty Acid Function Immunological role – Cell growth and maintenance – Metabolized to form immune cells – Derived from cell membrane phospholipids Immune Immune System Acquired – Specific learned response – Infers resistance vaccination – T cells/B cells antibodies cytokines Controlled by fatty acid derived compounds: Eicosanoids Essential Fatty Acid Deficiency Impaired brain/neural development Memory disturbances Loss of visual acuity Reproductive disturbances Immune system? Cardiovascular system? Metabolism? Immune Immune System Innate immunity – Non-specific Non– First line of defense – Barriers to prevent infection Barriers to prevent infection Eicosanoids Hormone-like substances Hormone– Prostaglandins, Leukotrienes, Thromboxanes Leukotrienes, Produced from cell membrane phospholipid – Omega-6 / Omega-3 fatty acid tail Omega- Omega- Mediate a wide range of physiological functions – Trigger cytokine release – Modulation of inflammation 3 Cytokines OmegaOmega-6 or Omega-3 Omega- Chemical messengers Cellular concentration reflects diet – Regulate cellular activity Signal cell division and differentiation – Increase cell number in inflammation High levels of cytokines are destructive – α-linolenic acid and linoleic acid compete in elongation – Eicosapentanoic acid (omega-3) or arachidonic acid (omega(omega(omega-6) can be used interchangeably Physiological responses to EPA/AA products differ – Increase inflammation – Muscle wasting, bone mass loss You are what you eat EPA Eicosanoids Leukotriene 4 Prostaglandin E2 Leukotriene 5 Prostaglandin E3 Eicosanoids OmegaOmega-6 to Omega-3 Ratios Omega Western diet: 10:1 to 20:1 Ancestral diet: 1 to 2:1 Greenland Eskimos: 4:1 Arachidonic Acid Eicosapentanoic acid 4 Greenland Eskimos High dietary omega-3 fatty acids from fish omega Low rate of autoimmune and inflammatory disorders compared to westernized ethnic counterparts Potential Benefits: Preliminary Research EvidenceEvidence-Many Studies Ongoing Inflammatory/Autoimmune diseases Cardiovascular disease Metabolic Syndromes Metabolic Syndromes Pregnancy Cancer ?? Simopoulos (2002) Potential But Not Proven Benefits - Inflammation Rheumatoid Arthritis – Reduced inflammatory response – Reduce pain and stiffness – Reduce NSAID use Inflammation Inflammation Normal response to injury – Increased blood flow and capillary permeability – Immune cells concentrate at the site of infection (non-steroidal antiinflammatory drug) (non- Surgery complications Anti-inflammatory Anti– Reduce sepsis – Reduced hospital stay Inflammation Undesirable response when chronic or in excess – Rheumatoid arthritis Rh – Gastrointestinal diseases – Cardiovascular disease – Post-surgery Post- Immunomodulation Alternate forms of immune messengers – Differential physiological effects effects Regulation of genes coding for immune components – Differential cell signaling 5 Cytokine release Leukotriene 4 Prostaglandin E2 Leukotriene 5 Prostaglandin E3 Eicosanoids Arachidonic Acid Eicosapentanoic acid Potential Not Proven Benefits Omega 3 Fatty Acids - Cardiovascular Cardiovascular disease and stroke – Anti-inflammatory Anti– Anti-arrhythmic Anti– Anti-thrombotic thrombotic – Reduces restenosis – Reduces plaque formation – Reduces blood triacylglycerol Potential Benefits Omega 3 Fatty Acids - Metabolic Metabolic Syndrome, diabetes, obesity – Increase glucose uptake – Improves lipid profile – Favors fatty acid oxidation fatt acid – Aids in weight loss Genetic Control Direct interaction – Genes found with PUFA sensitive regions Reduced transcription of immune components – Enzymes – Cytokines Supports effects of altered membrane composition Related Potential Beneficial Effects: Omega 3 Fatty Acids Anti-arrhythmic Anti– Alter ion currents within the myocardium – Reduces risk of fatal rhythm irregularities Improve endothelial function – Enhance Nitric oxide production – Reduce vasoconstriction Energy Balance: PUFA vs Monounsaturated Polyunsaturated fatty acids instead of monounsaturated influence metabolism – Favor fatty acid oxidation over storage Alter gene transcription – Reduced adipose stores – Reduced fatty liver Decreased plasma triglycerides Increase insulin sensitivity – Increase glucose transport 6 Genetic Control by Polyunsaturated Fatty Acids Suppression of fat storage and synthesis – Acetyl-CoA carboxylase Acetyl– Fatty acid synthase Induction of fatty acid oxidation – Carnitine palmitoyltransferase – Fatty acyl-CoA synthase acyl- Induction of thermogenesis Summary Omega-3 PUFA act though both specific Omegaand combined mechanisms May be useful in treating and preventing di disease conditions Increasing omega 3:6 ratio is key Essential Fatty Acids: Pregnancy Essential for healthy fetal development Slightly longer pregnancy – Lower risk of pre-term birth pre– Lower risk of preeclampsia – Reduced disease risk for offspring in in later life Cardiovascular disease Diabetes Recommended intake Cardiovascular disease – 1-4 g/day in studies Average US intake US intake – 0.1-0.5 g/day 0.1EPA+DHA Recommendation by American Heart Association – 1.3-2.7 g/day 1.3EPA+DHA Recommended intake General Recommendations – Increase fish intake – Supplements may be required for effective dose – Reduce omega-6 : omega-3 ratio omegamega- Fish intake Risk reduction Monthly ~20% Weekly ~30% Several times per week ~34% Potential Risks: Fatty Fish Intake Presence of carcinogenic and toxic substances – DDT, PCB, Methyl mercury PCB, Methyl mercury Present in low levels in lakes, rivers, ocean Higher concentrations are in fat and skin Higher risk for children and pregnant women 7 Potential Risks: Supplements Supplemental fish oil may be safer due to purification processes – Pharmaceutical grade – Free of all heavy metals and contaminants 8 ...
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This note was uploaded on 12/09/2011 for the course HUN 4445 taught by Professor Sitren during the Spring '08 term at University of Florida.

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