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Omega 3overview-professorphilipcalder-121230045819-phpapp01
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Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
Omega 3overview-professorphilipcalder-121230045819-phpapp01
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Omega 3overview-professorphilipcalder-121230045819-phpapp01

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  • 1. Omega-3 Fatty Acids :Naming, sources, intakes, metabolism and health benefits Philip Calder Professor of Nutritional Immunology University of Southampton
  • 2. This lecture will coverFatty acid structure, nomenclature, sources, andintakesMetabolic relationship between α -linolenic acid andlong chain omega-3 fatty acidsOmega-3 fatty acids and cardiovascular healthOmega-3 fatty acids and visual and braindevelopmentRecommendations for omega-3 fatty acid intake
  • 3. Fats in the diet CH2.O.CO.R1 CH2.O.CO.R1R2.CO.OCH R2.CO.OCH CH2.O.CO.R3 CH2.O.POO.O.Base Triglycerides Phospholipids Also sphingolipids cholesterol and cholesterol esters
  • 4. Fatty acid structureH3C COOH
  • 5. Fatty acid structure and nomenclature H3C COOH 18:0 Stearic acid H3C 9 COOH 18:1ω-9 Oleic acid H3C COOH 18:2ω-6 Linoleic acid 6 H3C 3 COOH 18:3ω-3 α-Linolenic acidMammals cannot insert double bonds in here Omega = ω - = n-
  • 6. Saturated Monounsaturated PolyunsaturatedSunflower oil Corn oil Soybean oil Olive oil Pig fat Beef fat Butter 0 20 40 60 80 100
  • 7. Latest fatty acid intake data for adults in UK (g/day) Males FemalesTotal fat 87 (36% energy) 61 (35% energy)Saturated 33 23Trans 3 2Monounsaturated 29 20Omega-6 PUFA 13 9Omega-3 PUFA 2.3 1.7
  • 8. Omega-3 PUFAsH3C COOH α -Linolenic acid (18:3ω -3)H3C COOH EPA (20:5ω -3) COOHH3C DPA (22:5ω -3)H3C COOH DHA (22:6ω -3)
  • 9. These have different dietary sources and their intake differs markedly
  • 10. α -Linolenic acid (18:3ω -3)Found in green plant tissuesFound in some vegetable oils (e.g. soybean,rapeseed)Found in some nuts (e.g. walnut)Found in linseed (flaxseed) and linseed oilContributes 85 to 95% of ω -3 PUFA intake inUK adults (ca. 2.1 g/day in males; 1.5 g/day infemales)
  • 11. Long chain ω -3 PUFAs (EPA, DPA, DHA)- oily fish are the only rich sourceof preformed long chain ω -3PUFAs- adults in the UK consume onaverage 1/3 of a portion of oilyfish per week (53 g/week)- fish consumers consume 1.3portions of oily fish per week(about 195 g/week)- average long chain ω -3 PUFAintake is < 0.2 g/day (200 mg/day)- long chain ω -3 PUFAs are foundin fish oils
  • 12. Long chain ω -3 PUFA content of fish EPA DPA DHA Total (g/100 g food) g/portionCod 0.08 0.01 0.16 0.30Haddock 0.05 0.01 0.10 0.19Herring 0.51 0.11 0.69 1.56Mackerel 0.71 0.12 1.10 3.09Salmon 0.55 0.14 0.86 1.55Crab 0.47 0.08 0.45 0.85Prawns 0.06 0.01 0.04 0.06
  • 13. α -linolenic acid is metabolicallyrelated to long chain ω -3 PUFAs α -Linolenic acid (18:3ω -3) Delta 6-desaturase 18:4ω -3 Elongase 20:4ω -3 Delta 5-desaturase EPA (20:5ω -3) DPA (22:5ω -3) DHA (22:6ω -3)
  • 14. α -Linolenic acid This pathway does not work very well in humans EPA DHA
  • 15. Key points (so far)ω -6 and ω -3 PUFAs are distinct fatty acidfamiliesMost ω -3 PUFA in the diet is in the form of α -linolenic acidLong chain ω -3 PUFAs are found in oily fish(fish oil capsules)Average intake of long chain ω -3 PUFAs is <0.2 g/dayα -Linolenic acid is poorly converted to longchain ω -3 PUFAs in humans
  • 16. Omega-3 PUFAs and human health
  • 17. From a survey of distribution of diseases in Greenland EskimosDisease Expected ActualMyocardial infarction 40 3Psoriasis 40 2Bronchial asthma 25 1Diabetes 9 1Multiple sclerosis 2 0 Kromann & Green (1980) Acta Med. Scand. 208, 410-406
  • 18. Many studies report an inverse correlation between fish consumption or ω-3 PUFA status and CHDKromhout et al. 1985 Fish ↓ CVD mortalityShekelle et al. 1985 Fish ↓ CVD mortalityNorelle et al. 1986 Fish ↓ CVD mortalityDolecek et al. 1992 Dietary ω -3 PUFA ↓ CVD mortalityFeskens et al. 1993 Fish ↓ CVD mortalitySiscovik et al. 1995 Fish ↓ CVD mortalityKromhout et al. 1995 Fish ↓ CVD mortalityDaviglus et al. 1997 Fish ↓ CVD mortalityAlbert et al. 1998 Fish ↓ sudden cardiac deathPedersen et al. 2000 Adipose tissue ω -3 PUFA ↓ MI mortalityAlbert et al. 2002 Whole blood ω -3 PUFA ↓ sudden deathHu et al. 2002 Fish and ω -3 PUFA intake ↓ CHD mortalityHu et al. 2002 Fish and ω -3 PUFA intake ↓ non-fatal MITavani et al. 2001 Fish and ω -3 PUFA intake ↓ non-fatal MIGualler et al. 2003 Adipose tissue DHA ↓ first MILemaitre et al. 2003 Plasma EPA and DHA ↓ CHD mortality
  • 19. Prospective: Long chain ω -3 PUFA status and sudden deathRelative risk of sudden death Adjusted for age & smoking 1 Also adjusted for BMI, diabetes, hypertension, 0.8 hypercholesterolemia, alcohol, 0.6 exercise & family history of MI 0.4 0.2 0 1 2 3 4 Quartile of blood ω -3 PUFAs Albert et al. (2002) New Engl J Med 346, 1113-1118
  • 20. Risk factors for atherosclerosis LDL-cholesterol Elevated blood lipids Hypertension Triglycerides Endothelial dysfunction Inflammation
  • 21. Meta-analysis of trials of fish oil and blood pressure Geleijnse et al. (2002) J. Hypertens. 20, 1493-149936 controlled trials reviewed incl. 22 double blindFish oil:- decreased systolic BP by 2.1 mm Hg(95% CI 1.0, 3.2; P < 0.01)- decreased diastolic BP by 1.6 mm Hg(95% CI 1.0, 2.2; P < 0.01)Effects greater in older subjectsEffects greater in hypertensive subjectsConclusion “increased intake of fish oil may lower BP,especially in older and hypertensive subjects”
  • 22. Relationship between dietary long chainω -3 PUFAs and blood TAG concentrations Review of 72 placebo-controlled human trials All > 2 weeks duration Harris (1996) Lipids 31, 243-252 10 0 % Change Placebo -10 Fish oil -20 Difference -30 TAG < 2 mM TAG > 2 mM
  • 23. Endothelium dependent coronary vasodilatation in patients with CHD before and after fish oil (4 months) 300Increase in coronary blood flow (%) 200 CHD patients after fish oil Controls 100 CHD patients before fish oil 0 Acetylcholine
  • 24. Fish oil and an inflammatory marker (sVCAM-1)Healthy subjects aged > Pre55 y PostSupplemented diet with 1000a moderate amount of sVCAM-1 (ng/ml) 800 *fish oil (= 1.2 g 600EPA+DHA/day) for 12 400weeks 200Plasma soluble VCAM-1 0concentrations Placebo FOmeasured Miles et al. (2001) Clinical Science 100, 91-100
  • 25. Risk factors for atherosclerosis Elevated blood TAG Hypertension Endothelial dysfunction Inflammation N-3 PUFA
  • 26. Secondary prevention: DART1015 men aged < 70 y who hadhad a MI Oily fishAdvised to eat oily fish or take 100 No advicefish oil capsules vs. no advice % SurviviorsCardiovascular events and 95mortality followed for 2 yearsRelative risk death 0.77 90Relative risk IHD death 0.84 85 0 200 400 600 800 Time (days) Burr et al. (1989) Lancet ii, 757-761
  • 27. Secondary prevention: GISSI Study2836 men who had had Relative risk in fish oil groupa MI within the last 3months assigned to fish All fatal events 0.80oil (0.85 g LC ω -3 CV death 0.70PUFA/day) vs. placebo Coronary death 0.65Follow up for two years Sudden death 0.55356 deaths and non-fatalCV events in fish oilgroup vs. 414 in placebogroup GISSI Prevenzione Investigators (1999) Lancet 354, 447-455
  • 28. There are also non-cardiovascular actions of long chain ω -3 PUFAs
  • 29. DHA concentration in different human tissues 20.0 17.5% Total fatty acids 15.0 12.5 10.0 7.5 5.0 2.5 0.0 Adipose Erythrocyte Placenta Liver Testis Brain Retina
  • 30. DHA status and infant mental development (1 year of age) Development Index 140 Bayley Mental 120 100 80 60 3 6 9 12 Infant red cell DHA (%)Gibson et al. (1997) Eur. J. Clin. Nutr. 51, 578-584
  • 31. Helland et al. (2003) Pediatrics 111, 39-44“Maternal supplementation with very long chain n-3 fatty acidsduring pregnancy and lactation augments childrens IQ at 4 years ofage”Placebo vs. 2.4 g long chain ω -3 PUFAs/day (50:50 EPA & DHA)from week 18 of pregnancy until 3 months post partumKaufman Assessment Battery for Children performed at 4 years ofage - a measure of intelligence and achievement designed forchildren aged 2.5 to 12.5 yearsAt 4 years of age:Children of mothers in control group = 102.3 (11.3)Children of mothers in fish oil group = 106.4 (7.4)
  • 32. Omega-3s in children with ADHD EPA in plasma phospholipids 0.25 0.2 0.15 0.1 0.05 0 Control Few ADHD Many ADHDBurgess et al. (2000) Am. J. Clin. Nutr. 71, 327S-330S
  • 33. The Durham TrialA randomised controlled trial of fish oilsupplementation (vs. placebo) in children (5 –12 years old) with developmental co-ordinationdisorder (n = 117)Placebo vs. 550 mg EPA + 175 mg DHA/day for3 monthsThen all onto EPA + DHA for a further 3 months Richardson & Montgomery (2005) Pediatrics 115, 1360-1366
  • 34. Omega 3 Placebo Placebo then Omega-3120 105110 100100 9590 90 Baseline 3 mo 6 mo Baseline 3 mo 6 mo Reading age Spelling age
  • 35. HyperactivityOmega 3 Placebo Placebo then Omega-3 63 61 59 57 55 Baseline 3 mo 6 mo
  • 36. Long chain ω -3 PUFAs are important in:- membrane structure- brain and visual development- maintenance of cognitive and neurological function(during development & with aging)- regulation of - blood pressure - platelet function, thrombosis, fibrinolysis - blood lipid concentrations - vascular function - cardiac rhythmn - inflammation - immune response - bone health - insulin sensitivity
  • 37. Long chain ω -3 PUFAs promote- optimal brain growth- optimal visual and neural function
  • 38. Long chain ω -3 PUFAs are (or may be) protective against- hypertension- hypertriglyceridemia- thrombosis- vascular dysfunction- cardiac arrhythmias- cardiovascular disease- inflammatory conditions- allergic conditions- immune dysfunction- insulin resistance- psychiatric and neurological diseases of children and adults- neurodegenerative diseases of ageing- bone loss- some cancers
  • 39. Summary: Long chain ω -3 PUFAsLong chain ω -3 PUFAs have a number of physiologicaleffectsThrough their physiological effects they alter risk of a -wide range of human diseasesLowered disease risk occurs through plausiblebiological mechanismsThere are newly emerging mechanisms of action oflong chain ω -3 PUFAs in some conditionsLong chain ω -3 PUFAs exert health benefits rightthrough the life cycle (womb to tomb!)
  • 40. Long chain ω -3 PUFAsCurrent intakes vs. Recommendations (g/day)Current av. UK intake < 0.2ISSFAL 1999 0.65BNF 1999 1.0-1.4AHA 2003* 1.0AHA 2003** 2 to 4SACN/COT 2004 0.45 (minimum)*For patients with CHD**For patients with hypertriglyceridaemia
  • 41. What about α -linolenic acid?
  • 42. Consensus statementSanderson et al. (2002) Brit. J. Nutr. 88, 573-579“The studies …. suggested little, if any, benefitof α -linolenic acid, relative to linoleic acid, onrisk factors for cardiovascular disease ….”
  • 43. However, α -linolenic acid may exert health benefits through conversion to longer chain derivativesBut, this may require high intakes of α -linolenic acid

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