Dyerberg Discovery. Greenland Eskimos have low rates of heart disease while their diet is high in saturated fat and cholesterol. That s strange. Why?

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John Lindsey
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1 Omega-3

2 Dyerberg Discovery Greenland Eskimos have low rates of heart disease while their diet is high in saturated fat and cholesterol. That s strange. Why? They eat a large amount of omega-3 (10g /d) in fish, whale and seal meat. Acta Med Scand 1981;210:245-8

3 Fish and CHD Mortality Western Electric Study 38% lower risk for 35g fish/day and 67% lower risk of non-sudden death from heart attack Nurses Health Study 34% lower risk of CHD for eating fish 5 times/wk N Engl J Med 1997;336: JAMA 2002;287:

4 Fish and CHD Mortality? While some studies have reported a benefit of fish consumption, other major studies including: US Physicians Health Study Health Professionals Follow-Up Study 7 Country Study EURAMIC study found no association between eating fish and CHD incidence and mortality. Circulation 2002;106: Am J Clin Nutr 1997;65:1083-6

5 Fish, Supplements and Risk of Stroke Meta-analysis of 38 studies involving 800,000 people in 15 countries indicated that 2 to 4 servings of fish per week was associated with a 6% reduction in risk of cerebrovascular disease 5 or more servings of fish per week was associated with a 12% reduction, compared with one serving or less per week. Use of fish oil supplements were not significantly associated with a reduced risk of stroke. Chowdhury, Univ of Cambridge BMJ 2012

6 Eating Fish- Is There a Catch? Due to overfishing, fish cannot be considered a sustainable or renewable resource. Pollution and climate change have had their effect on supplies also. Therefore, fish cannot be considered the long term solution as an omega-3 source. Scientists are looking to plant sources.

7 Long-term Solution for DHA, EPA Red and brown seaweed Microalgae DHA supplements

8 Dietary ω-3 Fatty Acids Plant source: ALA α- linolenic acid 18:3n-3 Fish and seaweed sources: EPA eicosapentaenoic acid 20:5n-3 DHA docosahexaenoic acid 22:6n-3 The microalgae Crypthecodinium cohnii and Schizochytrium are rich sources of DHA (22:6 ω-3) and can be produced commercially in bioreactors.

9 Omega-3 Sources ALA EPA DHA soy, flaxseed, walnuts, green vegs, chia seed fatty fish, seafood; seaweed fatty fish; eggs; some soymilks; algal supplements; snack bars

10 Omega-3 in Plant Sources Flax seed oil, 1 tsp 2.5 g Walnuts, 1 oz 1.93 Flaxseed meal, 1 Tbsp 1.7 Canola oil, 1 Tbsp 1.6 Chia Seed, 1 oz 1.1 g Hemp seed oil, 1 Tbsp 1.0 gm Soybean oil, 1 Tbsp 0.95 Tofu, ½ c 0.41 Soymilk, 1 c 0.21 Broccoli, 1c 0.19 Wakame seaweed, 100g 0.19 (DHA/ EPA) Green peas, ½ c 0.16

11 The Power of Three (ω3) Reduces blood triglyceride levels by inhibiting VLDL synthesis and enhanced VLDL turnover - 1 Tbsp fish oil for 6 mo dropped TG 64% Reduces the risk of blood clots and blood viscosity, hence reduced risk of stroke and heart attack Reduces risk of arrhythmias Improves vascular endothelial function Circulation 2002;106: J Intern Med 1990;227:347-53

12 The Power of Three (ω3) No effect on total and LDL- cholesterol, unless TG levels are high Anti-inflammatory activity. May alleviate joint tenderness, pain & stiffness in patients with rheumatoid arthritis DHA needed for normal brain development and function, and infant vision May protect against cognitive decline and dementia May help alleviate depression

13 Omega-3 Conversion ALA conversion to EPA and DHA is gender specific. Conversion Men* Women** ALA to EPA 2.8% 21% ALA to DHA * Burdge, et al. Br J Nutr 2003;90: ** Burdge et al. Br J Nutr 2002;88: Up-regulation of the conversion of EPA DHA has been suggested, as a result of action of estrogen on Δ-6 desaturase.

14 Conversion of α-linolenic acid to Long Chain ω-3-31% -28% -12% -9% Welch, et al. J Hum Nutr Diet 2008;21:404

15 Plasma n-3 to Dietary Intake of ALA The ratio is 22% higher in vegetarians than fish-eaters indicating a greater conversion of ALA (to EPA, DPA, DHA) than in fish eaters. Welch, et al. J Hum Nutr Diet 2008;21:404

16 DHA Status of Vegetarians Vegetarian diets that include dairy food and eggs provides about 20mg DHA/day. DHA is usually absent from vegan diets. The intake of α-linolenic acid is often greater in vegans & vegetarians, depending upon oils used. Supplements of ALA increase proportion of EPA but not DHA in blood lipids. TA Sanders. Prostaglandins Leukot Essent Fatty Acids 2009;81(2-3):137-41

17 DHA Status of Vegetarians (cont d) Supplements of DHA (200 mg +) increase proportion of DHA in blood lipids of vegetarians and vegans substantially. There is no evidence of adverse effects on health or cognitive function with lower DHA intake in vegetarians. TA Sanders. Prostaglandins Leukot Essent Fatty Acids 2009;81(2-3): DHA is now available from eggs, microalgae supplements, DHA-fortified soymilk & breakfast foods

18 Concerns with Seafood 1. Exposure to sewerage and Norwalk s virus (gastroenteritis) 2. Poisonous substances a. tetrodotoxin from puffer fish b. ciguatera poisoning from barracuda, red snapper c. red tide d. paralytic shellfish poisoning

19 Concerns with Seafood-2 3. Sodium content from storage of fish in brine 4. Carcinogenicity of heterocyclic amines in grilled and broiled fish 5. Heavy metal content of fish/seafood 6. PCB s and DDT from land run-off 7. Dimethylamines in squid and stomach cancer 8. Cholesterol content of fish: mg/110g 9. Vitamin A and D toxicity if liver consumed

20 Safety of Fish Oil Supplements Tufts reviewed 148 studies to evaluate adverse events from the use of omega-3 supplements (mostly fish oils). More than half reported that no adverse events. Most studies were small. About 10,000 subjects had taken these supplements in various forms and dosages ranging from 0.3 to 8 g/day for up to 7 years.

21 Safety of Fish Oil Supplements In general, side effects were minor, primarily gastrointestinal in nature (such as diarrhea), and reported by fewer than 7% of subjects. Omega-3 fatty acids did not affect the frequency of bleeding events. Institute of Medicine

22 Summary Fish supplies cannot provide for world s appetite for omega-3 Good plant sources of omega-3 include seaweed, flax, walnuts, chia, and soy Omega-3 lowers TG levels and lowers risk of blood clots Omega-3 is important for brain function and may protect against cognitive decline Plant ALA difficult to convert to DHA Seafood has some potential problems Purified fish oil supplements are safe

Omega-3 requirements - length matters!

Omega-3 requirements - length matters! http://www.rejuvenal.info/ images/terminology/omega3.png Professor Peter Howe Nutritional Physiology Research Centre University of South Australia Food Industry Forum