Latest Research
This section will be regularly updated - recently added items tagged NEW! . Click on blue titles for further information.
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REPORT from The Omega-3 Centre's Scientific Consensus Workshop 2007 NEW!
OMEGA-3 FATTY ACIDS: ESSENTIAL NUTRIENTS FOR OUR CHILDREN
Excerpts available below and full report available to purchase
Introduction
A workshop of key experts was convened by The Omega-3 Centre to develop a scientific consensus paper on omega-3 fatty acids and children...read more
Panel of Experts
See who advised The Omega-3 Centre...click here
Recommendations
Key recommendations include advice to parents, health professionals, government and researchers.
1. Preformed long chain omega-3s are necessary in the diet of children for optimal nutrition as children are not able to adequately convert ALA to DHA
Read other recommendations...click here
Conclusions
The panel considered the areas discussed in the Workshop and ranked them according to the level of evidence available...click here
Purchase the Full Report
The Full Report includes the papers from each of the expert participants. This is available as a hard copy at $100 plus $10 GST. Please contact us...click here
Access ARBOR NUTRITION Clinical Nutrition Update special supplement on the Scientific Consensus Workshop OMEGA-3 FATTY ACIDS: ESSENTIAL NUTRIENTS FOR OUR CHILDREN...click here
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Conversion to long chain omega-3s
ALA limited conversion to long chain omega-3s
The researchers state that alpha-linolenic acid (ALA) appears to be a limited source of longer chain omega-3s in humans. They suggest that adequate intakes of preformed long chain omega-3s, in particular DHA, may be important for maintaining optimal tissue function.
Burdge GC, Calder PC. Conversion of alpha-linolenic acid to longer-chain polyunsaturated fatty acids in human adults. Reprod Nutr Dev. 2005;45(5):581-97.
Stable isotope studies reveal low conversion of ALA
This paper indicates that feeding and stable-isotope studies using ALA have addressed the question of bioconversion of ALA to EPA and DHA. It appears that in adult men conversion to EPA is limited to approximately 8% and conversion to DHA is extremely low at less than 0.1%. In women conversion to DHA appears to be greater.
Williams CM, Burdge G. Long-chain n-3 PUFA: plant v. marine sources. Proc Nutr Soc. 2006;65(1):42-50.
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Consumer research
Kids Eat kids play - survey of Australian children underway
Kids Eat Kids Play is the name of the National Children’s Nutrition and Physical Activity Survey which will provide information about the dietary intake and body size of 4,000 children aged 2-16 years. Funded by the government and food industry the survey will be completed later in 2007. This will be the first national survey of Australian children's nutrition since 1995 and the first national physical activity survey since 1985.It is expected that important new information on intakes of long chain omega-3s willbe made available.
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Omega-3 containing foods
paper 1 - Attitudes and purchase intentions
paper 2 - Barriers to purchase
Craig Patch from the University of Wollongong has conducted some well designed studies into people's attitudes and intentions toward purchasing foods enriched with omega-3 fatty acids and barriers to their purchase. The people in the Attitudes study responded to advertisements so may reflect consumers with a greater interest in foods and health.
One finding is that people are more likely to purchase products when they understand the benefits of omega-3s - a challenge for food manufacturers when claims are very resticted by food law.
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Risks and benefits
Fish advice for pregnant women - is it too restrictive?
Hibbeln et al reported on the neurodevelopmental outcomes
in children whose mothers’ fish intake was monitored during pregnancy
(The ALSPAC study, an observational study conducted in the UK). In this
study, 11,875 pregnant mothers completed a food frequency questionnaire assessing
seafood consumption at 32 weeks’ gestation. Low maternal seafood
intake (less than 340 grams per week) was associated with increased risk of
their children being in the lowest quartile for verbal IQ compared with mothers
who consumed more than 340 g/week. The authors pointed out that an important
message was that the benefits from consuming higher fish intakes clearly
outweighed any potentially negative effects of trace contaminants and that
suggestions to limit intakes of fish to pregnant women was not justified.
Hibbeln JR, Davis JM, Steer C, Emmett P, Rogers I, Williams C, Golding J.
Maternal seafood consumption in pregnancy and neurodevelopmental outcomes in childhood (ALSPAC study): an observational cohort study. Lancet. 2007;369(9561):578-85.
The Risk Assessment and Safety of Bioactive Substances in Food Supplements
This report has been developed by members of the IADSA scientific group with the guidance of experts in the bioactive substances covered. See page 52 for Omega-3 information...
Fish intake, contaminants and human health
This review evaluates the benefits and risks of the following:
- intake of fish or fish oil and cardiovascular risk
- effects of methylmercury and fish oil on early neurodevelopment
- risks of methylmercury for cardiovascular and neurologic outcomes in adults
- health risks of dioxins and polychlorinated biphenyls in fish.
The authors conclude that for major health outcomes among adults, based on both the strength of the evidence and the potential magnitudes of effect, the benefits of fish intake exceed the potential risks. For women of childbearing age, benefits of modest fish intake, excepting a few selected species, also outweigh risks.
Mozaffarian D, Rimm EB. Fish intake, contaminants, and human health: evaluating the risks and the benefits. JAMA. 2006;296(15):1885-99.
The case of health benefits and risks from eating seafood
The US Center for Food, Nutrition, and Agriculture Policy has found that there is significant confusion among consumers about the relative benefits and risks of seafood consumption. Overall the benefits are found to outweigh the risks with current advice to increase seafood consumption substantiated. More more information on Seafood Risks and Benefits click here.
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Weight
Fish oil plus exercise for body fat loss
Fish oil in combination with exercise reduced fat mass by 1.6 kg with no significant change in lean tissue in this well-designed study by Peter Howe's group at the University of South Australia. The fish oil alone also lowered triglycerides and increased HDL cholesterol – the ‘good’ cholesterol.
The subjects were overweight volunteers with high blood pressure, cholesterol or triacylglycerides randomly assigned to one of four interventions: 6g fish oil (FO)daily, FO and exercise, 6g sunflower oil (SO) daily or SO and exercise. The exercise was walking for 45 minutes 3 times a week. The authors concluded that
"FO supplements and regular exercise both reduce body fat and improve cardiovascular and metabolic health. Increasing intake of omega-3 fatty acids could be a useful adjunct to exercise programs aimed at improving body composition and decreasing cardiovascular disease risk".
Hill AM, Buckley JD, Murphy KJ, Howe PR.
Combining fish-oil supplements with regular aerobic exercise improves body composition and cardiovascular disease risk factors. Am J Clin Nutr. 2007;85(5):1267-74.
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Eyes
Eat fatty fish to reduce the risk of age-related macular degeneration
A few studies have now linked greater fish consumption to reduced eye problems with age. This is not too surprising when you consider that the retina contains high concentrations of DHA. Eating more than 2 serves a week of fatty fish was associated with a 39% reduced risk of neovascular age-related macular degeneration in this study. Intake of total long chain omega-3sand intake of DHA were both also associated with a decreased risk.
The 4,519 subjects in this Age-Related Eye Disease Study were aged 60 to 80 years at enrollment. Estimates of their habitual nutrient intake were made through a self-administered food frequency questionnaire. This was compared to severity of age-related macular degenration. The authors concuded that a higher intake of long chain omega-3s and fish were associated with decreased likelihood of having neovascular age-related macular degeneration.
SanGiovanni JP, Chew EY, Clemons TE, Davis MD, Ferris FL 3rd, Gensler GR, Kurinij N, Lindblad AS, Milton RC, Seddon JM, Sperduto RD; Age-Related Eye Disease Study Research Group.
The relationship of dietary lipid intake and age-related macular degeneration in a case-control study: AREDS Report No. 20. Arch Ophthalmol. 2007 May;125(5):671-9.
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The brain and neurodevelopmental disorders
Durham study on children published
Portwood discusses the first randomised placebo controlled trial to
be carried out on children in Durham with developmental coordination disorder which
demonstrated significant effects of fatty acid supplementation on behaviour, reading and
spelling performance. This group is conducting further scientific studies within Durham
and neighbouring Authorities in the North of England.
Portwood MM.
The role of dietary fatty acids in children's behaviour and learning.
Nutr Health. 2006;18(3):233-47.
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Framingham study links higher DHA to reduced risk of dementia
Schaefer et al conducted a prospective follow-up study in 899 men and
women who were free of dementia at baseline, had a median age of 76.0 years, and
were followed up for a mean of 9.1 years for the development of all-cause dementia and
Alzheimer disease. The top 25% of plasma DHA concentrations (in the PC fraction of
plasma) was associated with a significant 47% reduction in the risk of developing allcause
dementia in the Framingham Heart Study.
Schaefer EJ, Bongard V, Beiser AS, Lamon-Fava S, Robins SJ, Au R, Tucker KL, Kyle DJ,
Wilson PW, Wolf PA. Plasma phosphatidylcholine docosahexaenoic acid content and risk of dementia
and Alzheimer disease: the Framingham Heart Study.
Arch Neurol. 2006;63(11):1545-50.
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Omega-3 and ADHD
 This review focuses on the possible role of omega-3 in attention-deficit/hyperactivity disorder (ADHD) and related childhood developmental disorders, evaluating the existing evidence from both research and clinical perspectives. The author Dr A. J. Richardson of Oxford University concludes that although omega-3s are not supported by current evidence as a primary treatment for ADHD or related conditions, given their relative safety and general health benefits, omega-3 fatty acids offer a promising complementary approach to standard treatments.
Richardson AJ.Omega-3 fatty acids in ADHD and related neurodevelopmental disorders. Int Rev Psychiatry. 2006;18(2):155-72.
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Mood disorders
A review of high quality trials of omega-3 fatty acids' antidepressant effects. NEW!
Lin & Su analysed ten double blind, placebo controlled studies in patients with mood disorders receiving long chain omega-3s with the treatment period lasting 4 weeks or longer (n=329). A significant anti-depressant effect of long chain omega-3s was found, along with significant reduced depression in patients with clearly defined depression or with a bipolar disorder. The authors concluded that due to publication bias and heterogenity, more large-scale, well controlled studies are needed to determine favourable target subjects, doses and composition of long chain omega-3s.
Lin PY, Su KP. A meta-analytic review of double-blind, placebo-controlled trials of antidepressant efficacy of omega-3 fatty acids.J Clin Psychiatry. 2007 Jul;68(7):1056-61.
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Depressed post-MI patients have lower omega-3
Schins et al measured the serum AA/EPA ratio and plasma CRP levels
in 50 post-myocardial infarction (MI) patients, of which 29 were depressed
and 21 non-depressed. Depressed post-MI patients had lower levels of long chain Omega-3s
as measured by mean AA/EPA ratio and no signs of increased inflammation as determined
by CRP levels. This is consistent with previous data in depression but a first for
those with depression after a heart attack.
Schins A, Crijns HJ, Brummer RJ, Wichers M, Lousberg R, Celis S, Honig A.
Altered omega-3 polyunsaturated fatty acid status in depressed post-myocardial infarction patients. Acta Psychiatr Scand. 2007;115(1):35-40.
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Meta-analyses show omega-3 benefit in depression
Freeman et al review the of use of omega-3 fatty acids in psychiatry.
The preponderance of epidemiologic and tissue compositional studies supports a protective
effect of omega-3 fatty acid intake, particularly eicosapentaenoic acid (EPA) and docosahexaenoic
acid (DHA), in mood disorders. Meta-analyses of randomized controlled trials
demonstrate a statistically significant benefit in unipolar and bipolar depression (p =
.02), with less evidence of benefit in schizophrenia.
Freeman MP, Hibbeln JR, Wisner KL, Davis JM, Mischoulon D, Peet M, Keck PE Jr, Marangell
LB, Richardson AJ, Lake J, Stoll AL. Omega-3 fatty acids: evidence basis for treatment and future research in psychiatry. J Clin Psychiatry. 2006;67(12):1954-67.
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Part of brain associated with omega-3 deficiency and depression
McNamara et al report a selective deficit of DHA in the brain orbitofrontal
cortex (decision making region of the cortex) of patients (n=15) with major depressive
disorder (MDD). This finding adds to a growing body of evidence implicating omega-3 fatty acid deficiency as well as the orbitofrontal cortex in the pathophysiology and potentially pathogenesis of MDD.
McNamara RK, Hahn CG, Jandacek R, Rider T, Tso P, Stanford KE, Richtand NM.
Selective Deficits in the Omega-3 Fatty Acid Docosahexaenoic Acid in the Postmortem Orbitofrontal Cortex of Patients with Major Depressive Disorder.
Biol Psychiatry. 2006 Dec 21; [Epub ahead of print]
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Dietary deficits of omega-3 and mood disorders
The authors provide an overview of epidemiological and treatment studies which suggest that dietary deficits in omega-3s may be a cause of mood disorders. They argue for studies to clarify the efficacy of omega-3 supplementation for depressive disorders and to elucidate whether EPA or DHA are likely to provide greatest benefit.
Parker G, Gibson NA, Brotchie H, Heruc G, Rees AM, Hadzi-Pavlovic D. Omega-3 fatty acids and mood disorders. Am J Psychiatry. 2006;163(6):969-78.
click here for information on The Black Dog Institute
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Heart Research NEW!
Long chain omega-3 supplementation almost doubles walking distance NEW!
Madden et al provided 1g EPA and 0.7g DHA/day from fish oil for 12 weeks to patients with claudication secondary to peripheral arterial disease - an atherosclerotic disease. The authors found that walking distance to first pain and the total distance walked increased significantly after the fish oil treatment. The increase in walking distance was dependent on BMI and inflammatory genotypes examined.
Madden J, Brunner A, Dastur ND, Tan RM, Nash GB, Ed Rainger G, Shearman CP, Calder PC, Grimble RF. Fish oil induced increase in walking distance, but not ankle brachial pressure index, in peripheral arterial disease is dependent on both body mass index and inflammatory genotype. Prostaglandins Leukot Essent Fatty Acids. 2007 Jun;76(6):331-40. Epub 2007 Jun 27.
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Foods containing omega-3s help to lower blood pressure NEW!
The International Study of Macro- and Micro-nutrients and Blood Pressure (INTERMAP) is an international cross-sectional epidemiologic study of 4680 men and women aged 40 to 59 yrs from 17 population-based samples in China, Japan, United
Kingdom, and United States. The study reports on associations of food omega-3 fatty acids intake (total, linolenic acid, long-chain) of individuals with blood pressure. In
summary, food omega-3 intake from both linolenic acid and long chain omega-3s related inversely to blood pressure, including in nonhypertensive persons, with small estimated effect size. The authors concluded that food omega-3s may contribute to prevention and control of adverse blood pressure levels.
Ueshima H, Stamler J, Elliott P, Chan Q, Brown IJ, Carnethon MR, Daviglus ML, He K, Moag-Stahlberg A, Rodriguez BL, Steffen LM, Van Horn L, Yarnell J, Zhou B; INTERMAP Research Group. Food omega-3 fatty acid intake of individuals (total, linolenic acid, long-chain) and their blood pressure: INTERMAP study. Hypertension. 2007 Aug;50(2):313-9. Epub 2007 Jun 4.
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Both EPA & DHA recommended for cardiovascular prevention NEW!
von Schacky reviewed omega-3 ethyl esters (EPA and DHA) for cardiovascular prevention. Although slight differences in biological activity exist between EPA and DHA, both exert a number of positive actions against atherosclerosis and its complications. EPA and DHA as ethyl esters inhibit platelet aggregability, and reduce serum triglycerides, while leaving other serum lipids essentially unaltered. Glucose metabolism has been studied extensively, and no adverse effects were seen. Pro-atherogenic cytokines are reduced, as are markers of endothelial activation. Endothelial function is improved, vascular occlusion is reduced, and the course of coronary atherosclerosis is mitigated. Heart rate is reduced, and heart rate variability is increased by EPA and DHA - both beneficial. An antiarrhythmic effect can be demonstrated on the supraventricular and the ventricular level. More importantly, two large studies showed reductions in clinical endpoints like sudden cardiac death or major adverse cardiac events. As a consequence, the author concluded that relevant cardiac societies recommend using 1 g/day of EPA and DHA for cardiovascular prevention, after a myocardial infarction and for prevention of sudden cardiac death.
von Schacky C. A review of omega-3 ethyl esters for cardiovascular prevention and treatment of increased blood triglyceride levels.Vasc Health Risk Manag. 2006;2(3):251-62.
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Omega-6s and Omega-3s
Ratio of omega-6 to omega-3 important
A wide range of studies indicate that humans evolved on a diet with a ratio of omega-6 to omega-3s of around 1. In Western diets today the ratio is 15/1 or higher which, the author states, promotes the pathogenesis of many diseases such as cardiovascular disease, cancer, osteoporosis, and inflammatory and autoimmune diseases. Both omega-6 and omega-3 fatty acids influence gene expression and omega-3s have anti-inflammatory effects whereas omega-6s do not. The author suggests that because of genetic variation, the optimal omega-6/omega-3 ratio would vary depending on the disease under consideration.
Simopoulos AP. Evolutionary aspects of diet, the omega-6/omega-3 ratio and genetic variation: nutritional implications for chronic diseases. Biomed Pharmacother.
2006;60(9):502-7.
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The Omega-3 Index
A new biomarker for heart risk
Dr Bill Harris, co-author of the American Heart Association guidelines on fish, fish oil, omega-3 fatty acids, argues the case for using the Omega-3 Index (the EPA+DHA level in red blood cells) as a new risk factor for heart disease in his recently published paper.
The activity of Omega-3 fatty acids begins with the incorporation of EPA and DHA into cell membranes where they alter membrane physical characteristics and the activity of membrane-bound proteins. They can then interact with ion channels, be converted into a wide variety of bioactives and influence gene expression. Blood levels of EPA and DHA are a strong reflection of dietary intake and this forms the basis of an omega-3 biomarker, the Omega-3 Index. Harris demonstrates how this index compares favourably with other risk factors for sudden cardiac death. The Omega-3 Index fulfils many of the requirements for a risk factor including consistent epidemiological evidence, a plausible mechanism of action, a reproducible assay, independence from classical risk factors, modifiability, and most importantly, the demonstration that raising tissue levels will reduce risk for cardiac events.
Harris WS.
Omega-3 fatty acids and cardiovascular disease: a case for omega-3 index as a new risk factor.
Pharmacol Res. 2007;55(3):217-23.
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Pregnancy NEW!
World-wide values for DHA and AA in human breast milk NEW!
Brenna et al reported on the world-wide values for DHA (0.32%) and AA (0.47%) in 65 studies of human milk samples from 2474 women.
Brenna JT, Varamini B, Jensen RG, Diersen-Schade DA, Boettcher JA, Arterburn LM
Docosahexaenoic and arachidonic acid concentrations in human breast milk worldwide. Am J Clin Nutr. 2007 Jun;85(6):1457-64.
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Fish oil supplementation improves foetal long chain omega-3 status NEW!
Krauss-Etschmann et al report that fish oil supplementation from week 22 until delivery improves the foetal long chain omega-3 status. In addition, folate supplementation was associated with increased maternal DHA plasma proportions.
Krauss-Etschmann S, Shadid R, Campoy C, Hoster E, Demmelmair H, Jimenez M, Gil A, Rivero M, Veszpremi B, Decsi T, Koletzko BV; Nutrition and Health Lifestyle (NUHEAL) Study Group. Effects of fish-oil and folate supplementation of pregnant women on maternal and fetal plasma concentrations of docosahexaenoic acid and eicosapentaenoic acid: a European randomized multicenter trial. Am J Clin Nutr. 2007 May;85(5):1392-400.
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EPA and DHA as precursors to bioactives
Long chain Omega-3 form potent bioactives
The author states that recent findings indicate that EPA and DHA are precursors to potent bioactive mediators which have both anti-inflammatory and protective properties. These mediators have been named resolvins, docosatrienes, and protectins. They each have unique chemical structures and are biosynthesized by new pathways. It is suggested that further work in this area will identify novel bioactives with wide implications.
Serhan CN. Novel eicosanoid and docosanoid mediators: resolvins, docosatrienes, and neuroprotectins. Curr Opin Clin Nutr Metab Care. 2005;8(2):115-21.
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Blood clotting
Fish oil reduces coagulation factors
The researchers concluded high fasting triacylglycerol concentrations predict high procoagulant activity, and fish oil reduces thrombin generation by addressing triglycerol and other coagulation factors.
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