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Omega-3 fatty acids are beneficial for health and can only be obtained through our diets - they cannot be produced by the human body. Omega-3’s can come in several forms; the most common ones are EPA, DHA and ALA. Fatty fish, walnuts, flaxseed, and canola are good sources of omega-3s. Many Americans don’t get enough of these foods, and therefore don’t get enough omega-3 circulating in their blood and brain. Omega-3s have been researched to show benefits for heart health, immune and inflammatory responses, metabolism, and the health of skin, hair, nervous system, joints, eyes, and brain.
Smoking has been known to have a negative effect on the immune system and can alter omega-3 fatty acid concentration. One study showed that smokers have lower concentrations of DHA than non-smokers. It’s therefore especially beneficial for smokers to supplement with fish oil.
Omega-3 Levels and Nicotine Dependence: A Cross-Sectional Study and Clinical Trial
Zaparoli JX, Sugawara EK, de Souza AA, Tufik S, Galduróz JC., European addiction research, 2016
Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease. One softgel of Wild Alaskan Salmon Oil provides 200mg of EPA and DHA omega-3 fatty acids.
FDA Announces Qualified Health Claims for Omega-3 Fatty Acids
Federal Drug Administration, FDA News Release, 2004
Fish oil has shown initial promising results as an ingredient for joint health. A 12 month, double-blind, placebo-controlled study found that patients taking 2,600mg of omega-3 per day experienced less joint pain than those taking a placebo. Patients also reported less use of concomitant antirheumatic medications during the period of fish oil supplementation.
An in-vitro study in 2000 examined the molecular mechanisms by which omega-3s can affect inflammatory markers in cartilage. The study found that omega-3 fatty acids create a reduction in the expression and activity of aggrecanases, proteoglycan-degrading enzymes, the expression of inflammation-inducible cytokines interleukin (IL)-1alpha and tumor necrosis factor (TNF)-alpha, and cyclooxygenase (COX-2), but not the constitutively expressed cyclooxygenase COX-1.
Long-term effect of omega-3 fatty acid supplementation in active rheumatoid arthritis. A 12-month, double-blind, controlled study.
Geusens P, Wouters C, Nijs J, Jiang Y, Dequeker J., Arthritis and Rheumatism, 1994
n-3 fatty acids specifically modulate catabolic factors involved in articular cartilage degradation.
Curtis CL, Hughes CE, Flannery CR, Little CB, Harwood JL, Caterson B., The Journal of Biological Chemistry, 2000
The American Heart Association recommends people eat two servings of fish per week due to its beneficial omega-3 fatty acids. If you are don’t often eat fish, supplementation may be beneficial to you.
Fish and Omega-3 Fatty Acids
American Heart Association®, American Heart Association®, 2015
Omega-3 Content of Frequently Consumed Seafood Products
Seafood Health Facts, Seafood Health Facts (website), 2016
There has been a lot of research on omega-3 fatty acids and EPA or DHA separately for its effect on cognitive performance. There have been mixed reviews on whether both EPA and DHA are beneficial. We reference some positive evidence for omega-3’s and cognitive health here; however, the clinical and observational results are mixed.
485 healthy subjects were enrolled in a randomized, double-blind, placebo-controlled study. They were given 900mg of DHA or a placebo and performed Paired Associate Learning (PAL), visuospatial learning, and episodic memory tests. At 24 weeks, the DHA group performed better on the PAL test, and DHA supplementation was also associated with improved immediate and delayed verbal recognition memory scores. However, DHA did not improve working memory or executive function. Plasma DHA levels doubled in the DHA group.
Another study used a computerized cognitive test to assess the cognitive performance of a DHA group vs a placebo group. This study found improvements in reaction time of episodic and working memory in the DHA group.
In a 2005 clinical study, omega-3 supplementation was associated with an improvement in attention and mood for the omega-3 group versus the placebo group. A population-based study performed a year earlier found that people who consumed more fish in their diet performed better on cognitive battery tests.
The effects of omega-3 fatty acids have also been studied for children. Two groups of children with ADHD were randomly assigned EPA or a placebo for 15 weeks in a clinical study. Teachers reported better behavior in the EPA group, but parents did not. Children with lower serum EPA concentrations at baseline showed better response to treatment.
Residents 65 years or older were recruited for a prospective cohort study. Cognitive assessment tests were performed three times over six years. Fish intake was associated with a slower rate of cognitive decline. In fact, people who ate two or more servings of fish per week were found to have a 13% slower cognitive decline.
Plasma levels of EPA and DHA were studied to predict atrophy in the medial temporal lobe gray matter regions in 281 subjects aged 65 or older. Plasma fatty acid levels were reviewed at baseline and again four years later. The study concluded that higher plasma EPA, but not DHA, was associated with lower gray matter atrophy of the right hippocampal/parahippocampal area and of the right amygdala.
In a 2012 study, a group of 1,575 dementia-free patients were reviewed for their red blood cell fatty acid levels. Participants in the lowest quartile of red blood cell DHA levels had smaller brain volume and greater white matter hyperintensity volume. Participants with lower DHA also had lower scores on tests of visual memory, executive function and abstract thinking models.
Similar results were found in another study of serum phospholipid levels. Higher DHA levels were associated with better performance on tests of nonverbal reasoning, and improved mental flexibility, working memory, and vocabulary on neuropsychological tests. EPA and ALA levels did not show any effect on cognitive performance.
A 2008 clinical study assessed the effect of omega-3 on patients with Alzheimer’s disease and patients with mild cognitive impairment. 1,800mg of omega-3 from fish oil elicited cognitive improvements in patients with mild cognitive impairment, but no benefit was found for the Alzheimer’s patients. Higher proportions of EPA were also associated with better cognitive performance.
Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline.
Yurko-Mauro K, McCarthy D, Rom D, Nelson EB, Ryan AS, Blackwell A, Salem N Jr, Stedman M; MIDAS Investigators., Alzheimer's & dementia: the journal of the alzheimer's association., 2010
Cognitive and physiological effects of Omega-3 polyunsaturated fatty acid supplementation in healthy subjects.
Fontani G, Corradeschi F, Felici A, Alfatti F, Migliorini S, Lodi L., European journal of clinical investigation, 2005
DHA supplementation improved both memory and reaction time in healthy young adults: a randomized controlled trial
Stonehouse W, Conlon CA, Podd J, Hill SR, Minihane AM, Haskell C, and Kennedy D., The American Journal of Clinical Nutrition, 2013
Dietary intake of fatty acids and fish in relation to cognitive performance at middle age
Kalmijn S, van Boxtel MP, Ocké M, Verschuren WM, Kromhout D, Launer LJ., Neurology, 2004
EPA supplementation improves teacher-rated behaviour and oppositional symptoms in children with ADHD.
Gustafsson PA, Birberg-Thornberg U, Duchén K, Landgren M, Malmberg K, Pelling H, Strandvik B, Karlsson T., Acta Paediatrica, 2010
Fish consumption and cognitive decline with age in a large community study.
Morris MC, Evans DA, Tangney CC, Bienias JL, Wilson RS., Archives of neurology, 2005
Plasma long-chain omega-3 fatty acids and atrophy of the medial temporal lobe.
Samieri C, Maillard P, Crivello F, Proust-Lima C, Peuchant E, Helmer C, Amieva H, Allard M, Dartigues JF, Cunnane SC, Mazoyer BM, Barberger-Gateau P., Neurology, 2012
Red blood cell ω-3 fatty acid levels and markers of accelerated brain aging.
Tan ZS, Harris WS, Beiser AS, Au R, Himali JJ, Debette S, Pikula A, Decarli C, Wolf PA, Vasan RS, Robins SJ, Seshadri S., Neurology, 2012
Serum phospholipid docosahexaenonic acid is associated with cognitive functioning during middle adulthood.
Muldoon MF, Ryan CM, Sheu L, Yao JK, Conklin SM, Manuck SB., The journal of nutrition, 2010
The effects of omega-3 fatty acids monotherapy in Alzheimer's disease and mild cognitive impairment: a preliminary randomized double-blind placebo-controlled study.
Chiu CC, Su KP, Cheng TC, Liu HC, Chang CJ, Dewey ME, Stewart R, Huang SY., Progress in neuro-psychopharmacology and biological psychiatry, 2008
Studies on omega-3 for eye health are emerging, with more research activity in the past ten years. Some research has focused on people with recent cataract surgery. A 2016 study found that patients who supplemented with omega-3 fatty acids from fish oil experienced less dry eye symptoms after cataract surgery.
Another study on dry-eye syndrome was developed for healthy individuals who use the computer for 3+ hours per day. This study demonstrated the beneficial effect of omega-3 fatty acids in alleviating dry eye symptoms, decreasing tear evaporation rate in patients suffering from computer related dry eye. A clinical study carried out by the American Academy of Ophthalmology also demonstrated that omega-3 supplementation is associated with a decrease in the rate of tear evaporation, an improvement in dry eye symptoms, and an increase in tear secretion.
518 patients with dry eye symptoms were enrolled in a 2013 study. 65% of patients in the omega-3 group and 33% of patients in placebo group had significant improvement in symptoms at 3 months.
The US Twin study of Age-Related Macular Degeneration was done to determine genetic and environmental risk factors for age-related macular degeneration. 681 twins were surveyed for food diaries and risk-factor questionnaires and given eye examinations. Smokers had almost double the risk of macular degeneration compared to non-smokers, and increased intake of fish reduced the risk of macular degeneration.
Effects of adjuvant omega-3 fatty acid supplementation on dry eye syndrome following cataract surgery: A randomized clinical trial
Mohammadpour M, Mehrabi S, Hassanpoor N, Mirshahi R., Journal of Current Ophthalmology, 2016
Oral omega-3 fatty acids treatment in computer vision syndrome related dry eye.
Bhargava R, Kumar P, Phogat H, Kaur A, Kumar M., Contact lens & anterior eye, 2015
Short-term Consumption of Oral Omega-3 and Dry Eye Syndrome
Kangari H, Eftekhari MH, Sardari S, Hashemi H, Salamzadeh J, Ghassemi-Broumand M, Khabazkhoob M., Ophthalmology, 2013
A randomized controlled trial of omega-3 fatty acids in dry eye syndrome
Bhargava R, Kumar P, Kumar M, Mehra N and Mishra A, International journal of ophthalmology, 2013
Cigarette smoking, fish consumption, omega-3 fatty acid intake, and associations with age-related macular degeneration: the US Twin Study of Age-Related Macular Degeneration.
Seddon JM, George S, Rosner B., JAMA Ophthalmology, 2006
Omega-3 from fish oil has been extensively researched for its benefits on the heart, with studies performed to assess its effects on cardiovascular disease, cholesterol and hypertension. In fact, the American Heart Association recommends eating fish, particularly fatty fish, at least two times per week. Fatty fish like salmon, mackerel, herring, lake trout, sardines and albacore tuna are high in omega-3 fatty acids. For more information about the research on omega-3 fatty acids for heart health, please see the links below:
Omega-3 fatty acids for cardioprotection.
Lee JH, O'Keefe JH, Lavie CJ, Marchioli R, Harris WS., Mayo clinic proceedings, 2008
Fish and Omega-3 Fatty Acids
American Heart Association®, American Heart Association®, 2015
Omega-3 Fatty Acids
Office of Dietary Supplements, National Institutes of Health, 2016