Omega-3 Fatty Acids: The Most Powerful Brain Supplement?
Fish oil is one of the most popular OTC (over-the-counter) supplements in the world. Extracted from fatty fish such as salmon, mackerel and sardines, fish oil high in both EPA (eicosapentaenoic acids) and DHA (docosahexaenoic acid) fatty acids are purported to have a myriad of health benefits, including brain health.
But is this really the case?
In today’s piece, we’ll examine the scientific evidence and discuss what, if any, effect(s) omega-3 fatty acids have on brain health, cognitive function and neurodegenerative diseases.
Omega-3 Fatty Acids: What are they?
Before we delve into the science behind omega-3 fatty acids, it is essential to look at what they are and what role they play within the body.
As mentioned above, fish oil, a polyunsaturated fat, contains two primary forms of omega-3 fatty acids: EPA (eicosapentaenoic acids) and DHA (docosahexaenoic acid), which exist in cell membranes and exhibit powerful anti-inflammatory action. In short, they are recognised as having crucial roles in both human development and cardiovascular health1.
Aside from fatty fish, common food sources found in the human diet are lacking in both EPA and DHA; therefore, the vast majority of people do not consume sufficient amounts of EPA and DHA2. It is possible for the body to manufacture EPA and DHA from a fellow omega-3 acid, ALA (alpha-linolenic acid), which is found in a plethora of food sources, including, but not limited to flaxseeds, chia seeds, walnuts and soybeans.
However, the human body is not particularly efficient at converting ALA to both EPA and DHA, with only around 10% of the former converted to either of the latter3. Therefore, the consumption of fish oil supplements rich in omega-3 fatty acids is a quick and convenient way for those who don’t or can’t eat fish to get these vital omega-3 acids in their diet.
Omega-3 Fatty Acids & The Brain
There are no two ways about it; omega-3 fatty acids such as EPA and DHA are vital for brain development and function throughout the entirety of life. Research has shown that both of these fatty acids play a crucial role in brain development in babies, with studies discovering an association between a pregnant mother’s intake of fish or fish oil and higher levels of brain function and intelligence test performance in their children.4
Furthermore, they are also essential for normal cognitive function at all stages of life given that they are densely populated in the cell membranes of brain cells, where they preserve cell health and promote communication between brain cells5.
Studies in both animals and humans have shown the importance of omega-3 fatty acids and cognitive function. Research indicates that animals fed a diet devoid of omega-3 have decreased levels of DHA within the brain, which, in turn, adversely affects both memory and learning, with similar findings in humans. A study published in the Neurology Journal in 2012 concluded that “Lower…DHA levels are associated with smaller brain volumes and a “vascular” pattern of cognitive impairment even in persons free of clinical dementia.”6.
Therefore, it is imperative that sufficient levels f omega-3 fatty acids are consumed if one wishes to stave off a reduction in brain DHA levels, which, as shown above, may induce negative effects on the brain and cognitive impairment.
Omega-3 Fatty Acids & Memory
As we’ve already established above, fatty acids commonly found in fish oil play a vital role in both brain function and development; however, there have been claims made in relation to omega-3’s ability to enhance cognitive function in those who suffer from memory problems, such as those with neurodegenerative diseases such as Alzheimer’s disease.
Alzheimer’s disease is the most common form of dementia and has a profound effect on both brain function and the quality of life of millions of adults across the glove; therefore, finding a supplement that could help to enhance brain function and potentially even reverse the effects of neurodegenerative conditions such as Alzheimer’s disease would be a monumental breakthrough in science.
Is omega-3 the answer to this problem? Is it a ground-breaking supplement that will changes the lives of millions of elderly people worldwide?
Evidence suggests not.
A wide-ranging review of research found no convincing evidence that omega-3 fatty acid supplementation, such as fish oil capsules, enhance brain health and cognitive function in those with Alzheimer’s disease7.
However, numerous studies have found that consumption of fish oil supplements may enhance and improve cognitive function in those with milder (brain-related) conditions, such as age-induced cognitive decline or MCI (milder cognitive impairment)8. While these types of conditions aren’t as debilitating as Alzheimer’s diseases, they still induce memory loss and can impair brain function.
Studies into the effect of DHA and omega-3 fish oils on more mild forms of brain condition have shown positive results. A study published in 2008 investigated the effects of 1800mg of omega-3 fish oils (in supplement form) per day for a total of 24 weeks, finding that omega-3 improved cognitive function in those with MCI (mild cognitive impairment) but not in this with Alzheimer’s disease9.
Furthermore, a study published in 2010 examined the effects of 900mg of DHA on almost 500 adults for a period of 24 weeks, with researchers discovering a positive correlation between DHA consumption and improved cognitive function, concluding “Twenty-four-week supplementation with 900mg/d DHA improved learning in ARCD (age-related cognitive decline) and is a beneficial supplement that supports cognitive health with ageing.”10.
The takeaway point? From the research presented above, omega-3 supplementation may be beneficial in the primary stages of cognitive decline, but may not benefit at all further down the line if neurodegeneration occurs.
Omega-3 Fatty Acids & Depression
Mental health is one of the biggest pandemics that the global population face on a daily basis, and, unfortunately, it will continue to exist indefinitely unless a cure is found. Many natural and non-pharmaceutical compounds, supplements and like have been touted as effective treatments for mental health problems, but is there any evidence that proves this claim?
Well, given that fish oil supplements are generally considered as one of the most effective health supplements currently available, researchers decided to review a wide array of clinical studies that examined the effect(s) of omega-3 supplementation on people with depression.
Their findings?
Omega-3 – particularly EPA – improved depressive symptoms in those suffering from depression, with the effects being comparable to those of pharmaceutical antidepressant drugs. However, what was even more astounding was the fact that the most significant improvements occurred in those who were already taking antidepressant medication(s). Researchers concluded “…the present meta-analysis observed a beneficial overall effect of omega-3 PUFA (omega-3 polyunsaturated fatty acid0 supplementation in patients with MDD (major depressive disorder)…which seemed larger in studies that supplemented with higher doses of EPA and included patients taking antidepressants.”11.
However, the exact mechanism behind omega-3’s impressive effects on those with depression still remains a mystery. Some researchers have suggested that omega-3’s interaction (and the subsequent effect on) serotonin receptors are behind the positive results of omega-3 fatty acids on symptoms of depression. On the other hand, it has also been suggested that it is the anti-inflammatory effects of omega-3 that is responsible for the effects it induces.
Omega-3 & Normal, Healthy Brains
The bulk of this article has predominantly focused on the effects of omega-3 fatty acids on those with mild cognitive decline, age-related cognitive decline and dementia (Alzheimer’s disease for example), but what about the impact omega-3 supplementation has on those with normal, healthy brains?
There have been numerous observational studies that have discovered that eating greater quantities of omega-3 fatty acids from fish is positively correlated with increases in brain function. However, these studies focussed on the consumption of actual fatty fish, rather than omega-3 in supplement form. Moreover, correlational-type studies like these aren’t able to prove cause and effect12.
If we delve deeper and review the highest-quality studies that examine the effects of omega-3 supplementation on brain function, it is apparent that omega-3 from fish oil supplements does not appear to enhance cognitive function in those who don’t suffer from any form of memory problem. A study published in 2012 looked into the effects of 1000mg of fish oil (per day) for 12 weeks on young adults aged between 19-35. It concluded that fish oil supplementation did not improve brain function – although it “may reduce mental fatigue at times of high cognitive demand.”13. Further studies have backed up these findings14.
Omega-3 Fatty Acids: Should you take them from brain function and health?
If we take all of the current evidence into omega-3’s effects on brain health and cognitive function into account, it is apparent that those with mild cognitive decline (or similar) or who have been diagnosed with depression may experience a positive effect from fish oil supplementation.
At present, there are no official guidelines as to how much fish oil (in supplement form) you need to take to see benefits in cognition and mental health, as the amounts used in all of the studies mentioned in this article varied from study to study.
The US FDA suggests an upper limit of 3,000mg per day, whereas the EFSA (European Food Safety Authority) recommends a limit of 5,000mg per day.15 As with most supplements, starting with lower doses to assess tolerance is advised. Those with symptoms of depression should opt for supplements with higher quantities of EPA. Always read the label, as the amount of EPA and DHA will vary from brand to brand.
Omega 3 Fatty & Brain Function and Health: A Conclusion
To conclude, EPA and DHA are essential for normal cognitive function, brain development and health. However, unless you’re suffering from mild cognitive decline or depression, supplementing with fish oils rich in omega-3 fatty acids is unlikely to have any positive effects aside from maintaining the current, healthy functioning of the brain.
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References:
1. Swanson, D., Block, R. & Mousa, S.A., 2012. Omega-3 fatty acids EPA and DHA: health benefits throughout life. Advances in nutrition (Bethesda, Md.). Available at: https://www.ncbi.nlm.nih.gov/pubmed/22332096
2. Papanikolaou, Y. et al., 2014. U.S. adults are not meeting recommended levels for fish and omega-3 fatty acid intake: results of an analysis using observational data from NHANES 2003-2008. Nutrition journal. Available at: https://www.ncbi.nlm.nih.gov/pubmed/24694001
3. Gerster, H., 1998. Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)? International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition. Available at: https://www.ncbi.nlm.nih.gov/pubmed/9637947
4. Helland, I.B. et al., 2003. Maternal supplementation with very-long-chain n-3 fatty acids during pregnancy and lactation augments children’s IQ at 4 years of age. Pediatrics. Available at: https://www.ncbi.nlm.nih.gov/pubmed/12509593
5. Dyall, S.C., 2015. Long-chain omega-3 fatty acids and the brain: a review of the independent and shared effects of EPA, DPA and DHA. Frontiers in aging neuroscience. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4404917/
6. SM;, I., Dietary (n-3) Fatty Acids and Brain Development. The Journal of nutrition. Available at: https://pubmed.ncbi.nlm.nih.gov/17374644/
7. Burckhardt, M. et al., 2016. Omega-3 fatty acids for the treatment of dementia. The Cochrane database of systematic reviews. Available at: https://www.ncbi.nlm.nih.gov/pubmed/27063583
8. Chiu, C.-C. et al., 2008. The effects of omega-3 fatty acids monotherapy in Alzheimer’s disease and mild cognitive impairment: a preliminary randomized double-blind placebo-controlled study. Progress in neuro-psychopharmacology & biological psychiatry. Available at: https://www.ncbi.nlm.nih.gov/pubmed/18573585
9. Chiu, C.-C. et al., 2008. The effects of omega-3 fatty acids monotherapy in Alzheimer’s disease and mild cognitive impairment: a preliminary randomized double-blind placebo-controlled study. Progress in neuro-psychopharmacology & biological psychiatry. Available at: https://www.ncbi.nlm.nih.gov/pubmed/18573585
10. Yurko-Mauro K;McCarthy D;Rom D;Nelson EB;Ryan AS;Blackwell A;Salem N;Stedman M; ; Beneficial Effects of Docosahexaenoic Acid on Cognition in Age-Related Cognitive Decline. Alzheimer’s & dementia : the journal of the Alzheimer’s Association. Available at: https://pubmed.ncbi.nlm.nih.gov/20434961/
11. Mocking, R.J.T. et al., 2016. Meta-analysis and meta-regression of omega-3 polyunsaturated fatty acid supplementation for major depressive disorder. Translational psychiatry. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4872453/
12. Kalmijn, S. et al., 2004. Dietary intake of fatty acids and fish in relation to cognitive performance at middle age. Neurology. Available at: https://www.ncbi.nlm.nih.gov/pubmed/14745067
13. Jackson PA;Deary ME;Reay JL;Scholey AB;Kennedy DO; No Effect of 12 Weeks’ Supplementation With 1 G DHA-rich or EPA-rich Fish Oil on Cognitive Function or Mood in Healthy Young Adults Aged 18-35 Years. The British journal of nutrition. Available at: https://pubmed.ncbi.nlm.nih.gov/21864417/
14. Dangour AD;Allen E;Elbourne D;Fasey N;Fletcher AE;Hardy P;Holder GE;Knight R;Letley L;Richards M;Uauy R; Effect of 2-y n-3 Long-Chain Polyunsaturated Fatty Acid Supplementation on Cognitive Function in Older People: A Randomized, Double-Blind, Controlled Trial. The American journal of clinical nutrition. Available at: https://pubmed.ncbi.nlm.nih.gov/20410089/
15. ;, K.-E.P.M.H.W.S.A.L.J., Fish Consumption, Fish Oil, omega-3 Fatty Acids, and Cardiovascular Disease. Circulation. Available at: https://pubmed.ncbi.nlm.nih.gov/12438303/