Cutting The Fat: The Science of Omega-3 Fish Oil

Cutting The Fat: The Science of Omega-3 Fish Oil

omega 3 science

In the world of nutrition, there are certain elements that stand head and shoulders above the rest in regards to how crucial and beneficial when it comes to the cardiovascular system, metabolism, cells and overall health, and in this case, omega-3 fatty acids are one of them. Often considered to be a ‘super’ fat, if used properly, omega-3s can greatly improve cardiovascular health, reduce inflammation both chronic and acute, improve insulin sensitivity, increase cognitive function and aid in overall metabolism. This article will cover what omega-3s are, where you can get them, the benefits they provide and discuss fatty acid dietary intake balance and their impact on daily health.

Omega-3s – The Overview

By definition, omega-3s are polyunsaturated fatty acids (known as PUFAs for short) and while there are numerous omega-3 fatty acids, the three that are utilized in the human physiology are eicosapentaenoic (EPA), docosahexaenoic (DHA) and a-linolenic (ALA) acid (1). All three of these are critical for the normal function of the human body, and it is important to note that the body is unable to synthesize the longer chain omega-3s (DHA & EPA) so the must be obtained through diet. However, interestingly, these longer chain omega-3s can be formed from ingestion of the shorter chain ALA through diet (2).

The first of the three, eicosapentaenoic acid (EPA) primarily acts as a prostaglandin (fatty acid compounds that modulate healthy inflammation response) precursor and is obtained through diet from sources such as the flesh of cold-water fish such as mackerel, herring, tuna, halibut, salmon, cod liver and is additionally found in human breast milk. In addition to these sources, it can also be sourced from ALA if there is an adequate supply available, and furthermore, EPA itself can act as a precursor to the omega-3 fatty acid DHA (3).

Docosahexaenoic acid (DHA) is one of the main structural components of critical areas in the human body including the brain, skin, cerebral cortex, retina, testicles and sperm production. Like EPA, it can be obtained through the consumption of cold-water fish, algae or human breast milk or be created from adequate ingestion of the fatty acid ALA (4). Most notably, DHA is essential for the growth and functional development of the brain in infants and for maintenance of normal brain function in adults (5).

α-Linolenic acid (ALA) is one of the two essential fatty acids as it is crucial for health and cannot be synthesized in the body and furthermore, is a precursor for the two longer chain omega-3 fatty acids (EPA & DHA) and is an isomer of the polyunsaturated fatty acid gamma-linolenic acid (GLA) (6). Primary sources of ALA include chia seeds, flax seeds, canola oil, pumpkin seeds, perilla seed oil, walnuts, and tofu.

For the consumption of EPA and DHA, the ratio of which you should consume each is dependent on what the individual’s specific goals/health focus is. The general ratio recommended is 3:2 in favor of DHA if you are looking to reduce total triglyceride counts, increase HDL (good) cholesterol, improve cognition slow mental decline or quell neurological response. On the other hand, you would be better suited to employ the same 3:2 ratio in favor of EPA if your emphasis is to lower overall LDL (bad) cholesterol and/or improve the modulation of stress-affected immune activity (7).

In regard to overall daily intake, there are no standard amounts, however, the general recommendation is a minimum of 250mg combined EPA and DHA for general health, with the American Heart Association recommending 1 gram per day for those with heart disease and a dosage of 2-4 grams per day for lowering triglycerides (8).

When it comes to who should consider using omega-3 supplements, they are a great staple supplement for everyone to ensure that you’re meeting the daily intake of 250mg and ideally come from a combination of whole food and supplementation and the more DHA/EPA consumed through diet, the less is needed from supplementation. More specifically, if you are interested in using omega-3 for helping with specific health conditions of interest, it is encouraged that you examine the individual research on the specific conditions and talk with your healthcare provider.

Omega-3 Sources – Animal vs. Plant

There has been some debate in regard to what the ideal source of dietary omega-3 is with strong proponents on both sides of the fence for both animal and plant sources. As listed earlier, the primary sources for animal-based include cold water fish, krill and the oils from such fish. On the other hand, the primary sources of plant-based intake include chia seed, hemp, perilla, and flaxseed.

The main reason that some are opposed to getting their intake of omega-3s from cold water fish are dietary beliefs such as vegan/vegetarian and that there is concern over potential contamination in fish/fish oil with pollutants or heavy metals like mercury.

It is widely advised that it is preferable to consume your omega-3s through animal sources opposed to plant, and this is based on the nutritional content. Marine animals such as those we discussed earlier contain readily available EPA and DHA while the plant sources such as chia, hemp and the like provide primarily ALA which must be synthesized into EPA and DHA. This isn’t ideal as ALA has a very poor conversion rate to EPA and DHA with less than 5% of ALA getting converted to EPA, and less than 0.5% of ALA converting to DHA. Making matters worse is that research has indicated that diets rich in omega-6 polyunsaturated fats can have conversion further reduced by 40 to 50% (9). Further attesting to animal sources over the plant-based source is that almost all of the health benefits discovered in research are based on animal-based DHA and EPA and not plant based ALA.

Do keep in mind that while it isn’t ideal to use plant-based sources for your EPA and DHA intake via conversion of ALA, plant-based sources are in no way harmful or warrant avoidance. There are great benefits from these plants including the additional ALA as well as fiber and other mineral content for health. Ideally, aim to get plant sources in addition and by combination such as adding chia or flax seeds to your diet in addition to your animal sourced omega-3s.

The Alpha of the Omegas – Benefits

There are many benefits associated with having adequate levels of omega-3 fatty acids and in fact, the American Journal of Clinical Nutrition even has published three separate studies on the effects of EPA and DHA intake and its role in populations. The researchers found that those with low intakes of EPA and DHA had increased risk of mortality and even accelerated cognitive decline (10). On the flip side, adequate consumption via whole food and supplementation of omega-3s has been shown to play a positive role in:

  • Reducing/improving blood triglycerides (11)
  • Improving depression comparable to that of pharmaceutical drugs (12)
  • Improving ADHD symptoms in children (13)
  • Reducing blood pressure in those with hypertension (14)
  • Increasing HDL (good cholesterol) (15)
  • Reducing inflammation (chronic) (16)
  • Slow the progression and reduce the discomfort of rheumatoid arthritis (17)

In terms of potential side effects from omega-3 fatty acids, there are few if any associated with normal consumption of them through whole foods aside potential concern from mercury exposure from eating contaminated fish. The side effects that could potentially be associated with omega-3s, though minor, are associated with the supplementation route.

These include the possibility of an upset stomach or diarrhea so use caution when introducing supplemental omega-3s. The main concern of omega-3 supplementation is in relation to their anti-atherosclerotic and antithrombotic effects. While these are good properties in that they reduce the risk of coronary artery disease and clotting, though rare, this can be detrimental as they can thin the blood too much or prevent the necessary clotting for healing following surgery or the natural response to injury (18).

Modern Day Balancing Act – Omega-3 vs. Omega-6 Intake

Last but not least, one important area to address is the dietary intake of omega-6 fatty acids in ratio to omega-3 fatty acids. Omega-6 and Omega-3s are both unsaturated fatty acids, more specifically polyunsaturated fatty acids. While they are lipids by nature, they behave differently than other fats and instead of being stored or burned as energy, exert active effects such as lowering blood pressure, reducing triglycerides, boosting serotonin and dopamine and play a large role in metabolic processes such as inflammation and blood clotting.

Specifically for this discussion, it is important to note that omega-3 fatty acids are anti-inflammatory and omega-6 fatty acids are inflammatory. It’s important to have both as inflammation is essential for the natural mechanisms of healing and protective properties in the body, however, too much inflammation can result in an onslaught of serious health conditions.

This is especially important to note as an excess in omega-6 consumption can cause increased inflammation, and in modern society, there is an alarmingly high ratio of omega-6 to omega-3 consumption. The recommended ratio of omega-6 to omega-3 is 2:1, however it has been found that on average, especially in Western civilization, the ratio is an alarming 16:1 ratio (19). This is due to an overabundance of omega-6 containing oils including corn, canola, soybean oil and sunflower oils paired with an inadequate omega-3 intake.

Excessive omega-6 intake is associated not only with chronic inflammation but an increased risk of cardiovascular disease (20) and cognitive issues such as depression (21). Furthermore, making matters worse is that omega-6 fatty acids tend to be very reactive to oxygen, forming free radicals which can cause cell damage (22).

In order to improve the ratio of omega-6 to omega-3, the key thing to do is reduce the consumption of processed seed and vegetable oils as much as possible, including the foods that contain them as well with sunflower, canola, soybean, corn, and cottonseed being the highest omega-6 containing oils. Inversely, focusing on increasing your intake of omega-3s is ideal by way of eating seafood once or twice per week from items like wild caught salmon. In terms of meats, grass-fed meat is optimal for increasing omega-3 intake as conventionally raised meat has higher omega-6 content due to a grain-based diet and the same goes for farm-raised fish vs. wild caught. Lastly, if you find yourself eating mostly conventionally raised meats and little to no fish, you can supplement omega-3s with a high-quality fish oil.

Lastly, when it comes to what to look for in an omega-3 supplement, there are 3 common forms that are available today: natural fish oil, processed fish oil, and krill oil. Natural fish oil is as close as you can get to real fish and the omega-3 fatty acids are mostly present as triglycerides. Roughly 30% of the oil is omega-3 (EPA and DHA) with the remaining 70% consisting of other fatty acids that can help with absorption (23).

Processed fish oil is purified and/or concentrated and this also transforms the fats into the ethyl ester form. This process helps rid the oil of contaminants, such as mercury and PCBs and also concentrating the oil which increases EPA and DHA level to contain anywhere from 50–90% pure EPA and/or DHA. The downside, however, is that the ethyl ester form is hard for the body to absorb, but this can be countered by further processing to re-esterify them as another step, however, not all oils do this extra step and the ones that have been processed with this method are typically more expensive.

The other common form is often referred to as the best, and that is krill oil, which is a small shrimp-like animal. Though it isn’t fish, it has omega-3s in both triglyceride and phospholipid form, and the phospholipid form has even been shown in studies to be absorbed just as good and perhaps better than that of fish oil (24). The other benefits of krill over traditional fish oil is that it contains the antioxidant astaxanthin to resist oxidation naturally and since they have a short life-span, are naturally less prone to have accumulated many contaminants, meaning no processing resulting in ethyl esters (25).

When selecting an omega-3 supplement, things to look for are making sure it contains both EPA and DHA, and be sure it contains at least the 250mg recommendation of them. Also, referring to the form, look for free fatty acids vs the aforementioned ethyl ester form which is harder to absorb. Lastly, for safety and good practices on the manufacturing side, look for one that is GOED standard for purity or ‘third party tested’ and that they have an added anti-oxidant such as vitamin E to prevent rancidity and oxidation of the product.

The Omega Points – Conclusion

Omega-3s are one of the most beneficial fatty acids in the human diet today. They have a wide array of benefits when implemented correctly and adequately. A deficiency of them, especially if replaced with elevated omega-6 consumption can have detrimental effects, and negatively impact long-term health. With the information contained in this article, we hope that you now have a more thorough understanding of why they’re important, beyond the general “make sure to take your fish oil”.

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References

  1. Omega-3 fatty acids, hepatic lipid metabolism, and nonalcoholic fatty liver disease. Scorletti, E.2013, Annual Review of Nutrition, Vol. 33, pp. 231-248.
  2. U.S. Department of Health & Human Services.Omega-3 Supplements: In Depth. National Center for Complementary & Integrative Health. [Online] National Institute of Health. [Cited: November 29, 2016.] https://nccih.nih.gov/health/omega3/introduction.htm.
  3. Erdman, J.Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA). Nutrition and Traumatic Brain Injury: Improving Acute and Subacute Health Outcomes in Military Personnel. Washington D.C. : s.n., 2011.
  4. WebMD.DHA (DOCOSAHEXAENOIC ACID). WebMD. [Online] [Cited: November 29, 2016.] http://www.webmd.com/vitamins-supplements/ingredientmono-864-dha%20docosahexaenoic%20acid.aspx?activeingredientid=864.
  5. Health benefits of docosahexaenoic acid (DHA). Horroks, L.3, September 1999, Pharmacology Research, Vol. 40, pp. 211-235.
  6. University of Maryland.Alpha-linolenic acid. University of Maryland Medical Center. [Online] [Cited: November 29, 2016.] http://umm.edu/health/medical/altmed/supplement/alphalinolenic-acid.
  7. Effect of Omega-3 polyunsaturated fatty acids on inflammation, oxidative stress and recurrence of atrial fibrillation. Darghosian, L.2, January 2015, American Journal of Cardiology, Vol. 115, pp. 196-201.
  8. Effects of omega-3 fatty acids on postprandial triglycerides and monocyte activation. Schirmer, S.1, November 2012, Journal of Atherosclerosis, Vol. 225, pp. 166-173.
  9. Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)? Gerster, H.3, 1998, International Journal of Vitamin & Nutrient Research, Vol. 68, pp. 159-173.
  10. Long-chain n−3 fatty acids and mortality in elderly patients. Lindberg, M.3, s.l. : American Society for Clinical Nutrition, September 2008, American Journal of Clinical Nutrition, Vol. 88, pp. 722-729.
  11. Supplementation with omega3 polyunsaturated fatty acids and all-rac alpha-tocopherol alone and in combination failed to exert an anti-inflammatory effect in human volunteers. Vega-Lopez, S.2, February 2004, Journal of Metabolism, Vol. 53, pp. 236-240.
  12. Meta-analysis of the effects of eicosapentaenoic acid (EPA) in clinical trials in depression. Sublette, M.12, December 2011, Journal of Clinical Psychiatry, Vol. 72, pp. 1577-1584.
  13. Omega-3 fatty acid supplementation for the treatment of children with attention-deficit/hyperactivity disorder symptomatology: systematic review and meta-analysis. Bloch, M.10, October 2011, Journal of American Academy of Child & Adolescent Psychiatry, Vol. 50, pp. 991-1000.
  14. A systematic review of fish-oil supplements for the prevention and treatment of hypertension. Campbell, F.1, February 2013, European Journal of Preventative Cardiology, Vol. 20, pp. 107-120.
  15. A meta-analysis shows that docosahexaenoic acid from algal oil reduces serum triglycerides and increases HDL-cholesterol and LDL-cholesterol in persons without coronary heart disease. Bernstein, M.1, January 2012, Journal of Nutrition, Vol. 142, pp. 99-104.
  16. N-3 Polyunsaturated Fatty Acids: Relationship to Inflammation in Healthy Adults and Adults Exhibiting Features of Metabolic Syndrome. Robinson, L.4, April 2013, Journal of Lipids, Vol. 48, pp. 319-322.
  17. Influence of marine n-3 polyunsaturated fatty acids on immune function and a systematic review of their effects on clinical outcomes in rheumatoid arthritis. Miles, E.S2, June 2012, British Journal of Nutrition, Vol. 107, pp. 171-184.
  18. WebMD.Omega-3 Fatty Acids. WebMD. [Online] [Cited: November 30, 2016.] http://www.webmd.com/diet/supplement-guide-omega-3-fatty-acids#2.
  19. The importance of the ratio of omega-6/omega-3 essential fatty acids. Simopoulos, A.8, October 2002, Journal of Biomedical Pharmacotherapy, Vol. 56, pp. 365-379.
  20. Dietary fat and health: the evidence and the politics of prevention: careful use of dietary fats can improve life and prevent disease. Lands, W.December 2005, Ann. N Y Acad. Sci, Vol. 1055, pp. 179-192.
  21. Depressive Symptoms, omega-6:omega-3 Fatty Acids, and Inflammation in Older Adults. Kiecolt-Glaser, J.3, April 2007, Psychosematic Medicine, Vol. 69, pp. 217-224.
  22. Lipid peroxidation-induced DNA damage in cancer-prone inflammatory diseases: a review of published adduct types and levels in humans. Nair, U.8, October 2007, Free Radical Biological Medicine, Vol. 43, pp. 1109-1020.
  23. Digestion and lymphatic transport of eicosapentaenoic and docosahexaenoic acids given in the form of triacylglycerol, free acid and ethyl ester in rats. Ikeda, I.3, 1995, Biochim Biophys Acta., Vol. 1259.
  24. Incorporation of EPA and DHA into plasma phospholipids in response to different omega-3 fatty acid formulations–a comparative bioavailability study of fish oil vs. krill oil. Schuchardt, J.145, Aug 2011, Lipids Health Dis., Vol. 10, p. 145.
  25. Effect of temperature towards lipid oxidation and non-enzymatic browning reactions in krill oil upon storage. Lu, F.Aug 2014, Food Chemistry, Vol. 157, pp. 398-407.

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