Part 3: The Role of Omega-3 Fatty Acids in Metabolic Syndrome
Dr. Maille Devlin, ND is a licensed Naturopathic Doctor and corporate wellness consultant practicing in virtually for patients all across Ontario as well as in person in the east end of Toronto. Dr. Devlin has a clinical focus in: weight loss, cardiovascular disease, diabetes, hormonal issues, stress management and healthy aging. She considers true health not only the absence of disease, but rather a state where an individual is thriving both physically and mentally.
Dr. Devlin graduated from the Canadian College of Naturopathic Medicine (CCNM) and completed internships at the Robert Schad Naturopathic Teaching Clinic, Sherbourne Health Centre and the Rose Health Clinic. Prior to CCNM, Dr. Devlin obtained an undergraduate degree in Honours Biomedical Sciences with a minor in Nutrition at the University of Guelph.
Dr. Devlin believes that education and preventative medicine are the greatest steps toward wellness and is focused on empowering individuals to take the appropriate steps towards being their own health advocate. Dr. Devlin uses a combination of dietary changes, herbal medicine, supplements and lifestyle counselling to treat patients.
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The Role of Omega-3 Fatty Acids in Metabolic Syndrome
Dr. Maille Devlin, ND
Welcome back for part 3 of our discussion around the use of fats for improving metabolic health. In this article, I am going to focus in on one specific type of fat- omega-3 fatty acids.
Omega-3 fatty acids, an overview
Omega-3 fatty acids are a type of polyunsaturated fatty acid (PUFA). PUFAs are fat molecules that have more than one unsaturated carbon bond, which makes them liquid at room temperature. Omega-6 fatty acids also fall into the group of polyunsaturated fatty acids.
Omega-3 fatty acids are important components of cell membranes and have several functions such as regulating the immune system, nervous system, heart, lungs, and hormones.
As mentioned briefly in the second part of the metabolic series, omega-3 fatty acids are the more anti-inflammatory form of polyunsaturated fatty acids, whereas omega-6 fatty acids promote an inflammatory response in the body. Both inflammatory and anti-inflammatory processes are needed for optimal function. However, the ratio of anti- inflammatory to inflammatory molecules is disproportioned for most North Americans. Many individuals in western countries consume far too many omega-6 fatty acids and not enough omega-3 fatty acids.1
Omega-3 fatty acids and metabolic syndrome
Let’s look at the two types of PUFAs specifically for metabolic syndrome. If you need a refresher on what metabolic syndrome is, head over to the first article of the series.
Many nutrition guidelines now suggest ingesting PUFAs to benefit heart health, however a specification on omega-3 fatty acids over omega-6 fatty acids is not always highlighted. A 2020 study published in Clinical Nutrition aimed to evaluate the evidence for omega-3 fatty acids and omega-6 fatty acids and their impact on metabolic syndrome.2 Researchers analyzed thirteen different studies with over 36, 000 participants. They found that a higher omega-3 fatty acid intake in the diet and in blood levels were associated with a 26% reduction in the risk of metabolic syndrome. They did not find that an increase in omega-6 fatty acids was associated with a lower risk for metabolic syndrome.2
The impact of omega-3 fatty acids on triglyceride levels and HDL (two components of metabolic syndrome) are well documented.3 The impact of omega-3’s on insulin resistance is consistently demonstrated in animals, but not as well documented in humans.
Therefore, a study published in March of 2021 in Nature, authors examined the impact that omega-3 fatty acid supplementation have in humans with insulin sensitivity and obesity.4 The subjects all had an average BMI of 39 and had insulin sensitivity measured through euglycemic-hyper insulinemic clamp before omega-3 fatty acid supplementation and after 3 months of supplementation at 4g per day. Researchers found that specific fats which increase cholesterol levels in the body, were significantly reduced after supplementation with omega-3 supplementation. Systemic inflammation was also decreased significantly. There was an increase in the sensitivity of tissues to insulin seen with a 25% increase in glucose disposal. Authors concluded that a high dose omega-3 fatty acid supplement can modulate significant changes in the fatty acid profile, fat tissue, insulin sensitivity and inflammation in those with obesity and insulin resistance.4
Types of omega-3 fatty acids
Although so far, we have been talking about omega-3 fatty acids as one item, there are three distinct forms of omega-3 fatty acids which each have different impacts on the body.
Omega-3 fatty acids are essential, meaning the body does not create these fatty acids and we must obtain them through diet. The two forms of omega-3 fatty acids that the body uses are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Alpha-linolenic acid (ALA) is another form of omega-3 fatty acids that the body can use to synthesize EPA or DHA. However, the conversion of ALA into EPA and DHA has a very poor conversion rate, of about 8% from ALA to EPA and 0-4% to DHA in healthy young men.5 Therefore, the forms EPA and DHA are most important when looking at the types of omega-3 fatty acids to consume.
EPA and DHA also have separate functions in the body. The use of EPA vs. DHA for metabolic health usually favours EPA over DHA due to the more potent anti-inflammatory effect of EPA. However, newer research is finding that EPA and DHA both impact metabolic health in different capacities.6 Therefore, it is important to have both EPA and DHA in your supplement. I usually suggest a higher ratio of EPA to DHA for patients looking to improve metabolic health, but it is important to assess individual need.
Sources of omega-3 fatty acids
EPA and DHA omega-3 fatty acids are found mostly in seafood products. Fish high in omega-3 fatty acids include salmon, tuna, mackerel, anchovies, sardines, and herring. Algae is the only vegan source of EPA and DHA available. ALA is found in foods such as flaxseed, walnuts, and chia seeds. However, remember that ALA is not a very efficient source of omega-3 fatty acids and likely will not provide the appropriate amount needed for optimal health.
The dose of omega-3 fatty acids is also important to consider. Trying to obtain omega-3 fatty acids from food alone may not be sufficient, especially if looking to treat metabolic syndrome.
For example, the study mentioned above used 4g of omega-3 fatty acids to have significant clinical effects. 3 oz of wild salmon contains approximately 1.22g of DHA and 0.35g of EPA.7 Meaning, one would have to consume just under 8oz of salmon daily to hit this same quantity of omega-3 fatty acids. Consuming this amount of fish is not only unrealistic but is also not recommended due to the accumulation of heavy metals in the body with high amounts of fish consumption. Therefore, supplementation with a high-quality fish oil is often the best way to obtain high levels of omega-3 fatty acids in the blood.
What to look for in an omega-3 fatty acid supplement?
As mentioned above, you want to make sure your fatty acid supplement is in the EPA and DHA form, not an ALA form. If you do not consume animal products, look for an algae oil rather than something like a flaxseed oil. Secondly, you want to make sure there are no filler oils in the supplement. Some companies add in vegetable oils into the omega-3 supplement. This increases the omega-6 concentration, which we know moves the body towards an inflammatory state rather than an anti-inflammatory state. Make sure the supplement is third party tested. Fish oils are one of the most important supplements to have third party tested, for a few reasons. If not processed under specific conditions, fish oils will quickly oxidize, creating a rancid oil which is inflammatory to the body. Third party testing also ensures purity of the product which is critical for omega-3 fatty acid supplements to confirm that toxins such as heavy metals or PCBs are removed from the product.
Cold water distillation is important to look for as well. When oils are heated, the fatty acid becomes damaged, as well as oxidized. Therefore, selecting a fish oil, chose one that has a cold distillation process. This means the oil’s integrity is kept through the process and oxidation remains low. Secondly, the cold distillation prevents the fishy taste and smell associated with a fish oil which has gone through fractional distillation. Lastly, look for a triglyceride form of omega-3 fatty acids. Another popular form, ethyl ester, make the fats more susceptible to oxidization and impairs the ability of the body to absorb and use the omega-3 fatty acid. This form is also associated increased side effects such as fish burps, and gastrointestinal symptoms. The triglyceride form is much more stable, bioavailable and has decreased side effects because this is how the fats are found naturally in fish.
If looking for a specific recommendation, please consult your healthcare provider.
That wraps up our three-part series on metabolic syndrome and the importance of healthy fats. I hope you have learned something new to take with you whether you are preventing or treating metabolic syndrome. Please feel free to reach out with any questions you may have!
- Simopoulos AP. An increase in the omega-6/omega-3 fatty acid ratio increases the risk for obesity. Nutrients. 2016 Mar;8(3):128.
- Jang H, Park K. Omega-3 and omega-6 polyunsaturated fatty acids and metabolic syndrome: a systematic review and meta-analysis. Clinical Nutrition. 2020 Mar 1;39(3):765-73.
- Lopez-Huertas E. The effect of EPA and DHA on metabolic syndrome patients: a systematic review of randomised controlled trials. British journal of nutrition. 2012 Jun;107(S2):S185-94.
- Hernandez JD, Li T, Rau CM, LeSuer WE, Wang P, Coletta DK, Madura JA, Jacobsen EA, De Filippis E. ω-3PUFA supplementation ameliorates adipose tissue inflammation and insulin-stimulated glucose disposal in subjects with obesity: a potential role for apolipoprotein E. International Journal of Obesity. 2021 Jun;45(6):1331-41.
- Zhang, H.J., Gao, X., Guo, X.F., Li, K.L., Li, S., Sinclair, A.J. and Li, D., 2021. Effects of dietary eicosapentaenoic acid and docosahexaenoic acid supplementation on metabolic syndrome: a systematic review and meta-analysis data from thirty-three randomized controlled trials. Clinical Nutrition.