Tuesday, June 9, 2015

Omega-3 Supplements

One of my hobbies involves roaming supplement aisles. I like to see what’s for sale.  Whenever I look at the omega-3 supplements I see something new.
By Wuhazet (Henryk Żychowski) (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
There are supplements made from fish, krill, algae, flax, and hemp just to name a few sources. It can be overwhelming to stand in the aisle deciding what to do. I recently read a lot of literature about omega-3 supplements and this week I’ll summarize what I learned about omega-3 fats and supplements made from fish, krill, flax, algae, and hemp. 

What are essential fatty acids?

  • Omega-3 fatty acids and omega-6 fatty acids are polyunsaturated fats (PUFAs) that we need to eat because the human body cannot make them.
  • Sources of omega-3 and omega-6 fatty acids:
    • Omega-3 fats (examples): fatty and cold water fish (salmon, tuna, halibut), seaweed, walnuts, walnut oil, flaxseed, flaxseed oil, canola oil, and soybean oil. We tend not to get enough omega-3 fats in the diet.
    • Omega-6 fats (examples): 1 tablespoon of safflower oil, sunflower oil, soybean oil, or corn oil. A typical American diet contains 10 times more omega-6 (linoleic acid) than omega-3 fatty acids.(1) We easily get enough omega-6 fatty acids.
  • There are 2 kinds of omega-3 fats – EPA and DHA. We need EPA and DHA so that our bodies can make other fatty acids that are important for the body to properly function. Alpha-linolenic acid (ALA) is an omega-3 fatty acid. Flaxseed and walnuts contain a lot of ALA. The body can convert only a  very small amount of ALA to EPA and DHA. ALA is a healthy fatty acid, but we don’t seem to be able to use it to make EPA and DHA, which our bodies use to make other fatty acids.

Are omega-3 fatty acids good for the heart?

  • Most research shows that diets that contain lots of omega-3 fatty acids are associated with a reduced risk of heart disease, lower blood pressure, lower heart disease, less death with heart disease, and less incidence of stroke.(2, 3) But when a group of researchers systematically analyzed published research results from other studies and considered the evidence all together, they found no protective association between greater omega-3 intake and lower risk of heart disease in people with preexisting conditions.(5)

Are omega-3 supplements healthy?

  • Bioavailability refers to how much of a substance (omega-3 fatty acids) the body is able to use. Not everything that you ingest is bioavailable. For example, you may have heard that iron is difficult to absorb – it has low bioavailability.
  • As different sources of omega-3 supplements are introduced we have to find out if they are bioavailable, particularly in reference to the standard of fish (usually salmon). Algae oil and krill oil appear to be highly bioavailable. They are readily absorbed and used by the body. (4, 5). However, emerging research shows that different sources of omega-3 fatty acids work in different ways. While algae oil, krill oil and fish oil are all bioavailable they do different things in the body. So switching one source for another may not be entirely comparable. But, it isn’t at all clear if or how much that matters.
  • While most evidence supports that a diet rich with omega-3 foods is associated with reduced risk of heart disease, it isn’t at all clear  if omega-3 supplements have the same effect.(2, 3, 6, 7) Omega-3 supplements do not appear to have a consistent impact on inflammatory markers that are associated with heart disease. (8)
  • Sometimes physicians recommend that people with very high triglycerides take omega-3 supplements. According to the American Heart Association, consuming medically supervised doses of omega-3 supplements lowers triglycerides for patients.(9) Research shows that taking pharmacological doses of omega-3 fatty acids helps lower triglycerides for patients with clinically elevated levels. The amount needed to lower high triglycerides is not realistically attainable through diet and so it is necessary to take a supplement. Therefore, this is considered a pharmacological dose and must be medically supervised. Omega-3 supplements interfere with certain medications so it is important to discuss supplement use with your doctor.
  • Evidence indicates that flaxseed oil supplements are bioavailable and may be associated with improved blood pressure and blood lipid profiles. (1, 8, 10) Flaxseed oil contains ALA.
  • Hempseed oil is a source of ALA. It has not been well studied yet. Emerging evidence suggests that ALA from hempseed oil is bioavailable. (11) This is an understudied area of research.
  • DHA and the adult brain. DHA is present in nerve cells, the central nervous system, in the brain and in the eyes. Infant formula is supplemented with DHA because it is needed for brain development. Because of the role of DHA in the brain and central nervous system, there is interest in finding out if omega-3 fatty acids play a role in dementia, including Alzheimer’s disease. I expect we will learn more about omega-3 fatty acids and dementia in years to come. Some emerging research suggests that there is an association between altered omega-3 levels and dementia, although it is unclear what, how, or why. In 2012, a meta-analysis of data showed that omega-3 (EPA) levels were lower in predementia patients and that all levels of omega-3 (EPA, DHA, and total omega-3) in patients with dementia. (12) An epidemiological study noted an association between higher levels of omega-3 DHA and a lower risk of developing dementia (13). However, giving people DHA supplements has not been shown to reduce or delay the onset of dementia. (14) More research is needed to understand if and how omega-3 fatty acids impact the adult brain.

So many kinds of omega-3 supplements

Sources of EPA and DHA
  • EPA and DHA are the omega-3 fatty acids that the body uses to make other fats.
  • Fish and krill oil contain EPA and DHA and algae oil contains a lot of DHA.
  • Sometimes on the supplement label it will say that a supplement contains a specific amount of EPA, DHA or EPA+DHA.
  • Algal (algae) oil has become more popular recently because it is a vegetarian option and it is considered more sustainable than fish or krill because it is a plant and can be grown.  
  • Fish oil supplements are usually made from a variety of different types of fish like anchovies and salmon.(1) Krill are crustaceans that look like tiny shrimp.  Krill oil has become a popular alternative to fish oil because krill is a less popular dietary fish and so it is more available to be used for a supplement.
  • When I was doing research, I learned that algae are the only producers of omega-3 fats. I always knew that we get most of our omega-3 fats from eating fish, seafood, or seaweed but I didn’t realize that fish and seafood didn’t make omega-3 fats either! They get it from algae. It really isn’t surprising that interest in algae as a human source of omega-3 fatty acids has increased.(15) It is considered a renewable and more sustainable source of EPA and DHA.

Sources of alpha-linolenic acid (ALA)
  • ALA is the omega-3 fatty acid present in vegetables, seeds and nuts. You can easily find flaxseed, flaxseed oil, and supplements made of oil from flax. These provide ALA. Dietary sources from liquid oil like you find in the refrigerator section, ground flax, or flaxseed are dietary options and alternatives to supplemental sources.
  • Hempseed oil is not as readily available in stores. It is available online and in specialty shops.


Final Thoughts

Omega-3 fatty acids are healthy, polyunsaturated fats that the body needs. Research supports the use of the medically supervised use of omega-3 fatty acids for people with very high triglycerides. Whether eating more omega-3 fats is solely responsible for improving other aspects of heart health remains unclear. It is possible, and likely, that other dietary and lifestyle factors also contribute to the positive associations many researchers detect. 

The Dietary Guidelines for Americans recommend eating fish at least 2 times per week with an emphasis on fatty / cold water fish because they are a good source of omega-3 fatty acids that provide EPA and DHA. Krill and algae (like seaweed) also provide omega-3 fatty acids that contain EPA and DHA. Flaxseed, walnuts, soybean oil, and hempseed oil, etc. mostly contain a omega-3 fat called alpha-linolenic acid. The body doesn't make very much EPA and DHA from ALA, but research indicates that ALA may exert its own health benefits. 

By eating a variety of foods in moderation you get fats (like EPA, DHA, and ALA), carbohydrates, proteins, vitamins, minerals, fiber, and phytonutrients (plant chemicals) that your body needs to survive and thrive. It is not truly possible to mimic this through supplements, pills, shakes, and other non-food combinations. 

It is important to discuss supplement use with your healthcare practitioner and pharmacist. Supplements may interact with medications. The supplement industry is not regulated like the pharmaceutical industry (despite how you may feel about drug companies, they undergo more regulation and scrutiny than the supplement industry). What's in that supplement - part 2

References

1. Vannice G, Rasmussen H. Position of the Academy of Nutrition and Dietetics: Dietary Fatty Acids for Healthy Adults. Journal of the Academy of Nutrition and Dietetics.114(1):136-53.
2. Kris-Etherton PM, Harris WS, Appel LJ. Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular Disease. Circulation. 2002;106(21):2747-57.
3. Omega-3 Fatty Acids and Health. Fact Sheet for Health Professionals. National Institute of Health, Office of Dietary Supplements.;  http://ods.od.nih.gov/factsheets/Omega3FattyAcidsandHealth-HealthProfessional/#disc.
4. Arterburn LM, Oken HA, Bailey Hall E, et al. Algal-Oil Capsules and Cooked Salmon: Nutritionally Equivalent Sources of Docosahexaenoic Acid. J Am Diet Assoc. 2008;108(7):1204-9.
5. Wu WH, Lu SC, Wang TF, et al. Effects of Docosahexaenoic Acid Supplementation on Blood Lipids, Estrogen Metabolism, and in Vivo Oxidative Stress in Postmenopausal Vegetarian Women. Eur J Clin Nutr. 2006;60(3):386-92.
6. Flock MR, Harris WS, Kris-Etherton PM. Long-Chain Omega-3 Fatty Acids: Time to Establish a Dietary Reference Intake. Nutr Rev. 2013;71(10):692-707.
7. Rizos EC, Ntzani EE, Bika E, et al. Association between Omega-3 Fatty Acid Supplementation and Risk of Major Cardiovascular Disease Events: A Systematic Review and Meta-Analysis. JAMA. 2012;308(10):1024-33.
8. Barcelo-Coblijn G, Murphy EJ, Othman R, et al. Flaxseed Oil and Fish-Oil Capsule Consumption Alters Human Red Blood Cell N-3 Fatty Acid Composition: A Multiple-Dosing Trial Comparing 2 Sources of N-3 Fatty Acid. Am J Clin Nutr. 2008;88(3):801-9.
9. Fish 101 American Heart Association Accessed February 20, 2015 2015; https://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/Fish-101_UCM_305986_Article.jsp.
10. Tur JA, Bibiloni MM, Sureda A, et al. Dietary Sources of Omega 3 Fatty Acids: Public Health Risks and Benefits. Br J Nutr. 2012;107 Suppl 2:S23-52.
11. Schwab US, Callaway JC, Erkkila AT, et al. Effects of Hempseed and Flaxseed Oils on the Profile of Serum Lipids, Serum Total and Lipoprotein Lipid Concentrations and Haemostatic Factors. Eur J Nutr. 2006;45(8):470-7.
12. Lin PY, Chiu CC, Huang SY, et al. A Meta-Analytic Review of Polyunsaturated Fatty Acid Compositions in Dementia. J Clin Psychiatry. 2012;73(9):1245-54.
13. Schaefer EJ, Bongard V, Beiser AS, et al. Plasma Phosphatidylcholine Docosahexaenoic Acid Content and Risk of Dementia and Alzheimer Disease: The Framingham Heart Study. Arch Neurol. 2006;63(11):1545-50.
14.  Fares H, Lavie CJ, DiNicolantonio JJ, et al. Omega-3 Fatty Acids: A Growing Ocean of Choices. Curr Atheroscler Rep. 2014;16(2):389.
15. Deckelbaum RJ, Torrejon C. The Omega-3 Fatty Acid Nutritional Landscape: Health Benefits and Sources. J Nutr. 2012;142(3):587S-91S.

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