What is Fish Oil?

Fish oil is a form of omega-3 fatty acids found in naturally occurring foods. The body cannot make omega-3 fatty acids like it can other types of fats that are necessary for various functions in our bodies. This makes omega-3 fatty acids “essential fats” because they must be directly consumed in the diet or from supplements. Omga-3 fatty acids help our cells function and help make hormones that regulate blood clotting. They also affect how contracted or relaxed arteries are and have a role in inflammation within the body. There are three major dietary omega-3 fatty acids: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA). From dietary sources, EPA and DHA are mainly found in fish and shellfish. EPA and DHA are the two omega-3 fatty acids you will see as the primary components in majority of fish oil supplements. ALA can be found in certain plants such as flax seeds, flaxseed oil, walnuts, and leafy greens. ALA is not a typical part of fish oil supplements since it is primarily found in plants. Therefore, this article will focus on EPA and DHA, which are also referred to as “seafood-derived omega-3 fatty acids,” and “marine omega-3 fatty acids.”

Read our blog about fish oil in heart health

Sources of Fish Oil:

• Dietary Sources: Omega-3 fats are found in certain foods. The highest concentration of EPA and DHA can be found in fish and shellfish such as:
  o Anchovies
  o Catfish
  o Clams
  o Cod
  o Crab
  o Fish sticks
  o Halibut
  o Lobster
  o Mahi Mahi
  o Oysters
  o Salmon
  o Scallops
  o Shrimp
  o Swordfish
  o Tuna
• Prescription Medications: there are multiple prescription formulations of omega-3 fatty acids. These are regulated by the Food and Drug Administration (FDA) and will have very specific amounts of EPA or both EPA and DHA. Brand names of these prescription medications include Epanova®, Lovaza®, and Vascepa®.
• Over The Counter Supplements: over the counter supplements are not regulated by the FDA. Therefore, the components within any given over the counter supplement cannot be guaranteed. Fish oil supplements tend to include ingredients other than EHA and DHA such as other types of omega-3 fatty acids, other types of fats like monounsaturated and saturated fats, and glycerin or gelatin. Different supplements have different concentrations of EPA and DHA, so make sure to read the label and serving sizes on the bottle carefully if deciding to purchase an over the counter fish oil supplement.

Fish Oil Use in Cholesterol:

For medical purposes, fish oil is most commonly known for its relationship to cardiovascular disease.
There are multiple components of what we consider under the umbrella of “cholesterol.” One of those components is triglycerides, a type of fat that is found in the blood. High triglycerides levels have been linked to pancreatitis and atherosclerotic cardiovascular disease (ASCVD). High doses of fish oil may lower triglyceride levels 20-50%. Physicians may recommend certain patients to supplement with fish oil if high triglyceride levels are not lowered enough with other prescription medications. Fish oil supplementation is only recommended by the American Heart Association and American College of Cardiology for patients with specific heart disease risk factors and certain triglyceride lab levels. A discussion with a physician should occur before deciding whether or not it is safe and beneficial for you to take fish oil.

Resources:
1) Omega-3 Fatty Acids: An Essential Contribution | The Nutrition Source | Harvard T.H. Chan School of Public Health. https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/types-of-fat/omega-3-fats/#:~:text=What%20makes%20omega%2D3%20fats,of%20artery%20walls%2C%20and%20inflammation.
2) Fish oil: Physiologic effects and administration – UpToDate. https://www.uptodate.com/contents/fish-oil-physiologic-effects-and-administration?search=fish%20oil&source=search_result&selectedTitle=1~96&usage_type=default&display_rank=1
3) Fish oil – Mayo Clinic. https://www.uptodate.com/contents/fish-oil-physiologic-effects-and-administration?search=fish%20oil&source=search_result&selectedTitle=1~96&usage_type=default&display_rank=1
4) Hypertriglyceridemia in adults: Management – UpToDate. https://www.uptodate.com/contents/hypertriglyceridemia-in-adults-management?search=prescription%20fish%20oil&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H301630