Is Fish Oil the new Snake Oil?

Fish Oil Snake Oil

"Day 171: Benzonatate" by quinn.anya is licensed under CC BY-SA 2.0

Is Fish Oil the 21st Century Snake Oil?

Every year Americans spend close to $35 billion on vitamins, minerals, botanicals and various other substances that are advertised as improving health but mostly do nothing at all.[1]  Does fish oil fit into that category?  No -- fish oil does appear to be beneficial.  For fish oil, these might be more pertinent questions:

  • Who benefits from taking supplements?
  • Are prescriptions for omega-3 fatty acids better than eating fish or taking supplements?
  • How best to get fish oil into your body (prescription, supplements, or in your diet)?

The answers to these questions are important for the 10% of Americans -- nearly 19 million people – who currently take an omega-3 (short for omega-3 fatty acids) supplement daily.  Advice regarding fish oil supplements changes periodically, as health studies come to different conclusions about the effectiveness of supplements on specific health issues and populations. 

Omega-3s and their health effects

According to a number of professional objective sources, omega-3 fatty acids are good for you. [2], [3], [4], [5], [6] Omega-3s come from food rather than being produced by your body. While plants provide some omega-3s (alpha-linolenic acid or ALA), this article looks only at the two omega-3s (docosahexaenoic acid [DHA] and eicosapentaenoic acid [DPA]) in fish oil. 

The following bullets from the Mayo Clinic website provide a brief description of what the research says about how fish oil affects specific health issues:[7]

Fish Oil Chart

According to a Harvard Health blog on the Health Publishing website for Harvard Medical School, however, the impact of fish oil supplements on preventing a first heart attack or stroke was never clearly demonstrated.[8]  The authors describe a 2019 meta-analysis published in Journal of the American Heart Association that found that fish oil supplements lowered risk for heart attack and coronary heart disease death, that the higher the dose, the greater the reduction in risk, but that there was no effect on stroke.  Several further trials showed mixed results:

  • ASCEND, in which fish oil supplements did not reduce heart attacks or strokes in diabetic patients, but did lower the risk of death from heart attack or stroke.
  • VITAL, in which fish oil supplements did not reduce cardiovascular disease events in people with regular risk of heart disease; however, there were fewer heart attacks in subjects who took fish oil supplements, particularly in those who did not eat fish.
  • REDUCE-IT, in which high-dose fish oil supplements (4 grams of EPA and no DHA) were taken by people with high blood triglyceride levels.  There is now a a prescription version of this EPA fish oil that the FDA has approved for very high triglyceride levels which is taken along with statins and a low-fat, low-cholesterol diet.

The takeaway is that fish oil (including fish oil supplements) can be beneficial for individuals with specific health conditions and for those who do not eat fish.

Fish oil supplements vs. prescription version fish oil pills

The use of prescription fish oil is fairly new and only a medical doctor can advise regarding this course of treatment.  Articles touting the research regarding prescription fish oil have been critical of the studies of fish oil supplements conducted to date, stating that they have failed to show any significant clinical benefits beyond those of standard-of-care therapy. In comparison to the supplements, they say, prescription grade fish oil taken along with statins was more effective at reducing the chance of heart attacks for those who have a history of heart disease.[9]  This may be a medical breakthrough for those with cardiovascular disease (CVD) or who have major risk factors for it (who have diabetes or high blood pressure).[10] 

According to the lead investigator of the clinical trial, it would take 20-25 over the counter supplements a day to get to the amount of EPA in the prescription medication being studies (the only omega-3 in the medication).  High doses of omega-3 are not appropriate for everyone – side effects may include unpleasant taste, bad breath, heartburn, nausea, gastrointestinal discomfort, diarrhea, headache, and odoriferous sweat. In addition, omega-3 dietary supplements have the potential to interact with medications – specifically, fish oil might affect bleeding, especially in someone taking an anticoagulant (e.g., warfarin).[11]

The criticism of fish oil supplements is partly because the FDA regulates prescriptions but there’s no requirement that supplement companies establish safety before they market their products (they are required to report serious adverse events, and the FDA monitors those).[12]  Formulations of omega-3 dietary supplements vary widely, so it is important to check product labels to determine the types and amounts of omega-3s in these products. The Dietary Supplement Label Database[13] from the National Institutes of Health contains label information from many dietary supplements on the market that contain omega-3s.

Research into prescription fish oil medications appears to be promising for some individuals who have cardiovascular disease or major risk factors for it who are currently under a physician’s care and are  taking statins.

Seafood vs. supplements

For most people who are not at elevated risk (no congestive heart disease, normal blood pressure, normal cholesterol levels), eating two servings of fish per week may provide all the omega-3s you need.  The federal government’s 2015-2020 Dietary Guidelines for Americans notes that nutritional needs should be met primarily from foods.[14]  In 2018, the National Institutes of Health, National Center for Complementary and Integrative Health, determined that for some health conditions, the evidence for benefits from seafood (fish and shellfish) is stronger than the evidence for omega-3 supplements.[15] 

There are several possibilities for these results:

  • Seafood may provide enough omega-3s; more may not be better. 
  • Other nutrients in seafood besides omega-3s may play a role in its benefits.
  • Some of the benefits of seafood may result from people eating it in place of less healthful foods. 
  • There’s evidence that people who eat seafood have generally healthier lifestyles.

The US Department of Health and Human Services, National Institutes of Health, Office of Dietary Supplements says that fattier fish have more the omega-3s (e.g., salmon and trout, and shellfish) – the ODS website provides a wealth of information about omega-3s including the recommended intake and a table displaying sources of dietary omega-3s and how many grams you get per serving.[16] 

The upshot

Keep eating fish! 

Follow a heart-healthy diet full of fresh fruits and vegetables, with lean protein such as fish, as recommended by the American Heart Association.

The FDA has approved a qualified health claim for foods and dietary supplements that contain EPA and DHA:  “Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease.” In addition, the FDA specifies that the labels of dietary supplements should not recommend a daily intake of EPA and DHA higher than 2g.[17]

For those of us at highest risk, especially those with elevated triglyceride levels, it is worth speaking with your physician about high dose EPA fish oil supplements.[18] For patients who need to lower their triglycerides, the American Heart Association recommends 2–4 g/day of EPA plus DHA under the care of a physician.[19]

As always, you should talk with your health care provider about any complementary health approaches you use (including fish oil supplements).


[1] Haspel, Tamar. (2020, Jan. 27) Perspective | Most dietary supplements don’t do anything. Why do we spend $35 billion a year on them? Washington Post











[12] Haspel, Tamar. (2020, Jan. 27) Perspective | Most dietary supplements don’t do anything. Why do we spend $35 billion a year on them? Washington Post








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