Why You Should Doubt Fish Oil

A brand new study highlights the dangers of the supplement industry in regards to what you are actually getting in the bottle.

I’ll admit it. Whenever I look at a nutrition book, I always skim for what supplements they recommend. It’s an awesome thought that one substance can fix all our issues. Unfortunately, caution must be taken before you throw away money, or worse, your health.

Fish oil is a perfect example of the lifecycle of most supplements. Initial hype, exciting studies, large sales, better studies tempering excitement, and perhaps certain dangers are uncovered. The hype has died down a bit regarding fish oil and a daily dose to help prevent cardiovascular disease. Unfortunately, a brand new study highlights the dangers of the supplement industry in regards to what you are actually getting in the bottle.

This is the fatty acid (FA) content of 3 of the top selling fish oil supplements in the US (DS1, DS2, DS3). The data is presented as a percentage of total FA for any sample by weight. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the omega-3 fatty acids, the desirable stuff. (Source: Science Direct)

The study looked at three popular brands of fish oil that were purchased from a retail store. They had two major findings:

  1. The fish oil contained saturated fats. Up to 36% of the oil was a blend of different saturated fats. Fish oil is taken for its omega-3 content. Saturated fats, while a complicated issue, certainly don’t behave like omega-3 fats.
  2. The over the counter brands had oxidized lipids, while prescription quality omega-3s did not. This means that the fish oil you purchase at the store is very likely to have oxidized lipids, which can be harmful to your health. It can contribute to the so-called bad cholesterol having negative effects in your artery.

The researchers took small dense LDL particles, which are culprits in heart disease, from human volunteers. When these particles are oxidized, they become dangerous to us. The fish oil from supplements exceeded the recommended maximal amount of oxidation of the LDL particles. The oils from prescription omega-3 fatty acids passed the test.

There are several takeaways here:

  1. Sucking down fish oil pills, while already a questionable practice, may have a whole different issue of regarding what is in the bottle.
  2. It’s hard to be sure what the best brand is, because a lot depends on storage and source. It appears best to take prescription level oil, if warranted by a medical professional.
  3. Eat a variety of fish 2-3 times a week and as always, whole foods are a preferred source of nutrients.


Mason, R. Preston, and Samuel C.r. Sherratt. “Omega-3 fatty acid fish oil dietary supplements contain saturated fats and oxidized lipids that may interfere with their intended biological benefits.” Biochemical and Biophysical Research Communications, December 21, 2016. doi:10.1016/j.bbrc.2016.12.127.

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