Smart Drugs,

#173: When Fish Oil Goes Bad…

March 24, 2017

Bad fish doesn’t exactly have a good reputation to begin with.

When it comes to food poisoning, eating fish past its prime is almost legendary in its power to make people sick.  But seafood is rightly considered “brain food” — and fresh, uncontaminated fish and seafood products are among the better things people can have in their diet.  Even vegetarians often make seafood the one nutritional region where personal health gets to trump their cross-species ethics.

Omega-3 fatty acids, which seafood provides in abundant amounts, are a topic we’ve covered many times previously — and it’s been recommended by past guests that as much as 5 grams of supplemental fish oil per day might be advisable, if you’re not getting much seafood in your regular diet.

Not so fast, says Chris Kresser

While Omega-3 fatty acids live up to their reputation for brain and body health if taken in a natural, unadulterated form…that can be a big “if,” according Chris Kresser, M.S., L.Ac. (also the host of Revolution Health Radio).  And sometimes the supplemental alternatives to getting these food in our diets can end up doing more harm than good — being pro-oxidative and pro-inflammatory when our goals in eating them is often just the opposite.

Studies like this one show that many over-the-counter Omega-3 supplements contain partially-oxidized lipids in amounts great enough to make them not only a waste of money, but counterproductive in improving your health.  What is a person to do?

According to Kresser, in both this interview and the recently-updated, thoroughly referenced post about fish oils on his website, the surest-fire way of ensuring that you’re getting the Omega-3’s your nervous system needs without taking in unintended, pre-oxidized chemicals is comparatively simple: Skip the supplements, go with honest-to-goodness, natural seafood.

For most people, two meals per week containing a helping of fatty, cold-water fish is just what the neurologist ordered.  Kresser is also a big proponent of shellfish.  But rather than re-hashing the dietary recommendations here — which includes interesting advice about the “smoke point” of various cooking oils — give the episode a listen. 

This episode is a slightly shorter one, but chunks of this interview branched into other topics — Kresser has a wide range of expertise — and we’ve saved some bits for future episodes, so add a mental “to be continued…” bookmark as you listen.

Read Full Transcript
Show Notes


  1. Alex says:

    What about oxidation of algal oils?

  2. ben says:

    Wow, first Chris Masterjohn, and now Chris Kresser, some of my favorite podcasters!

    In regard to rancid oils, does it also apply to canned fish (clams, oysters, tuna)? Obviously worse than fresh, but since not as processed as pills, I would think still better than nothing.. however, due to the long storage life, maybe it can be worse than nothing?!

    Not much polyunsaturated omega3/6, but I love macadamia nut oil, great taste with a high smoke point! Lard, ghee, coconut, and high oleic sunflower oil, also have a place on my shelf!

  3. This is one of the main reasons I buy the actual fish oil in liquid form. You can taste it so easily when it isn’t good. Menhaden fish is probably one of the best as it is a small fish with DHA / EPA and a newer fatty acid called DPA. Worth some research 🙂

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