Why Omega-3s Are Fishy

Healthy Aging

What exactly is in omega-3 supplements?

When we talk about omega-3 supplements, many of us forget that we’re really talking about fish oil (or krill or algae oil).

This week, let’s talk about what’s in omega-3 fish oil supplements… and, perhaps just as importantly, what’s not. In addition to sharing scientific publications, we also did our own mini investigation using an independent, third-party lab. Bottom line – the news isn’t great.

Okay, so, what is in omega-3 fish oil supplements?

Well, in addition to omega-3s, studies have shown that most of these supplements contain cell-damaging lipid peroxidation. When fragile fats (aka omega-3s) in oils are exposed to oxygen, the result is lipid peroxidation. Since oxygen is hard to avoid, it probably isn’t surprising that most omega-3 fish oil supplements are already oxidized in the bottle. For example:

• Albert et al. tested 32 different omega-3 supplements, and they found that 92% had lipid peroxidation levels higher than international safety levels.
• Jackowski et al. did a bigger study including omega-3 fish, algae, and krill oil supplements. Of 171 different omega-3 supplements tested, 50% exceeded the international safe lipid peroxidation levels.

Yikes. That’s at least a 1 in 2 chance that any given omega-3 supplement is oxidized.

In addition to lipid peroxidation, fish oil supplements have many other fatty acids other than omega-3s. Mason et al. showed that omega-3 supplements have over 30 different fatty acids – and up to 36% of these fatty acids are known to be pro-inflammatory.

Now, what aren’t in omega-3 fish oil supplements?

Alas, omega-3s. Well, at least not as much omega-3s as what are listed on the label. In their study, Kleiner et al. tested 47 different omega-3 supplements and found that  79% of supplements had less EPA and 75% had less DHA than what was on the label. Similarly, Albert et al. found that 91% of 32 omega-3 fish oil supplements had lower-than-advertised EPA and DHA.

Worse yet, of the omega-3s that were present in supplements, those that had oxidized didn’t work. Specifically, Mason et al.’s study by the Brigham and Women’s Hospital showed that oxidized omega-3s were no longer able to prevent oxidation of bad LDL cholesterol (a key touted benefit of omega-3s).

Then, we did our own study.

As self-professed nerds, we went to our local grocery store and selected eight omega-3 supplements, including fish oil, algae oil, and krill oil supplements. We also included a couple of omega-3 gummy supplements. We sent these supplements, unopened, to an independent, third-party lab to test for lipid peroxidation and fatty acid content.

Here’s what we found:

• Lots of lipid peroxidation. Based on international safety recommendations described by Jackowski et al. (peroxide values < 5 mEg/kg, anisidine values < 20, or TOTOX values < 26), 75% of these omega-3 supplements had lipid peroxidation above at least one of these levels.
• Gummies were the worst. The highest oxidation was among omega-3 gummies. High oxidation levels were also detected in the most expensive brands, as well as krill oil and algae oil supplements.
• Proinflammatory fats are there, too. All omega-3 supplements also contained between 11 to 32% proinflammatory fatty acids.

These results are similar to what has been reported in the peer-reviewed literature. Which is why there have been calls for better quality control of omega-3 supplements.

This high variation in quality is likely also why the NIH has recently concluded that omega-3 fish (or algae or krill) oil supplements don’t effectively prevent heart disease – or much else.