|The US' favorite fish oil supplements: Dirt cheap and still not worth the money. Better buy fish - fresh fish.|
And guess what!? The publication of a recent study by scientists from the Cardiovascular Division, Brigham and Women's Hospital at the venerable Harvard Medical School, gives me yet another reason to rant against the evermore popular fish oil supplements.
In their study, the scientists analyzed 3 commonly available fish oil dietary supplements and found that (a) their level of omega-3 fatty acids varied significantly, that (b) they contained tons of other fats that you would ask to be paid for to consume if you knew about them and, that (c) the caps were so full of oxidized fats that they exceeded international standards and may (d) may harm, rather than help with your health.
No, we're not talking about cheap Chinese internet purchases, bro!
The Harvard scientists bought the "three top-selling fish oil DS [dietary supplements] in the United States and to examine the extent of oxidative damage in the DS as compared with chemically characterized standards with respect to purity and ability to prevent human sdLDL oxidation in vitro" (Mason. 2016). The commonly heard excuse that this is "just a problem with the cheap Chinese stuff" is thus as useless as it is ridiculous in view of the data from the study at hand.
|Figure 1: The TOP3 US fish oil products are rancid... well, mostly (right hand side) and they have almost no ability to prevent human LDL particles from oxidation, as the results of the MDA test on the left indicates (Mason. 2016).|
Your fish oil contains 4000% more oxidized fats than prescription fish oil! That's a huge problem, because many of the studies you're so fond of, because they seem to prove how healthy fish oil is, have been done with medicinal grade fish oils. Accordingly, the results of these studies have ZERO predictive power with respect to what your "machine oil" fish oil will do to your health. Speaking of "your" - it is not impossible that the oxidative damage occured during storage, which reminds me to remind you NEVER to use fish oil in a bottle that's constantly exposed to pro-oxidative oxygen, whence you've opened the bottle. Note: If stored in the fridge (4°C) the shelf life of the fish oil in fresh fish is, as Boran et al. show in their 2006 paper in Food Chemistry ~ 90 days.In fact, the scientists measured not just primary oxidation products, as the highly elevated peroxide levels, an indicator of high levels of primary oxidation and hydroperoxides, confirm, but also secondary products of the decomposition of the primary oxidation products during continued exposure to oxidative conditions, as they ar detected in the p-anisidine test.
|Figure 2: Indeed, there was also some "fish oil" in the caps - emphasis on "also" and "some" (Mason. 2016)!|
Speaking of "for years": Is it possible that you've done more harm than good in the past years of consuming copious amounts of fish oil to your health? Yes, it is, but in view of the fact that even the "motor oil" version of fish oil in the average US dietary fish oil supplement (the brand names are obviously undisclosed = not mentioned in the paper) was still anti- and not pro-oxidative, it's more likely that you have only wasted time and money.
- Boran, Gökhan, Hikmet Karaçam, and Muhammet Boran. "Changes in the quality of fish oils due to storage temperature and time." Food chemistry 98.4 (2006): 693-698.
- Mason, PR and Sherrat SCR. "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 - Available online 21 December 2016 | In Press, Corrected Proof