Thank you for the thoughtful comments and questions. A few points of clarification based on recurring themes:
On krill oil: Several readers have asked whether krill oil escapes the problems described in this essay. Krill oil contains astaxanthin, a natural antioxidant that provides some protection against oxidation—more than fish oil capsules typically have. However, the fundamental chemistry remains: you are still dealing with highly unsaturated omega-3 fats (EPA and DHA with their five and six double bonds) that have been extracted, processed, and encapsulated. Whether krill oil oxidizes more slowly is a question of degree, not kind. The same three-legged stool framework applies: Is it necessary? Is it safe? Does it work? I have not reviewed the krill oil literature with the same depth as fish oil, so I cannot offer a definitive assessment—but the questions worth asking are the same.
On liquid fish oil (e.g., Carlson's): Liquid fish oil in dark glass bottles, kept refrigerated, allows you to smell what you're consuming—which is an advantage over capsules. If it smells rancid, you know. If it smells mildly fishy but not off, that's better information than a smell-proof capsule provides. However, liquid fish oil is still industrially processed, still subject to oxidation during manufacturing and shipping, and still contains the most oxidation-prone fats in nature. Refrigeration and dark glass slow degradation but don't prevent it. The nose test is useful but not definitive—early oxidation products are often odorless.
On canned fish: Sardines, mackerel, salmon, and other canned fish are whole foods. The omega-3s remain within cell membranes, protected by the fish's natural structure, and are heat-processed once during canning rather than subjected to the extended extraction, refining, and storage chain of supplements. Canned fish is not the same category as fish oil capsules. The essay's argument is against industrially extracted and encapsulated oils, not against eating fish.
On cod liver oil: Cod liver oil occupies a middle ground. Traditional cod liver oil was minimally processed, valued for vitamins A and D as much as omega-3s, and consumed fresh. Modern cod liver oil varies enormously by brand and processing method. The same questions apply: How was it processed? How long has it been stored? Can you smell it? The three-legged stool remains a useful framework.
On the omega-3 hypothesis itself: One commenter linked to research suggesting that both omega-6 and omega-3 PUFAs promote inflammatory pathways at the genomic level. This is worth investigating. The essay focused on the product quality problem—what's actually in the capsule—rather than questioning whether omega-3 supplementation is beneficial even in ideal conditions. That's a deeper question I may address in future writing.
On all-cause mortality: A sharp-eyed reader noted that the cardiovascular meta-analyses report reductions in specific endpoints (MI, CHD death) but don't always report all-cause mortality. This is an important point. A treatment that reduces heart attacks but increases deaths from other causes provides no net benefit. It's a limitation of much cardiovascular research that deserves more attention.
Thank you all for reading and engaging critically.
Thank you for this. On advise of my neighbor who has been taking it for years, I bought a bottle of capsules, took it for a few weeks and found no change. I do not use any seed oils, only olive and avocado oil, and coconut oil. He stipulated it helps with blood pressure. But mine went down when I stopped taking the meds the doctor had prescribed (for something entirely different). One of the side effects was high blood pressure!
olive isnt a seed .. its the fruiting body of a drupe I guess.. the oil isnt from the seed part. Avo oil isnt from the seed part either .. coconuts are plain weird.
I suppose canned sardines (which I love) and canned cod livers are no good either huh? Hard to get fresh or frozen sardines here and I have never seen fresh or frozen cod livers. I take a teaspoon of cod liver oil (refrigerated in a dark green glass bottle) a few times a week. I have been avoiding seed oils for decades, since getting off the vegan macrobiotic diet that almost killed me. But I like tahini which has sesame oil, and peanut butter - some mono and PUFAs there. Whole foods omnivore here, I cook with ghee, coconut oil, tallow and occasionally lard.
haha ! vegan macrobiotic nearly got you too ? It was dire. I still cant believe how bad that high effort diet was . Cod liver oil was defamed decades ago due to the accumulated mercury I thought. Id take canned fish over that stuff myself.
Yeah, I went on it in the nineties to deal with Multiple Chemical Sensitivities, and it did help for at least four years - but it never healed my gut dysbiosis or immune suppression, I got too skinny, accumulated too much arsenic from the brown rice, and then grew a malignant breast tumour...
oh heavens .. same here only I became too skinny and deathly for cancer to bother with me. I hope you recovered ok. Took me a long while t work it out sadly.
My purpose in commenting is not to discuss the pros and cons of fish oil, but to give you a source where you can check whether your product is what is says it is. Here is the site: https://certifications.nutrasource.ca/
As you will see at the Site, there are a total of 6 different tests. You can also read how the Certification process works for each category.
Why I haven’t supplemented with these for years. The last fish oil I got was from a refrigerated brand in a health food shop some years ago but how do I know that wasn’t just a subterfuge. Or the shop owner just bought the malarkey. Thanks. Saving this.
I gave up taking fish oil capsules years ago because of the rancid taste. I looked at other options
and then I started taking a Norwegian brand of Cod Liver Oil. I found that these capsules at times also left an after taste, although not as bad as the fish oil capsules. Then I came across a Zealand brand of Cod Liver Oil capsules and I have been taking them now for several years. I can't say that I feel any better? But I do know that I haven't had a cold, flu or covid, touch wood yet. (Although other family members have on going health issues re the above). I also take zinc and vit c powder. I actually like canned Portuguese Makrel and Sardines and try to have 2 serving per week. Time permitting, I catch my own whiting and bream. I'll be 76 this year and I still feel energetic and often forget that I'm really an old man! I don't know if this is psychosomatic or I'm in denial. Life is OK.
Processing isn’t the issue. Krill are crustaceans, not fish. They are harvested very quickly after they hatch, so they are not exposed to the toxins in the oceans for very long, while large, fatty fish are. The fat in large fish retains those toxins, which contributes to fish oil going rancid very quickly when exposed to air.
Krill oil can still go rancid, so yes, processing is an issue. The antaxathans in krill oil keep it from going rancid as quickly but it still can go south. You still need to keep it refridgerated and out of the light to help protect it. You aren't eating krill, you are still eating the extracted oil. Krill is whale food so I hope all these ships now harvesting krill aren't leaving the whales with nothing.
No, krill oil and fish oil are processed differently. Krill oil is extracted from Antarctic krill and is typically more stable, while fish oil is derived from the tissues of fatty fish and can be more susceptible to oxidation during processing.
"found that marine omega-3 supplementation was associated with statistically significant reductions in myocardial infarction (8%), CHD death (8%), and total cardiovascular disease (3-7%)."
The most important metric is not mentioned: All cause mortality. If CHD death goes down 8% but deaths from other causes (e.g. cancer) go up, then there is NO benefit at all!
Interesting point - and, I believe it was explained in this article that those reductions were relative (percent difference compared to the control group) rather than actual.
IE, if the treated group has 2 events, and the control group had only 1 event - that’s a 50% difference, relatively, and sounds great - but the actual number of reduced events is ONE.
right. I get that. But to me, those reductions in CHD metrics are meaningless if the study did not track and publish all cause mortality. If there was no reduction in deaths in the treated group, then the treatment has no benefit. Or worse, if the treated group had more deaths than the placebo, then the treatment is toxic. By not tracking or publishing these stats, the study missed the boat completely in my opinion.
l've read that the half-life of lenoleic acid - LA - is over 600 days. And LA is in seed oils in large amounts - I have a chart, I believe from Mercola, showing the percents of LA in various seed oils, ranging from 19% to 70%.
Does ‘half-life' mean it takes well over a YEAR for my body to metabolize LA in seed oils?
I mean, I may want that durability in my CAR OIL - but NOT in my body.
I’ve been 99% off seed oils for a few years now - but they are in LOTS of things.
I always made a point of chewing and tasting anything I eat .. must admit the few capsules ive ever tried tasted and smelled fine.. much better than real fish. As I understand it its the algae in fish oils that is harmful.. in the same way carrageen and chia can be harmfuly irritantl, Not sure if it is added or if it grows. Many of us dont want to kill/eat mammals so fish is the food of choice .. we are depleting the fisheries badly, so are fish oils better than nothing ? maybe.
Author's Note
Thank you for the thoughtful comments and questions. A few points of clarification based on recurring themes:
On krill oil: Several readers have asked whether krill oil escapes the problems described in this essay. Krill oil contains astaxanthin, a natural antioxidant that provides some protection against oxidation—more than fish oil capsules typically have. However, the fundamental chemistry remains: you are still dealing with highly unsaturated omega-3 fats (EPA and DHA with their five and six double bonds) that have been extracted, processed, and encapsulated. Whether krill oil oxidizes more slowly is a question of degree, not kind. The same three-legged stool framework applies: Is it necessary? Is it safe? Does it work? I have not reviewed the krill oil literature with the same depth as fish oil, so I cannot offer a definitive assessment—but the questions worth asking are the same.
On liquid fish oil (e.g., Carlson's): Liquid fish oil in dark glass bottles, kept refrigerated, allows you to smell what you're consuming—which is an advantage over capsules. If it smells rancid, you know. If it smells mildly fishy but not off, that's better information than a smell-proof capsule provides. However, liquid fish oil is still industrially processed, still subject to oxidation during manufacturing and shipping, and still contains the most oxidation-prone fats in nature. Refrigeration and dark glass slow degradation but don't prevent it. The nose test is useful but not definitive—early oxidation products are often odorless.
On canned fish: Sardines, mackerel, salmon, and other canned fish are whole foods. The omega-3s remain within cell membranes, protected by the fish's natural structure, and are heat-processed once during canning rather than subjected to the extended extraction, refining, and storage chain of supplements. Canned fish is not the same category as fish oil capsules. The essay's argument is against industrially extracted and encapsulated oils, not against eating fish.
On cod liver oil: Cod liver oil occupies a middle ground. Traditional cod liver oil was minimally processed, valued for vitamins A and D as much as omega-3s, and consumed fresh. Modern cod liver oil varies enormously by brand and processing method. The same questions apply: How was it processed? How long has it been stored? Can you smell it? The three-legged stool remains a useful framework.
On the omega-3 hypothesis itself: One commenter linked to research suggesting that both omega-6 and omega-3 PUFAs promote inflammatory pathways at the genomic level. This is worth investigating. The essay focused on the product quality problem—what's actually in the capsule—rather than questioning whether omega-3 supplementation is beneficial even in ideal conditions. That's a deeper question I may address in future writing.
On all-cause mortality: A sharp-eyed reader noted that the cardiovascular meta-analyses report reductions in specific endpoints (MI, CHD death) but don't always report all-cause mortality. This is an important point. A treatment that reduces heart attacks but increases deaths from other causes provides no net benefit. It's a limitation of much cardiovascular research that deserves more attention.
Thank you all for reading and engaging critically.
Back to sardines I guess. Just ditched my expensive capsules. Thanks for this info! I have read about this before but was stubborn.
frozen salmon is another option.
Thank you for this. On advise of my neighbor who has been taking it for years, I bought a bottle of capsules, took it for a few weeks and found no change. I do not use any seed oils, only olive and avocado oil, and coconut oil. He stipulated it helps with blood pressure. But mine went down when I stopped taking the meds the doctor had prescribed (for something entirely different). One of the side effects was high blood pressure!
Olive, avo and coconut are all seeds. Just bigger ones!
nope. olive and avo are fruits, the oils come from pressing the fruits.
olive isnt a seed .. its the fruiting body of a drupe I guess.. the oil isnt from the seed part. Avo oil isnt from the seed part either .. coconuts are plain weird.
Yes, you're correct. It's just that processed oils all have problems. Just more so with seed oils.
Excellent article.
I suppose canned sardines (which I love) and canned cod livers are no good either huh? Hard to get fresh or frozen sardines here and I have never seen fresh or frozen cod livers. I take a teaspoon of cod liver oil (refrigerated in a dark green glass bottle) a few times a week. I have been avoiding seed oils for decades, since getting off the vegan macrobiotic diet that almost killed me. But I like tahini which has sesame oil, and peanut butter - some mono and PUFAs there. Whole foods omnivore here, I cook with ghee, coconut oil, tallow and occasionally lard.
haha ! vegan macrobiotic nearly got you too ? It was dire. I still cant believe how bad that high effort diet was . Cod liver oil was defamed decades ago due to the accumulated mercury I thought. Id take canned fish over that stuff myself.
Yeah, I went on it in the nineties to deal with Multiple Chemical Sensitivities, and it did help for at least four years - but it never healed my gut dysbiosis or immune suppression, I got too skinny, accumulated too much arsenic from the brown rice, and then grew a malignant breast tumour...
oh heavens .. same here only I became too skinny and deathly for cancer to bother with me. I hope you recovered ok. Took me a long while t work it out sadly.
My purpose in commenting is not to discuss the pros and cons of fish oil, but to give you a source where you can check whether your product is what is says it is. Here is the site: https://certifications.nutrasource.ca/
As you will see at the Site, there are a total of 6 different tests. You can also read how the Certification process works for each category.
Why I haven’t supplemented with these for years. The last fish oil I got was from a refrigerated brand in a health food shop some years ago but how do I know that wasn’t just a subterfuge. Or the shop owner just bought the malarkey. Thanks. Saving this.
I gave up taking fish oil capsules years ago because of the rancid taste. I looked at other options
and then I started taking a Norwegian brand of Cod Liver Oil. I found that these capsules at times also left an after taste, although not as bad as the fish oil capsules. Then I came across a Zealand brand of Cod Liver Oil capsules and I have been taking them now for several years. I can't say that I feel any better? But I do know that I haven't had a cold, flu or covid, touch wood yet. (Although other family members have on going health issues re the above). I also take zinc and vit c powder. I actually like canned Portuguese Makrel and Sardines and try to have 2 serving per week. Time permitting, I catch my own whiting and bream. I'll be 76 this year and I still feel energetic and often forget that I'm really an old man! I don't know if this is psychosomatic or I'm in denial. Life is OK.
The Omega 3 hypothesis is also flawed...
https://haidut.me/?s=Omega
Omega-6 and omega-3 PUFA promote inflammatory pathways at the genomic level; SFA do not
https://haidut.me/?p=2852
Looks like good watching. Thank you. Love to keep learning.
I have been aware that fish oil is unstable for years, yet doctors continue to encourage people to take it. Krill oil is a much safer option.
But isn’t the krill oil processed in the same manner as the fish oil?
Processing isn’t the issue. Krill are crustaceans, not fish. They are harvested very quickly after they hatch, so they are not exposed to the toxins in the oceans for very long, while large, fatty fish are. The fat in large fish retains those toxins, which contributes to fish oil going rancid very quickly when exposed to air.
Krill oil can still go rancid, so yes, processing is an issue. The antaxathans in krill oil keep it from going rancid as quickly but it still can go south. You still need to keep it refridgerated and out of the light to help protect it. You aren't eating krill, you are still eating the extracted oil. Krill is whale food so I hope all these ships now harvesting krill aren't leaving the whales with nothing.
If they don’t stop putting windmills and 5G towers up in the ocean, we won’t have any whales to be concerned about. They’re all washing up on shore.
Thank you.
No, krill oil and fish oil are processed differently. Krill oil is extracted from Antarctic krill and is typically more stable, while fish oil is derived from the tissues of fatty fish and can be more susceptible to oxidation during processing.
"found that marine omega-3 supplementation was associated with statistically significant reductions in myocardial infarction (8%), CHD death (8%), and total cardiovascular disease (3-7%)."
The most important metric is not mentioned: All cause mortality. If CHD death goes down 8% but deaths from other causes (e.g. cancer) go up, then there is NO benefit at all!
Interesting point - and, I believe it was explained in this article that those reductions were relative (percent difference compared to the control group) rather than actual.
IE, if the treated group has 2 events, and the control group had only 1 event - that’s a 50% difference, relatively, and sounds great - but the actual number of reduced events is ONE.
right. I get that. But to me, those reductions in CHD metrics are meaningless if the study did not track and publish all cause mortality. If there was no reduction in deaths in the treated group, then the treatment has no benefit. Or worse, if the treated group had more deaths than the placebo, then the treatment is toxic. By not tracking or publishing these stats, the study missed the boat completely in my opinion.
Oh ok, I get it - thank you very much.
I learned a lot, thank you 🙏
You talked a lot about capsulated fish oil but what about bottled fish oil like Carlson’s Norwegian Wild Fish Oil?
l've read that the half-life of lenoleic acid - LA - is over 600 days. And LA is in seed oils in large amounts - I have a chart, I believe from Mercola, showing the percents of LA in various seed oils, ranging from 19% to 70%.
Does ‘half-life' mean it takes well over a YEAR for my body to metabolize LA in seed oils?
I mean, I may want that durability in my CAR OIL - but NOT in my body.
I’ve been 99% off seed oils for a few years now - but they are in LOTS of things.
Isn't there a claim that fish oil is good for brain health and as a prevention for dementia?
Is there any evidence to support this? Presumably the oil being oxidised would negate any such effects.
I always made a point of chewing and tasting anything I eat .. must admit the few capsules ive ever tried tasted and smelled fine.. much better than real fish. As I understand it its the algae in fish oils that is harmful.. in the same way carrageen and chia can be harmfuly irritantl, Not sure if it is added or if it grows. Many of us dont want to kill/eat mammals so fish is the food of choice .. we are depleting the fisheries badly, so are fish oils better than nothing ? maybe.