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Tests find many popular omega 3 supplements are rancid (medicalxpress.com)
97 points by clumsysmurf 4 days ago | hide | past | favorite | 82 comments

> The researchers found a total of 45% of flavored and unflavored supplements tested positive for rancidity, with 32% of flavored supplements testing positive and 13% of unflavored pills.

They added percentages of two separate groups to get the total rate of rancidity. Seems like the overall rate of rancidness is roughly 1/4, not 45%. Makes me think either 1) this was not written by a human or 2) the human who wrote this made a pretty egregious error.

Overall takeaway is: don't buy flavored omega-3 supplements.

From the actual paper, it looks like what they did was worse than just adding the two and the article is nonsensical

>Overall, our results revealed that 68% (23/34) of flavored and 13% (5/38) unflavored consumer Ω3 supplements exceeded the TOTOX upper limit set by the Global Organization for EPA and DHA (GOED) voluntary monograph standard of ≤ 26, with 65% (22/34) flavored supplements and 32% (12/38) unflavored supplements failing the PV upper limit of ≤ 5 and 62% (21/34) flavored supplements exceeding the p-AV upper limit of ≤ 20.

Olive oil is also frequently rancid. I frequently find packaged nuts and trail mix routinely rancid.

Sesame oil is the worst. It has a shelf-life of a week or two.

I've been using the same bottle of toasted sesame oil for at least two years now with no ill effects

oil rancidity doesn't cause ill effects in general, just off smells and taste. Which, if you don't notice, is fine, the more things taste good to one, the better off one is.

I keep mine refrigerated.

What kind of sesame oil are you getting...

I think unopened sesame oil can have years of shelf-life. I certainly never had a problem with the smell and we use sesame oil quite a bit in our household.

Same for me - I’m quite sensitive to rancid oil and have never experienced an issue with any brand of sesame oil kept unrefrigerated for a long period of time.

Refrigerate it and the shelf life after opening increases greatly.

Rapeseed oil is what I use. It can be kept in the fridge, and from what I manage to read online there are no real benefits of olive oil over it except maybe taste and vitamin e content, and people claiming otherwise seem to never really be able to back up their claims.

It works just as well except when you want the taste of olive oil. I find it superior when I stir fry things since the smoke point is higher.

I now taste test most everything.

One challenge is not knowing how something should taste.

I once got harvest fresh olive oil (as a gift). Wow! Total game changer.

~TLDR~ FYI: The good stuff should make you cough a little bit after you swallow it.

Three sentences with a "tl;dr" at the end?

Attentions spans are getting very… wait what was I doing?

Also the tldr is new information not a summary of or even present in the ostensibly too long text!

I don’t think that’s uncommon.

If you're in the US, I recommend the terra delyssa brand for olive oil (many grocery stores carry it)

I’d rather recommended only buying bottles of olive oil with printed harvest dates on the bottle within the last year. It’s absurd that stores are selling two year old oil. There’s a real problem with grocery stores having too many options for a single product and then most of the product on the shelves is unacceptably old.

See also: coffee.

We could have better food with fewer preservatives and less processing if the supply chain would pay attention to this problem.

It’s absurd that most coffee, even high end beans, is sold with only a use by date (often a year or more after roasting).

If you buy directly from a roaster they'll always tell you the roasting date, but most supermarkets actively forbid them from putting that on the bags sold there.

I solve for this by roasting my own

Abstract doesn't mention anything about tocopherols (vitamin e) that is frequently added to these oils as an antioxidant. Would these be expected to be effective at scavenging oxygen from the capsules?

Another reason to avoid random supplements. Most people don't benefit from Omega supplementation. Add the risk of contamination and increased chance of afib ... the supplement industry really has successfully brainwashed the public into ingesting all kinds of substances without clinically validates effect.

What is this risk of afib you talk about?

If you are in the EU, I can wholeheartedly recommend omega3zone[1]. Their fish oil actually tastes pretty nice and absolutely not like fish, keeps in the fridge for quite a while and has insane concentrations of the 'good stuff' (EPA and DHA in triglyceride-form). It is admittedly expensive (though you can dose it way lower than they recommend, given how concentrated it is), but to me it's worth it.

[1]: https://omega3zone.de/products/omega-3-fischol-500ml

Worth it why? What does it do?

The researchers found a total of 45% of flavored and unflavored supplements tested positive for rancidity, with 32% of flavored supplements testing positive and 13% of unflavored pills.

The above math looks wonky to me but fits with the TLDR at the end of the piece:

Both Frame and Hands suggest exercising caution with flavored fish oil supplements at this point due to the uncertainty of how the flavoring may affect their freshness and, thus, any potential health benefits.

I feel like this is an example of reporting on a paper misunderstanding some of the details. Specifically that probabilities can’t simply be added together.

May not have been a human writing it. :/

$62 to access the paper

Note, even the "good" brand can go rancid if you don't take care of your stash. I highly recommend cutting one open for a smell test if you're unsure. Also, if you're getting gross burps, your batch may be bad.

I've used Aqua Omega (unaffiliated) with great success for years.

It’s probably best to take your omega 3 in liquid form rather than capsules.

best is from dietary sources.

Dietary sources are not vacuum-distilled for removal of heavy metals and microplastics.

Does vacuum-distilling foods have a special name?

I’m skeptical that it can remove heavy metals but can’t find any info.

You have any idea how much salmon you’d have to eat? Supplements are more concentrated.

You don’t have to eat that much salmon, just a typical 5oz serving 2-3 times a week? And it doesn’t have to be salmon either, you can get DHA and EPA from Sardines, Oysters, Mackerel, Herring, Trout, Anchovies…

I would be shocked if the average person eats salmon 2 or 3 times a year.

We eat Kimberley Barramundi every week - slighly over two thirds of the protein + omega 3 per unit of wild salmon .. but much cheaper as we catch most of it ourselves and freeze it for later.

Salmon's not a local fish here being the main reason - and catching Barra makes for time well spent outdoors.

I went to Alaska and ate Salmon almost every day for 2 weeks.

I probably eat salmon once every other week.

There's a mail order fish company that would love for you to eat more salmon.

Depends on where you live I imagine

eat your greens

That's news to me. I previously heard flax seed and walnuts were the only good vegeterian sources of omega 3.

A quick search agrees that greens, like spinach, broccoli and cabbage, do contain small quantities of omega 3. I'm having trouble getting a clear idea here of how helpful they are in comparison to the standard recommendation of fish oil.

Anyone have any good sources of info on how to get enough omega three from vegetarian sources?

It's unclear if it's bioavailable from those sources at all. There's two forms ALA and DHA; the first is found from nuts and the second from algae. The fish get it from the algae.

IIRC there is some evidence that ALA is only bioavailable for women and not for men, but I don't remember if that's reliable.

I had heard that flax seed may not be bioavailable. Walnuts are my go to as the only vegetarian source I understand to have substantial amounts of bioavailable omega 3.

Would love to get a clearer idea of how much I really need and how much produce I consume may be defraying that number.

It's difficult to find EPA or DHA from vegetarian sources (other than algal oil), although ALA is easier (e.g., walnuts, flax, chia).

Camelina oil is another good source of ALA if you can find human-grade versions of it. I thought it was nice as a sort of alternative to olive oil raw (like served with bread, or maybe tossed in cold salads), although it had its own flavor (sort of a grassy flax-like flavor), and is impossible to find now it seems. It wasn't something I would probably use a lot of but had a solid niche.

At one point there was some interest in transgenic camelina oil because it was easily converted into varieties expressing EPA and DHA. For example:


I've never seen that sold anywhere though.

One cup of Kale provides a 121 mg of omega-3 fatty acids. I would need 13 cups a day. The recommendation should be "eat your nuts and legumes", if you want to stay away from meat.

Vegetables are an inefficient delivery mechanism for most nutrients, you have to eat huge quantities to meet quotas. I don’t see the point of them.

Wouldn't the capsule provide an additional barrier to oxygen, ceteris paribus?

Maybe. But with the liquid form, you can smell and taste when it's rancid. You could take a whole bottleful of capsules and have no idea they've gone bad.

Ah, I pop them in my mouth for QC but I might just be weird.

Just eat canned sardines in water, drink the juice. It's an excellent source of omega-3s and protein.

Sardines can have a lot of arsenic. Also, for those of us that are vegan, they are not an option.

Slightly off-topic, but does anyone here notice a positive difference from omega 3 supplementation?

I haven't died of cardiovascular disease this week!

So I was prescribed vascepa to lower my triglycerides. They’re now low enough that I was taken off them.

But I’ve also significantly cut down on the calories I’ve been eating.

That’s so gross. Ick. Great finding. I’ve actually wondered about this in the past.

Does anyone here have access to the list of rancid brands and can they post it?

It’s majority flavored are rancid, so just go unflavored and you have an 87% chance of being fine.

Just curious. Are the rancid ones bad for ones health or ineffective in any way?

I’ve read in a few places that it’s bad for you, but I’ve not done a deep dive and formed an “I’m confident” level of knowledge. The wikipedia article suggests that it might be bad, but there’s not a lot of research on it.


Seems like the claim is they are less effective but not actively harmful. But don’t have access to the full paper.

on the peter attia podcast, rhonda patrick said omega 3 should be on the fridge. https://www.youtube.com/watch?v=zkp0DRUQ33g

I keep them in the freezer and haven't had a fish oil burp since.

Upvoted. I've been doing this. Glad to be validated.

(Also, Dr Patrick is the best.)

Dietary supplements in America are very loosely regulated. The law that governs this is the Dietary Health Supplements Act. Tl;dr DSHEA classified dietary supplements as a food or food product which the FDA classifies as "generally recognized as safe." (GRAS)

It also said that so long as a manufacturer is using a vitamin, mineral, or dietary substance that was available before 1994 then are ok to manufacturer and it would be considered safe (GRAS.)

There are additional requirements about manufacturing processes available before and after that date but that is the gist.

The problem with this law is that supplements are not required to undergo any kind of testing or validation. If a dietary supplement causes a problem, the FDA does not really have the authority to order a recall. Instead it has to depend on the Federal Trade Commission, which can order a recall and levy sanctions due to mislabeling.

Anyone can manufacture and sell a dietary supplements and sell them to anyone, there are no age restrictions. It's something that IMO needs greater oversight.

DSHEA: https://ods.od.nih.gov/About/DSHEA_Wording.aspx

General Recognized as Safe: https://ask.usda.gov/s/article/What-are-Generally-Recognized...

FTC and FDA: https://www.ftc.gov/news-events/news/speeches/ftc-dietary-su...

Congressional Research Service, 2021: "Regulation of Dietary Supplements" https://sgp.fas.org/crs/misc/R43062.pdf

I hate that the actual paper is behind a huge ($100+) paywall and the article doesn’t call out any brands. I take an Omega 3 supplement and want to know if mine is rancid :p

Same here. Assuming this is the case for fish oil capsules, even though you don't really taste the supplement itself?

The article specifically says < 15% rate of rancidity for pills which looks like it includes capsules since the only other category they call out is flavored supplements.

I don’t think they’d want to name and shame as that attracts litigation.

It probably is.

I use unflavored pills. The article says those are rancid at a rate of < 15% so probably not.

Supplements are easily the biggest single scam against consumers in existence. Just walked out of a CVS where I saw a large bottle of Vitamin C pills for $42. That's easily a 10,000% markup or more on the raw ascorbic acid in those pills. Not to even mention the lack of health benefits.

It's like a lot of things: A lot of dietary supplements are scams, but a lot of them are legitimate. The core issue for people who take dietary supplements is that a) they probably don't need it, b) they may be taking too much, and c) unless they are getting a mineral and metabolic panel, etc. they have no idea if they even need the supplement.

IMO before taking any supplements one should get a panel done to see if you even need it.

I don’t know. I buy caffeine pills, whey powder, and a few other supplements. They are certainly marked up but simultaneously the nest efficient way to get caffeine, protein, etc per dollar.

Gotta have my creatine

You think that's bad, just wait till you hear about bottled water! Or maybe it's a convenience thing and that's worth something to some people.

Do people really not get that you’re paying for the shipping, not the water?

> "Just walked out of a CVS"

Well, there's your problem. CVS and Walgreens are the two best places to go if you don't care about your money. Otherwise, at a grocer, Walmart, or Amazon, a bottle of a decent brand of VitC can be had for $7.5.

Depends on the supplement.

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