10 replies to this topic

[Debaser]

I love fish, but I'm aware that the oily fish tend to contain high levels of mercury and other pollutants, so I don't want to eat it more than about twice a week.

 

Are plant sources of omega-3 any good? I was looking at this hempseed the other day, and I nearly bought it with the intention of adding it to my porridge, since it contains useful minerals and omega-3. But then I realised that it has about 3.5 times as much omega-6 as omega-3. Isn't the ratio important, since they compete for the same metabolic enzymes? If it means consuming that much omega-6, then surely it kind of defeats the purpose of eating it to get omega-3. The omega-6 in it would cause inflammatory metabolites to be created and compete with the omega-3. Is this correct?

[Jeoshua]

Plant-derived omega 3 is generally ALA, whereas fish-derived omega 3 is mostly EPA and DHA. These are very different molecules. While ALA does turn into EPA and DHA, it does so at a metabolic cost. ALA has its own benefits, but they are different from straight and direct supplementation with DHA and EPA.

Standord study, PDF

[Phoenicis]

Actually, algae derived EPA & DHA is great since this avoids the problem of mercury/pcb/dioxin bioaccumulation.  Jeo's reply is sort of misleading, the origin of EPA/DHA in aquatic ecosystems is algae (see bellow).

 

Omega-3 Fatty Acids for Nutrition and Medicine: Considering Microalgae Oil as a Vegetarian Source of EPA and DHA -

 

"Along with pollutants certain fish acquire high levels of EPA/DHA as predatory species. However, the origin of EPA/DHA in aquatic ecosystems is algae. Certain microalgae produce high levels of EPA or DHA. Now, organically produced DHA-rich microalgae oil is available. Clinical trials with DHA-rich oil indicate comparable efficacies to fish oil for protection from cardiovascular risk factors by lowering plasma triglycerides and oxidative stress."

 

Just an eg. http://opti3omega.com/

 

It is also not unheard of for fish derived omega 3s to be contaminated with mercury. Molecular distillation is normally required to remove such contaminants, but I prefer to avoid fish oil as a precaution.

 

• Hoh E, Lehotay SJ, Pangallo KC, Mastovska K, Ngo HL, Reddy CM, Vetter W. Simultaneous quantitation of multiple classes of organohalogen compounds in fish oils with direct sample introduction comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry. J Agric Food Chem. 2009 Apr 8;57(7):2653-60.
• Rawn DF, Breakell K, Verigin V, Nicolidakis H, Sit D, Feeley M. Persistent organic pollutants in fish oil supplements on the Canadian market: polychlorinated biphenyls and organochlorine insecticides. J Food Sci. 2009 Jan-Feb;74(1):T14-9.

Edited by Phoenicis, 27 April 2014 - 12:00 AM.

[Debaser]

 

Jeo's reply is sort of misleading, the origin of EPA/DHA in aquatic ecosystems is algae (see bellow).

 

 

I think he's right about most vegetable oils. The omega-3s tend to be ALA, which it says on Wikipedia (with source) the body can only convert to EPA/DHA with an efficiency of a few percent. It seems that the presence of omega-6 analogues will slow the process further.

 

Algae sources look like a good way of getting EPA/DHA, since that is where the fish get it from. Hopefully more such products will come on the market and prices drop. I might give Opti3 a try. The price isn't too bad, especially with 3for2.

Edited by Debaser, 27 April 2014 - 01:34 AM.

[Jeoshua]

I'm voting you down because you voted me down, wrongly. You're, of course, completely right about algae being the ultimate source of DHA in the marine food chain. You'll note that I never claimed in the first place that the fish, themselves, were the source of DHA. Algae is also only marginally to be considered as a plant on a purely technical basis, since when most people say "plant" (in this case, including the OP) it is understood that they mean terrestrial plants. Land-based terrestrial plants do, in fact, produce overwhelmingly ALA, which is in fact converted to DHA/EPA in the body at a metabolic cost. Hemp is a terrestrial plant, which is the source of omega 3s that the original post was in fact questioning the veracity of, and therefore "plant" means, in my post, land-based plants, and not the algae that the fish get their DHA from. If my post were to be taken on face value, even a sloppy reading of it would show that I was talking about the differences between ALA and DHA/EPA, and upon looking for DHA/EPA one might find an algal source of DHA/EPA and rightly consider that I was including them in the "good" category. And moreover, I'm not trying to mislead anyone, you just disagreed with my wording which was referencing the original post, and not 110% scientifically precise.

Additionally I would like to add my observation that Arctic sources of marine omega 3's tend to contain higher amounts of DHA, relative to the EPA content. I do not know why this is, but it likely has something to do with its possible usage as an antifreeze for cellular membranes. I don't know if that observation is useful, but I have noticed that Arctic and Norwegian Cod liver oil is generally more expensive than other kinds of Fish oil, and I have personally noticed a higher effaicity with these oils for usage in Happy's Stack type of stacks than other types of Omega 3 (in which, admittedly, I have only tried Flax and various types of Fish and Algal oils)

Finally, the threat of mercury in Fish Oil is vastly overstated. Yes, Fish can contain Mercury, due to their high position on the food chain. This can easily be avoided by picking "Molecularly Distilled" forms of Fish Oil, as opposed to relatively unprocessed smelly cod liver oils, that nobody really prefers, anyways. These types of Fish Oil don't produce fishy-smelling burps, taste almost like thick water, generally have some kind of citrus flavor added to them, and contain far less Mercury. And any reliably good source of Fish Oil would test for Mercury, anyways. Overall, Fish Oil is one of those supplements that you should never pick the lowest possible price for, unless it's a really good store brand which is on clearance.

Edited by Jeoshua, 27 April 2014 - 02:10 AM.

[Phoenicis]

I just thought it was curious to mention fish oil for EPA/DHA without mentioning a vegetarian source of it (notably low on mercury) when the OP specifically mentioned that mercury from fish was a concern.

 

Regarding the safety of the fish oil - we all know its essential to molecularly distill the oil, so obviously the risk is serious enough to warrant this. Bio-accumulation is the underlying point. Why take the risk when there's a safer alternative? 

 

Edited by Phoenicis, 27 April 2014 - 03:47 AM.

[Jeoshua]

But the question wasn't about Vegetarian sources of EPA/DHA, Phoenicis. It was about plant-sources of omega 3 in comparison to Fish Oil, the question asked, in the most succinct post possible as I walked out the door. Yes, I could have mentioned Algae as a lower-mercury source of EPA/DHA, but I didn't. Honestly, I'm not a vegetarian, I don't really think about those kind of things, and in my mind Algal and Fish Oil EPA/DHA is extremely similar in both packaging and effect, so I didn't specifically mention it. On a related note, why do Vegans/Vegetarians vote down so many of my posts en-masse? (My nominally omnivorous yet low-meat consumption diet just horribly offends you, doesn't it, Vegans? ).

Anyhow, is the danger of Molecularly Distilled Fish Oil's supposed Mercury content really that great? I know the stuff builds up, but the amounts of Mercury in these supplements is almost nill. Any cheap supplement with a high enough mercury content to be really dangerous would be quickly taken off the market. There is no market in killing your customers. Hell, even coke dealers cut their product to try and prevent people dying. It's harder to get money, that way.

Here is a good site containing a breakdown of mercury content in Fish Oil, to show I'm not just talking out of my ass.
 

Every fish oil supplement contained measurable amounts of mercury, with the category averaging 2.9 PPB (parts per billion) of mercury. LabDoor set its upper limit for mercury content at 10 PPB. The worst offenders were Nature Made Cod Liver Oil and Natrol's Omega-3, which both recorded mercury levels of 6 PPB.

https://labdoor.com/rankings/fish-oil

Measurable doesn't mean problematic. In this case it is Parts Per BILLION. That's nanograms per gram - vanishingly small, and way below any kind of problematic dose. You could probably get a bigger dose from licking a mercury thermometer.

Edited by Jeoshua, 27 April 2014 - 04:11 AM.

[timar]

To say that Jeoshua's post, which unjustifiably got two downvotes, would be misleading is by itself misleading.

 

The question was: "Hemp seed and plant sources of omega-3" and Jeoshua aptly responded to that question with a short and accurate classification of the types of polyunsaturated fatty acids generally occuring in fish and plant foods and only left out the subject of microalgae which, although they are the original source of all marine EPA and DHA, has no dietary relevance whatsoever - people just don't eat microalgae - period. The oil that derives from such algae has only recently become available as a supplement and, as it is still far from being economically competitive with fish oil, is prefered only by vegans and people irrationally concerned about toxins in fish oil (although heavy metals don't accumulate in the oil and dioxins and other fat soluble toxins are generally way below any toxicity threshold even if one consumes much more EPA and DHA through fish oil than would be advisable on  its own).

 

 

Regarding the safety of the fish oil - we all know its essential to molecularly distill the oil, so obviously the risk is serious enough to warrant this. Bio-accumulation is the underlying point. Why take the risk when there's a safer alternative? 

 

It is essential to distill the oil in order to 1) increase oxidative stability, undistilled oil goes rancid much more quickly, 2) improve the organoleptic properties of the oil, and 3) to increase the relative content of EPA and DHA. That distillation also lowers the lels of some pollutants is only a welcome side effect. As I said, the remaining levels in the oil are so low, that they are well below any toxicity threshold even if you take copious quantities of it. And such threshold values for persistent organic pollutants are calculated by lifetime exposure. There are ethical concerns about fish oil, but no rational concerns about toxins (well, unless you are an immortalist I suppose).

Edited by timar, 27 April 2014 - 09:03 AM.

[Debaser]

Jeoshua's answer was actually exactly what I was looking to know: whether something like hempseed is a valuable source of omega-3. I think the consensus is that it isn't all that useful as an omega-3 source, although it might still be good for other reasons or at least not harmful to eat.

 

I'm taking fish oil at the moment, but I'm interested in alternatives. Phoenicis' post was also useful to me because I wasn't aware that algae-derived omega-3 was an option.

 

Another possible issue with the distilled fish oils is that they're actually ethyl esters:

 

 

Fatty acid ethyl esters are a class of lipids that are derived by reacting free fatty acids with ethanol (alcohol)³. Called trans-esterification, the process involves a reaction whereby the glycerol backbone of a TG is removed and substituted with ethanol⁴. The resulting EE allow for the fractional distillation (concentration) of the long chain fatty acids at lower temperatures. Commonly referred to as molecular distillation in the fish oil industry this step allows for the selective concentration of the EPA and DHA fatty acids to levels greater than found naturally in fish3. The resulting EPA and DHA concentrate is typically the end product that is subsequently marketed and sold as “Fish Oil concentrate”

 

These ethyl esters require further processing by the body to get them to the form you find naturally in fish, so they take longer to absorb. Rather than try to explain it myself, probably better to read the source. I don't think this is a huge issue though.

 

They also often have vitamin E to stabilise them. Supplementation with high levels of vitamin E has been found to increase mortality, and I get more than the RDA from my diet. They also often contain vitamin A, too much of which is bad for you. I also get plenty of vitamin A from my diet so I'd prefer not to take it in supplements.

Edited by Debaser, 27 April 2014 - 03:11 PM.

[timar]

Another possible issue with the distilled fish oils is that they're actually ethyl esters

 

Actually, most are not. Molecular distillation doesn't equal re-esterification. You only need that step if you want to increase the concentration of EPA and DHA to more than 60%. As a rule of thumb, a fish oil that has more than 60% EPA and DHA comes as ethyl ester, and those with 25-30% (single concentrated) and 50-60% (double concentrated) come in their natural triglyceride form.

 

They also often have vitamin E to stabilise them. Supplementation with high levels of vitamin E has been found to increase mortality, and I get more than the RDA from my diet. They also often contain vitamin A, too much of which is bad for you. I also get plenty of vitamin A from my diet so I'd prefer not to take it in supplements.

 

Cod liver oil contains high amounts of vitamin A and should be avoided or taken in very limited amounts for that reason, but distilled fish oil usually doesn't contain any vitamin A.

 

The vitamin E in fish oil is really a non-issue, as I have explained elsewhere. Moreover, you need to add an antioxidant to the oil regardless of whether it is derived from fish or microalgae (sometimes rosemary extract is used instead of tocopherols).

 

Edited by timar, 27 April 2014 - 03:28 PM.

[Jeoshua]

 
Another possible issue with the distilled fish oils is that they're actually ethyl esters:
 

 
Fatty acid ethyl esters are a class of lipids that are derived by reacting free fatty acids with ethanol (alcohol)³. Called trans-esterification, the process involves a reaction whereby the glycerol backbone of a TG is removed and substituted with ethanol⁴. The resulting EE allow for the fractional distillation (concentration) of the long chain fatty acids at lower temperatures. Commonly referred to as molecular distillation in the fish oil industry this step allows for the selective concentration of the EPA and DHA fatty acids to levels greater than found naturally in fish3. The resulting EPA and DHA concentrate is typically the end product that is subsequently marketed and sold as Fish Oil concentrate

 
These ethyl esters require further processing by the body to get them to the form you find naturally in fish, so they take longer to absorb. Rather than try to explain it myself, probably better to read the source. I don't think this is a huge issue though.

You're right, it's not a huge issue. The EFA esters are only more slowly absorbed, not less completely. EFA supplementation help only with chronic dosing, so how quickly it absorbs isn't in important. There are not really that many acute effects to begin with.