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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 13 of 13. This is the beginning of the thread.
Posted by Mats on April 4, 2003, at 6:10:57
How much actual fish is 1 mg of fishoil?
/Mats
Posted by linkadge on April 4, 2003, at 7:45:59
In reply to Another fish oil question!, posted by Mats on April 4, 2003, at 6:10:57
I know that 1 gram of (epa+dha) is about 5 cans of tuna. So the standard single fish capsule
is about 2 cans of tuna.
I'm just going by the stoll study that
said the 9.6 g (epa+dha) of fish oil = 37 cans of tuna.
Linkadge
Posted by Larry Hoover on April 4, 2003, at 8:03:04
In reply to Another fish oil question!, posted by Mats on April 4, 2003, at 6:10:57
> How much actual fish is 1 mg of fishoil?
>
> /MatsDepends on the fish. For example, one capsule of salmon oil (one gram = 1000 mg) represents the fatty acids from about 40 grams of raw pink salmon (based on the USDA database).
If you want to compare different seafoods, go to:
http://www.cs.princeton.edu/~ah/food/data/fishshellfish.lipids2
http://www.cs.princeton.edu/~ah/food/data/fishshellfish.lipids3EPA is listed as 20:5, and DHA is 22:6.
Lar
Posted by Viridis on April 4, 2003, at 23:07:46
In reply to Re: Another fish oil question!, posted by Larry Hoover on April 4, 2003, at 8:03:04
Hi Larry,
That's a very helpful link, but in the version that I pull up, there doesn't seem to be a "20:5" (= EPA) column. So, is EPA in there under another heading?
Also, just to clarify -- I'm not a chemist, although I am a biologist: I assume that the first value refers to the number of carbons in each chain, and the second describes the degree of "unsaturation" (i.e., number of C=C double bonds).
I could look this up, but am hoping that besides verifying (or correcting) this, you might elaborate a bit on the nutritional value of long vs. short-chain fatty acids and level of hydrogen saturation.
Thanks!
Viridis
Posted by Viridis on April 4, 2003, at 23:12:15
In reply to Re: Another fish oil question!, posted by Larry Hoover on April 4, 2003, at 8:03:04
Duh -- I see that EPA is in the second link. But I'd still appreciate any insights on my other questions.
Thanks!
Posted by noa on April 5, 2003, at 10:00:13
In reply to Re: Another fish oil question! » Larry Hoover, posted by Viridis on April 4, 2003, at 23:07:46
I am not a scientist at all, but from the diagram my pdoc gave me, I *think* you're right about the 20:5 meaning 20 carbons, 5 double carbon=carbon bonds. DHA is 22:6
Posted by Larry Hoover on April 5, 2003, at 11:25:39
In reply to Re: Another fish oil question! » Larry Hoover, posted by Viridis on April 4, 2003, at 23:07:46
> Hi Larry,
>
> That's a very helpful link, but in the version that I pull up, there doesn't seem to be a "20:5" (= EPA) column. So, is EPA in there under another heading?I know you've found the answer to this one. I don't know why the different fatty acids are organized the way they are, but you'll find them (EPA and DHA) on different pages.
Incidentally, if you shorten the URL to the word food, you'll get to an index page that sorts foods by a huge variety of nutrients. Play with it.
http://www.cs.princeton.edu/~ah/food/
> Also, just to clarify -- I'm not a chemist, although I am a biologist: I assume that the first value refers to the number of carbons in each chain, and the second describes the degree of "unsaturation" (i.e., number of C=C double bonds).
Exactly right. However, as a short-hand, it has a peculiar weakness. It doesn't tell you where the double bonds lie. For example, gamma-linoleic and alpha-linoleic are both 18:3, but one is omega-3 and the other omega-6.
> I could look this up, but am hoping that besides verifying (or correcting) this, you might elaborate a bit on the nutritional value of long vs. short-chain fatty acids and level of hydrogen saturation.
>
> Thanks!
>
> ViridisA bit? This is a huge topic.
Some gross generalizations:
1. Saturated fats are heart-neutral. They are sources of energy. Short-chained sats, as found in e.g. coconut oil, may have health-promoting effects. (The general shunning of sat fats is not supported by the evidence.) The worst thing McDonald's ever did was turn away from beef tallow for frying french (freedom??) fries.
2. Trans-fats are bad. Much of the negative publicity given to sat fats really belongs to trans fats. Trans fats are man-made, arising from incomplete saturation of the polyunsaturates found in vegetable oils. If a product has "hydrogenated", or worse, "partially hydrogentated", as part of its ingredient list, steer clear. These modifications are solely to improve the profitability of the food processor, by extending shelf-life of the product (among other things).
3. Mono-unsaturates are good. Olive oil, the dominant dietary source of monounsaturates, is good.
4. Polyunsaturates are good, with one qualifier. Most people get too much omega-6, and not enough omega-3. Don't be surprised if you come across a new medical disorder "omega-3 deficiency syndrome", sometime in the near future.
What makes polyunsaturates special? Each unsaturated position is a reactive site. That means the body's enzymes can modify the chemical structure of the polyunsaturates once, twice, many times over. These modifications turn them into signalling/regulatory compounds. We're just starting to understand how this all works, but if you plug eicosanoid or prostaglandin into your search engine, be prepared to be overwhelmed with information.
Another thing that makes polyunsaturates special is the effect each double bond has on fluidity. Saturated fats are solid, even at physiological temperatures. Polyunsaturates are key components of cell membranes, and their fluid nature ensures proper functioning of receptors. Moreover, when a receptor is activated, it can take a part of the cell membrane adjacent to it, and modify and release some of those polyunsaturates as signalling compounds (termed second-messengers).
Bottom line? I think low-fat dieting is a horrid mistake.
I'm having trouble restricting my reply. Perhaps specific questions are appropriate now?
Lar
Posted by Viridis on April 5, 2003, at 16:03:30
In reply to Re: Another fish oil question!, posted by Larry Hoover on April 5, 2003, at 11:25:39
Hi Larry,
Thanks very much, and sorry for making my question so open-ended. I guess what I'd really like to know in sorting through all of this are the relative utilities of the various unsaturated fats and the functional differences between omega 3s vs. omega 6s. Not that that's a simple question either, but here's my current approach:
I have a fairly low intake of saturated fats, but don't really worry about them (e.g., I'll use butter over margarine any day). I avoid artificially hydrogenated oils as much as possible and am pretty alert to where they're used. In cooking, we use mostly monounsaturates (primarily olive oil, some peanut), and occasionally canola. I take fairly high doses of fish oil, with an intake of around 1.2 g EPA and 1 g DHA/day.
Now, I think all of this is pretty sensible. Where I really get confused is with the multitude of other oils that are touted for their health benefits. I use various oils (hemp, walnut, grapeseed etc.) as flavorings, in salad dressings, and so on, and I assume that adding this variety has some benefits. But what about additional supplementation with flaxseed, borage, evening primrose, etc. -- is there anything special about these that "rounds out" the range of lipids that your body needs, or do I have it pretty much covered anyway?
And, finally, just what is the significance of the position of the C=C bonds -- why is it their precise location apparently so important?
I guess I've still left you with a huge amount of material that potentially could be covered, but I'd appreciate your insights into the above.
Thanks again,
Viridis
Posted by Larry Hoover on April 5, 2003, at 17:37:12
In reply to Re: Another fish oil question! » Larry Hoover, posted by Viridis on April 5, 2003, at 16:03:30
> Hi Larry,
>
> Thanks very much, and sorry for making my question so open-ended. I guess what I'd really like to know in sorting through all of this are the relative utilities of the various unsaturated fats and the functional differences between omega 3s vs. omega 6s.In general terms, most people get far too much omega-6, relative to omega-3. Estimates of the ratio between them run from 15:1 to 50:1, based on assessments of typical Western diets. "Ideal" ratios would be somewhere around 2:1. Your diet sounds like it's closer to the latter than the former.
Omega-6s are pro-inflammatory. That's probably the biggest issue.
> Not that that's a simple question either, but here's my current approach:
>
> I have a fairly low intake of saturated fats, but don't really worry about them (e.g., I'll use butter over margarine any day). I avoid artificially hydrogenated oils as much as possible and am pretty alert to where they're used. In cooking, we use mostly monounsaturates (primarily olive oil, some peanut), and occasionally canola. I take fairly high doses of fish oil, with an intake of around 1.2 g EPA and 1 g DHA/day.
>
> Now, I think all of this is pretty sensible.Looks good to me.
>Where I really get confused is with the multitude of other oils that are touted for their health benefits. I use various oils (hemp, walnut, grapeseed etc.) as flavorings, in salad dressings, and so on, and I assume that adding this variety has some benefits.
The whole idea of flavour helps to describe the benefits; it's the components that give flavour that confer extra health benefits, e.g. the flavonoids and terpenes and so on. You've already covered the fatty acid profiles nicely. You don't need large quantities of anything else, with one possible exception (below). So, go ahead and use these oils as you have been. Most people touting all the health benefits of e.g. hemp oil also sell it, right? Go figure.
>But what about additional supplementation with flaxseed, borage, evening primrose, etc. -- is there anything special about these that "rounds out" the range of lipids that your body needs, or do I have it pretty much covered anyway?
What makes borage, evening primrose and black currant seed oils special is their high GLA (gamma-linoleic acid) content. Although this is an omega-6 fatty acid, in the presence of sufficient omega-3 intake (you've got that well covered), this particular fatty acid will be diverted into the production of anti-inflammatory prostaglandins. So, you might get a little bit of a health benefit from adding one of the three I mentioned. Flax oil has high ALA (alpha-linoleic acid), the omega-3 version. You won't get appreciable benefit from flax oil because you're male. There's a gender difference in the ability to elongate and desature.
> And, finally, just what is the significance of the position of the C=C bonds -- why is it their precise location apparently so important?One of the ways that polyunsaturates are turned into signalling compounds is by the formation of a ring structure. The enzyme we know as COX (cyclo-oxygenase) does that. The ring takes up six carbons, so for a 20-carbon fatty acid like EPA, you'll have these two tails comprising 14 carbons in total sticking out. Something about just what sticks out has meaning to your body. After the ring is formed, other modifications occur which further change the "information" carried by the molecule. You can get cytokines, interleukins, prostaglandins,....all kinds of stuff, depending on the modifications. I don't pretent to know anything about the coding per se, but the three-dimensional configuration, surface electron density and so on can switch biological systems on and off.
Just to show you how little we really know, it is only recently that the natural signalling chemical for what we call the cannabinoid receptor was identified. It's called anandamide, and it's an amide derivative of the 20:4 polyunsaturate arichidonic acid. The arichidonic acid is itself derived from neuronal membrane fatty acid stores.
> I guess I've still left you with a huge amount of material that potentially could be covered, but I'd appreciate your insights into the above.
>
> Thanks again,
>
> ViridisIf I've missed the mark, try some new questions.
Lar
Posted by Viridis on April 7, 2003, at 23:55:56
In reply to Re: fatty acids » Viridis, posted by Larry Hoover on April 5, 2003, at 17:37:12
Hi Larry,
Thanks again -- it sounds like I'm on the right track. I'll continue to do what I've been doing, and maybe throw in a bit of evening primrose oil, as I have been doing here and there.
BTW -- Re: some other people's comments on reactions to these oils, I bought some borage oil a while ago. I had no problem with it, but my wife tried it a couple of times (not for psychiatric reasons, just for general health and out of curiosity). She said it made her feel feverish and very irritable each time. Of course this is anecdotal, but I found it interesting given the reaction of some others to these supplements. Fish oil, evening primrose, etc., don't bother her, but she definitely seemed to react negatively to borage oil.
Posted by noa on April 8, 2003, at 19:11:57
In reply to Re: fatty acids » Larry Hoover, posted by Viridis on April 7, 2003, at 23:55:56
I take fish oil (have for about 3 months) and it has helped me a lot, but when I was out of it and the store was out of it, I bought the same brand of cod liver oil, and took it once and felt horrible--had terrible akithisia all night. Maybe it was a coincidence, I don't know. To get a better idea, I'd need to try the cod liver oil again, which I am loathe to do!
Also, keep in mind that some of these substances affect hormones and of course, in different ways in men and women.
Posted by Franz on April 9, 2003, at 1:04:41
In reply to Re: fatty acids » Viridis, posted by noa on April 8, 2003, at 19:11:57
Hi, please explain if cod liver oil can replace fish oil.
I do not understand.
Thanks> I take fish oil (have for about 3 months) and it has helped me a lot, but when I was out of it and the store was out of it, I bought the same brand of cod liver oil, and took it once and felt horrible--had terrible akithisia all night. Maybe it was a coincidence, I don't know. To get a better idea, I'd need to try the cod liver oil again, which I am loathe to do!
>
> Also, keep in mind that some of these substances affect hormones and of course, in different ways in men and women.
Posted by Ed O`Flaherty on April 9, 2003, at 2:41:33
In reply to cod liver oil can replace fish oil?Re: fatty acids » noa, posted by Franz on April 9, 2003, at 1:04:41
Cod liver oil is fish oil with a high level of Vitamin A and D. A small amount of cod liver oil is safe but taking a high dose opens up the possibility of excessive intake of these vitamins.
This is the end of the thread.
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