Posted by Larry Hoover on February 22, 2003, at 10:52:43
In reply to Larry Hoover - about CLA Abstracts and taurine, posted by IsoM on February 20, 2003, at 2:06:41
> Larry, I'm reposting here in case you missed the archived post for you.
>
> This is to do with the abstracts on CLA. You mentioned that lab produced CLAs would have a higher proportion of c9t11-CLA & t10c12-CLA as opposed to what occurs naturally in the fat of ruminants.I'm not sure what I said before, but I've spent some time researching this further, as my opinions were somewhat coloured by inference.
What is clear to me now is that the dominant CLA isomer in ruminant food products is the c9t11 isomer (85%, more or less); only synthetic products have a substantial amount of the t10c12 isomer. It is now apparent that the isomer that enhances lean/adipose ratios is the latter, synthetic isomer.
> But in the abstracts, when studies were done on possible benefits, what CLAs were used for these studies? It seems to imply that the man-made isomer mixes were used, not extracts from the fat of the ruminants. I found quite a few more abstracts on CLAs but in all of them, it implies or directly states that the CLAs used were the supplemental ones sold. Do you want to clarify anything about this as I'm curious to what was used & how that would compare to the actual fat of grass-grazed ruminants. Does that change any of the results of the studies & what they'd be like if actual fat was used instead?
Isolating CLA from natural food products is much more costly (prohibitively so) than synthesizing CLA via base-catalyzed isomerization. The problem (if it is one) with the latter process is that is so non-specific that many "unnatural" isomers are produced as well. The health effects of the latter are of some concern, but as revealed in these following references, there are high-quality products on the market which are virtually pure c9t11-CLA & t10c12-CLA.
http://www.lipid.co.uk/infores/others/claintro.html
http://www.lipid.co.uk/infores/topics/cla/file.pdf
http://www.britanniafood.com/german/invite_08.htm
> Got a few more questions -
> 1. The newer methods that labs use now to separate racemic mixtures in lab synthesized compounds (like thalidomide) - can these methods (or similar ones) be used in separating isomers of fatty acids? And if they can be used, are they actually in use or is the method still prohibitory expensive?Fatty acids are not chiral, so there are no racemates. So called physico-chemical processes can separate fatty acids, e.g. distillation. Chromatography also works, but it is not practical for bulk samples.
> 2. What exactly is done in the labs to ordinary sunflower oil (or other polyunsaturated ones) to make CLAs? What's the method?The fatty acids are exposed to base (e.g. potassium hydroxide). There is an addition-elimination reaction which either produces the parent compound again, or a positional isomer of the parent (it's a statistical process). As the product of the isomerization can further isomerize, other products begin to grow in concentration as time goes on. At some point, an equilibrium would occur, but the process would likely be stopped when "primary" isomers predominate, and secondary ones had not yet had much chance to increase in concentration.
> 3. Considering what's done with the excess of beef tallow in the food industry, would it be feasible for labs to extract the CLAs from beef fat rather than synthesize it from vegetable oils?
As it stands now, the PUFAs are saturated via hydrogenation, and there aren't any such by-products.
> 4. As I said earlier, I prefer to get mine from real food, but is the high price of CLA supplements justified by the cost of production?Yes, it's a costly process. Is it a justifiable price? Probably not.
> 5. Is there much difference that you know of in the fatty acids of pork & chicken fat between those factory produced animals & those raised "free range"?Substantial difference. Most of the difference is in the PUFAs.
>I know the fatty acids of eggs show a difference. I'm curious as pork & chicken fat is much less solid than beef & sheep (lamb) fat at room temperature.
That has much to do with what the liver does with excess calories than anything else. Each species has a dominant storage fatty acid(s), and that's what determines the melting point of the adipose fat.
> 6. And finally - the values used in the USDA sites of nutrient breakdown - these would all be the averages, I assume, so they'd be the values from that of factory produced animals. Am I correct?You can be certain those are from factory animals.
(My assumption).> As an extra for you about taurine - I wondered why cat food needs to have taurine added to the food. I knew that cats have a higher requirement of taurine than most animals. If it had to be added, I wondered where they would've got it from before pet foods had it added. Did some checking & comparing, & found some of the highest levels of taurine are found in rodents. If I wouldn't be grossed out skinning the little beggars, I'd add them to the meat mix I use in making my cats' home-made food. I'm not at all squeamish but that's going a bit too far. I buy it as a powder & add it instead. Humans get plenty in their foods if they get enough protein, correct?
Cats are obligate taurine consumers; they've lost the capacity to synthesize it, just like we've lost the capacity to synthesize vitamin C. From an evolutionary stand-point, the loss of the enzyme to create taurine is of no consequence as kitties eat lots of rodents, unless we prevent their access to same, and provide them inadequate dietary content as a replacement.
poster:Larry Hoover
thread:139853
URL: http://www.dr-bob.org/babble/20030219/msgs/202795.html