Posted by Larry Hoover on August 20, 2004, at 8:21:24
In reply to thanks, but doesn't the post partum thing relate, posted by joebob on August 19, 2004, at 12:31:03
> directly to the need for dha by the fetus and suckling infant?
And adult women, too.
DHA is a structural component of, among many other sorts of membranes, the membranes covering nerve cells and brain cells.
When a cell senses certain kinds of signals from the environment, it snaps off a piece of the membrane, and that membrane fragment is broken, to release a fatty acid. If that fatty acid is DHA, it goes down to the DNA, and changes the "volume control" on the synthesis of all sorts of different proteins, including receptors. If that fatty acid is AA (arichidonic acid), then different things happen altogether (a whole different group of genes are up- and down-regulated). When you are DHA deficient, your body substitutes arichidonic acid, but that changes the other things that happen afterwards. Your body might 'want' the DHA-mediated effect, but it gets the AA-mediated effect, instead.
> and it seems to me that the implication re epa conversion to dha might also imply that there was no increased need for dha, so no conversion takes place
That is a plausible rationale, but it doesn't fit the science. Enzymes are "stupid little machines". If they get more raw material, they make more product. As simple as that. There ought to have been *some* increase, for two reasons: a) feedback regulation (the signal that would shut down the stupid little machines) only occurs if the body has enough of the substance; b) what are thought of as "normal concentrations" of DHA are not normal. They are *typical* concentrations, and the typical person is DHA deficient (unless you are Inuit, and eat whale blubber all the time).
That's my interpretation, anyway. Others are certainly going to differ.
> the research about epa conversion to dha did not come from horrobin, as was cited later in my post, and i am sure i recall a replication study more recent than the one i copied in my postThe references at the bottom of the page had Horrobin as first or second author. <shrug> In any case, most nutrition scientists are now recognizing that the interconversion argument is a straw-man argument. If you obtain DHA from diet, and EPA from diet (or supplements), interconversion is not a factor. Period. Recent thinking is that EPA and DHA are at least "conditionally essential nutrients". Some are starting to call them "essential nutrients", in their own right. Just like the essential fatty acid alpha-linolenic acid, I believe that DHA and EPA are themselves essential (or so darn close to it that the ability to make a little bit inside our own bodies is a trivial consideration).
> thanks so much, i value your opinion highly and enjoy the exchange/debate aspect, as i am a curious boy and like to get informedMe too, dude.
> one last thing did you follow the selegine/phenalynine post? see below....
> do you think that the phenalynine would compete for absorption with other aminos, like tyrosine,taurine, theanine? is this combo worth a try? actually i tried 5mg sele and 500 mg phenal this morning and will report subjective results as i become clear on what i experience....I didn't comment because this is a preliminary trial. We'll see what comes of it. Theories do not substitute for empirical evidence. In other words, having an idea why something may or may not work is not the same thing as what is confirmed in an experiment. An experiment might work, but for a completely different reason than that in the hypothesis. "This works" is a different entity than "This works because..."
Lar
poster:Larry Hoover
thread:377821
URL: http://www.dr-bob.org/babble/alter/20040815/msgs/379838.html