Reducing One Amino Acid Could Increase Lifespan
John Bryson writes "Eating less of one amino acid might lengthen your life. There have been lots of previous studies showing that many species live long on highly restricted calories, but a lot of this benefit may be possible by only restricting one amino acid. Amino acids that have shown this have been tryptophan and methionine. A recent study, published online December 2 in Nature, a highly respected journal, may help explain some of the health benefits of restricted-calorie diets."
how do you screen for one amino acid that may keep popping up in a hundred different foodstuff in various amounts? Unless you took a daily dose of something to chelate out that one a.a. from the body. Hmm....
Karma fed to this user will be promptly burnt. Be warned; be wary.
RTFA indeed, if you read as far as the third paragraph you'd know that it was also proven on mice, dogs, and baboons. That makes this pretty likely to apply to humans as well. Though I'm confused as to why the summary says that tryptophan also has this property, as the article doesn't even use the word. I couldn't find the original Nature article, but the linked one certainly said nothing about it.
Quidquid latine dictum sit, altum videtur.
What's methionine found in?
From wikipedia: Methionine is one of only two amino acids encoded by a single codon (AUG) in the standard genetic code (tryptophan, encoded by UGG, is the other). The codon AUG is also the "Start" message for a ribosome that signals the initiation of protein translation from mRNA. As a consequence, methionine is incorporated into the N-terminal position of all proteins in eukaryotes and archaea during translation, although it is usually removed by post-translational modification.
Wild speculation on my part is that methionine and tryptophan could be amino acids that have particularly strong effects on protein synthesis generally (e.g if you don't have enough methionine you can't even start making each protein).
So... what they discovered is that limiting diets reduce reproduction at the expense of lifespan?
Color me skeptical, but this is not exactly new. It's well known that limited diets reduce reproductive metabolism in favor of survival. After all, what good is reproduction if you don't live to do it.
Now, I'm not saying this is all bunk. I don't know. What I am saying is that all this really proves is that methionine is necessary for egg-laying and lifespan in Drosophila. That's a far stretch from saying that reducing methionine increases lifespan in well-fed humans. In fact, what TFA says is that there is a discrepancy in studies. In fact, TFA doesn't even mention tryptophan, so I don't know where the submitter got that.
Unfortunately, I can't access the Nature article right now. However, I'll definitely be taking a look at it tomorrow, because I am extremely skeptical of these claims.
True, to get sleepy from the tryptophan in turkey, one would have to figure out how to eat that turkey without eating the other amino acids present... it only promotes sleepiness when consumed on its own.
However, there is still a twisted nugget of almost truth if you follow one of the current theories on postprandial sedation. The whole chain goes something like this:
Eating large amounts of starchy food -> increased blood sugar levels.
elevated blood sugar -> insulin release
elevated insulin levels -> increased absorption of long chain amino acids into muscle tissue
increased absorption of long chain amino acids -> decreased blood serum levels of long chain amino acids
decreased serum long chain amino acid levels -> increased serum ratio of short chain/long chain amino acids
tryptophan is a short chain amino acid, and higher serum ratios of tryptophan lead to increased production of seratonin and melatonin, leading to sleepiness.
So yes, there is some tryptophan in turkey. And tryptophan supplements can induce sleepiness, but they need to be taken on an empty stomach to do so. That is because digesting pure tryptophan will also increase the serum ration of tryptophan to other amino acids. However in a traidional thankgsiving feast, it's the massive overload of carbs in the stuffing, corn, bread, mashed potatoes, green bean casserole, sweet potatoes, cranberry marshmallow fluff, pie, whipped cream and even gravy (it's thickened with starch) that lead to the sleep inducing increased serum ratio of tryptophan. Some of the sleepiness can also be blamed on redirecting a good portion of blood flow to the digestive system to tackle the huge meal just consumed. A glass of wine or two can provide enough alcohol for the final KO providing the need to sleep.
I'll never make that mistake again, reading the experts' opinions. - Feynman
Bronze age != hunter gathers.
:S
/.er wants to, go right ahead.
And the abundance thing is true in some places... In places where we still see hunter gather societies they haven't grown because their food is such a pain in the ass to get it sucks up all their time. And the reason hunter gather groups were LIMITED to sizes of about 50 people was because of scarcity. If food were less scarce larger populations could have been supported. Perhaps there was a good food:human ratio but like starving people in africa prove. Food existing doesn't mean you can get at it.
Err... and you get progressively more 'naturalistic fallacy' and end up on the bible
I got work or I'd debate, if another