Meanwhile, to fuel the controversy a little more. It seems that models of longevity are characterized by low choline levels (1):
In terms of metabolic commonality, three metabolites choline, TMA and mobile lipids (mainly VLDL) were significantly altered (decreased) in all three long-lived mice [dietary restriction, Ames dwarf, Irs-/-] relative to their appropriate controls.
So, I would be very careful with choline supplementation given all the data we have. Just try getting the Adequate Intake without any free choline and keep meat intake low for now. The evidence for higher choline dosing is weak anyway.
A very important finding, Kismet -- thanks! Have you seen the full text? I wonder if the study reports one way or the other on carnitine: lab mouse chow is vegetarian and doesn't contain carnitine, so you wouldn't expect it to be there to modulate.
On the one hand, this may mean that CR mice (and people?) are less prone to release free choline into the blood and possibly to convert it to TMA, meaning that CR folk are somewhat protected from this effect. On the other hand, it may mean that this is somehow an important mediator of some CR benefits, and overconsuming phosphatidylcholine or taking 'free' choline or carnitine supplements could nix some of our CR benefits.
It also adds another dimension to
my previous comments to the effect that since TMA-induced atherosclerosis could not explain Spindler's finding that carnitine supplementation slightly decreased the LS of AL mice (since mice don't
get atherosclerosis without special modifications to alter their cholesterol metabolism), "the sum of the rodent and human evidence seems to imply a double whammy: accelerated atherosclerosis, AND some other, unguessed mechanism of increased mortality to boot."
This new research implies, first, the possibility that suppressing TMA production is somehow important to the BENEFIT of CR even in genetically normal mice (which don't develop atherosclerosis), and that TMA per se may be bad even for AL mice.
(By the way, it's not just Spindler who has reported a deleterious effect of carnitines on lifespan in healthy mice. Weindruch, who is also one of the very few scientific researchers who really runs proper LS studies (ie, where the controls are not obese, or sickly, or genetically fucked-up, or what have you, but have normal, proper survival from the get-go) found that two separate *cocktails* of supplements *including* /acetyl/ -L-carnitine (ALCAR) slightly shortened the lives of otherwise-healthy mice: one cocktail of ALCAR with lipoic acid, lycopene, and alpha-tocopherol, and one cocktail of ALCAR with CoQ10, lipoic acid, and NADH:
(This is the only reporting of these data that I know. These results come from the
LEF LifeSpan Project, very little of which have ever seen the light of day ...
Reference1. J Proteome Res. 2012 Apr 6;11(4):2224-35. doi: 10.1021/pr2010154. Epub 2012 Feb 27.
Metabotyping of long-lived mice using 1H NMR spectroscopy.
Wijeyesekera A, Selman C, Barton RH, Holmes E, Nicholson JK, Withers DJ.
Edited by Michael, 09 September 2013 - 12:56 PM.