Origins of CR Benefits

[Guest guest]

Hi folks:

Here's a thought. Perhaps, just maybe, there is a way to reconcile some of the

apparently conflicting evidence we have been discussing recently about how CR

works.

Just as Dr. Heaney believes it is a mistake to assume that only one disease will

be caused by a deficiency of a single vitamin, perhaps it may also be mistaken

to believe that the multiple benefits of CR are the result of a single

mechanism, resulting from a single restricted dietary component.

As previously noted, there is some evidence that restriction of methionine alone

accounts for most of the reduced aging rate associated with CR in mice. It is a

small step from that to imagine that MET restriction alone might therefore

account for the majority of the extension of maximum lifespan observed with CR.

But what of all the other benefits ........ those which result in a

rectangularization of the survival curve without, necessarily, being accompanied

by an extension of maximum lifespan: dramatically reduced deaths from cancer

(observed in mice); dramatically improved cardiovascular risk biomarkers,

observed in many species including humans; improved diabetes risk indicators;

enormously improved biomarkers of inflammation, a phenomenon common to so many

diseases in humans and animals; to name a few of the more remarkable of CR's

benefits. Certainly these will improve average lifespan, but they may have

nothing at all to do with extending maximum lifespan.

Is there some good reason to suppose that it is exactly the same mechanism which

accounts for all these benefits, including the benefit for maximum lifespan? Or

might it just possibly be that the maximum lifespan benefit derives almost

entirely from one aspect of CR, while the rectangularization benefits might each

be explained by the restriction of other dietary components - or combinations of

components - and not from MET restriction at all?

So, while, perhaps, restriction of some specific amino acids may explain all of

the extension of maximum lifespan, maybe the restriction of some carbohydrate or

fat or other amino acid components may explain the other - rectangularization -

benefits. We know for sure, I think, that some dietary fat molecules are

implicated in worsening cardiovascular risk biomarkers.

So, might CR researchers be falling into the same type of logical error Dr.

Heaney attributes to the 'one-vitamin-deficiency-one-disease' conventional

wisdom?

Rodney.