An interesting short paper on glucose metabolism and aging caught my eye today; the full PDF is also freely available for those who like more detail.

There is an ever increasing scientific interest for the interplay between cell's environment and the aging process. Although it is known that calorie restriction affects longevity, the exact molecular mechanisms through which nutrients influence various cell signaling/modulators of lifespan remain a largely unresolved issue.

Among nutrients, glucose constitutes an evolutionarily stable, precious metabolic fuel which is catabolized through glycolytic pathway providing energy in the form of ATP and consuming NAD.

Accumulating evidence shows that among the important regulators of aging process are autophagy, sirtuin activity and oxidative stress. In light of recent work indicating that glucose availability decreases lifespan whilst impaired glucose metabolism extends life expectancy [in nematode worms], the present article deals with the potential role of glucose in the aging process by regulating - directly through its metabolism or indirectly through insulin secretion - autophagy, sirtuins as well as other modulators of aging like oxidative stress and advanced glycation end-products (AGEs).

Drench your diet in glucose and calories and pay the price, in other words. For all that various studies have shown that much of the interesting biochemistry of calorie restriction hinges on protein restriction - rather than cutting the carbohydrates like glucose - this paper is an argument for a specific set of calorie restriction benefits to stem from cutting down glucose.

I think that it's plausible based on what we know today to divide the results of calorie restriction into two parts, one relating to protein intake and the reaction of various controlling machineries of metabolism, and the other to the interconnected fat-levels-and-insulin-signaling systems. Sirtuins, a well-funded area of research at the moment, seem to lump into the latter rather than the former in the view put forward in this paper.

If you read around the past few years of calorie restriction research, you'll see a lot of interesting contradictions and poking of holes in tentative theories as new data arrives at a fast rate. That's the way science moves forward, and metabolic biochemistry is a fearsomely complex beast. I suspect researchers will find some presently strong hypotheses to be wrong or incomplete, or that calorie restriction does in fact work differently in important ways when comparing yeast, flies, mice, worms and humans. In many ways, this field is coming to the interesting part - enough data, funding and hard working researchers to pull it all together within the next five years.

Posted by Reason at April 11, 2008 6:59 PM | TrackBack (0)