Part 6: The 9 causes of aging - Nutrient detection

Part 6: The 9 causes of aging - Nutrient detection

Les causes du vieillissement -

The sixth cause of aging that we address is linked to the poor functioning of the nutrient detection chain over time. But what causes this mechanism to malfunction?

Nutrient sensing pathways

In cells, nutrient-sensing pathways adapt the behavior of our cells and the activity of their metabolism to the amount of nutrients available to our cells.

Roughly speaking, at the body level, if there is not enough to eat, the body tends to reduce the animal's sexual appetite and put the body into survival mode to be able to live longer and reproduce in better times. A similar phenomenon occurs at the cell level.

Caloric restriction is also the only scientifically validated method to increase healthy life expectancy in all mammals tested. This increase can lead to a life expectancy extended by 30%, in certain primates for example.

Nutrient sensing involves, not surprisingly, signaling pathways related to insulin and cell surface glucose sensing. This also relates to the sort of central switches that are the AMPK enzyme, which senses nutrient scarcity, and the mTOR complex, which senses amino acid abundance. Sirtuins are also central switches that detect low energy states by detecting the concentration of NAD+ which is also the fuel for proteins that repair DNA...

In theory, it is now assumed that during aging, cellular stress and the number of cell lesions would increase. The levels of free radicals in the body would increase in parallel with this phenomenon, in order to preserve the organism.

Beyond a certain point, these levels would cease to maintain cellular balance and could worsen problems associated with age. The role of free radicals is therefore not yet clear to scientists; This is a question that is really debated.

To summarize, this link between nutrient sensing and longevity explains why some diabetes drugs, such as metformin, appear to extend lifespan via AMPK activation in worms and mice. Moreover, some studies are encouraging regarding its effect on humans. More comprehensive studies are underway on this subject.


Guilhem Velvé Casquillas on