Why Do We Age?

Dr. Monica Menesini talks us through it:

Bit by bit

Aging is not one thing, and is rather a whole bunch of things that interact with each other, but it generally refers to the gradual accumulation of internal biological damage and environmental adverse effects—such as ultraviolet radiation, pollution, and dietary toxins—that alter the structure and function of molecules and cells, ultimately leading to the decline of tissues, organs, and the entire organism (that’s you):

• DNA damage accumulates throughout life through normal DNA replication, cellular metabolism, and environmental exposures, creating lesions and mutations that impair cellular function. Mitochondria, which generate ATP for cellular energy, regulate many cellular processes, and help control programmed cell death, are especially vulnerable to damage, and declining mitochondrial function contributes to the deterioration of cells, tissues, organs, and ultimately the organism itself (once again: that’s you).
• Epigenetic alterations matter too; aging changes which genes are switched on or off, altering gene expression patterns so that genes largely inactive in newborns can become more prominent later in life, increasing susceptibility to age-related diseases such as Alzheimer’s disease, and accelerating biological decline in general.
• Declining cellular regeneration is another cornerstone of aging: telomeres, the protective structures at the ends of chromosomes, shorten with each cell division, and when they become critically short, cells stop dividing or die, reducing tissue renewal. Cellular senescence, a protective mechanism that halts the division of damaged or potentially cancerous cells, becomes more common with age, further limiting regeneration. Meanwhile, stem cells, which normally divide without limit to replenish tissues, decrease in number and lose regenerative capacity, impairing tissue repair and maintenance of normal organ function.
• Loss of cellular function and communication is quite an underrated one: aging cells become less effective at identifying and removing damaged proteins, allowing dysfunctional and potentially toxic proteins to accumulate. Alongside this, age-related changes can also disrupt cellular metabolism (per what we talked about up top), increasing stress on cells, while communication between cells becomes less efficient, weakening coordination among tissues and reducing overall physiological function too.

And of course, each of these things makes the others worse—though this does work both ways; improving one can be moderately protective against the others, too.

There’s still more that remains unknown though:

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Want to learn more?

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Take care!