The Damage Done
Aging is wear at the molecular and cellular level, changes that build up over time and lead to malfunction and failure of the systems built of macromolecules and cells. At the high level, this picture is only slightly complicated by the fact that your biochemistry can repair and reconfigure itself in response to circumstances - repair systems wear, malfunction and fail too.
Some forms of damage are more consequential than others, leading to more rapid or serious failure in capacity. Here is one, for example:
The effects of ageing on progressive deterioration of renal function, both in human and experimental animals, are described elsewhere, but the effect of renal damage on overall survival and longevity is not yet clearly established. The wild-type animals of various genetic backgrounds, fed with regular diet, overtime develop severe age-associated nephropathy, that include but not limited to inflammatory cell infiltration, glomerulosclerosis, and tubulointerstitial fibrosis. Such renal damage significantly reduces their survival. Reducing renal damage, either by caloric restriction or by suppressing growth hormone (GH)/insulin-like growth factor-1 (IGF-1) activity could significantly enhance the longevity of these animals. Available survival studies using experimental animals clearly suggest that kidney pathology is one of the important [non-cancerous form of damage] that could affect overall survival, and that restoration of renal function by preventing kidney damage could significantly extend longevity. Careful long-term studies are needed to determine the human relevance of these experimental studies.
Another good reason to be practicing calorie restriction. While we live in an age in which we can seriously consider engineering the restoration of function in complex organs like the kidney in the near future - or even complete replacement with new undamaged tissue grown to order - we don't know when such goals will be accomplished. Why chance damaging yourself enough to miss out on the arrival of that technology?
Technorati tags: health, medical research