Longevity, old age, long duration of life. All these are words that have been frequently spoken in recent decades. And it is a fact that life expectancy has been increasing; when we look back 30 years: on average, humans lived 62 years in 1980 compared to 74 years in 2011, according to data from the IBGE demographic census.
Aging is a natural yet complex process associated with the loss of physiological functions. However, the concern with the signs of aging has contributed to a healthier old age.
Currently, those who have just entered the elderly age group are much more active than they were in the 80s. Perhaps we can't even call them elderly - the vast majority are not only concerned with minimizing the signs of age but also with keeping their body and mind in constant activity, even keeping up with the rapid advancement of technology, which rejuvenates them day by day.
But there are studies that show it is possible to act on longevity by modulating some metabolic processes. Caloric restriction (CR) is a possible intervention; it is a reduction in the level of calories consumed that can act on reducing body fat and insulin signaling, on reducing the production of reactive oxygen species, and on attenuating oxidative damage. The mechanisms, as well as the effects, especially in humans, are still not well understood.
That is why researchers work with hypotheses, since CR acts on reducing processes generally related to cellular aging, such as oxidative damage, inflammatory and neurodegenerative processes, in addition to being beneficial for the cardiovascular system and lipid metabolism (Genaro, OS, et al, 2009).
Stem cells also lose their activity with aging. Thus, caloric restriction had a beneficial effect, maintaining the functionality of hematopoietic stem cells in mice.
The same result can be observed in a specific population of stem cells, those from muscle tissue in mice, called satellite cells, which are adjacent to the myofibrils. In the study conducted by Cerletti and colleagues in 2012, the observed increase in the frequency and function of satellite cells in animals treated with CR may be promising for improving, in the future, the effectiveness of treatments in the context of muscle diseases or dysfunctions and even for degeneration caused by aging.
As mechanisms, the group proposes that a metabolic reprogramming is occurring that favors oxidative metabolism due to changes occurring in the regulators of mitochondrial activity, such as the sirtuin protein (SRT1).
This axis, sirtuin, caloric restriction, and longevity has been extensively studied, including other substances that may favor it, such as resveratrol. It has been proposed that resveratrol, a polyphenol present in plants, has antioxidant activity promoting protection of the nervous system against oxidative stress.
Thus, Rascón and colleagues demonstrated that bees treated with resveratrol had an increase in their life expectancy and a decrease in preference for sucrose.
As I mentioned above, the mechanisms are still poorly understood, and the results are sometimes controversial, as researchers use different models for their studies (bees, mice, humans, etc.). Furthermore, in many circumstances, it is difficult to distinguish the effects of a balanced and healthy diet from those arising from CR.
Well, at this moment, we are left to follow the scientific advances that always enhance our network of knowledge.
References
Cerletti M, Jang YC, Finley LW, Haigis MC, Wagers AJ. Short-term calorie restriction enhances skeletal muscle stem cell function. Cell Stem Cell. 2012 May 4;10(5):515-9. doi: 10.1016/j.stem.2012.04.002.
Patrícia de Souza Genaro, Karin Sedó Sarkis1, Ligia Araújo Martini. The effect of caloric restriction on longevity. Arq Bras Endocrinol Metab. 2009;53/5: 667-672.
Rascón B, Hubbard BP, Sinclair DA, Amdam GV. The lifespan extension effects of resveratrol are conserved in the honey bee and may be driven by a mechanism related to caloric restriction. Aging (Albany NY). 2012 Jul;4(7):499-508.
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