Why we get old, and ways to prolong life

Aging is the process that follows a human being from birth to death. There are many factors that cause aging, and many theories that use these factors to explain aging. Aging cannot be stopped; however, the debate stands on how life can be prolonged. This essay will discuss theories of aging, and ways that these theories give for life prolonging.

Aubrey de Grey uses the analogy between a human being and a machine. He states that the same way machines deteriorate, the human body gets old. Similarly to machines in need repair, humans use different medications in order to cure their diseases and prolong their lives[1]. However there is still no unique definition on the cause of aging but there are many theories on what causes aging.

In order to define aging, Grey quotes Edward Masoro’s : “deteriorative changes with time during postmaturational life that underlie an increasing vulnerability to challenges, thereby decreasing the ability of the organism to survive.”[2] Grey is a renowned scientist who graduated in Cambridge. Grey thinks that life can be prolonged to extremes. According to Grey there are seven components of aging. The Economist properly paraphrases him when saying “The seven sisters that Dr de Grey wishes to slaughter with SENS are cell loss, apoptosis-resistance (the tendency of cells to refuse to die when they are supposed to), gene mutations in the cell nucleus, gene mutations in the mitochondria (the cell's power-packs), the accumulation of junk inside cells, the accumulation of junk outside cells and the accumulation of inappropriate chemical links in the material that supports cells.”[3] Grey proposes a method that contains two steps by which the seven components of aging can be stopped and life can be extended. The first one is to slow down or prevent the seven components from making our organs grow older. The first step will deal with the last five components of aging. This process includes using antioxidant chemicals such as Vitamins to stop the deterioration while the second step relaties on the process of replacing deteriorated cells with stems cells. Thomas Kirkwood is another eminent biologist who proposed the Disposable Soma Theory. According to Sharon Phaneuf, the Disposable Soma Theory :”[…] does not implicate genes as being involved in the aging process but focuses on the idea that cell maintenance (DNA repair, protein turnover, antioxidant defenses, etc) is costly.”[4] The theory is basically focused on the energy that human body (soma) spends, which in turn causes aging. Kirkwood describes aging by categorizing cells and their food consumption in the following way: “Two types of cell - those connected with reproduction and those connected with body maintenance - vie for the body's resources, and the sex cells win. Aging is the price we pay for sex.”[5] The only way that the body gets energy is through food. Therefore, we make the assumption that in order to live longer a human body has to be supplied with the proper amount of food. On the other hand, many experiments have been done on different animals. They conclude that if the body is supplied with less amount of food than normal it can live longer. The experiments that started in 1930 prove the opposite. These researches say that “From threadworms to mice, putting an animal on a diet that is near, but not quite at, starvation point prolongs life--sometimes dramatically.” [6] However, living in starvation makes the level of reproduction lower than normal. David Sinclair, a professor at Harvard Medical School, instead on focusing on the theories of aging, channeled his research on the way we can extend our life. Referring to the experiments conducted on mice (mentioned above) , Sinclair agrees that even though eating less than normal extends lifespan, it lowers chances to give birth to healthy children. He claims that women, who are always on a diet, have lower chances to have children. Sinclair proposed a solution on how to maintain good reproduction while prolonging life. Sinclair suggests that eating less than normal is not the perfect solution since it lowers reproduction level. According to Sinclair “The billion-dollar trick would be to persuade the body it is starving when it is not. That way people could live longer while eating normally. They might even, if the mechanism can truly be understood, be able to reproduce, as well.”[7] Sinclair states that in order to live longer we need to make our organism produce more sirtuins (a particular kind of proteins), which “control[s] the abundance of a regulatory molecule called nicotinamide adenine diphosphate which, in turn, controls the release of energy in the mitochondria.”[8] Sinclair found out that red wine has a certain kind of molecule that activates sirtuins. Aubrey de Grey and David Sinclair agree that the Mitochondria are the cause of aging.. “ Mitochondria has two characteristics, which lead to cellular decline. The first is their absolute indispensability to the cell […] and the second is their vulnerability.”[9] Grey suggests that antioxidants and the proper use of vitamins will help us defeat the effects of mitochondria in contrast to Sinclair, who says that resveratrol (found in red wine) will help. These all are hypothesis while no one has managed to find out the exact cause of aging. These are all arguments that are based on biological research, however it is difficult to find the cause of aging, since the process of aging involves different cells. If it is true that eating less will make us live longer, it is still a fact that it will make us weaker, which results in an increased probability of cessation.

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[1] DE GREY 193-194

[2] The economist. 1/5/2008, Vol. 386 Issue 8561, p 76-78
[3] http://grove.ufl.edu/~cleeuwen/Theory.pdf
[4] http://www.timeshighereducation.co.uk/story.asp?storyCode=158498§ioncode=26
[5] The economist. 1/5/2008, Vol. 386 Issue 8561, p 76-78
[6] The economist. 1/5/2008, Vol. 386 Issue 8561, p 76-78
[7] The economist. 1/5/2008, Vol. 386 Issue 8561, p 76-78
[8] De Grey: The Mitochondrial Free Radical Theory of Aging p.14