Why Can't We Live Forever?

Humans have lusted after immortality for as long as they have been alive. Once, alchemists sought to create the Philosopher's Stone that could be used to create the Elixir of Life; legends of various cultures' mention searching for the Fountain of Youth. So far, the quest has been unsuccessful, we still die.

The more days that you have been alive, the more likely you are to die. Why? What do you do every day that leads inexorably to your death? The answer has been well-documented in 70 years of scientific literature: you have been eating and breathing. Eating provides your body with the energy stored within the carbon bonds that are contained within the fats, carbohydrates, and proteins that make up your diet. Breathing brings oxygen to your mitochondria to carry away the carbon debris that forms when these bonds are broken apart. This single critical activity, called oxidative metabolism or respiration, which is absolutely essential for your daily survival, is the most important factor that very slowly, minute-by-minute and day-by-day, ages you until you die. In addition to oxygen, the air you inhale contains 73 percent nitrogen. During respiration, nitrogen and oxygen are converted into highly reactive molecules that initiate a series of biochemical changes that lead to your death.

The generation of reactive oxygen and nitrogen species is an inevitable consequence of life. Ordinarily, the formation and degradation of reactive oxygen and nitrogen species are regulated by cellular defense systems that include a group of scavenging enzymes able to remove oxidants or their precursors. In addition, non-enzymatic antioxidants such as Vitamins E and C delay or prevent the production of reactive species. Repair and removal systems complete the damaging defense. However, even if these preventive and repair systems are working efficiently, they cannot fully prevent oxidative damage. This imbalance between the excessive production of reactive species and the body’s ability to detoxify them or repair the resulting damage is termed “oxidative stress.” Oxidative stress predisposes us to numerous physical and psychiatric illnesses that may last for many decades. For example, oxidative and nitrosative stress mediate the cross-sensitization between bipolar disorder and migraine.

Oxidative stress directly damages cellular proteins throughout the body. The protein damage is recognized as a significant pathophysiological event leading to disease and aging. Damaged proteins predispose humans to numerous age-associated diseases, including (but not limited to) Alzheimer’s disease, alcoholic liver disease, coronary artery disease, chronic obstructive pulmonary disease, non-alcoholic fatty liver disease, mild cognitive impairment, metabolic syndrome, Parkinson’s disease, rheumatoid arthritis and Type 2 diabetes, lethal prostate cancer, sickle-cell disease, sepsis, psoriasis, interstitial lung disease, multiple sclerosis, renal failure, autism spectrum disorder, diabetic complications and oral squamous cell carcinoma. The critical role of these toxic byproducts of protein oxidation and nitration is so well understood that they are now being used as biomarkers of disease status in clinical settings.

Mitochondria are the primary generators of age-enhancing oxidative and nitrative byproducts. Smoking, obesity, excessive caloric intake associated with extreme exercising, heavy metal exposure, pollution, and excessive alcohol consumption also contribute to the augmented formation of reactive oxygen and nitrogen byproducts that accelerate multiple aging processes.

That’s why we are constantly being reminded to consume fewer calories every day (the only scientifically valid way to slow the aging process), eat anti-oxidant rich fruits and vegetables (to defend your body from the consequences of breathing), stop smoking, and reduce exposure to pollutants (both produce oxidative stress and inflammation) to live a healthier life. However, even if you do all of these things, you will not live forever.

It is currently thought that the maximum life span of about 117 years. Obviously, most of us do not live that long. Why? Part of the answer is that we eat all of the time, and move around all of the time, and therefore must keep breathing; thus, we are vulnerable to the consequences of oxygen permeating our body. If you could only stop eating and breathing, well, you would die. There is no way out of this conundrum because billions of years ago our cells became dependent upon mitochondria. Unless you can find the Philosopher's Stone.