by the quality of the air we breathe, by our diet, by tobacco, by drugs and toxic substances, by physical exercise, by mental strain, by the stress we undergo, as well as by the love and friendship which we receive. In the past few years, science has confirmed the validity of these obvious truths. Scientific proof showing that quality of life, psychologically as well as in terms of our environment, modify the state of our genes by activating or deactivating them. Most geneticists now believe that our genes’ behavior can be modified by our life experiences, and that these changes can even be transmitted to future generations. Genetically identical twins with significant differences in lifestyle were studied, for example. As they grew and developed, they were exposed to different experiences, in different physical and psychological environments, and their appearance changed. One stayed healthy while the other contracted cancer. How was this possible? This can be explained by an epigenetic mechanism linked to living conditions. Cancer-protection genes were deactivated in one and not the other. Although they are genetically identical, this is not the case epigenetically. Dr. Arturas Petonis, from the University of Toronto, believes epigenetics may hold the answer to certain unsolved mysteries: why would one monozygotic twin develop a chronic illness and not the other? Why are certain diseases more common in men than in women? It is now accepted that epigenetic alterations play a part in the appearance of cancer, and that they are often far more important than the alteration of the genes themselves. Certain genes are activated or deactivated by living conditions. Cigarettes, for example, not only cause genetic mutations, but also epigenetic alterations, by activating certain genes. Yet another example: researchers have seen more than 220 harmful genes being activated in cancerous cells in severely depressed women with poor emotional support networks; while these same disruptive genes remained inactive in women who were well integrated socially.
These discoveries will have major repercussions on cancer therapy; as epigenetic alterations are reversible, it may not be necessary to systematically kill cancer cells. Restoring the proper activation or repression of certain genes could be essential.
If everything is working properly, our cells regularly renew themselves throughout our life. Some die, others divide, producing two new cells, and this cycle is continually perpetuated. Unfortunately, environmental aggressions can bring about epigenetic alterations which will accumulate with time. Today we can bring these alterations to light at the cellular level and we indeed find that the elderly have more epigenetic alterations than younger individuals. It is even possible to guess someone’s biological age simply by analyzing their epigenetic diagram. The good news is that our epigenetic configuration is not unalterable, we only need to modify our living conditions (diet, breathing, physical exercise, stress levels) for it to improve. Rachel Yehuda, of the Mount Sinai School of Medicine in New-York, studied stress in pregnant women who were in or near New York’s World Trade Center during the events of September 11th 2001. She measured cortisol levels, which indicate stress, in the children once they were born, and these turned out to be quite high. The mothers’ stress had been transmitted to their children. She also tested WWII concentration camp survivors, as well as their children, born much later. She also discovered that cortisol levels in these children were much (up to three times) higher than in the general public. Yet these children, now adults, never experienced the camps beyond what they had been told about them. And they were no more exposed to traumatic events than the rest of the population. Could this effect be due to their parents speaking about this trauma in front of them? Although this could be a partial answer, it cannot explain every case, as even babies less than one year old, to whom these events have not yet been described, have high cortisol levels. Stress levels in these individuals are therefore directly linked to past psychological trauma which their parents underwent. They were transmitted to them epigenetically, in the absence of any other traumatic event. Even more surprising; research shows that parents will ‘anticipate’ their children’s genetic characteristics in the months leading up to conception (Alain Boudet).
In the final stages of sperm and egg maturation, a process called ‘genomic imprinting’ adjusts the activity of specific groups of genes which will shape the identity of the yet to be conceived child (Surani, 2001; Reik& Walter, 2001). Research suggests that events taking place in parents’ lives when genomic imprinting occurs have a profound influence on their child’s body and mind. Being the product of love or of indifference makes a difference; being in the womb of a mother who wishes to be pregnant or one who does not matters (Bruce Lipton).The quality of our intrauterine life will program our vulnerability to cardiovascular disease, heart attacks, diabetes, obesity and myriad other future conditions. Mounting evidence is showing that our intrauterine living conditions are just as influential as our genes on our long-term health and therefore on our longevity. This intrauterine life will determine our future behavior, both psychologically and physiologically, and will continue to influence us throughout our lives.
When speaking about the component parts of our lifestyle, we should not forget to include our thought patterns. Our fears, our anxieties, our inhibitions, are the product of our reactions to the events we live through. They influence our DNA epigenetically. The more questions we ask, the more curious we are, the more we enjoy life, and the more our neurons activate, the more connections are established, the more our brain stays in shape. Aging is best fought off by staying active, intellectually and physically.
Aging as we see it today is the result of all of these disruptive phenomena coming together to increasingly upset our cellular world. We can certainly focus on aggravating factors and reduce risk. Some risks we choose to subject ourselves to: sun exposure, smoking, drinking too much coffee, too much alcohol, taking drugs, eating too much fat etc. This is all the more significant when we combine several of these behaviors. Other risks we endure: extended exposure to low doses of radiation, to pollutants – air pollution from nitrogen oxide and asbestos, dust, rug and carpeting adhesives, cleaning products. All of these disturb our body’s metabolisms. We have good reasons to be optimistic, however, as our lifespan and health are continually improving despite all of this. A girl born in France today has a one in two chance of living to be 100. Today, 90% of women reach their 80s. In 2004 life expectancy was 76.7 for men and 83.8 for women, or an average of 80 years of age for both genders. We could extend lifespan by an extra thirty years for most people, and especially ensure that these extra years be lived in good health. Although we can’t have much influence on our genetic heritage or the environment we live in, we can control our lifestyle, our diet, how we maintain our body, our sleep, our tolerance to stress. The challenge today is not to become immortal, but rather to thrive throughout our expanded longevity.