Genes and the Mind
While it has become generally accepted that our state of mind plays some role in health and disease, most people believe that the ultimate determinant of longevity resides in their genes. Whenever I have asked a patient how long he or she expects to live, their first instinct is to say, “Well, my mother died at age X, and my father…” This is another way of saying that my genes are my fate.
The twenty-first century has been heralded as the age of the genome, and medical genetics is widely touted as the future of health care. Diseases will soon be diagnosed by identifying the faulty gene; therapy will either fix or replace it. While genes are undeniably important factors in causing disease, their roles have been vastly overemphasized. For the most common diseases such as cancer and atherosclerosis, genes are predispositions, not inevitabilities.
Identical twins have the same genetic risk for disease, yet several studies have shown substantial differences in their health histories. This is because another crucial factor in determining one’s propensity for disease: an individual’s environment. According to Craig Venter, former CEO of the company that first decoded the human genome, “The wonderful diversity of the human species is not hard-wired in our genetic code. Our environments are critical.”
A recent report in the New England Journal studied 44,788 twins to evaluate the comparative importance of genes and the environment in causing the most common types of cancer. The study concluded: “Inherited genetic factors make a minor contribution to susceptibility in most types of cancer. The overwhelming contributor to the causation of cancer is the environment.” It is now widely accepted that 80 to 90 percent of human cancer is due to nongenetic factors.
The overriding importance of environmental elements is also clear in the development of atherosclerosis, the number one killer in the United States. Atherosclerosis is a multifactoral disorder resulting from an interaction of several predisposing abnormalities such as high cholesterol, hypertension and diabetes. Research has conclusively shown that reducing these risks substantially decreases the probability of having a heart attack or stroke. For example, a loss of just 7 percent of body weight in obese people reduces the incidence of diabetes by 58 percent, while shedding 10 pounds will normalize the blood pressure of those with borderline hypertension, no matter what their genetic propensity.
The human genome project has given us a more nuanced understanding of how genes work. It is now clear that they are not static blueprints that dictate our biological behavior. Most genes have switches, called promoters that control how, when, and even if they become active, a phenomenon known as gene expression. Other regulatory elements, called gene enhancers, also play a role. Even slight alterations in promoters or enhancers can lead to dramatic changes in gene expression. But the factors that determine whether or not genes are turned on or off, and for how long, remain largely unknown.
Animal studies have begun to show that social, behavioral and environmental elements can determine whether or not genes are expressed. For example, stress has been demonstrated to cause diabetes in genetically prone animals, while those with the same genetic susceptibilities not exposed to stress are less likely to develop the disease.
Recent insights into Pavlov’s famous conditioning experiments in dogs provide another striking example. A century ago, the Russian scientist showed that the brain of dogs could be trained to anticipate the arrival of food. We now know that this type of training changes the brain through the expression of seventeen genes that have been given the name CREB genes.
These findings demonstrate that a change in mental conditioning not only affects gene expression, but also can actually change the way our genes operate. They prove that our genes no longer should be thought of as immutable determinants of our fate, but as dynamic entities, switching on and off in response to outside influences, as much the result as the cause of our mental, emotional, and biological processes.
People with a strong will to live understand that when they take life-enhancing measures, their health and longevity will be favorable affected, regardless of their genes. They take responsibility for their lives instead of being victims of events. Each and every one of us has the resources within to affect our health and longevity.
Richard Helfant, MD, a Harvard-trained cardiologist, pioneered the development of cardiac electrophysiology and nuclear cardiology. Courageous Confrontations, Dr. Helfant’s latest work, is about how to use the mind-body relationship to combat disease.
Our Genes are Not Our Fate
While it has become generally accepted that our lifestyles play a role in health and disease, most people believe that the ultimate determinant of longevity resides in their genes. Whenever I have asked a patient how long he or she expects to live, their first instinct is to say, “Well, my mother died at age X, and my father…” This is another way of saying that my genes are my fate.
The twenty-first century has been heralded as the age of the genome, and medical genetics is widely touted as the future of health care. Diseases will soon be diagnosed by identifying the faulty gene; therapy will either fix or replace it. While genes are undeniably important factors in causing disease, their roles have been vastly overemphasized. For the most common diseases such as cancer and atherosclerosis, genes are predispositions, not inevitabilities.
Identical twins have the same genetic risk for disease, yet several studies have shown substantial differences in their health histories. This is because another crucial factor in determining one’s propensity for disease: an individual’s environment. According to Craig Venter, former CEO of the company that first decoded the human genome, “The wonderful diversity of the human species is not hard-wired in our genetic code. Our environments are critical.”
A recent report in the New England Journal studied 44,788 twins to evaluate the comparative importance of genes and the environment in causing the most common types of cancer. The study concluded: “Inherited genetic factors make a minor contribution to susceptibility in most types of cancer. The overwhelming contributor to the causation of cancer is the environment.” It is now widely accepted that 80 to 90 percent of human cancer is due to non-genetic factors.
The overriding importance of environmental elements is also clear in the development of atherosclerosis, the number one killer in the United States. Atherosclerosis is a multifactoral disorder resulting from an interaction of several predisposing abnormalities such as high cholesterol, hypertension and diabetes. Research has conclusively shown that reducing these risks substantially decreases the probability of having a heart attack or stroke. For example, a loss of just 7 percent of body weight in obese people reduces the incidence of diabetes by 58 percent, while shedding 10 pounds will normalize the blood pressure of those with borderline hypertension, no matter what their genetic propensity.
Genetic diseases generally fall into one of three categories. The first, called “chromosomal disorders,” are caused either by excess or a deficient number of genes. Down’s syndrome is an example of this type of disorder. The second, referred to as “simple inherited disorders,” are primarily determined by a single abnormally altered or mutant gene. An example is sickle cell anemia, a disease affecting red blood cells.
The last and most common group is called “multifactoral disorders” because they result from an interaction of multiple genetic and environmental factors. Coronary artery disease and most cancers fall into this category. Genetics experts agree that the risk of inheriting a disease is substantially lower in the multifactor group than it is in the first two groups.
Experience has convinced me that in addition to genes themselves, our minds’ conclusions about our genes—something I call mental genetics—also has a major influence on our health and longevity. When we conclude that our parents’ medical histories and their lifespans determine our own, that belief can create its own reality.
Some time ago, I met a man named Jerry who wanted to talk about his heart problem. He began by telling me not about himself, but about his father. Years before, Jerry was with family and friends in the woods near their cabin when suddenly a large snake appeared. Jerry’s father ran up an incline to the cabin, ran back down with a rifle in his hands, shot the snake, and then fell to the ground. He was dead of a massive heart attack at age sixty-four. For jerry, who was thirty-seven at the time, heart disease became “my bugaboo.” As he entered his sixties, he became filled with ominous thoughts and anxieties. His father’s death felt “like a shadow pursuing me.” It culminated in a heart condition when Jerry turned sixty-four. Fortunately, Jerry was lead to a physician whom he respected and whose advice he took. He began a program of exercise, stress reduction and a sensible diet, and has done well since.
People with a strong will to live understand that when they take life-enhancing measures, their health and longevity will be favorably affected regardless of their genes. They take responsibility for their lives instead of being at the mercy of circumstances. Remember: at times, our thoughts about our genes can have as much impact on our health and the genes themselves.
Richard Helfant, MD, is a Harvard-trained cardiologist. His book Courageous Confrontations includes stories which illustrate that genes do not determine our fate.