The basics of genetics are pretty simple — if you have the gene for brown eyes, you are going to have brown eyes. It’s a little more complicated for things such as height or intelligence, but if you have the genes to be tall or smart, you are certainly more likely to be so. Beyond these simple concepts, the study of genetics gets more complex. Unfortunately, we have a tendency to apply simplistic thinking about genetics to more complicated areas such as health and disease. We assume that if you have the genes for high blood pressure, or Alzheimer’s, or obesity, well, that is the hand you were dealt.
The relationship between genetics and disease runs the gamut from very simple to quite involved. Like having the gene for brown eyes, there are relatively rare diseases that are fully genetic, such as sickle cell anemia and hemophilia. Some diseases have a strong genetic component, although having the gene does not always cause the disease. Having the BRCA gene — as Angelina Jolie does — has been estimated to carry a 70 percent chance of developing breast or ovarian cancer.
In fact, the majority of our current health problems are not due to faulty genes, even though genetics may be involved. With all the research being done on the genetics of diseases such as type 2 diabetes and breast cancer, one would get the impression that these are, at their core, genetic. Nothing could be further from the truth. These are primarily lifestyle diseases. For example, only 5-10 percent of all breast and ovarian cancers are thought to be genetic.
Your lifestyle usually determines whether or not you get sick, but your genetic makeup affects which disease you will develop if you do get sick.
One of the best illustrations of this is the “hangover gene” story. Researchers have discovered that some people are less efficient at processing alcohol, due to their genetic makeup. Not surprisingly, these people are more prone to hangovers. This was quickly dubbed “ the hangover gene.”
But is this the whole story? Do people with the “hangover gene” have them every morning? Once a week? How often does this gene actually cause a hangover? Or is that in the genes too?
Of course the answer should be obvious — the hangover gene does not cause hangovers — it’s just that people with this gene would be more likely to get a hangover when they drink too much.
To apply this to our current situation: If you take several people who live a typical American lifestyle — chronically high stress levels and a diet full of refined and processed foods, along with low activity levels — it is highly likely that many of them will eventually develop chronic illnesses. But their diagnoses will be different — some may become diabetic, others will develop heart disease, some will have high blood pressure, some will become overweight and others will have hormonal problems. Some will have several of these problems. These diseases are caused by lifestyle, but each person’s genes influence which of the diseases they develop. Of course, members of a family will tend to come down with the same diseases, which would make one think they are genetic. But family members usually share a similar lifestyle, and it is the lifestyle that actually causes them to lose their health. Once that has happened, their genetics causes them to express similar health problems.
A new area of study in genetics is the field of epigenetics, which looks at the difference between your genetic code, which is inherited, and genetic expression, which looks at which genes are actually activated and affect your health. Epigenetics has shown that lifestyle affects genetic expression. Our genetic code has been compared to a library, full of many different books. Just as we select the books we want to read, leaving others unread, we “choose” which genes will be expressed — and which ones remain unexpressed — by how we live our lives. This is especially true of the foods we eat; different genes will be activated by a meal of whole, intact foods compared to a meal of processed foods and artificial ingredients.
Poor lifestyle is the root of our chronic disease epidemic, not genetics. You might say that our modern lifestyle is the genetic equivalent of reading a Stephen King novel. Researchers contacted 153,000 Americans and asked them about their lifestyles. Their conclusion? Only 3 percent of Americans can actually claim to live healthy lives.
We do have a tendency to like our issues simple, cut and dried. It’s easier to believe that if you have healthy genes you will be healthy, and if you have “bad genes” you will get sick. Of course, that belief takes you off the hook and means you don’t really need to change your lifestyle. We tend to want the easier way out; probably it’s genetic.
Dr. Michael Noonan practices chiropractic, acupuncture and other wellness therapies in Old Town.