Just a cigarette. (Credit: Ben Raynal via Flickr)

It’s no secret that diet and exercise can directly impact our health. But for many people, genetic predisposition to disease – be it hypertension or diabetes or cancer – is often perceived as a risk that is out of their hands. New findings in the field of epigenetics, however, suggest that we may have more control than previously thought when it comes to preventing the onset of sporadic or even heritable diseases. Our daily routine, from what we eat for breakfast to the distance we travel to work, could determine whether or not our gene sequences activate or prevent the development of cancer within our bodies.

Researchers from the Boston University School of Medicine put forth an exciting theory earlier this year that, if proven correct, will perhaps identify preventable or stoppable causes of carcinogenesis. They have proposed the existence of processes within our cells that activate specific sequences of DNA that function as epigenetic on/off switches for cancer.

Cancer is the second most common disease in the United States, and scientists have yet to find a prevention and cure that is applicable to all the many varieties of the disease. Yet with this new discovery, we may be closer than ever to understanding where cancer begins – and even where it might end.

The “on/off switch” hypothesis originates from a basic understanding of epigenetics – a field that has been evolving for more than 20 years. This genetic science investigates the expression or suppression of the genes we inherit at birth. The field seeks to explain changes in the way our genes express themselves as a direct result of our behavior and nutrition, as well as our exposure to environmental factors.

Geneticists and oncologists have long recognized that some environmental agitators, like certain chemicals and radiation, cause DNA damage and can affect the way our genes are expressed – that’s how smoking cigarettes or exposure to asbestos can cause cancer. At the same time, most people have only a general acceptance of the fact that we, to a certain degree, determine the state of our own health.

Couch potatoing. (Credit: El Alvi via Flickr)

Many of my patients do not link this understanding with their risk, or their children’s risk, of potentially enhancing their chances of developing a disease. But that is what is at stake when we consider that our lifestyles can independently impact gene expression. These changes that were incorporated into our DNA can too be passed on to future generations.

Inactivity leading to weight gain and obesity, for instance, is a lifestyle choice that many people perceive to only indirectly lead to health problems – and a habit that could only afflict their children through habituation.

A Journal of the National Cancer Institute study published in June compiled the results from dozens of surveys and found that a sedentary lifestyle significantly increases the risks of developing some cancers. The study subjects who spent more time sitting during the day were 24 percent more likely to get colon cancer than those who spent the least amount of time in a chair. Those who watched the most television had a 54 percent increased risk than those who watched the least. The effects on uterine cancer were even starker for those who were the most inactive, with a 32 percent increased risk for women who sat a lot, and 66 percent for those who watched the most television.

Another recent study from the Aston University School of Medical Sciences in Birmingham, England, reported that high cholesterol levels were associated with an increase in a woman’s chance of developing breast cancer. Women with high cholesterol evaluated by the researchers were 64 percent more likely to develop the disease. This may be due to hormonal factors or epigenetic changes associated with persistent elevation of cholesterol.

Epigenetic findings like these are offering some clues to how our lifestyles actually influences processes within our cells that tell problematic genes to activate and start causing problems and helpful genes to deactivate and stop solving problems. Perhaps just as significant is research suggesting that epigenetic traits brought on by our diets and lifestyles can actually become heritable.

If some of our habits are able to cause changes to be incorporated into our DNA and expressed in successive generations (our children’s children), then negative health trends like obesity are an even greater cause for concern. But this understanding gives us the opportunity to responsibly mange our health in order to mitigate diseases that we previously thought were unavoidable.

So what does this all mean for us? We know because of constant reminders how our important our everyday health habits are – eat healthy, exercise, don’t smoke. But epigenetics ups the stakes. It means decisions we make about how much TV we watch or what we eat may actually impact whether or not we change our DNA. It means doctors like me who specialize in cancer care need to focus even more on encouraging people to live healthier, so they can potentially avoid the diagnosis in the first place.

We cannot rely on advanced treatments and new biotechnologies to overcome the personal value of making smart choices about the way we live our lives.