Have you been told you've got your father's eye color or your mother's curly hair? These physical traits are a product of genes you inherited from your parents. If your mom has heart disease and your dad has colon cancer, you might also have inherited a greater chance of getting these diseases. But don't worry, it's not a sure thing.
With conditions like cancer, Alzheimer's, diabetes, and heart disease, your genes aren't always destiny. You can likely overcome your heredity and stay disease-free by making smarter health decisions.
Genes and Disease
Genes lead to disease in different ways. "With some diseases, it's almost certain that if you inherit that gene you'll inherit the disease. But for other diseases it's a matter of increased risk," says Soren Snitker, MD, PhD. He's an associate professor of medicine at the University of Maryland School of Medicine.
Some conditions, like Huntington's disease, are caused by a change to a single gene. If you have a parent with this disease, then you've got a 50-50 chance of getting it yourself.
"A person can trump a lot of the inherited risk with very healthy behaviors," says Donald Lloyd-Jones, MD, ScM. He is chair of the department of preventive medicine at the Northwestern University Feinberg School of Medicine.
A good example of lifestyle trumping genes comes from a study of Amish people done by Snitker and other researchers. They looked at a gene called FTO, which contributes to obesity. Amish people with the gene who exercised didn't put on weight. They were able to overcome their gene by staying active.
Trump Your Genes
Not only can you override your genes by taking good care of yourself, you could even change how they function. A growing field of research is looking at how lifestyle choices affect our genetic makeup.
Behaviors don't change the genes themselves. They change the way the genetic information is used to make the proteins that control different body functions.
"The idea is that there are different ways that you can activate or inactivate genes based on what you do in your lifestyle," says Adam Rindfleisch, MD. He is an associate professor in family medicine and fellowship director of integrative medicine at the University of Wisconsin School of Medicine and Public Health.
Should You Get Tested?
Is it worth having a genetic test to learn your disease risk? In some cases seeing a genetic counselor and getting tested can be helpful.
One example is in women with a strong family history of breast cancer. Finding out that you carry a BRCA1 or BRCA2 gene mutation, which greatly increase breast and ovarian cancer risk, can help you take steps to prevent cancer.
With conditions like diabetes and heart disease, the benefits of genetic testing aren't as clear. "Because they come from so many different causes, there don't tend to be dominant genes that we can test for," Lloyd-Jones says.
Even if you know you're at risk for a disease, there may not be much you can do about it.
"In many of these cases, knowing the genetic background for the disease is not going to change the therapy," Snitker says. He mentions the APOE E4 gene for Alzheimer's disease. Even if you learn you have the gene, there aren't any treatments you can use to prevent the disease. That can lead to a lot of unnecessary worry.
In the future, we might have more control over our health thanks to personalized medicine. This practice is based on the idea that we can use our genes to diagnose diseases and hone in on treatments that have the best chance of success based on our unique genetic makeup.
For now, your best defense is to know your family history and your own health risks. Then you can make positive changes to your diet, exercise, and other habits to improve the odds that the disease line in your family stops with you.