Type 2 diabetes runs in families, but are you inheriting genes or behavior?

Is diabetes hereditary? The nature vs. nurture debate

Daughter Feeding Mom

A child grows up in a household in which a fast food restaurant makes dinner almost every night. The pantry is full of cakes, cookies, canned fruit and other high-sugar snacks.

Activities like playing outside or going for walks almost never happen, which is one reason why the 45-year-old mother was recently diagnosed with Type 2 diabetes.

Sound familiar? This type of lifestyle—full of high-calorie food and inactivity—is the perfect breeding ground for Type 2 diabetes.

Type 2 diabetes typically isn't an issue for kids. But because the mother was diagnosed before age 50, this child’s risk of developing Type 2 diabetes is 1 in 7, according to the American Diabetes Association. If the father is diagnosed as well, the child’s risk jumps to 1 in 2. The condition is an epidemic in the U.S. and rising fast among young people. 

Many kids grow up seeing parents or grandparents checking blood sugar levels and doing insulin injections. But here’s the question: If diabetes runs in your family, what’s being passed down—a genetic risk or the risky, unhealthy behaviors?

The answer: Both.

Nature: You Inherit More Than Looks

Genes are like instruction manuals for how our bodies will look, develop and function. But when these genes change, it changes how the body works as well. These changes can be passed from one generation to the next.

For Type 2 diabetes, scientists have found more than 65 genetic changes that can increase a person’s risk of type 2 diabetes by up to 30 percent, according to an August 2013 study in the journal Diabetes Care.

Most of these genes change how our bodies regulate insulin, a hormone that helps the body use or store energy from foods. But even if a person has the genetic changes that increase the risk of Type 2 diabetes, that doesn’t mean that the person will automatically develop the condition.

That’s because diet and exercise may actually play a bigger role—depending on what we learned from mom and dad.

Nurture: Eat and exercise like mom and dad

Genetics aside, there are specific risk factors for developing Type 2 diabetes.   

Type 2 diabetes is an obesity-related condition, meaning that if you’re obese, you’re at risk for developing Type 2 diabetes—and so are your children. That’s because the same unhealthy habits that lead to one also lead to the other—poor diet and lack of exercise.

Take lack of exercise, for example. One culprit is screen time—the 7 hours a day most children spend being sedentary in front of computers, tablets and televisions, says the American Academy of Pediatrics. It’s likely that this tendency to park in front of a TV instead of go to the park comes from the parents. If mom or dad watch two to four hours of TV everyday, their daughter’s risk of watching even more than that is nearly four times higher. Their son’s risk is more than 10 times higher than it would be if his parents turned the TV off, according to an April 2010 study in the journal BMC Public Health.

Moms are especially influential. If she makes exercise a priority, her children are likely to get more exercise as well, reported a March 2014 study in the journal Pediatrics. Regarding how children’s eating habits contribute to diabetes, there’s a lot of blame hurled at fast food restaurants, snack advertising and unhealthy school lunches.

But again, research shows that children are most likely to get unhealthy eating habits from their parents. When parents reach for sugary drinks and pass on the water, or grab the high-sugar processed snack instead of the fruit or vegetable, their children see this and develop the same tendency, according to an October 2013 study in the American Journal of Clinical Nutrition.

But when parents prefer low-fat, low-sugar foods and snack on fruits and veggies, kids learn to enjoy these foods as well, says the National Institute of Diabetes and Digestive and Kidney Diseases. Yes, if a child has a parent with diabetes, it’s possible there’s a genetic risk. But eating healthy and exercising can keep the diabetes risk in check—no matter what mom and dad do.