Understanding the role of genetics in our health has become a central theme in medical research as well as a wellness trend. More people are testing their genetics to better understand their health and know what diseases they may potentially be at risk for.
But if we strive to always eat healthy, drink enough water and exercise regularly, why should we also be worried about genetic risks? Can our genes really outweigh a healthy lifestyle when it comes to certain diseases?
Genes are pieces of DNA (deoxyribonucleic acid) inside our cells that tell the cell how to make the proteins the body needs to function. DNA is the genetic “blueprint” in each cell. Genes affect inherited traits passed on from a parent to a child, such as hair color, eye color and height.
A genome is all of the genetic material in an organism. A human genome is mostly the same in all people, but there are variations across the genome. This accounts for about 0.001 percent of each person’s DNA and contributes to the differences in appearance and health from person to person. People who are closely related have more similar DNA.
Not all differences in DNA have an effect on health or disease risk, but some do. So, as parents pass their genes onto their offspring, some diseases tend to cluster in families. This is why genetics often can tell doctors whether or not you have higher risks for certain diseases.
Although there are many possible causes of human disease, family history is often considered one of the strongest risk factors for many common diseases — things like cancer, obesity and even depression.
According to the American Cancer Society, changes in genes, called mutations, play an important role in the development of cancer.
Mutations can cause a cell to make (or not make) proteins that affect how the cell grows and divides into new cells. Certain mutations can cause cells to grow rapidly, which can lead to cancer. However, only about 5-10 percent of all cancers are thought to be strongly related to an inherited gene mutation. Also, typically several mutations are needed before a cell becomes cancer.
Most cancers start because of acquired gene mutations that happen over people’s lifetimes. Sometimes these gene changes have outside causes, such as sun exposure or tobacco. But gene mutations can also be random events that sometimes happen inside a cell without a clear cause.
While it may seem that environment and lifestyle would determine whether a person is more likely to become obese, according to the Obesity Medicine Association, recent studies suggest that genetics contribute to 40-70 percent of obesity with the discovery of more than 50 genes that are strongly associated with obesity.
One of these genes is the fat mass and obesity-associated gene (FTO), which is found in up to 43 percent of the population. People with this gene may have challenges when it comes to limiting their caloric intake. It also can cause things attributing to obesity like increased hunger levels, reduced satiety, reduced control over eating, increased tendency to be sedentary and increased tendency to store body fat.
Despite carrying the predisposition to increased appetite and slower metabolism, your genes don’t necessarily determine whether or not you will be obese. There are many effective approaches to nutritional, physical activity and behavior that can both prevent and treat obesity.
The Stanford School of Medicine estimates that 10 percent of Americans will experience clinical depression at some point in their lives. Research also shows that this type of depression is also more likely to be shared by siblings and children. A person with a relative who suffers from depression is almost five times as likely to develop it, meaning genetics play a role in our mental health.
However, there are no genetic studies that have identified what specific genes are associated with depression. It is likely that depression is a genetically complex condition involving multiple genes and possibly multiple modes of inheritance.
Whether or not you have a family history of depression, other factors can also contribute to depression, such as brain chemistry, brain structure, hormones and stress levels.
Nature and Nurture
Research and experts have linked genetics to certain diseases — specifically cancer, obesity and depression. But research also points out it’s not the only determiner in our health. Nature and nurture work together. If you do have genetic risks for cancer, avoid smoking and the sun. If your parent has experienced depression before, be aware of symptoms and environmental factors that could lead to developing depression. If you are at risk for obesity, work out and eat right. Knowing your family history can help you understand your risks for certain diseases, but it doesn’t determine if you will get them.