Maybe you know a smoker who never exercised but lived happily into his old age. Or you might read about a vegetarian-loving marathon runner who suffered a heart attack in middle age.
These stories can make you think: If your health is just written into your genes, what’s the point of all that exercise and healthy eating? Why not do what you want?
But these stories stick with us because they’re unusual, says Laura Zimmermann, MD, medical director of the Rush University Prevention Center. They are examples of what scientists call “outliers.”
The reality, Zimmerman said, is that for most people, lifestyle habits like eating healthy foods and exercising regularly are beneficial to age-related health problems such as heart disease, type 2 diabetes, cancer and Alzheimer’s disease. have a great impact.
So is it just a matter of lifestyle? not completely.
Zimmerman says your genes can increase your risk for a variety of diseases. But they don’t usually work alone. It’s rarely a single gene that determines whether you get sick.More often than not, you inherit some genetic traits that make you better possible Sick, she said.
Even this is not set in stone. That is, these genetic traits (genetic predispositions) may not affect you at all unless they are triggered by your surroundings (environmental factors) or some aspect of your lifestyle.
These “epigenetic changes” affect the way your genetic material, or DNA, functions in your body. In the case of cancer, for example, the changes might turn on a gene that makes abnormal cells grow, or the changes might switch. leave genes that inhibit their growth.
To further complicate matters, there isn’t just one switch per gene. Even six switches. “Probably hundreds or thousands,” said John Kelly, MD, MPH, president of the American College of Lifestyle Medicine.
This complexity makes it harder for scientists to pinpoint exactly which epigenetic change is responsible and how it increases your risk of a particular disease. But experts believe lifestyle factors such as poor diet, smoking and lack of exercise play a significant role. “They’re actually pushing gene expression into negative territory,” Kelly said.
They play such an important role in so-called “diseases of aging” such as diabetes and heart disease that they are best described as “diseases caused by toxic lifestyles over time,” Kelly said.
For example, heart disease is the number one killer of men and women in the United States. Why?
“I have a colleague who says coronary heart disease is a food-borne disease,” Kelly said. “He’s right! For the vast majority of people, it’s food-induced and can be reversed.
Food directly affects your health through nutrition. It is also indirectly linked to heart disease risk factors such as obesity and high blood pressure. For example, there are more than 300 genetic variants that may increase the risk of high blood pressure. But even with high-risk genes, you can usually reduce your risk of heart disease by a third through a healthy diet and regular exercise. (You may also need medication to lower your blood pressure—ask your doctor.)
For optimal heart health, experts recommend eating a plant-based diet. That doesn’t necessarily mean you have to eat a vegan or even vegetarian diet, Zimmerman said. “The goal is to replace some processed foods with whole foods, including fruits and vegetables.” Look for whole grains, lean proteins (including nuts and seafood), and check the packaging for added salt and sugar. If you’re not sure how to design your own heart-healthy diet, talk to your doctor.
For exercise, experts recommend 150 minutes of moderate physical activity per week. That’s 2 hours and 30 minutes per week, less than 30 minutes per day. And you don’t have to run the Boston Marathon. Taking a walk around the block, or doing some gardening, or even dancing can do the trick.
By investing this little time, you can lower your risk for a variety of diseases, whether or not you’re genetically predisposed to any one disease. However, Zimmerman said, most people simply don’t do this.
Smoking is one of the greatest risk factors for heart disease. This is true whether or not you have a genetic predisposition to heart disease. If you smoke, consider quitting, especially if you have or are at risk for heart disease.
Your doctor can also help you find a program to help you quit smoking.
Your health habits and environment interact with your genes in similar ways for other diseases, including type 2 diabetes, obesity, high blood pressure, and, to a lesser extent, some types of cancer.
Type 2 diabetes often runs in families. Multiple genetic variants, including KLF14, ENPP1, and many others, can increase the risk of diabetes by up to 30%. But dietary factors, including how much you drink, whether you smoke, and how active you are, may alter the balance in some way, perhaps by turning a genetic switch on or off.
It is estimated that nine out of 10 cases can be prevented through healthy lifestyle changes.
The landmark Diabetes Prevention Program found that people’s risk of developing diabetes can be reduced by about 65% through a careful diet and exercise plan, while using the blood sugar-lowering drug metformin can only reduce it by 35%.
There is no doubt that genetic factors play a role in many cancers. For example, women with BRCA1 or BRCA2 gene mutations have a much higher than average chance of developing breast cancer in their lifetime, ranging from 45% to 72%. But many women without any known genetic mutations also develop breast cancer.
Perhaps more importantly, there is evidence that good lifestyle habits can help reduce the risk of cancer in people with and without genetic predispositions to various cancers.
While a healthy lifestyle by itself does not prevent all cancers, there is growing evidence that it plays an important role. A study led by Cancer Research UK has found that around four in 10 cancers can be prevented through smart lifestyle choices, such as not smoking, maintaining a healthy weight and eating a healthy diet. Limiting sugar, alcohol and sun exposure may also help.
Indeed, certain mutations in the APOE gene increase the risk of Alzheimer’s disease. If you have a version called APOE4, you’re two to three times more likely to have this condition than the average person. People who inherit two copies may be at 12 times the average risk.
But if you don’t have the APOE mutation, it’s possible, and even common, to develop Alzheimer’s disease. While other as-yet-undiscovered genetic factors may play a role, research suggests lifestyle is an important factor.A meta-analysis of multiple studies, published in Lancet Neurology, About one-third of cases are found to be caused by factors you can control, such as diet and regular exercise.
Again, research shows that diet and exercise are important. While most healthy diets should help, the MIND (Mediterranean DASH Intervention for Neurodegenerative Delay) diet—which emphasizes brain-boosting foods like vegetables, berries, fish, and olive oil—appears to be the best.
Scientists still have a long way to go to unravel the complex interactions between genes and the environment. Zimmerman is careful to note that the impact of these factors varies from disease to disease and from person to person. She said there are undoubtedly situations where you can do all the right things and still develop a serious illness or disease.
The best thing you can do, Zimmerman says, is try to change factors you can control, such as diet, exercise, regular physical exams and taking prescribed medications.
