How much do genes determine your future health? Genes carry the information that codes for physical characteristics. For example, you have blue or brown eyes because of the eye color genes you inherited from your mother and father. These genes determine how much melanin, or pigment, is inside the cells that make up the iris of your eyes.
What are genes anyway? They’re segments of DNA that carry the information that makes you a living organism. This information determines your physical characteristics and even your risk of developing certain diseases. In fact, genes carry the information that tells your cells what proteins to produce and how to do it and that affects how you look, feel, act, and function. But as you’ll see, it’s not all set in stone.
You can’t change the sequences of DNA, or genes, you inherited, since they’re determined before birth, so you might think you’re stuck with the genes you have and you have little control over how they behave. Yet scientists believe that’s not the case. In fact, you may be able to change how and whether certain genes are expressed based on your environmental exposures and lifestyle.
The Expression of Some Genes is “Flexible”
Although your genes determine certain immutable things about you, such as the color of your hair and eyes, many genes you carry in your DNA may or may not express themselves fully or at all, depending on outside influences, including lifestyle. Thanks to a relatively new science called epigenetics, scientists now say you can turn on and off the expression of some genes in response to factors like lifestyle and environmental exposures.
Here’s an example: You may have inherited genes from your parents that increase your risk of developing heart disease or a heart attack, but if you eat a heart-healthy diet, exercise, manage stress, and get enough sleep, those genes may not express themselves or may do so to a lesser degree.
As a result, you might avoid that heart attack or develop it much later in life than you would have without those lifestyle changes. The same is true of other health problems, such as type 2 diabetes or cancer. In fact, scientists believe that lifestyle habits account for 80% of disease risk, whereas genes are responsible for 20% at most.
You inherited a certain “line of code,” referring to the genes you got from your parents, but you may be able to change to what degree those genes are “turned on”. Here’s another example. Studies show exercise reduces the risk of heart attack even in people at high risk genetically. It can do this in several ways, by improving lipid levels, helping with blood sugar control, reducing inflammation, reining in stress, and lowering blood pressure.
Exercise may also reduce cardiovascular risk at the epigenetic level, by turning on or off genes that affect blood sugar, blood lipids, and blood pressure. You can further reduce your risk by not smoking or using excessive alcohol, eating a healthy diet, and managing stress. You have more control over your health future than you think, so why not take advantage of it?
Most Disease Risk is Impacted by Multiple Genes
In most cases, a single gene doesn’t determine disease risk. Instead, multiple genes and their interactions contribute to the risk of developing a particular health problem. This is true of diseases like type 2 diabetes, cardiovascular disease, and cancer. Plus, environmental exposure and lifestyle influence the expression of these genes. This means there’s even more opportunity to lower the risk of chronic health problems through diet and lifestyle. Know your family history but realize it’s not destiny.
Even diseases that have a strong genetic component can have incomplete penetrance or varying degrees of expression. Penetrance refers to whether a disease is expressed at all. For example, a gene that has a low penetrance may be silent. Expression and expressivity are the degree to which a gene manifests. It may be partially expressed, so that it has some impact, but not as much as you’d expect if it had complete expression. Lifestyle habits can affect penetrance and expression too.
The Bottom Line
Now you know why a healthy lifestyle is so important. You can’t rewrite your genes, but you can influence the expression of some genes through lifestyle. This is especially true for health problems caused by multiple genes, like cardiovascular disease, cancer, and type 2 diabetes. It’s a compelling reason to upgrade your diet, how physically active you are, and how you manage stress. These are factors you have some control over, so take advantage of them.
Don’t assume that genes are destiny; you have more control over your health future than you think. It’s easy to assume that your health is determined by your genes, that it’s “in your DNA”, and that there’s little you can do about it. That’s a dangerous mindset because it ignores the things you can do to have a positive impact on your health, like stopping smoking, eating more healthily, and exercising regularly.
You can’t control the circumstances into which you were born or the family you were born into; but you can control most of the choices that you make today, including how you eat and how much exercise you take. Take advantage of what you can control, as it turns out, it’s more than you think!
References:
Environ Health Perspect. 2006 Mar; 114(3): A160-A167.doi: 10.1289/ehp.114-a160.
Biomed Res Int. 2017; 2017: 9158572.Published online 2017 Jul 13. doi: 10.1155/2017/9158572.
Physical exercise and epigenetic adaptations of the cardiovascular system. March 2015Herz 40(3) DOI: 10.1007/s00059-015-4213-7.
MedLinePlus.gov. “What is a gene?”
Centers for Disease Control and Prevention. “Genetics Basics”
Epigenetic Influences and Disease. Danielle Simmons, Ph.D. Citation: Simmons, D. (2008) Epigenetic influence and disease. Nature Education 1(1):6.
N Engl J Med 2018; 378:1323-1334. DOI: 10.1056/NEJMra1402513.
Ther Adv Chronic Dis. 2014 Jul; 5(4): 178-187.doi: 10.1177/2040622314529325.
MedlinePlus.gov. “What does it mean to have a genetic predisposition to a disease?”
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