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10 Things DNA Tests Can Tell You About Your Nutrition

Juliette Siegfried, MPH
10 Things DNA Tests Can Tell You About Your Nutrition
Science has pretty clearly demonstrated that the saying “you are what you eat” is often true. Since our food choices are pretty much up to us, it could seem like any diet-related health problems we have are mostly our fault. However, new research has shown that our DNA can play a big role in our overall nutrition, too.

Our genetics can affect our weight, food choices, tolerances, preferences, disease risk, and metabolism, among other factors. In turn, what we eat can affect our DNA and how it functions. That means that some of the home DNA test kits that are commercially available can provide useful information to help you understand your personal nutritional needs, and ultimately make changes that can positively affect your health. 

With that in mind, here’s our list of ten things DNA testing can help you understand.

1. What kind of exercise you should be doing

Studies have shown that at least 13 genes are involved in the three main components of fitness: cardiovascular fitness, muscular strength, and anaerobic power. One example is your genetic predisposition to fast- versus slow-twitch muscle fibers, which affects whether you are better at sprinting and muscle building or endurance sports. 

Apparently, your genetics can influence up to 50% of your ability to succeed in one type of training or another, which means that the remaining 50% could be influenced by your diet and training approach. So getting a DNA test could help you focus your workout on the training that will be most effective for you. 

Here are some additional tips to help you choose a training approach and stay motivated to exercise

2. How dairy affects your digestive system

The enzyme lactase helps us digest lactose, a carbohydrate present in milk. In many people, lactase production stops after we stop drinking mother’s milk, and those people will be unable to consume milk products without experiencing digestive problems. Others continue to make lactase in their adult lives and are able to consume milk with no problem. 

It turns out that your ability to make lactase is at least partially genetically determined, and a test could reveal your status. Northern Europeans, or people of northern European descent, are more likely to be “lactose persistent” and produce lactose in their adult years. 

3. Your metabolic response to starch and risk of obesity

Starch is broken down by an enzyme in our saliva called alpha-amylase. Some people have a genetic predisposition to produce lots of alpha-amylase, while others do not—all based on variations in a gene called AMY1. 

If you have more alpha-amylase, your body will break down starches better, meaning you will be less likely to gain weight or have a high body mass index (BMI). A genetic test should be able to tell you whether starches are going to be worse for you than the average person. 

Some DNA tests focus specifically on insights regarding how your body processes food and the genetic influences like this one that might affect your metabolism and eating habits.

If a genetic test shows you are at greater risk of gaining weight than the average person, don’t worry. You can still lose weight and stay healthy, potentially by using some of these science-backed weight-loss plans

4. Your likelihood of developing certain diet-related cancers

There is evidence that, just as genetic variants can lead to vitamin deficiencies, vitamin deficiencies can lead to DNA damage and a higher risk of certain cancers. Specifically, deficiencies in iron, zinc, and the vitamins folate, B12, B6, and C have been associated with a higher risk of cancer. 

At-home DNA kits such as LetsGetChecked can tell you if you have any vitamin deficiency that you should look out for. Your doctor can advise you about foods to eat and supplements to take to help counter your risk. 

Whether you’re at risk from MTHFR

5. Whether you’re at risk from MTHFR

MTHFR stands for methylenetetrahydrofolate reductase, and it’s a common genetic mutation. People with this mutation are at greater risk of certain health conditions, such as ovarian cancer, and it generally affects the body’s ability to process folate and other B vitamins. 

Interestingly, the MTHFR mutation can also potentially affect the success of your body’s response to platinum-based chemotherapy. 

The 23andMe DNA testing service offers testing for this variant. If you find out you have it, dietary supplementation or eating foods rich in folate can potentially help counter your risk.

6. What kinds of vitamins you might be missing

Your genetics can influence your body’s ability to process vitamins A, B, and D, which can affect your risk of disease. Vitamin D deficiency can affect your bones and teeth and might increase your risk of certain cancers. Vitamin A deficiency can lead to eye problems and even blindness, and Vitamin B deficiency can increase your risk of vascular disease and neuropathy, among other conditions.

Thankfully, LetsGetChecked offers home test kits for vitamin deficiencies, too.

7. The best weight-loss strategies for you

Studies have shown that both persistent thinness and persistent obesity can be genetically determined. There are plenty of at-home DNA testing kits for weight loss and diet. However, that doesn’t mean that obese people cannot lose weight or that thin people cannot gain it.

Instead of just trying the latest fad diet you read about on social media, you can use the results of these DNA tests to help you choose a diet and fitness regimen better suited to your particular body and genetic makeup. That could mean better results in less time.   

8. Whether you are likely to have problems with cholesterol and heart disease

Hypercholesterolemia is a condition that causes very high cholesterol levels and increases your risk of early coronary artery disease (before age 50), heart attack, and stroke. There is an inherited form of this condition called familial hypercholesterolemia (FH), and about 1 in 250 people have it. It is caused by inherited changes in three genes. 

Unfortunately, only about 10-20% of people with FH know they have it, so if a family member has hypercholesterolemia or your doctor suspects you might, genetic testing for FH could be a good idea. 

9. Your risk of developing diabetes

Diabetes has both a strong environmental component and a strong genetic component. Estimates of the heritability of type 1 diabetes are around 30%, while for type 2 diabetes, the genetic component is between 20% and 80%.

FuturaGenetics offers a home DNA test kit that tests for 30 different conditions, including the gene mutation that predisposes people to type 1 and type 2 diabetes. If you are found to be predisposed to diabetes, you can talk to your doctor about more intensive monitoring and a healthy lifestyle plan to help prevent its development. 

10. How strongly you taste specific foods

Food preferences are shaped by many factors, including age, parental feeding practices, and society and culture. They are also shaped by our genes. Our genetic makeup can predict not only our food preferences and tolerances, but the perceived intensity and taste of things like sugar, salt, and bitter flavors. 

In fact, genetics accounts for up to 30% of the variation in how people perceive sweetness. There’s a gene variant that causes people to consume more sodium than people without the variant, and there’s another that means those who have it will not be able to taste bitter substances. There is even a gene variant that affects our responsiveness to the taste of fat. 

While it may not be the most crucial thing to find out about your health, knowing how you experience different tastes could still be useful, such as if you want to keep your salt intake low. Plus, it’s just fun to know the ins and outs of your body.

Home DNA Tests and Your Nutrition

When you’re deciding whether to order a home DNA test for your nutrition, you’ll want to consider the following. 

In addition to genetics, there are many other factors to take into account when making food and diet choices, such as your lifestyle, culture, medical history, and preferences. It’s also important to remember that the reports generated from home-based genetic tests only tell you if you are at risk for certain health conditions, not whether you have them or will get them in the future. 


Your personal genetic makeup can influence your response to foods, diet, and exercise, and the food choices you make can also influence your DNA and how it functions. Genetic testing can shed light on your personal genetic makeup and how your body will respond to what you eat. 

If you decide to pursue genetic testing and you find out anything of concern, the most important next step is to contact your doctor or a genetic counselor. They will be able to help you interpret the results and schedule any further testing or treatment that’s needed.

Juliette Siegfried, MPH
Juliette Siefried contributes to Top10.com as a biomedical writer, editor, and translator with over 30 years of experience. After working as a health communications specialist for the National Institutes of Health in Bethesda, Maryland, and its contractors, Juliette established ServingMed.com, a medical communications business for hospitals, universities, research foundations, and individual healthcare professionals.