Just How Accurate Is an At-Home DNA Test for Diet and Exercise?

DNA tests are exploding on the market. In fact, you can probably name a few people who’ve taken one. Maybe you’ve taken one. These tests can tell you if you’re at risk for a disease and even shed light on your — or your pet’s — ancestry.

The latest DNA tests claim to use genetics to build personalized meal plans and workouts to help you achieve your nutrition and fitness goals. But can you really build a DNA test for diet and exercise, and would it really work?

How Do I Take an At-Home DNA Test?

You’ll receive a DNA test kit in the mail, and you’ll either spit in a tube or take a swab of your cheek for your DNA sample. Then you ship the cells off to a lab for analysis. If you’ve already taken an at-home DNA test, you might be able to use those results.

A DNA test for diet and exercise looks for certain mutations in your genes and for any predispositions you might have — say, if you’re lactose intolerant or injury-prone. The test will also show you how your body metabolizes fat, carbohydrates and protein, and it’ll uncover markers that are related to exercise performance.

Based on your results, you’ll be given a personalized meal plan, exercise routine and other support services to meet your fitness, weight loss or wellness goals.

Does It Really Work?

That’s tough to say. An at-home DNA test doesn’t have to meet the same medical or scientific standards set for clinical genetic tests.

“It’s too soon to say whether these services are helpful in the way people want them to be,” said Katherine Carithers, MHA, RD, CSO, LDN, CNSC, a clinical nutrition manager at Lahey Hospital & Medical Center in Burlington. “These tests are so new that there’s not enough evidence to know if they’re validated.”

One study in the journal Nature found that direct-to-consumer genetic tests had a false-positive rate of 40 percent. This can lead to a lot of unnecessary stress and worry when it’s related to something serious, such as your risk for disease.

Carithers says that it’s important to make sure you’re not getting information you don’t want — such as your disease risk — and to find out if the company provides an adequate interpretation of the results you’re getting. Many at-home DNA tests simply provide results without any explanation as to what they actually mean. For instance, you may test positive for a certain mutation, but the test might not tell you exactly what it means for your health.

“Nutritional genomics is still a new science, so, as a dietitian, I wonder what people will do once they receive test information,” Carithers said. “Do you get access to a genetic counselor or someone with training in genetics to help you make sense of the results? Will people decide not to see their doctor based on their results?”

What Should I Look For?

Although DNA tests for diet and exercise don’t have enough evidence to back up their use in a clinical setting, Carithers says she’s excited about the possibility of someday using genetic information to tailor wellness recommendations. The Academy of Nutrition and Dietetics has been keeping tabs on this technology and its emerging research. It doesn’t recommend using these DNA tests in medical practices, but it thinks that more dietitians could be trained to use and interpret this information as data accumulates.

If you decide to try one of these services, do your research. Not all services provide the same level of detail, and they’re not all tailored toward the same goals. Some take an overall lifestyle approach, while others are more focused on exercise or sports performance. The National Institutes of Health provides some advice on what to look for when picking a test.

  • Get a detailed list of what genetic variations are being tested and the scientific evidence showing how those variations affect your nutrition.
  • Ensure the sample will be sent to a laboratory that’s certified to meet the federal regulatory standards set by the Clinical Laboratory Improvement Amendments.
  • Find out how your data will be kept safe. You’re sharing a large amount of personal information when you send in a DNA sample. Some of these genetic-testing companies — such as Ancestry and 23andMe — have sold DNA information to researchers compiling statistics on global health. Find out if the company will share your information with any other parties before sending a sample in.

Adopting a healthier lifestyle involves commitment and changes to your normal routine. These can be hard to stick to. Nutritionists and registered dietitians are always valuable resources to help you develop personalized meal plans or exercise routines that fit within your lifestyle, and they’ll encourage your success along the way.

“In our nutrition clinic, we tailor plans for people based on their medical history, current lifestyle and changes they’re willing to make,” Carithers said. “We try to meet people where they are, and make smart goals based on what their motivation is.”

For more information on Lahey Health’s nutrition services, visit our website.


*The content on this website is for informational purposes only and is not medical advice. Please consult a physician regarding your specific medical condition, diagnosis and/or treatment.

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