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Q: I am considering ordering a genetic test to see if I am at risk for cancer or Alzheimer’s disease. What are the pros and cons?

A:

That’s a question many people are asking now that the FDA has given the green light to third-party direct-to-consumer (DTC) test kits that look for genetic risk information.

A DTC test is a sort of do-it-yourself genetic fact finder. The tests, which cost a few hundred dollars, are not covered by insurance, and the results are delivered directly to you.

The test kit is shipped to you, with instructions. In the privacy of your home, you collect cells — typically, using either a cheek swab or a saliva collection tube — and then send them to a lab. The test results are usually posted on a secure website, where you view your information.

DTC tests can accurately detect genetic markers that increase disease risk. But being at increased risk for a disease doesn’t mean you will definitely get the disease.

For example, if most people have a one-in-a-thousand chance of getting a disease, but you have a marker that triples your risk, that means your risk is three in a thousand — still a very low risk.

There are thousands of markers that indicate you are at increased risk for different conditions, but they don’t perfectly predict whether you will get those conditions. For example, if you have one copy of the APOE4 gene marker, it triples your risk for developing Alzheimer’s disease.

Likewise, if you carry a certain marker within the LRRK2 gene, it increases your risk for developing Parkinson’s disease two to three times. Still, many people with these genetic markers do not get the diseases for which they are at increased risk.

In contrast, some genetic markers indicate you are at very high risk. If you have one of the classic BRCA1 mutations, and you live long enough, you have a 60 to 70 percent chance of developing breast or ovarian cancer.

Before ordering a genetic test, be sure that you really want to know the results, and whether you would make changes in your life based on the findings. If you do decide to order a genetic test, it’s best to choose one that is FDA-approved, and that provides a very clear explanation of the results.

Share the results with your primary care doctor. If the results suggest a higher than average risk of a particular disease, your doctor can advise you on ways to lower the risk.

On the other hand, a test result showing a lower than average risk might falsely reassure you and lead to your paying less attention to a healthy lifestyle.

Q: I want to eat healthier. But I find food labels such as “natural” and “organic” confusing. Does it really make a difference?

A:

You have lots of company. A new language has developed to describe meats, vegetables, fruits and other products in the grocery store.

Not only are the terms confusing, but so are the various associated health claims. The phrases on packaging usually don’t tell you if the food is truly better for your health.

The FDA doesn’t have a formal definition for “natural.” But the agency doesn’t object to the term if a food does not contain added color, artificial flavors or synthetic substances.

For a food to be certified “organic,” the U.S. Department of Agriculture requires the food to be produced according to strict farming and production standards — without genetic engineering, radiation, sewage sludge, or synthetic pesticides and fertilizers.

Animals raised on organic farms receive no antibiotics or growth hormones, are given feed that has been grown organically, and are able to roam around outside. Processed organic foods must not contain synthetic additives. Only foods that are 95 percent organic can carry a “USDA Organic” seal.

Organic foods don’t appear to have a nutritional advantage over conventionally grown food. Both methods use pesticides, and it’s unclear if the pesticides used in organic farming are safer than those used in conventional farming.

We don’t have enough information yet to know if the lack of hormones and antibiotics in organic animal products makes them healthier than conventional animal products, but it’s a reasonable possibility.

For example, pasture-raised chicken contains more omega-3 fatty acids. Grass-fed beef is leaner. Wild-caught salmon tends to have lower levels of toxins, such as mercury.

You likely have seen foods marked as non-GMO. These foods do not contain GMOs (genetically modified organisms). GMOs are created when scientists alter plant DNA to make crops resistant to bugs or fungi.

It’s heavily debated whether using GMOs alters the nutritional quality of food or poses a threat to health. So food labels do not currently need to specify their presence. Certified organic food is free of GMOs.

Organic and “natural” foods are more expensive than conventionally produced foods. Are they worth it? There’s no clear answer; it depends on your budget.

Whatever you choose, it’s always best to go with non-processed products.

Howard LeWine, M.D., is an internist at Brigham and Women’s Hospital in Boston and assistant professor at Harvard Medical School. For additional consumer health information, visit www.health.harvard.edu.

© 2018 President and Fellows of Harvard College. All Rights Reserved. Distributed by Tribune Content Agency, LLC.