Drs. Oz & Roizen: Don’t rely on mail-in genetic testing

I’m thinking about using one of those mail-in genetics tests. Are they reliable? —Gini W., Brooklyn, New York

 

You didn’t say why you wanted a mail-order genetic test done: To find out your ancestry? To determine paternity? To find out if you are at risk for, or may pass on, any inherited conditions? The wisdom of a mail-in test depends on the info you hope to get from it and what you plan to do with it.

For ancestry: Variations in your DNA can reveal where your ancestors might have come from and with whom they might have comingled. The most inclusive test (works on men and women) is single nucleotide polymorphism (SNP) testing: A large number of your SNPs (pronounced snips) are identified and compared with the SNPs of lots of other folks to determine your racial and/or ethnic background. It’s even possible to see how much of the Neanderthal genome still lives on in you.

However, results can change from one service to another depending on the DNA database they use for comparison. Home genetic ancestry tests are not FDA-regulated.

For paternity: These saliva or cheek swabs use around 15 markers to compare a child and a man’s DNA, so that’s pretty good. But it takes Mom, Dad and the child to raise the test’s reliability to 99.9 percent.

But, labs analyzing home samples aren’t necessarily accredited or regulated; some do not do duplicate tests to verify results; and sample errors can happen with contamination in collection, shipping or analysis.

To assess disease risk: Mail-order DNA tests evaluate your potential risk for genetically transmitted diseases, such as some forms of breast cancer or sickle-cell anemia.

The test cannot, though, say for certain that you or your offspring will develop a disease (many risks are modifiable with smart lifestyle choices), how severe symptoms will be or if the disorder will progress over time. You want expert genetic counseling and top-quality medical care before deciding how to act on the information.

I was at the mall when the kids had a day off from school, and it seemed like there were an enormous number of overweight children. Why is this happening to kids?

—Audrey S., Lexington, Kentucky

Your eyes did not deceive you. There are several scientific explanations for the current epidemic of childhood obesity. For example, kids don’t get outside as much these days, are glued to screens and don’t have much free time to just play. But we think environmental exposure to various substances plays a large part, too.

The Five Food Felons contribute to obesity by altering metabolic functions, plus dishing up extra empty calories. These fat-makers include added sugars and syrups, such as high fructose corn syrup (which wasn’t in our food supply before the obesity epidemic); an overabundance of saturated and trans fats in snacks, baked goods and packaged meats; and processed grains.

Then there are endocrine disruptors, such as phthalates and bisphenol A (BPA), found in everything from home cleaning products to pesticides, plastics and printed heat-transfer receipts. They are yet-to-be-fully-recognized villains in this epidemic.

BPA (and its cousin BPS) does its dirty work by imitating estrogen. Lab studies have recently found that it knocks out the balance of bodily hormones responsible for hunger and satiety, ghrelin and leptin. When pregnant women and young children are exposed to BPA, ghrelin (the “I’m hungry” hormone) and leptin (the “I’m full” hormone) don’t develop properly. A child may end up unable to regulate his or her appetite.

So what can parents do? Limit screen time; get kids moving at least 90 minutes a day. Upgrade your family’s nutrition (say no to the Food Felons). Limit exposure to BPA and BPS: Always wash hands after handling thermal paper receipts; never microwave plastics; store food in glass containers. And if using plastic containers, avoid those with recycle codes 3, 6 and 7.

Mehmet Oz, M.D. is host of “The Dr. Oz Show,” and Mike Roizen, M.D. is Chief Wellness Officer and Chair of the Wellness Institute at the Cleveland Clinic. Email your health and wellness questions to Dr. Oz and Dr. Roizen at youdocsdaily@sharecare.com.

 

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