Alternative Medicine Magazine

2006

Heal Thyself—Unlocking the Secrets of DNA

By Lisa Marshall

Thirty-five pounds overweight, with an unhealthy diet and a sedentary lifestyle, 49-year-old Roger Spahr knew he had to make a change. But whenever he set out to get healthy, the common sense advice to “eat right and exercise” just didn’t motivate him: He wanted specifics.

So the Indianapolis physician dragged a cotton swab across the inside of his cheek and sent it off to a laboratory. Three weeks later he received a detailed report complete with specific dietary recommendations tailored to 19 of his genes. The good news: His body metabolizes B vitamins and flushes out toxins well. The bad news: He appears genetically predisposed to both heart disease and diabetes.

The report made quite an impact. “It’s one thing to say, ‘I should get around to it. I need to get healthy,’ but quite another to be handed a sheet of paper that says ‘There is no getting around to it,’” says Spahr, who has since lost 20 pounds and lowered his cholesterol by 30 points. “No question that I have to watch this, this, and this because my genes say that if I don’t I may not be around to enjoy my kids.”

Like Spahr, an increasing number of Americans have turned to the burgeoning science of nutritional genomics in their quest for better health. The field hinges on the notion that different genes prompt people to respond differently to the same nutrients, and that some nutrients can actually alter the way our DNA expresses itself—decreasing or increasing our risk for disease. Well under the radar screen a decade ago, nutritional genomics has garnered tremendous attention since the completion of the historic Human Genome Project in 2003—which created a broad base of information for scientists already studying the gene-nutrition link.

Today, researchers have identified hundreds of possible gene-diet interactions, with new studies coming out almost weekly. As a result, prestigious universities across the country host thriving nutritional genomics research programs. Consumers can already choose from dozens of tests—available either online, through healthcare practitioners, or over the counter—that range in cost from $100 to $1,000 depending on the number of genes examined.

Some caution we should view this new field with skepticism, pointing to the paucity of long-term studies showing that basing your diet on your genetic make-up will truly make you healthier. Nonetheless, many predict that in 10 years, nutritional genomics will make one-size-fits-all diet fads seem quaint. Instead, nutritionists will base their advice on DNA, and companies will tailor foods and supplements toward specific gene types.

“It’s not a matter of if, but when,” says Ruth DeBusk, PhD, a registered dietitian and former genetic researcher in Tallahassee, Florida. “The field of nutritional genomics will change the choices we make and the foods available to us.”

Tinkering with fate
Scientists already know a lot about the link between certain genes and the risk for heart disease, diabetes, cancer, and various autoimmune diseases. And each day they learn more about how nutrition can either aggravate or alleviate those risks.

Take APOE, for instance. Perhaps the best studied gene in the field, APOE plays an integral role in regulating levels of cholesterol in the body and comes in several variations: E3 (the most common, present in about 77 percent of the population), E2 (present in 8 percent), and E4 (a particularly problematic variant—present in roughly 15 percent). Studies suggest that people with the E4 variant are at a disadvantage in several ways: They have the highest levels of fat in their blood, face a greater risk of diabetes, tend to have lower levels of good cholesterol, have a five-fold increase in the negative heart effects associated with smoking, and tend to respond less to exercise. But the news is not all grim: E4 people also seem to respond particularly well to a diet low in saturated fat.

So while the E4s may have been dealt a poor hand, genetically speaking, they can affect the outcome if they play their cards right. “If you identify someone that is an E4 and you are very aggressive in terms of making him or her reduce fat and cholesterol, this person is going to eliminate most of his or her genetic predisposition to heart disease,” says José Ordovas, PhD, director of the Nutrition and Genomics Laboratory at Tufts University.

Recent research has also homed in on genes associated with an individual’s propensity for chronic inflammation, ability to flush out toxins, and susceptibility to bone loss associated with caffeine consumption. One study conducted at Creighton University followed 96 three-cups-a-day coffee drinkers for three years and found that those who carried a particular variant of the vitamin D receptor gene (VDR) suffered bone loss at a far more rapid rate because of their susceptibility to caffeine’s adverse effects.

Answers and questions
A pioneer in the field for two decades, Ordovas believes that DNA specifics may provide the motivation people need to make common sense changes. “If somebody says ‘Here is what’s going on with your genes, and here is how you can fix the problem,’ they will probably be more enthusiastic.”

Look, for example, at the APOA1 gene, which regulates the body’s production of HDL (good) cholesterol. Preliminary research shows that when people with the more common G/G version of APOA1 eat a diet high in polyunsaturated fats, their good cholesterol drops, putting them at greater risk of heart disease. But for those with the less common A version of this gene (which about 30 percent of us have), the opposite occurs: A diet high in polyunsaturated fats can actually raise levels of good cholesterol, offering added protection against heart disease. “It is a common mutation,” says Ordovas, and “if you carry it, the low-fat advice might not be good for you.”

While the promise of nutritional genomics may seem patently positive, some believe the field is jumping the gun. “I think it is certainly something that, in the future, will be helpful, but I think offering these broad tests right now is very premature,” says Jamie Erskine, PhD, associate professor of dietetics at University of Northern Colorado.

She fears that such tests, particularly without an in-person professional to help interpret them, could give someone a “false sense of security” or prompt them to make unnecessary dietary changes. Critics have also suggested that some online companies use the tests as a way to sell proprietary dietary supplements created for certain gene types.

Critics also point to a glaring ethical question: Should people know about a gene variant that carries risks they can do nothing about? Researchers have already linked the APOE4 gene variant with not only a higher risk of heart disease, but also a greater likelihood of developing dementia. Should a mail-in test deliver this news? “That gets into a very tricky situation,” says Ordovas, noting that some companies have declined to test for APOE4. “You have to balance here between the potential good you can do and the potential harm you can do.”

Ordovas and DeBusk both concede that the field is young and the consumer tests it currently offers are limited in their usefulness. “When we look back in 10 years, we will probably chuckle at how primitive they are,” says DeBusk.

But primitive or not, they’ve made Roger Spahr a believer. He was so impressed with how the test results jump-started his dietary and lifestyle changes that he got tests for his wife and 20-year-old daughter and now recommends them to his patients. “It’s pretty amazing how motivated people get when they look at the results of these tests.”

The Do-It-Yourself DNA Kit
In the fall of 2005, Boulder, Colorado-based Sciona Inc. became the first and only company in the nation to offer genetic test kits (called Cellf) over the counter. Consumers can choose any one of the five tests—heart health, bone health, inflammation, insulin resistance, or detoxification capabilities and antioxidant production. A sixth test, which covers all 19 of the gene variants Sciona tests for, is available online.

To complete a test, consumers fill out a questionnaire about their diet and lifestyle and send it, along with a cotton swab of cells from the inside of their cheek, to a lab where their package is numbered to protect their anonymity. A computer program, designed by geneticists and dietitians, collects the information and generates a detailed report recommending gene-specific diet and lifestyle changes. For more information, log on to www.sciona.com.