DDC Mythbusters: Genetic Diets
Posted February 21, 2008
In recent years, the use of DNA has migrated from very scientific, regulated purposes (such as forensics, and paternity testing) into the retail, unregulated sector, with more companies offering to analyze an individual’s DNA and predict many different things, based on his or her genetic makeup. Some opportunistic testing companies have taken this concept even further by offering nutritional analyses or weight loss advice based solely, they claim, on an analysis of an individual’s DNA.
While scientists who study nutrigenomics—the study of interactions between nutrients and genes—agree that there is a link between physiology, food and physique, they vehemently point out that the notion of tailoring a nutritional or weight loss plan based on a genetic readout is a reach at best.
Companies like Suracell, Sciona and Genelex offer nutrition and health plans that they claim are specifically tailored to an individual’s DNA makeup. Scientists argue that the common-sense health advice these companies offer, like exercising more, losing weight, or quitting smoking, is more likely based on the lifestyle questionnaire submitted with the consumer’s DNA samples and not their genetic makeup.
Other scientists agree. As Dr. Louis Aronne of New York-Presbyterian/Weill Cornell is quoted as saying in an article on abc.com, "The biggest issue is that these diets haven't been tested," she said "So the question, really, is what happens if you put someone on a diet based on the genetic information? And the bottom line is we have no clue that they will be better."
The fact that these tests are medically unproven is also the key argument in a Dec. 2007 article in Genetic Engineering & Biotechnology News. The article warned consumers that unlike paternity, ancestry or other medically-approved genetic testing for diseases like Down’s Syndrome or Cystic Fibrosis, these nutrigenetic tests are unregulated and the results are largely left up to the test-providers’ interpretation.
“No matter how valuable this information potentially is, without an appropriate regulatory framework consumers are at risk of receiving data of dubious quality, of misinterpretation of the results, or of being misled by unproven claims or beliefs,” Gail Javitt, J.D., Genetics and Public Policy Center of Johns Hopkins University said in the article.
To alert consumers to the potentially fraudulent claims made by nutrigenetic companies, the federal government has researched the products being offered. The “investigative arm” of Congress, the Government Accountability Office (GAO), issued a report in July 2006 questioning the validity of nutrigenetic diets. The report stated that, “Even if the predictions could be medically proven, the way the results are presented renders them meaningless.”
Nutrigenetic companies also recommend that consumers purchase their company’s nutritional products to maximize the diet’s supposed benefits.
“In addition to providing the consumer with common-sense dietary recommendations, such as eat more fruits and vegetables, some companies are even using the DNA testing market to promote their expensive dietary supplements,” DDC Assitant Laboratory Director Dr. Melissa Kahsar said. “These supplements, which can cost the consumer over $1,000 per year, have been found by the GAO to contain the same ingredients as a generic multivitamin from your local drugstore.” Some companies have long-term contracts for their recommended supplements, with penalties as high as $1,000 for early cancellations.
The costs of these diet analyses and subsequent recommendations range from $250 to $1200. This price generally does not include nutritional products or supplements many “diets” recommend.
It seems that spending hundreds of dollars on tests that scientists deem “dubious” is indeed a gamble—you’d be best advised to consult your doctor prior to the investment.
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