Looking for clues in the double helix Scientists say DNA could tell us what to eat, how to live

By Lisa Marshall, Camera Staff Writer
February 7, 2005

The proponents of the Atkins and South Beach diets have their theories. So does the federal government, which last month released its own guidelines for what Americans should and should not be eating. But Jim Bruce believes the prescription for better health lies not in the diet fad of the day, or even in the advice of a panel of federal nutrition experts. Instead, he says, it rests in our DNA.


"No longer is it the one-size-fits-all approach. Drugs and nutrition and exercise programs can now all be customized according to your genetic variations," says Bruce, president of Boulder-based Sciona, a company that specializes in the emerging field of nutritional genomics.

Within a year, Bruce projects, Boulder shoppers should be able to pick up a kit at a local retail store, rub a cotton swab across the inside of their cheek, put the swab — chock full of their genetic material — in an envelope, and send it to a genotyping lab. There, it will be bar-coded (to preserve the person's anonymity) and examined in detail. Within a few weeks, customers will get a detailed report showing not only what variations they may have in their genes, but also what those variations mean in terms of how they respond to various foods and supplements. Within a few years, Bruce says, such tests should also be available for offering advice on which exercise plan a person should follow, or which skin care products she should choose.

"I think this is going to be nothing short of monumental. It will absolutely commonplace in the next 10 years," says Bruce.

Opinions differ on just how soon genetic testing will be broadly used for dietary counseling, and some believe it's too early for a reliable test to be brought to market. But experts in the field of human nutrition seem to agree that it will happen.

The notion that each individual has different, genetically pre-determined nutritional needs dates back to 1956 when a University of Texas professor named Roger Williams published a book called "Biochemical Individuality." But only recently, as scientists have begun to pinpoint which genes do what — and what happens when there is a variant in that gene — have scientists been able to put the theory of nutritional individuality into action.

For more than a decade, Jose Ordovas, director of Tufts University's Nutrition and Genomics Laboratory, has been testing how people with different genetic make-ups respond differently to the same nutrients. While some respond well to a general low-fat, low cholesterol diet, others might respond better to more selenium in their diet, or more olive oil.

"People are going from one diet to another. It's a matter of trial and error," says Ordovas. "We believe that each one of us is geared to respond best to a specific diet, whether it is Mediterranean or Atkins or low fat."

Ordovas says that because our response to food is based on thousands of genes that interact with each other, it is far too early to put out a reliable, comprehensive test that will dictate the ideal diet for one person. But he believes tests like Sciona's are based on accurate science and will serve as "a good beginning" for the fledgling field.

Joanna Kriehn, a registered dietitian at the University of Colorado's Center for Human Nutrition, is more cautious.

"This is an emerging field. And maybe in the future we will be able to use it, but I don't think there is enough science to justify it at this point. I would say hold off," she says. Plus, she adds: "It's almost making people too worried about their health."

Sciona's test, marketed as the Cellf test and available on the Internet for about $400, tests for 19 genes covering seven different areas of health: B-Vitamin metabolism; antioxidant capacity; detoxification; bone health; heart health; immune function; and insulin sensitivity.

"We are taking a snapshot at very specific positions in the person's genome of places that we know, through credible scientific studies, are related to nutrition," said Rosalynn Gill-Garrison, chief science officer for Sciona.

For instance, the test may detect that a person is missing the gene GSTM1, which plays an important role in detoxification, and be told to eat more broccoli, which seems to help compensate for the loss of activity of that gene. Or, it may detect a variant in a gene which prompts peopleto experience accelerated bone loss when they take in too much caffeine.

Similar gene variations have also been linked to whether people respond better to a long run than to a visit to the weight room, or how well their aging skin responds to an expensive skin cream. So ultimately, the technology can be applied to lifestyle choices, like how to work out and what makeup to buy, Gill-Garrison said.

Both she and Ordovas concede that some of the post-test recommendations — "Eat your broccoli," "Cut back on the coffee," — seem like common sense.

But the "eat less, exercise more" mantra is seldom enough to get people to change their lifestyle, they say.

"This is so obvious and common sense that people are not going to follow it," says Ordovas. "We have to take a more scientific approach to convince them. By taking those tests, people may feel they are more tailored to them."

Dr. Roger Spahr, one of the few thousand consumers who have already taken Sciona's test, agrees.

At age 50, after years of consuming what he calls the "average American diet," he wasn't happy with what he was seeing in the mirror, and he was worried about his health. His test indicated that caffeine was particularly bad for his bones, and that he had difficulty absorbing calcium. It also indicated that, yes, he needed to eat less and exercise more.

So he did.

A year later, he is thinner, in better shape, and overall, feels better.

So, he is now recommending the test to his patients.

"The good news with this is, you learn about your DNA," says Spahr, a family practice physician in Indianapolis. "The bad news is, once you find out about it, it is not going to change. You either do something about it, or you are doomed to face the results of not paying attention."

http://www.dailycamera.com/bdc/heal...3528920,00.html

I think that this is a great idea. As I have posted on other threads, I think there is quite a lot to do with genetic makeup that points to an ideal diet for each person.

I use the example of how tall fair people who are Nordic with paler skin cannot tolerate the sun as well as short dark people who are Mediterranean.

Thousands of years where generations have lived in a certain area of the world, have similar physical traits, and eaten certain types of foods more than likely affects the optimum diet for that culture or racial type.

In today's age where genetically and racially we are very mixed, and certainly where there is a greater variety and quantity of food (at least in industrialized countries) finding the ideal diet can be a guessing game.

Carbohydrate sensitivity varies a great deal among people.