University Times

Imagine a day when you visit your doctor and along with having your temperature and blood pressure taken, you get a quick check of your DNA.

That day may not be too far off, as researchers learn more about the relationship between a person’s genetic makeup and his or her response to particular nutrients or medications as well as possible predispositions for certain diseases.

The completion of the Human Genome Project in 2003 opened the door to deeper research into human genetics and sparked the ability to study the links between genes, life and health.

Last year the FDA approved a blood test that detects genetic variations that may affect how drugs are broken down and cleared by the body. The genetic test is one of a growing number of assessments doctors can use to personalize dosages of medication for a particular patient to maximize benefits and minimize possible side effects.

Another facet of personalized medicine takes food into account. The interrelated fields of nutrigenomics and nutrigenetics aim to determine the relationship between genes and nutrition and how that interaction may influence a person’s health.

While nutrigenomics studies the effect of nutrients on health or disease risk by the effect food has on influencing gene expression, nutrigenetics covers the other side of the coin by studying how an individual’s genes affect his or her response to certain nutrients.

In the not too distant future, health care will be customized based on gene type, said Leslie Bonci, director of sports medicine nutrition for the Department of Orthopaedic Surgery and UPMC’s Center for Sports Medicine.

She believes genetic testing soon will become part of the array of tests and care routinely offered in clinical settings so that unique combinations of diet and medicine may be tailored to optimize an individual’s health.

Although personalized medicine is in its infancy today, it is decidedly on the rise.

“Now we can truly customize and individualize so we can get people to get well and stay well and not incur any other health problems,” she said. “I see five years from now this being more routine.”

Studies have found that deficiencies of certain vitamins or other nutrients can cause DNA damage that may be mitigated by megadoses of those nutrients.

While some deficiencies are related to poor diet, others may be attributed to minute differences in a person’s genetic makeup, leading to the exploration of whether someone who is genetically susceptible to certain types of damage could offset the risk through diet or lifestyle changes.

Right now, few dietitians are equipped to use the principles of nutrigenetics or nutrigenomics, but soon it will be commonplace, Bonci predicted.

“It’s an area in which dietitians are going to have more expertise. It’s going to appear more in graduate and undergraduate curriculums,” she said.

U.S. Food and Drug Administration commissioner Mark B. McClellan, in a 2003 speech at the Harvard School of Public Health, predicted that someday foods might be designed with specific genetic profiles of certain categories of people in mind. While we have yet to see such specialized foods hit the shelves at local grocery stores, commercial applications of nutrigenetic concepts already have made it to the marketplace.

A Colorado-based company, Sciona Inc., is marketing on line and via certain retailers (none in the Pittsburgh area) a simple test kit to identify genetic variations that may be associated with potential health risks. After the cheek swab sample is analyzed to map out the variations in more than a dozen genes, a personalized nutrition and health report is generated. The customer is encouraged to share the results with a health professional.

Sciona sells test kits to analyze for bone health, heart health, anti-oxidation/detoxification, inflammation and insulin resistance.

The biggest seller is the heart health kit, said company spokeswoman Donna Moore. The majority of customers are health-conscious women aged 35 to 64 who are willing to try new things, she said, declining to reveal sales figures.

And, while the concept may hold promise, not everyone is convinced that the test kit is an idea whose time has come.

Right now, such tests have limited value, said Richard D. Wood, leader of Pitt’s molecular and cellular oncology program.

“All they can do is look at the common differences between you and me,” he said, noting that there are some 2 million differences between human beings. “If you have a very common polymorphism that half the population has, that means it’s essentially been non-selected through evolution, and in most cases neutral,” he said.

The idea that a certain genetic profile may influence cancer disposition, heart health or aging is one thing. Using single nucleotide polymorphisms (SNPs) — simple variations in the genetic code —to identify them may be a leap, he said.

“Only in a very, very few cases do SNPs really have a proven functional effect,” he said. “In most cases by far there’s no proof at all. It’s far too premature,” he added.

Because the science is still in its infancy, Madelyn Fernstrom, founder and director of the UPMC Weight Management Center and associate professor of psychiatry, epidemiology and surgery, likewise isn’t convinced that paying for nutrigenetic testing is a good value, even if it’s a good idea to be aware of healthful eating habits.

“At the very least, it’s a waste of money; at the very best, it might provide information to help improve your diet,” she said.

Essentially the analysis provides sound dietary advice, tweaked for people who have certain combinations of a few genetic markers, she said. “Sometimes, it’s just common sense,” Fernstrom said.

For the money, she said, “You might as well get a one-on-one consultation with a nutritionist or certified health care consultant.”

Or, merely observe those around you who share some of your genes.

“If you have a history of osteoporosis in your family, it would be good to exercise, take calcium and Vitamin D. You don’t need them to tell you that and you don’t need a genetic marker to tell you that. Just look at your family tree,” she said.

—Kimberly K. Barlow