Voices from the community:
You are what you eat
From designer diets to disease treatment, nutrigenomics may make us look at food in a whole new way.
"Let food be your medicine and your medicine be food." These words from the ancient Greek physician Hippocrates are taking on new meaning today. Until now, dietary recommendations (for example, that everyone should eat less fat) have been based on a one-size-fits-all approach. In future, however, thanks to increased knowledge of genetics and availability of genetic testing, it may be possible to develop "designer diets"-diets tailored to an individual's genetic make-up that will reduce risk factors for certain diseases.
This fledgling science is called nutrigenomics: the study of the interaction between genes and nutrition. It is one of the major interests of Dr. David Castle, Canada Research Chair in Science and Society and co-author of Science, Society, and the Supermarket, the first book on nutrigenomics.
"Nutrigenomics is one of the first tangible results of the Human Genome Project, the 13-year project that identified and sequenced all the genes in human DNA," says Dr. Castle. "Researchers are taking this information about genes and investigating the roles nutrients play."
By way of example, Dr. Castle points to recent studies suggesting that high blood levels of an amino acid called homocysteine put people at elevated risk for heart disease. Folic acid, which is present in leafy green vegetables, helps break down homocysteine in the body, but some people have gene variations that make it difficult for their bodies to use folic acid. One recommendation might be for these people to consume higher doses of folic acid; although they wouldn't be able to metabolize it very well, increasing the amounts would increase the benefit.
"While there are still questions about the science behind nutrigenomics, there is good evidence that some nutrients can play an active role in metabolism, just as drugs do. Researchers are also discovering that nutrient–gene associations have a role to play in reducing your relative risk for certain diseases, and that by modifying your diet you can reduce your risk. People sometimes overextend the claims for nutrigenomics and talk about nutrigenomics in terms of treating disease; however, there is currently no clinical work that demonstrates disease treatment."
Dr. Castle points out that nutrigenomics is already being offered directly to consumers. A number of companies (mainly in the United States) offer testing services. A customer sends in a DNA sample, taken by a brush swab on the inside of the cheek, and-for a fee-the company tests for variants of several genes that might indicate risk for certain diseases or physiological imbalances. The company provides dietary recommendations based on the test results.
"The downside of nutrigenomics going direct to consumers is the extreme shortage of healthcare professionals who can help consumers interpret the results of nutrigenomics testing. Few primary-care practitioners know much about nutrition, except for those in a dietetics practice, and very few know much about genetics. An even smaller subset know about both nutrition and genetics. This is going to be a difficult hurdle to overcome.
"I think it is inevitable that, as we learn more about how nutrients impact gene expression we're going to realize that the bioactivity of some nutrients is as great as, if not greater than, [the activity of] some pharmaceutical components. The growth of the science will pose some interesting questions for the regulation of foods and drugs and the impact on the safety of patients and consumers. I'm looking forward to how this will unfold."