Diet and DNA.

The emerging field of nutrigenomics explores how nutrients in foods interact with genes that contribute to chronic diseases. The goal of nutrigenomics is to understand individual nutrient genotypes to design dietary interventions that restore health or prevent disease, eventually improving the health of the population at large as well as that of specific subpopulations. The fledgling held is packed with promise, and two new research initiatives aim to help deliver on that promise.

A Center of Excellence for Nutritional Genomics was established in 2003 at the University of California (UC), Davis, to coordinate nutrigenomics studies among participating institutes. A five-year, $6.5 million grant from the NIH National Center on Minority Health and Health Disparities funds the project. Genetics professor Raymond Rodriguez directs the new center, which unites 25 experts in nutrition, molecular biology, bioinformatics, and related fields from UC Davis, the Children's Hospital Oakland Research Institute, the U.S. Department of Agriculture Western Human Nutrition Research Center, and the Ethnic Health Institute at Alta Bates Summit Medical Center. Center members will explore how different foods interact with genes to increase the risk of type 2 diabetes mellitus, obesity, heat disease, and cancer.

Across the Atlantic, the European Nutrigenomics Organisation (NuGO) was launched in February 2004. This network of 22 scientists from 10 European countries will receive 17.3 million [euro] from the European Union over six years to develop new technologies, improve model systems, and advance nutritional bioinformatics. "Particular attention will be given to studies of human volunteers, and both biomarkers and new methods will be developed and validated," says Sian Astley, NuGO's communications manager.

"Nutritional genomics connects the Human Genome Project to human health in the most personal ways--through the foods we eat several times a day," says Rodriguez. "A better understanding of how diet and genes interact will enable us to better manage our own health and possibly prevent, mitigate, or delay the onset of chronic and age-related diseases."

People react to certain nutrients differently, depending on their genetic makeup. Lactose intolerance, a well-known example of nutrigenomies, afflicts largely Asians and Africans, and far fewer people of northern European descent. That's because a single base pair change in DNA occurred in northern Europe about 6,500-12,000 years ago, which allowed people there to digest lactose--in an environment with a short growing season, access to the additional nutritious food source of milk was helpful for survival, says Jim Kaput, a pioneer of nutrigenomics and founder of the diagnostics company NutraGenomics.

Today's nutrigenomics researchers hope to find gene variants that explain why, for instance, some people can lower their blood pressure through dietary changes, while others need drugs. Other variations might explain why some people are more susceptible to gastrointestinal cancers, inflammatory diseases, and osteoporosis.

Scientists are finding that biologically active components of foods can alter gene expression. For example, a deficiency of folic acid may lead to breaks in DNA that mimic radiation damage. Other nutrients are involved in molecular processes related to DNA structure, gene expression, and metabolism, which contribute to the development of chronic illnesses.

The nutrigenomics approach resembles pharmacogenomics, which looks at the relationship between single-nucleotide polymorphisms in genes and patients' responses to drugs to personalize medicine. Although progress in pharmacogenomics currently surpasses that in nutrigenomics, the two are closely linked. "Without nutrigenomics, pharmacogenomic data cannot be interpreted correctly, because diet may affect the expression of genes involved in drug metabolism," says Kaput. He proposes that pharmaceutical companies should include nutrigenomics in the design of new drugs because, he says, "what you eat affects a drug's efficacy."