Steven Zeisel, MD, PhD, director of the UNC Chapel Hill Nutrition Research Institute, explains what personalized nutrition is and how it is the mission of his institute to advance the field so that nutritional decisions are based on genetic information. The result: healthier people and new avenues to prevent and treat disease.
Physicians know that some people respond to certain medications and some people don’t. Similarly, it is not a secret to medical professionals that some people metabolize medications quickly and others slowly. Whether a person is a responder or non-responder or a fast or slow metabolizer of medicine is based primarily on their genetics.
“In the past, physicians have dealt with everybody as if they are the same metabolically. We know that people are different in metabolism, many for genetic reasons,” stated Steven Zeisel, MD, PhD, director of the UNC Chapel Hill Nutrition Research Institute (NRI) at the NC Research Campus. “In medicine, we’ve known this, (and) had this idea of personalized medicine. Before you get a drug like Warfarin (also known as Coumadin or Jantoven) you get a genetic test that determines your dose.”
Through his research, Zeisel came to realize that what is true for medicine is also true for nutrition.
Genetics and Nutrition
“We are born with many variants or misspellings in our genetic code called single-nucleotide polymorphisms (SNPs). Some of them affect metabolism in very important ways,” Zeisel continued. “As we understand which genetic differences make you a fast or slow metabolizer for a specific vitamin, mineral or nutrient, we should be able to tell you to eat more or less of specific foods.”
The nutrient choline is an example. Zeisel was the first scientist to bring to light the important role of choline in human health. Choline is needed for the nerve cell division that forms the memory center of the brain called the hippocampus. Zeisel found a SNP in the gene PEMT (phosphatidylethanolamine N-methyltransferase) that impacts the production of choline in the liver. About fifty percent of all women have the SNP, meaning they do not produce enough choline. These women need to eat more choline-rich foods like eggs and meat. When they are pregnant, consuming high levels of choline is essential to the proper development of their baby’s brain.
Other scientists throughout the NRI are making breakthrough discoveries as well. One example is Carol Cheatham, PhD, who found out why only 15 percent of infants respond to the addition of the omega-3 fatty acid DHA (docosahexaenoic acid) to baby formula.
“If the mother can make this fatty acid because she has the right genes to do that, she puts it into the milk and across the placenta. The baby doesn’t need it from the formula,” Zeisel explained. “If the mother has a gene variant that makes her very slow to make this DHA then her baby benefits a great deal from DHA in infant formula. So we know that if you want to target who should buy infant formula with DHA, you can do a blood test and tell the mother whether or not her baby needs this type of formula. This changes how we deal with normal development, disease, lifestyle and nutrition.”
At the Beginning
Zeisel admitted that “we are still at the beginning of personalized nutrition right now (because) there may be 100 gene differences for which we can make definite recommendations to eat more or less.”
Part of the mission of the NRI is to build the catalog of gene differences until it becomes worthwhile for a person to receive nutrition advice based on their genetic profile. That advice may not only make people healthier, but could help reduce the incidence of diseases like cardiovascular, diabetes or cancer.
“Once we know where there is a bottleneck in metabolism that makes a person need more folic acid, for instance. They may be the people who take folic acid and have less heart disease,” Zeisel said. “Through the evolution of our research at the NRI, we will reach a finer identification of who will respond and who doesn’t respond to certain nutrients. It will change our understanding of what things you can do in diet that might help prevent the development of disease and better treat it.”
Learn more, visit the NRI’s website, www.uncnri.org.