Nutritional Genomics Correlations between… Diet Disease Gene variants Basic idea behind nutritional genomics Genotype individuals Identify gene variants Suggest appropriate changes in diet. Several published studies have indicated a relationship between common gene variants, diet, and disease. Such results set the foundation for the burgeoning field of nutritional genomics, also called nutrigenomics. Take the example of apolipoprotein E (APOE), which is involved in cholesterol metabolism. The E4 variant is present in roughly 18% of the population. Males with the E4 variant have a predisposition to heart disease; however, by exercising and avoiding alcohol these men can dramatically reduce their chances of heart disease. Interestingly, men possessing other variants of APOE are less able to control their cholesterol levels through diet and exercise. In the case of variants of the manganese superoxidase dismutase gene, men with a particular mutation are more likely to develop prostate cancer, but a diet rich in selenium can decrease this risk by a factor of 10! Nutritional genomics aims to uncover such relationships and to suggest changes in diet to people based on their specific gene variants. © 2005 Prentice Hall Inc. / A Pearson Education Company / Upper Saddle River, New Jersey 07458

Public and Private Initiatives National Center for Excellence in Nutritional Genomics $6.3 million European Nutrigenomics Organization € 23 million Nestle $50 million The promise of nutritional genomics has already encouraged several public and private initiatives around the world. In the United States, the National Center for Excellence in Nutritional Genomics was established in 2003 with a budget of $6.3 million. Similarly the European Union has established the European Nutrigenomics Organization at a cost of 23 million euros. Private corporations have begun to see the potential in nutritional genomics as well. Nestle, one of the world’s largest food companies, has already dedicated $50 million to research and development in this area. In fact, some smaller companies are beginning to see revenue from services in nutritional genomics, though many scientists question their scientific validity. © 2005 Prentice Hall Inc. / A Pearson Education Company / Upper Saddle River, New Jersey 07458

Caveats Gene variant – diet – disease correlation not always clear Need to consider nutritional genomics in the context of entire metabolome, not just single genes Some companies exploiting nutritional genomics based on poor science Despite the promise of nutritional genomics, many hurdles remain. One problem is that the correlations between disease, diet, and gene variant are not always clear. Studies are often contradicted by other studies and many researchers believe that it is difficult to make sense of nutritional genomics without taking the entire metabolome into consideration. These researchers contend that single genes rarely interact with diet in an isolated fashion, rather they are constantly interacting with other genes in ways that we do not yet fully understand. However, these doubts haven’t stopped several companies from marketing services to genotype consumers and then suggesting changes in diet or the consumption of nutritional supplements. Companies such as these appear to be more interested in marketing than science, but may nonetheless be quite successful. As one consumer of “nutritional genomics” services put it: “It’s very personal and people love that, they just love it. It’s like reading your horoscope – but this is even better because it’s based on science.” © 2005 Prentice Hall Inc. / A Pearson Education Company / Upper Saddle River, New Jersey 07458