Nutrigenomics Part I

As 21st century Americans, we live in a world of excess. In no other period in history would we have seen such a great mobilization of resources and efforts to restrict our caloric intake. Every couple of years bears witness to another diet fad, if not several - Atkins, Mediterranean, Blood type and Paleolithic, just to name a few. Most of these try to seduce consumers using some kind of scientific logic, and although it may be easy to wade through the BS of the Air Diet, others may appear perfectly reasonable. However, according to oncologist Dr. David Agus (see notes on his talk here), the only diet unequivocally condoned by the current scientific data is the Mediterranean Diet. 

So why is it exactly that so many diet trends are (futilely) pumped out year after year? Why hasn't the diet that helped Aunt Marge lose 20 pounds done a whit for Uncle Vernon? A good part of our answer lies within our genes.

There has been a recent explosion of research in nutrigenomics, a field that is still very much in its infancy. While the ancients were aware of the empirical effects of food on physical well being, it wasn't until the completion of the Human Genome Project in 2001 that scientist were able to begin dissecting the effects of genes on metabolism and, conversely, the epigenetic effect of food on gene expression. The results of these studies suggest a new perspective on food - food as a drug.

If you stop to think about it, the concept of food doesn't slide too far from that of drugs. Sure, it may not be in any purified form but the chemical agents contained in it, once ingested, impact real physiological changes that can have lasting, global effects. Fats can alter our hormonal expression (even contributing to dementia), and too much sugar floating around our bloodstream can deliver a multitude of unwelcome pathologies including nerve damage and compromised immunity. As Americans know better than anyone, food can also be dangerously addictive, and studies have shown that a high-fat diet mediates the destruction of neurons that are key in self control, leading to the propagation of a vicious cycle. 

In my recent interest in nutrigenomics, I came across a short albeit enlightening podcast on NPR featuring several experts in the field - Drs. Raymond Rodriguez and Jim Kaput from the UC Davis Center for Excellence in Nutritional Genomics, and Dr. Marion Nestle, a professor of Food Studies at NYU and author of Food Politics and Safe Food. The podcast discussed the use of nutrigenomics in finding a "most efficient" diet for the individual consumer, which makes sense given that our overall metabolic balance doesn't depend solely on the equation of caloric input vs. output but also the congruity in the distribution of energy sources (fats, sugars, proteins) our body utilizes vs. the distribution we consume. Evidence for genetic differences in food utilization is perhaps best demonstrated in the wide disparity in prevalence of Type II diabetes across ethnic groups within the U.S. These numbers are 5% among whites, 7% blacks, 14% Latinos, 15% Asians, 37% Native Americans, and up to 50% Pima Indians. This spread reflects the diverse cultures and histories of our ancestors and the power of microevolution within even a short timeframe. However, the effect of hard-wired genes have the potential of playing a much more marginal role in disease if we can correct for our internal environments, for example, by controlling the chemicals (including edible ones) that we expose ourselves to. After all, it is estimated that within the realm of chronic diseases (including cancer, Type II diabetes, and cardiovascular disease), only 5-10% of cases can be attributed to genetics; the rest is in gene/gene and gene/environment interactions.

Even with the rapidly growing body of knowledge on how different chemicals modify gene expression, we are still a moonshot away from the day we can send in a swabbing of our cheek cells (and $X) in exchange for a genetically-tuned diet plan. Let's say that we are now decades into the future and this momentous day arrives... will we be be able to anticipate its consequences? Such knowledge will not only spread its tentacles into the health of society but also the politics and economics. The expert nutrigenomic panel on NPR postulated that 30% of Americans will be able to afford a nutrigenomic analysis service and enact corresponding changes to their diet. What of the other 70%? Will this open the door to even greater disparities between the upper and lower socioeconomic classes and new forms of social stigma? What are the implications of applying nutrigenomic research to the world's food supply? 

We will continue to explore the different scientific and social aspects of nutrition in future articles, so stay tuned!

Until then, happy eating :)
-Sophia