Imagine a diet plan that saw through to the core of your being and beyond, that took into account not just the foibles and little secrets no one else knows about (it’s awfully easy to dispose of incriminating Wendy’s bags and 3 Musketeers wrappers) but even the secrets that you don’t know – secrets that can help keep you alive longer and in better health.
This is the promise – and the threat – of the latest scheme for dramatic health improvement to fall out from the big bang of the Human Genome Project. Nutritional genomics – or nutritional genetics, or nutrigenomics – examines your diet and your genes to determine how they interact. Proponents argue that nutrients in food alter gene expression or structure, acting differently on different people according to their genetic makeup. Once these interactions are understood, the story goes, people can make up for inherited weaknesses or genetic flaws by eating differently and, when necessary, taking dietary supplements. Understanding the links between genes, specific nutrients, and a range of diseases – from diabetes and heart disease to less obvious diseases like some cancers and neurodegenerative syndromes – will result in a diet plan tailored to your very own gene profile.
If genes are destiny, science has been doing its best to alter that destiny, and of course venture capitalists, burned and jaded by high tech, are looking for ways to turn the science into profit. The new field of nutritional genomics is taking off in both the United States and Europe, with geneticists, nutritionists, and informatics specialists collaborating to analyze data from long-term health studies using powerful new genomic techniques. The deliberate pace of careful scientific research isn’t fast enough, though, for baby boomers willing to spend whatever it takes to stave off if not vanquish the depredations of age. So companies are springing up, vying to take a swab from your cheek, test your DNA for a few genetic variants, and tell you that if you don’t follow their guidelines you’re headed for trouble. Given the state of current research, nutritional genomics hasn’t progressed very far beyond standard, sensible dietary advice. But if you’re paying a lot for the advice, it probably means you’ll take it seriously.
I recently filled out a diet survey devised by one of the most ambitious of the new companies and got my score from the director of diet and nutrition. The biggest surprise was that what I eat is not more alarming. Perhaps because I write about food and am a restaurant critic, I eat a very peculiar and imbalanced diet (or perhaps I am simply peculiar and imbalanced, which is common in the food-writer game).
I skipped the company’s genetic workup, which I didn’t have time to take. Or so I said. The reality is that the number of diet-gene interactions that are sufficiently well understood to lead to specific and helpful advice is very small, and the number of relevant genetic variants for which it is practical or feasible to screen is even smaller; whereas a condition like obesity can involve hundreds of genes interacting in complex ways. In addition to these limitations, there are the uncertainty and risk of obtaining any genetic information about yourself. Companies, of course, promise complete confidentiality, but you never know. And the results of genetic screening are almost invariably ambiguous, with few straight paths from individual variant to effective intervention. I found it telling that the academic researchers I asked hadn’t had themselves screened (or bothered to try the experiment I had in mind, of submitting the same swab with two or three completely different diet surveys).
My discussions with several researchers and one dietician did make me think that the field of nutritional genomics has real promise. And I might even start eating more fatty fish – though I fear that like many people told to eat fatty fish, I’m likelier to line the pockets of the dubious dietary-supplement industry. That industry, like all the big food processors, is looking hungrily at every development in nutritional genomics.
A leading research center in the new field is the Center of Excellence for Nutritional Genomics at the University of California, Davis. It owes its prominence to a five-year, multimillion-dollar grant from the National Institutes of Health, and to the efforts and vision of its director, Raymond L. Rodriguez, a cellular and molecular biologist. Rodriguez had been working to reengineer common food plants like rice, enriching them with important nutrients, and became increasingly curious about how human genetic variants enable or hinder metabolism of nutrients.
Like all geneticists, Rodriguez was excited by every step of the decade-long Human Genome Project, and like every shrewd grant applicant, he tried to imagine the next big use for the information it yielded. Its first large and obvious commercial and scientific application was in pharmacogenomics – matching drugs to populations with certain genetic characteristics. Many researchers, Rodriguez among them, realized that they could apply a similar approach to nutrition, matching the effects of nutrients to genetic variants. Many drugs, Rodriguez says, are metabolites engineered to work on specific sites in the body to achieve specific goals. So is food, although food incorporates dozens or hundreds of metabolites, and they are usually very imprecisely engineered by nature. The action of specific nutrients on the body could be correlated with individual genetic profiles to similar useful effect – maybe even to similar profitable effect.
“You bring two things to the table,” says Rodriguez, an affable man of medium height and luxuriant gray hair. “Your appetite and your genotype.” He believes that the public, however buffeted by changing health messages, is ready to alter its diet according to gene type. There has been a “paradigm shift,” he claims, in the public understanding of food, from the conception of it as a means of survival in a hostile environment, to the 20th-century demand for tasty and wholesome food, to the recent fear of food-borne microbes and a search for food free of them. Now people can intuitively grasp that food affects the way genes behave, for good and for ill. “When you consume a food, your genes are like a Christmas tree, red and green lights that flip on and off and flicker back and forth,” says Rodriguez. “My Christmas lights differ from yours and flicker at a different rate. Over time, depending on your types of genes and how frequently they’re turned on and off, you’ll either be healthy or in a disease state.”
In 2001, Rodriguez asked Wasyl Malyj, a colleague at Davis with a background in molecular biology and informatics, if he would be interested in working on nutrition. Malyj began looking for tools but knew there was no such thing as a molecular video camera that can provide continuously refreshed data on how an entire genome responds to diet and environment. Malyj and his colleagues would have to content themselves with the expensive and partial snapshots provided by existing technologies. (One of these is the GeneChip from Santa Clara, CA-based Affymetrix, which can register the presence of particular biomolecules.) And Malyj recognized that algorithms developed at Stanford University in the 1990s could yield information about diet-gene interactions by helping to identify underlying patterns in hundreds of data sets involving thousands of different genes.
“Most investigators,” Rodriguez says, “are under the false impression that one lab can do it all, or collaborate with a few others and computational scientists and crack the code. We wanted to network metabolic databases, genetic databases, and medical records.” Malyj, a bearish man with great enthusiasm for his subject, adds, “We realized early that this would have to be multidisciplinary, and that not many people were doing it.”