Food With a Purpose
There's an old medical saying that we dig our grave with our spoon. Enter nutrigenomics, a new field that tailors your food to your genes. It just might be the answer to our epidemic of obesity and metabolic syndrome. It could even improve how we age, better our bone and brain health, and lower our risks for certain cancers. Built around the idea that one person's medicine is another's poison, nutrigenomics, and its related technologies of proteomics (the proteins that genes order up) and metabolomics (the soup of molecules that results from metabolic activity), provide a personalized dietary road map. The field is exciting and promising but is by no means ripe for the picking--despite some commercial ventures telling you otherwise. Before we turn an important new domain of nutrition into unappetizing snake oil, let's understand what it is and isn't.
Customizing one's diet to one's genes and metabolism isn't anything like the traditional, one-size-fits-all food pyramid. That approach is geared toward preventing nutritional deficiencies. The recommended daily allowances, or RDAs, printed on food labels tell you the macronutrients (carbohydrates, protein, and fat) and micronutrients (vitamins and minerals) you need. Even in the newer and booming field of functional foods, in which certain foods and supplements are singled out for health benefits beyond basic nutrition, it is assumed they'd bring value to everyone. Functional foods include megavitamins, animal extracts such as fish oils, and concentrates of the many biologically active plant chemicals that make fruits and vegetables veritable treasure troves of prevention for heart disease and cancer.
There are also energy drinks, gels, and power bars full of all the stuff that can provide an extra power jolt when you need it. Some of the best work on functional foods comes from the military. U.S. Army scientists created HOOAH! bars to deliver steady energy and optimize soldier performance during high-intensity and stressful maneuvers. But their work is aimed at a fairly homogeneous group of young and fit soldiers engaged in standardized activities. Meanwhile, consumers in all their diversity have embraced functional foods, making it a multibillion-dollar market. Yet most consumers are in the dark as to what they're buying.
I blame their struggle squarely on the national neglect of nutrition research and education. I'll bet most doctors couldn't draw the latest food pyramid if their licenses depended on it and don't have a clue about functional foods. That's not surprising, since nutrition makes only a ghostly appearance in most medical school curricula, and nutritionists on medical faculties are scarce. Researchers all too often throw up their hands, as complexity and compliance make long-term clinical trials just too darn hard. No wonder conflicting reports on what's good in your diet give more whiplash than guidance. How sad, when food is our most intimate interaction with the environment.
Eating plans. That's where nutrigenomics will make our day. Nutrigenomics and metabolomics should allow us to develop eating plans based on each food's chemical profile and our individual metabolism. For example, some chemicals in food promote genetic stability in less stable genomes, or modify proteins once formed, that might regulate tumor incidence or behavior. Others can alter the level of certain proteins that control how much dietary fat is stored as body fat versus being burned up as calories.
Imagine a doctor's being able to quickly identify a patient's DNA profile for type 2 diabetes or obesity and then get a dynamic snapshot of his or her metabolic response to a particular diet. Food shopping might be like going to the shoe store. You'd have the size and, combined with your taste and energy expenditure (yes, exercise is a partner of nutrition), you'd select what fits. But this approach is several years away, as our knowledge of chronic disease susceptibility genes is limited, and metabolomics is an entirely new endeavor.
Companies are already pushing DNA diets, which concerns John Erdman, a professor of food sciences and human nutrition at the University of Illinois-Urbana-Champaign. "Identifying a handful of genes from a snippet of hair or a mouth swab and returning with a diet plan and a bill for several hundred dollars is a waste of money and is way premature," says Erdman. In a field known for fads and reckless health claims, we will have to struggle to keep nutrigenomics from being hijacked by the P.T. Barnums. HOOAH!
This story appears in the February 13, 2006 print edition of U.S. News & World Report.