When Charlotte Benkner died last year at age 114, a dining hall in Ohio was named in her honor. Benkner, briefly acclaimed as the world’s oldest living person, was known for eating a lot; one obituary listed her appetite as “voracious.” It’s enough to make the average person bitter: How could Benkner survive to truly old age on pork chops and cake when the rest of us may not make it to 70 without three servings of broccoli a day?
The answer lies in the fledgling science of nutritional genomics, the study of how our genes interact with the nutrients in the foods we eat. While a handful of food-gene interactions have been studied before—lactose intolerance, for instance, is known to be caused by a variation in the lactase gene—most are only now being charted.
“What constitutes good nutrition is actually a very individual prescription, depending on your particular set of genes,” says Jose Ordovas, a biochemist at Tufts University who has studied the nutritional genomics of cardiovascular disease. In certain men, for instance, eating a low-fat diet may actually increase the risk of heart disease. This occurs because a polymorphism—a minor change in one gene—causes the person’s LDL cholesterol level to rise when the amount of saturated fat in his or her diet drops too low.
The average human has between 150,000 to 300,000 of these minor variations, known as single nucleotide polymorphisms, within individual genes. Together they are believed to account for most of the minor differences between people: variations in hair or eye color, metabolic rate, and one’s susceptibility to such diseases as diabetes and osteoporosis. Many of these genes are activated by chemical triggers. Eat broccoli, for instance, and the vitamin B6 it contains will spur the tryptophan hydroxylase gene to produce L-tryptophan, an amino acid used in the synthesis of serotonin, a neurochemical mood stabilizer.
“The gene is the gun, but the environment is the finger on the trigger,” says Ordovas. “These mutations have been with us for thousands, or in some cases hundreds of thousands of years, passing from one generation to the next, because until now our diet didn’t trigger any negative effects.”
