Editor's Note: This is the third in a series of six features on the science of food, running daily from March 30 through April 6, 2009.
DAVIS, Calif.—Ann Wigmore was not enamored with the American diet. Having moved from Lithuania after World War I, she was appalled by our white breads and other abominations and dearly missed the treats her grandmother once prepared, including a savory "gruel made from crushed rye grain and diluted goat's milk."
One day, after struggling for years with ill health, she wandered out to an abandoned parking lot and, as she wrote in her memoir Why Suffer? How I Overcame Illness and Pain Naturally, "There, spread out before my eyes, were hundreds of square feet of the most luscious weeds I had ever beheld." So began Wigmore's faith in the healing powers of wheatgrass, a belief that made her a pioneer of the raw foods movement and inspired thousands to forgo one of man's earliest innovations and feast exclusively on raw sprouted grains, raw nuts and crunchy carrot sticks. Although Wigmore's own life was cut short when she died in a fire in Boston in 1994 at age 85, her legacy lives on through a number of foundations, including the Hippocrates Health Institute she started in 1956 in West Palm Beach, Fla.
Although it may be easy to sneer at the most ardent adherents of "Raw Foodism," Wigmore's atavistic philosophy has influenced how most mainstream Americans eat and think about eating. We may prefer a sizzling sauté of veggies over Wigmore's astonishingly bland recipes, but it's hard to dismiss that lingering sensation that raw veggies might just be healthier for us.
Over the years, scientists have also had trouble dismissing the Raw Foodists. Proponents of raw cuisine like to point out that cooking breaks down a number of beneficial enzymes and vitamins, but critics note that stomach acid inactivates enzymes anyway, and moderate cooking can also help release other nutrients—such as a tomato's lycopene (an antioxidant with potential health benefits) or folic acid and beta-carotene from spinach. The fact is that, in general, the mechanics of how our digestive systems break down solid foods and reap their benefits are poorly understood.
The U.S. Food and Drug Administration's nutrition label on the back of that package of Planters peanuts is strictly based on chemical analysis of the nuts, and it doesn't tell you what fraction of those heart-healthy monounsaturated fats your body actually absorbs. Since 2004 two European research teams have sought to fill that gap by simulating the stomach in vitro with a kind of robo-stomach. And now Paul Singh, at the University of California, Davis's Department of Food Science & Technology, has taken the project to the digital realm to simulate digestion "in silico".
One afternoon in October, Singh pulled up a graphic video on his computer monitor in his office. A glistening pink mass that appears to have a clenched mouth was violently gurgling and contracting like the parasitic monster from the first Alien film. This was no parasite but a rare view of the inside of a human stomach as it performed rhythmic peristalsis, crushing and churning solid foods into particles one tenth of an inch (2.5 millimeters) in diameter. Exactly what these particles look like after being chomped by our teeth and churned by our stomachs is key to understanding what happens when they finally slip though the pyloric valve and into the small intestine where nutrients are absorbed. For the most part, this process has been invisible to scientists like Singh. After all, we can only look inside empty stomachs, because mushed up food would cloud the view. "How do we know what is really going on?" he asks.