Twenty years ago, after Bob Quinn began growing Khorasan wheat, an ancient and vanishing Egyptian grain with an oversized, banana-shaped kernel, he noticed something unusual. Not only could people who have trouble eating regular wheat digest Khorasan, but it actually made them feel better. Today, food from the grain, which the Montana farmer has branded Kamut, is sold in health stores around the world and is prescribed by some doctors as a treatment for wheat allergies. Yet, says Quinn, ”we don’t know how it’s really acting in the body to create these differences.”
Now, though, two scientists at the Institute for Food Research (IFR) in Norwich, England, might be able to offer some answers. Later this year, Martin Wickham and Richard Faulks plan to feed Quinn’s pasta to the world’s first and most sophisticated artificial stomach and compare the output to that from a meal of conventional pasta. Not only does the IFR’s ”model gut,” as it’s called, break down food with the proper quantities of enzymes and acids, it also mimics the physical motion—the mixing and shearing—that occurs inside the stomach. Besides clarifying our understanding of digestion, the invention may revolutionize the way processed foods are designed and how drugs are delivered. Since the machine began operating, in November 2006, some 10 to 15 companies have used it to test their products.
The model gut originated with a study that aimed to uncover how carotenoids—pigments that color foods such as tomatoes and carrots—are released from food and absorbed by the body. Faulks, a food chemist and nutritionist, and Wickham, a chemist specializing in colloidal mixtures, were unable to measure exactly what transpires in the stomach. Clinical trials are difficult and expensive. ”You can’t obtain samples of solid dinner because you can’t easily aspirate them—you can’t suck them up through a pipe,” says Faulks. ”You have to physically get in there. This, of course, then generates huge ethical problems.”
Advances in echo-planar imaging, an ultrafast type of magnetic resonance imaging, provided a breakthrough. This technique relies on just a single excitation of the molecules under study rather than the sequence of energy bursts in a traditional MRI, allowing it to capture 10 images or more each second. Echo-planar imaging ”allows us to collect data from people’s stomach and small intestine while they’re digesting foods,” says Wickham, without invasive probes.
Given the mystery that has shrouded the workings of the stomach, it’s fitting that the bulk of Faulks and Wickham’s model is behind smoky plastic: a literal black box. One day in October 2007, the scientists agree to demonstrate the device for IEEE Spectrum. They place two cans of soup on the countertop and prepare to feed the machine a late-morning meal.
The machine is the result of nearly a decade’s worth of effort and more than US $2 million, financed by the British government. After capturing data from hundreds of volunteers and drawing up a provisional design, Wickham and Faulks went to engineers to actually build the device. ”We had to help specify what materials were to be used, what size things were, how fast things moved,” says Wickham. ”Unless you can describe it to an engineer, an engineer can’t create it,” adds Faulks.
With Wickham at the computer manning the controls, Faulks pours a can of chunky chicken and vegetable soup into the blue funnel encased in a clear plastic cylinder at the top of the machine. This serves as the fundus, the curved, upper portion of a human stomach where newly arrived, chewed food gets gently massaged.
To measure this movement, Faulks and Wickham prepared beads of various densities made from agar, a seaweed gel. ”We got volunteers to swallow these, and then we MRI imaged the stomach to see when the stomach could break them up,” says Faulks. Still, he adds, designing the fundus was the most challenging aspect of the project. In the model, the massaging is replicated by a pressurized warm-water bath that surrounds the blue envelope, squeezing it to a rhythm that Wickham now sets.