Fighting disease with food

Food scientist Steven Schwartz believes that functional foods may one day be an important weapon for helping to prevent illnesses.

Steven Schwartz
Steven Schwartz

It’s hard to go wrong, nutrition wise, with a crisp apple or a snappy carrot stick. But when it comes to preventing disease, a select number of fruits and vegetables, alone or in combination, may be able to serve as the basis for so-called functional foods. Functional foods are those that go beyond merely providing nutrients—they actively help prevent diseases for those at high risk, such as cancer, diabetes or heart disease. And products based on these foods could play a key role in the fight against disease, says Steven Schwartz, an associate director of the Food Innovation Center and director, Center for Advanced Functional Foods Research and Entrepreneurship at the Ohio State University.

In fact, Schwartz and his colleagues are hoping that a new tomato-soy juice they’ve developed will demonstrate just what functional foods can do in this arena. The team chose tomatoes and soy because epidemiological research has linked both to a decreased risk of prostate cancer, Schwartz says. He and his colleagues are just wrapping up clinical trials testing the juice in prostate cancer patients.

Our focus is to try to understand the food itself, not a single compound. I think it’s the synergistic effects of the many components in foods that might be beneficial.”
—Steven Schwartz

“We decided we would create a unique food product that could be used as a sort of model for the study of functional food,” he says.

Anti-cancer compounds in food

Schwartz began his career at the University of Wisconsin, Madison, where he completed a joint doctorate in food science and environmental toxicology in 1982. Early on, he explored whether natural colorants used in foods could be potential carcinogens. Then he read about new research showing that some carotenoid compounds—a class of natural pigments found in many fruits and vegetables—had the potential to prevent cells from becoming cancerous.

Those findings flipped Schwartz’s interests upside-down. Ever since, he’s been exploring naturally occurring compounds in food that have the potential to prevent—rather than cause—cancer.

One such compound is lycopene, a carotenoid pigment that gives tomatoes their crimson hue. When a large epidemiological study in the mid-1990s linked tomato consumption to a decreased risk of prostate cancer, Schwartz, then at North Carolina State University, took note.

To explore the link between tomatoes and prostate cancer, Schwartz began collaborating with Dr. Steven Clinton, a physician-scientist now also at Ohio State University. Their long-term collaboration has since grown to include other researchers on campus, and their efforts, along with director Ken Lee, helped launch the university’s interdisciplinary Food Innovation Center in 2009.

Juicing up prostate cancer research

The tomato-soy juice project, says Schwartz, perfectly illustrates how functional foods research benefits from interdisciplinary collaboration.

Schwartz and his colleagues started with a special high-lycopene tomato variety developed by David Francis, an OSU horticulture expert. “It’s a really dark, blood-red color, and has two to three times the typical concentration of lycopene,” Schwartz says. Next, he and his food science colleagues developed a juice from the tomatoes and combined it with an extract of soy isoflavones. Isoflavones are plant-derived compounds, commonly found in soy and other legumes, that weakly mimic the activity of the hormone estrogen.

Schwartz and his colleagues put the juice through sensory testing, fine-tuning the flavor and texture to create an appetizing product. After first studying the juice in healthy subjects, Schwartz, Clinton and their colleagues are now wrapping up a National Cancer Institute-sponsored clinical trial testing the juice in prostate cancer patients.

In the study, men with prostate cancer were randomly assigned to consume zero, one or two 6-ounce cans of the juice daily for three to four weeks before undergoing surgery to remove the prostate. Schwartz’s collaborators in the medical school are evaluating a host of outcomes, including how well the lycopene and soy isoflavones were digested and metabolized, and what effects, if any, the juice consumption had on tumor biomarkers and the proliferation of cancer cells.

Lycopene and soy isoflavones have plenty of company on the list of promising compounds, says Schwartz. Isoflavones are just one subset of a broad class of biologically active compounds called flavonoids, many of which have health-promoting potential. Schwartz is also interested in learning more about the compounds that give cruciferous vegetables like broccoli their cancer-prevention powers.

Juices like the tomato-soy drink are convenient, since they keep for a long time and are easy for consumers to grab on the go. But functional food products could run the gamut from drinks to desserts, says Schwartz, who is currently involved in collaborations testing a soy bread and a berry confection for oral cancer prevention.

Food synergies

When it comes to preventing disease with functional foods, Schwartz believes food trumps supplements. “Our focus is to try to understand the food itself, not a single compound,” he says. “I think it’s the synergistic effects of the many components in foods that might be beneficial.”

Indeed, evidence from Schwartz’s lab and others illustrates the importance of understanding how foods work together in the body. Eat a handful of plain carrots, and you won’t absorb much beta-carotene, a carotenoid compound converted in the body to vitamin A, a necessary nutrient. But add a little fat—a spoonful of salad dressing, say—and your body will absorb many times more beta-carotene, and convert it more efficiently to vitamin A.

Such findings could lead to simple dietary recommendations to help people maximize the health benefits of the foods they eat. And those recommendations could have global implications, particularly in developing nations where vitamin A deficiencies are both common and devastating.

The future of functional foods

Preventing vitamin deficiencies is important, of course, but Schwartz sees much broader benefits ahead from functional foods. He predicts that these products will show up first on grocery store shelves. But eventually, he adds, doctors may prescribe functional foods to help prevent—or perhaps even treat—specific diseases.

To glean the maximum benefit, however, he wants to understand how different food compounds affect different people. “I think one reason many studies [of food and health] are confusing is because there’s so much variability between individuals,” he says.

Genetics can influence how well (or not) a person absorbs and metabolizes the bioactive compounds in foods. The unique community of bacterial flora in each person’s gut probably plays a key role as well, Schwartz says. On top of that are countless environmental factors: Smokers, for instance, can metabolize compounds differently from non-smokers.

“We need to understand why people are different. Then we’ll have a better understanding of which functional foods are best for which groups of individuals,” he says.

Emerging Big Data technologies are making that possible, with ever more powerful computers and sophisticated software that can process vast quantities of data. That technology will allow scientists to catalogue an individual’s “metabolome”—the complete set of small-molecule chemicals involved in metabolic reactions in the human body. Just as our genomes are unique, so too are our metabolomes, Schwartz explains. And like the human genome, the human metabolome is complex. “We have no idea of the size of the human metabolome—but I know it’s thousands and thousands of compounds,” he says.

By 2050, Schwartz hopes his dream of personalized nutrition will be a reality. “When we better understand people’s genomes and metabolomes, we can have very targeted diets for individuals to provide a health benefit or decrease the risk of developing a certain disease,” he says.

And in the meantime? “I always grab a can of tomato juice when I can.”

Kirsten Weir

Kirsten Weir is a freelance science writer based in Minneapolis. Her work has appeared in New Scientist, Discover, Scientific American Mind, U.S. News & World Report and many others.

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