Research Unplugged
Doctor Darwin: How Evolutionary Medicine Improves Patient Care
A conversation with Burt Humburg, resident in internal medicine at Hershey Medical Center
Burt Humburg
"Today we're going to figure out how to treat inflammatory bowel disease, or IBD, using evolutionary medicine," announced Burt Humburg at the beginning of his Research Unplugged talk last Wednesday at the Penn State Downtown Theatre. "Researchers have looked for bacteria, fungi, and parasites which may cause this disease, but we can't find any and so today we're going to find a treatment ourselves."
Thus Humburg, a third-year resident at Hershey Medical Center, engaged the audience in a discussion of evolutionary medicine, a field that integrates medical research and patient care with Darwinian concepts such as adaptation and natural selection. Said Humburg, a background in evolutionary thinking can help clinicians and researchers better tackle medical mysteries. “If many diseases are the result of evolution,” he told the crowd, “then by applying concepts of evolutionary biology and by knowing and using evolution in our clinical practice, we can better treat disease.”
Humburg explained that the human bowel co-evolved with intestinal parasites that suppress immune responses in the gut. “Knowing that evolutionary fact, why do you think intestinal bowel disease became much more prevalent in the 1920s and ’30s, after more hygienic septic systems were introduced?” he asked the audience. “Why is this condition more prevalent in the northern region of the United States than in the South? And why is it almost non-existent in underdeveloped countries with poor sanitation systems?”
The answer, he suggested, is that, over time, humans evolved an adaptation to intestinal worms by “turning up” the inflammatory reaction in the bowel to keep infestations in check. With modern sanitation having almost eliminated worm infestations, some individuals are left with an overactive immune response that irritates the digestive tract.
“What are the treatment implications of this discovery?” Humburg asked the crowd. “Go on, say it,” he said with a laugh. “Give ‘em worms!” That’s exactly what a study from the University of Iowa College of Medicine did in 2003, when they administered whipworm eggs to patients suffering with IBD and observed that all patients reported an improvement in symptoms.
Evolution already informs medicine in an even more basic way, said Humburg. “Why is animal research—such as drug studies on rats, mice, and other animals—so reliably useful to clinical practice?” he asked. “Common descent! Our shared genes allow animals to take our place in scientific experiments.”
Humburg's intriguing conversation elicited many questions and comments from audience members. We look forward to next week's lecture "Alzheimer's Revisited: Questioning the Medical Model," with Jesse Ballenger, an assistant professor of science, technology and society.
Burt Humburg, M.D, is a third-year internal medicine resident at Hershey Medical Center. He can be reached at burt@dochumburg.com.
