Who can forget the stomach-churning moments when "Survivor" contestants forced down crunchy insects, among other unappetizing edibles, for a chance to win $1 million? In daring culinary challenges, the TV show's contestants exhibited gastronomic bravery as viewers watched in discomfort.
Digesting a crunchy critter starts with the audible grinding of its rigid protective covering -- the exoskeleton. Unpalatable as it may sound, the hard cover might be good for the metabolism, according to a new study, in mice, from Washington University School of Medicine in St. Louis.
The researchers, led by Steven Van Dyken, PhD, an assistant professor of pathology & immunology, found in mice that digesting chitin, an abundant dietary fiber in insect exoskeletons and also mushrooms and crustacean shells, engages the immune system. An active immune response was linked to less weight gain, reduced body fat and a resistance to obesity.
"Obesity is an epidemic," Van Dyken said. "What we put into our bodies has a profound effect on our physiology and on how we metabolize food. We're investigating ways to counteract obesity based on what we learn about how the immune system is engaged by diet."
The study is published Sept. 7 in Science.
The immune system is well known for safeguarding the body against various threats, including bacteria, viruses, allergens and even cancer. The researchers found that a particular arm of the immune system also is involved in chitin digestion. Stomach distention after chitin ingestion activates an innate immune response that triggers stomach cells to ramp up production of enzymes, known as chitinases, that break down chitin. Of note, chitin is insoluble -- incapable of being dissolved in liquid -- and thus requires enzymes and harsh acidic conditions to digest.
Do-Hyun Kim, PhD, a postdoctoral research associate and first author on the study, performed the experiments in germ-free mice lacking intestinal bacteria. His results show that chitin activates immune responses in the absence of bacteria.
Source: ScienceDaily
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