Physiology

Managing the Munchies

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Science  22 Jul 2011:
Vol. 333, Issue 6041, pp. 387
DOI: 10.1126/science.333.6041.387-a
CREDIT: ISTOCK PHOTO

Unfortunately for modern humans, we are adapted to pounce all over high-fat foods, presumably because the essential nutrients they provide were often scarce for our ancestors. In modern society, such preference for fatty foods in the face of their ample availability is a recipe for a major societal health problem. DiPatrizio et al. explored the mechanism by which the presence of fatty foods in the mouth stimulates the appetite of rats for more by surgically shunting ingested food from the stomach so that the rest of the digestive system was not affected. Surprisingly, the presence of fat in the mouth increased the synthesis of endocannabinoids (neurotransmitters related to the active substance in marijuana) in the small intestine. Severing the vagus nerve blocked the effect, showing that the signal must travel from the mouth to the brain and then to the intestine. Endocannabinoid blockade in the gut diminished the feed-forward (so to speak) effect of oral fat on further fat ingestion. The authors suggest that a strategy that diminishes endocannabinoid signaling in the gut could help reduce an excessive drive for fat intake without side effects on the brain, where endocannabinoids also function in reward pathways.

Proc. Natl. Acad. Sci. U.S.A. 108, 10.1073/pnas.1104675108.

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