Scientists at Northwestern University found that people became less sensitive to food odors based on the meal they had eaten just before. These findings show that just as smell regulates what we eat, what we eat — in turn — regulates our sense of smell. Phys.Org reports: The study found that participants who had just eaten a meal of either cinnamon buns or pizza were less likely to perceive “meal-matched” odors, but not non-matched odors. The findings were then corroborated with brain scans that showed brain activity in parts of the brain that process odors was altered in a similar way.
Feedback between food intake and the olfactory system may have an evolutionary benefit, said senior and corresponding study author Thorsten Kahnt, an assistant professor of neurology and psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine. “If you think about our ancestors roaming the forest trying to find food, they find and eat berries and then aren’t as sensitive to the smell of berries anymore,” Kahnt said. “But maybe they’re still sensitive to the smell of mushrooms, so it could theoretically help facilitate diversity in food and nutrient intake.”
Kahnt said while we don’t see the hunter-gatherer adaptation come out in day-to-day decision-making, the connection between our nose, what we seek out and what we can detect with our nose may still be very important. If the nose isn’t working right, for example, the feedback loop may be disrupted, leading to problems with disordered eating and obesity. There may even be links to disrupted sleep, another tie to the olfactory system the Kahnt lab is researching. Kahnt said with a better understanding of the feedback loop between smell and food intake, he’s hoping to take the project full circle back to sleep deprivation to see if lack of sleep may impair the loop in some way. He added that with brain imaging, there are more questions about how the adaptation may impact sensory and decision-making circuits in the brain. The study has been published in the journal PLOS Biology.
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