If you're an emotional eater (I confess, I am), then you know well the lure of something creamy (and probably sweet, too) when you're feeling stressed, overworked, or just plain blue. Apples and celery just don't cut it.
There's a reason why fatty foods are called comfort foods. They soothe the savage within us.
Have you ever wondered why?
This week a team of researchers, led by Lukas Van Oudenhove at the University of Leuven, Belgium, published images of activity in the brain during times of sadness. Then they looked at how the images changed when a fat solution was introduced into the stomach.
For the study, 12 healthy, nonobese volunteers had their brains scanned using functional MRI. These were brave, committed people; each had a gastric feeding tube positioned with its tip in the stomach. The volunteers didn't know what kinds of solution they were getting through the tube--but sometimes they got a simple salt solution and sometimes they got a fatty one.
The volunteers listened to pieces of sad or neutral classical music while they viewed images of human facial expressions depicting either sad or neutral emotion (of the same emotion as the music pieces).
At fixed time points during scanning, participants rated their sensations of hunger and fullness on a 9-point scale. At the same time, they rated their mood from sad (indicated by 1) to neutral (indicated by 5) to happy (indicated by 9).
Brain regions in which a significant fat-by-emotion interaction was found. HYPOTHAL, hypothalamus; THAL, thalamus; HIPPO, hippoc
The brain images revealed what ice cream lovers have long known: the brain's responses to sadness were significantly reduced when the fatty solution was infused into the stomach. Respondents also reported less hunger and a better mood when the fatty solution was given. The effect was significant in the pharmacological sense: the fatty solution reduced the intensity of sad emotions by almost half--which is about as much as any prescription antidepressant can achieve.
The study showed a pretreatment effect as well. When subjects were given the fatty acid solution ahead of time, their subsequent responses to sadness were diminished. At the same time, sad music and pictures reduced the sense of fullness that came from fat ingestion.
This study has clear implications for a wide range of disorders, including obesity, eating disorders, and depression. We understand too little about when and why we get the urge to eat and why we crave some foods over others. This new study helps us move one step closer to comprehending the powerful effect of the body on the mind.
For More Information:
Lukas Van Oudenhove, Shane McKie, Daniel Lassman, Bilal Uddin, Peter Paine, Steven Coen, Lloyd Gregory, Jan Tack, and Qasim Aziz. Fatty acid-induced gut-brain signaling attenuates neural and behavioral effects of sad emotion in humans. Journal of Clinical Investigation. Published online June 25, 2011.
Giovanni Cizza and Kristina I. Rother. Was Feuerbach right: Are we what we eat? Journal of Clinical Investigation. Published online June 25, 2011.