When you are feeling down what is the most likely comfort food you would choose? Something carbohydrate-based and sweet? In fact, according to researchers from University of Leuven, Belgium, in a study in the Journal of Clinical Investigation, the best mood-enhancer is fat.
Using functional magnetic resonance imaging (MRI) scans, the team led by Lukas Van Oudenhove, MD., PhD charted specific areas of the brain which are known to light up when a person is sad. For the study, they recruited 12 healthy individuals, none of whom was obese. They were then given an infusion of a fatty acid emulsion or saline solution via a feeding tube straight into their stomachs. This meant that taste was not involved and the participants did not know whether they were receiving saline or fat.
The fat was used because most comfort foods, such as chocolate, have a high fat content.
The researchers found that the levels of sadness among those fed the fat was approximately 50% lower compared to those fed saline solution, and say:
"These findings increase our understanding of the interplays among emotions, hunger, food intake and meal-induced sensations in general which may have important implications for a wide range of disorders including obesity, eating disorders, and depression."
In interview, a co-author, Giovanni Cizza, MD., said that he believes that the gut must be talking to the brain in some way:
"We did not know if you put fat in the stomach without pleasant stimulus, it could modulate our emotions ... There must be a way in which the gut talks to the brain."
The areas of the brain that get activated or suppressed as a result of emotion and mood were impacted by fatty acid emulsion. These fats reduced some of the emotion or neural changes, and this is a phenomenon that many patients have described.
"Many things in obesity have been said to be psychological and this adds to the body of evidence that something physical is going on."
Unfortunately, the recommendation to come from this study wasn’t that, perhaps, people who are sad or depressed might benefit from eating more fat, as you might have supposed, but that if scientists can identify what is going on, there might be a potential for new drug developments!
Oh, well, you can't win them all!
Van Oudenhove L, McKie S, Lassman D, et al. Fatty acid-induced gut-brain signaling attenuates neural and behavioral effects of sad emotion in humans. J Clin Invest. 2011. doi:10.1172/JCI46380.