“Eating fat seems to make us less vulnerable to sad emotions, even if we don’t know we’re eating fat,” said psychiatrist Dr. Lukas Van Oudenhove, co-author of a study that tracked people’s responses to sad and neutral experiences while fatty acids were inserted into their stomach. The food appeared to cause emotional and physical changes.
Anyone who’s ever dipped into a pint of premium ice cream after a breakup knows that certain foods feel emotionally healing. But is it all in the mind — a connection to, say, childhood comforts? Or are there signals that go from mouth or stomach to the brain?
Researchers previously have tackled these questions by focusing on how the smell, taste and appearance of food affect emotions, said Van Oudenhove, a postdoctoral researcher at the University of Leuven in Belgium. But this new study is a first, he said, because “we bypassed sensory stimulation by infusing fatty acids directly into the stomach, without the subjects knowing whether they were getting fat or saline.”
For the study, published in the August issue of the Journal of Clinical Investigation, the researchers recruited 12 non-obese, healthy volunteers who received fatty acids or a saline solution through a feeding tube. Using functional MRI, the researchers also scanned the volunteers’ brain waves as they were exposed to sad and neutral music, and sad and neutral facial expressions.
One might assume they would already be a bit sad because of the medical procedure, but Van Oudenhove said they weren’t particularly uncomfortable.
On its own, the efforts to induce sadness — through music and images of frowns — caused people’s moods to fall by 2.5 points out of 10, Van Oudenhove said. But the fatty acids helped reduce the dip to about 1 point.
In the brain itself, researchers found that induced sadness produced a change of about 3 to 4 percent, “which is quite a lot,” Van Oudenhove said. But the level of change shrank to less than 1 percent once the subjects got a dose of fatty acids, at least in most regions of the brain that were analyzed.
It’s not clear if other ingredients in food would have a similar effect. Van Oudenhove said more research is needed to determine whether the findings may have any value in treatment of obesity, depression or eating disorders.
The authors of an accompanying journal editorial pointed out several limitations of the study, including the small number of participants and the absence of an obese cohort. Still, they said the findings may help further the understanding of obesity.
“The next step would be to test the effects of food that contain both high-fat and high-sugar,” said Sonja Yokum, a research associate at the Oregon Research Institute in Eugene, who’s familiar with the study findings. “It would be interesting to test if fat, sugar or the combination decreases negative mood and for how long.”
Also of interest, she said, would be a study involving both “emotional eaters” (people who use food as solace) and successful dieters.
Ultimately, it would be “very helpful” to find a way to prevent people from craving high-fat and high-sugar foods when they’re depressed, Yokum said.