Ever had a bad day where you feel a little depressed? Failed a test? Got in a fight with a friend?Or just not feeling great?
Other than alcohol, the most common substance that people (especially college students) will turn to is fast food, chock-full of fatty acids! Who doesn't feel better, mentally at least, after a huge burger, salty fries and an ice-cold milkshake? According to a recent study, there may actually be some physiological evidence based on mood and fatty food.
Oudenhove and his colleagues (2011) took a closer look at the physiology, neural activity, and behavioral effects of fatty acids on mood. What they knew prior to this study was that:
1) hunger/satiety signals from the gut to brain play a large role in feeding
2)food signals and stimuli are associated with cognitive-affective (emotions) processes
3) previous research has shown a connection between taste/smell and neural activity.
The current study used an fMRI during an intragastric(directly into the stomach) infusion of fatty acid (lipids). 3 minutes prior to the infusion, the patients were either induced with a sad emotion or neutral emotion (using complicated psychological stimuli) and the brain activity was measured to see if the brain was "sad" or neutral.
Neurological, multiple brain areas (brainstem, hypothalamus, cerebellum and others) were activated in both neutral and sad emotion induction when fatty acid was ingested over saline. In addition, prior to the ingestion, the sad emotion condition was shown to increase hunger significantly. And once the ingestion happened, the fatty acid was shown to satisfy this hunger and significantly (statistically) increase emotion.
According to the results and discussion, this present study presents evidence for a neurobiological basis for "emotional overeating" and "comfort feeding" and also appetite disturbances in mood disorders. The study does retract some of validty in saying that this study simply demonstrates the behavior and some of the neurology, but the mechanism is not fully understood.
Question Time:
1) Do you believe that hunger is related to affect/emotion? If so, how? Have you ever experienced the the feeling of being "hangry" (being hungry and angry)?
2) Big picture: How can we apply this information to human health and diet? Maybe recommend small amounts of fat to improve emotion daily?
Van Oudenhove, L., McKie, S., Lassman, D., Uddin, B., Paine, P., Coen, S., & ... Aziz, Q. (2011). Fatty acid--induced gut-brain signaling attenuates neural and behavioral effects of sad emotion in humans. Journal Of Clinical Investigation, 121(8), 3094-3099. doi:10.1172/JCI46380.
Fatty Foods and their correlation to emotional eating often links back to many of the same neural circuits involved with basic satiety. According to a study done at the University of Minnesota, palatability, how good something looks/tastes/smells, is one of the most rewarding human behaviors. The gratification of eating to satisfy hunger is often associated with the release of opioids and these opioids associate pleasurable feelings with eating. Thus, the behaviors of addictive-eating often associate not so much with fatty foods and sugar, but rather with the psychological reward-related circuitry of humans, which promote beneficial behaviors. Thus, highly fatty or sugary foods become addictive in a similar way as drug taking to substance dependence. Thus it is the opioid system that creates neural adaptation similar to that drug-induced substance dependence. Thus, this study shows that it is not the fatty/sugary foods that provide the pleasurable emotions; rather it is the opioid system stimulating the feeling of satiety that induces this substance “food” dependence.
ReplyDeletePawel K. Olszewski, Johan Alsiö, Helgi B. Schiöth, Allen S. Levine, Opioids as facilitators of feeding: Can any food be rewarding?, Physiology & Behavior, Volume 104, Issue 1, 25 July 2011, Pages 105-110, ISSN 0031-9384, 10.1016/j.physbeh.2011.04.033.
(http://www.sciencedirect.com/science/article/pii/S0031938411001922)
Well to start, I can tell you that no research grants were necessary to prove this. I often feel "hangry" and do enjoy a horrible (and yet delicious) McDonald's Big Mac at those times. However, there has to be some other hormone/signal in the body, other than emotion, that signals hunger in times of lowered emotional states
ReplyDeleteNot only lowered emotional states, but also the type of stimuli matter in the case of hunger. According to a study done by Piech et al, there was a significant decrease in the cognitive flexibility of people who were presented with food but were denied it than a group of people who were fasting (2009). I find it incredible that fasting - as in not eating for a certain amount of time - doesn't change our way of thinking more than being presented with food an hour after eating breakfast. So being constantly bombarded with food pictures on billboards and smelling the pizza walking by Regis Pizza is degrading my cognitive flexibility. Who knew?
Resource
Piech, R.M., Hampshire, A., Owen, A.M., & Parkinson, J.A. (2009). Modulation of cognitive flexibility by hunger and desire. Cognition and Emotion, 23(3), 528-540. DOI: 10.1080/02699930802012153