American Society For Nutrition

Can’t Get No Satisfaction: Retronasal Olfaction and Satiety Signals

Can’t Get No Satisfaction: Retronasal Olfaction and Satiety Signals

Excellence in Nutrition Research and Practice
Posted on 02/03/2010 at 07:58:10 PM by Student Blogger
By: Caitlin L.

Satiety:  Noun. The condition of being full or gratified beyond the point of satisfaction; surfeit.

A problem cited by many who are overweight is that they cannot stop eating.  They know they have eaten enough, they should be able to push the plate away and end the meal, but they can't.  I have heard a variety of reasons for this, from a childhood that was lacking food, to an overwhelming emotional response to food, to an unyielding portion distortion that exists at every restaurant in America.  Whatever the reason, many people have lost the ability to register satiety.  The mind body connection is no longer there.  It seems that if we can teach one to listen to the body, to reawaken the satiety signal so that one does not become “gratified beyond the point of satisfaction”, we could address a large part of the nations' obesity problems.   So how can we retrain a nation to listen to a satiety signal that has been overridden most of our lives?

While there is probably a wide spectrum of opinions on how to handle this issue, there appear to be two main schools of thought.   The first argues that teaching and implementing mindful eating techniques is adequate and can prove to be successful in retraining an individual to read his or her hunger and satiety cues and signals.  Behavioral therapy using cognitive restructuring and understanding stimuli, distractions, and underlying emotions are strategies used to retrain the brain and change the corresponding behavior.  But is this enough for someone who has viewed appetite satisfaction as synonymous with overeating for their entire lives; for a person who has never truly felt a normal sense of hunger and/or satiety?

The other main school of thought disagrees and focuses on food chemistry to solve the problem.  Researchers have been examining the role of aroma and its effect on hunger and satiation, or specifically odors that may activate the part of the brain that signals satiation and fullness.  A 2009 review published in the Journal of Agricultural and Food Chemistry concluded that preliminary studies point to promising results in this field, that we can essentially manipulate food to produce feelings of fullness in the brain, specifically through retronasal olfaction.  Retronasal olfaction occurs when aroma stimuli reaches the olafactory epithelium through the act of chewing rather than sniffing or smelling something .  Our olafactory epithelium communicates with our brain to detect smells and odors.  The hypothesis is that foods can be tailored to increase the levels and/or the quality of stimulation that in turn will lead to higher feelings of satiety.  The hope is that this will help people to stop overeating.   The next step, the researchers conclude, is to test this concept using real foods.

Are people actually so far removed from their own body regulations that they need to turn to manipulated food in order to stop overeating?  Or is it possible to retrain our bodies to listen to the inherent cues that we were born with?   In my optimistic heart, I like to believe that the latter is true.  But my brain knows that as a nation we want things done for us, and we look for quick fixes instead of looking at the source of the problem.  If an easier alternative is made available to help us stop overeating we may not do the work necessary to change our behavior.  

Source: Ruijschop, R.M.A.J. , A.E.M. Boelrijk, C. de Graaf, M.S. Westerterp-Plantenga. "Retronasal Aroma Release and Satiation: A Review." Journal of Agricultural and Food Chemistry. 57.21 (2009): 9888–9894
Posted Feb 05, 2010 7:48 PM by Peggy Fishman

I agree with you, Caitlin, that artificial manipulation of our food should not be the answer and, to me, is a frightening prospect. It would move people even further away from their body-food connection by solving the problem for them without any need for concious participation.

As a person who has been overweight most of my adult life, I know that one of the keys to successful management of my eating habits is knowing when I am satisfied -- and then having the desire to stop eating. This requires that I be conscious of my body every moment that I am eating AND that I be conscious of the food I'm consuming; how it tastes, how it makes me feel when I eat it, how much am I eating & how does that make me feel.

So much of the time we Americans spend eating is under hurried circumstances, I feel that most of us have lost the ability to be in touch with the food-body connection. The simple act of slowing down and paying attention to our food and the way it makes our bodies feel will be a much better solution than manipulating our food.

It very much a challenge.

erent cues that we were born with? In my optimistic heart, I like to believe that the latter is true

It truly is frightening to think that we may have gotten to the point that we need to manipulate our food to keep from eating it. Yikes!! I'm with you Caitlin. I would hope that we might be able to find effective ways to alter our behaviors and repair the disconnect that has occurred between our bodies and ourselves. Not only would it benefit us in terms of our relationship to food, eating and obesity, but to many others of our current health issues and challenges.

Hey Caitlin, appreciate this post a lot as it's going to help me in a project!