Obesity Linked to Abnormal ‘Reward Circuitry’ in Brain

Dec 05, 2008

Using brain imaging and chocolate milkshakes, scientists have found that women with weakened “reward circuitry” in their brains are at increased risk of weight gain over time and potential obesity. The risk increases even more for women who also have a gene associated with compromised dopamine signaling in the brain.

The results, drawn from two studies using functional magnetic resonance imaging (fMRI) at the University of Oregon’s Lewis Center for Neuroimaging, appear in the Oct. 17 issue of the journal Science. The first-of-its-kind approach unveiled blunted activation in the brain’s dorsal stratium when subjects were given milkshakes, which may reflect less-than-normal dopamine output.

“Although recent findings suggested that obese individuals may experience less pleasure when eating, and therefore eat more to compensate, this is the first prospective evidence for this relationship,” said Eric Stice, lead author and senior researcher at the Oregon Research Institute (ORI) in Eugene. “The evidence of temporal precedence suggests it is a true vulnerability factor that predates obesity onset. In addition, the evidence that this relation is even stronger for individuals at genetic risk for compromised signaling in these brain regions points to an important biological factor that appears to increase risk for obesity onset.”

Dopamine is the primary neurotransmitter in the brain's reward pathways. Food intake is associated with dopamine release, while pleasure from eating correlates with the amount of dopamine release. Previous studies have suggested that obese individuals have fewer dopamine receptors in the brain and have to eat more than lean people to be satisfied.

Using fMRI, Stice’s team measured the extent to which the dorsal striatum was activated in response to an individual’s receipt of a taste of chocolate milkshake or a tasteless solution. One study involved 43 female college students ranging in age from 18 to 22 with a mean body mass index (BMI) of 28.6. The second study looked at 33 adolescent girls, ages 14-18, with a mean BMI of 24.3. Most of the participants were tested for the presence of a genetic variation known as the Taq1A1 allele, which is linked to a lower number of dopamine D2 receptors.

Researchers tracked changes in BMI over a year. Results showed that participants with decreased striatal activation in response to receiving milkshake and those with the A1 allele were more likely to gain weight over time.

“I was quite excited by the study itself, as it is the first prospective study to utilize fMRI and genetic data to predict unhealthy weight gain,” said Bohon, whose doctoral work is done on both the UO campus and the nearby ORI facility. “The findings suggest that certain biological factors may impact one’s risk for weight gain, which is important in order to better understand how we can eventually intervene and prevent obesity.”

© 2015 by IDEA Health & Fitness Inc. All rights reserved. Reproduction without permission is strictly prohibited.

0 Comments

Trending Articles

How to Teach HIIT to Everyone

High-intensity interval training has been riding a wave of popularity, and it seems everyone wants to give it a try. However, intense interval training is nothing new. Group fitness instructors have b...

Cut Risk of Alzheimer’s with MIND Diet

Conservative adherence to a new diet, appropriately known by the acronym MIND, could significantly lower a person’s risk of developing Alzheimer’s disease, according to a paper published o...

Yes, You CAN Develop Better Eating Habits

Analogous to laying out your exercise gear so it’s the first visual reminder you have of your commitment to exercise each day, imagine...

Mindful Walking

Walking can be more than just moving physically from one location to another. It can be a metaphor for your larger life journey. Things you&...

Smooth Move: Creative Additions to Consider for Smoothies

When looking for a quick breakfast or post-workout nourishment, almost nothing beats a smoothie. Whirl in the right ingredients and the blen...

20 IDEA World-Renowned Presenters Share Advice on Success and Happiness

We asked some of this year’s most influential and motivating IDEA World Fitness Convention™ presenters to share the single piece of advice they would give another fitness/health pro to hel...

7 Ways to Help a Client Boost Adherence

Once a client has decided to make nutritional changes to support weight loss, you can play a key role in developing an action plan that is m...

Nuts and Peanuts Reduce Cardiovascular Risk and Prolong Lifespan

While there have been numerous studies in recent years touting the health benefits of nuts and peanuts, new research published online March ...

Low Intensity vs. High Intensity: Which Is Best for Obese Adults?

The debate continues regarding the most effective exercise measures for reducing abdominal obesity and improving glucose measures.

Recipe for Health: Picadillo-Stuffed Peppers

If you don’t believe that authentic Mexican cookery is “whole” and healthy, you need to take a deep dive into Mexico: The Cookbook (Phaidon 2014), the first truly comprehensive bible...

Show More