Feeding Your Gut Bacteria May Be the Next Step to Curbing Your Appetite

Author:  Dana Lowry

Institution:  Queen's University


Researchers in the UK have created a possible supplement that may be used for managing weight loss in the future. The scientists have developed a powdered form of a molecule that is digested by our gut bacteria. These bacteria then produce a substance able to curb appetite and decrease desire for junk foods.

Imperial College London and the University of Glasgow are testing the effect of the potential supplement, called inulin propionate ester, has on human appetite. These substances are important for our gut because of the microorganisms that already live within us. Since the human digestive system is unable to digest certain dietary compounds, including inulin and inulin propionate ester, the bacteria in the gut digest the compounds for us. These compounds are broken down into less complex molecules, such as acetate and propionate, both of which have been shown to reduce appetite. The researchers of this recent study have tested the possibility of making our gut bacteria produce more of these appetite-suppressing compounds. In this case, the compound in question is propionate.

Inulin is the substance that is digested to specifically produce propionate. The researchers wanted to try and increase the yield of propionate per molecule of inulin digested by slightly modifying the chemical structure of inulin. In doing so they formed inulin propionate ester to test on individuals for increased production of propionate, and hopefully increased appetite repression.

Dr. Gary Foster explains: “The amount of inulin-propionate ester used in this study was 10g - which previous studies show increases propionate production by 2.5 times. To get the same increase from fibre alone, we would need to eat around 60g a day. At the moment, the UK average is 15g.”

The recent study using this modified substance tested 20 non obese male volunteers by handing them each a chocolate milkshake for breakfast. The volunteers were either given a milkshake laced with inulin, as a control, or inulin propionate ester, the test ingredient. The volunteers were then shown a series of photographs of high calorie foods including pizza, cake, and healthy food such as fish and vegetables. During this sequence their brains were monitored for increased or decreased activity in areas that are linked to hedonistic eating and reward processing behavior. The results show that participants who ingested the inulin propionate ester displayed less activity in these brain regions than control group volunteers.

The participants were also asked to rate the appeal for the foods. The results from the inulin propionate ester group indicate a decreased desire for the high calorie foods.

Next, the volunteers were given a baked pasta dish and were asked to eat as much as they wished. The participants who ingested the inulin propionate ester ate 10% less than the group that only had inulin in their morning milkshake.

A study run by the same group of scientists in 2013 tested the weight gain of overweight volunteers over a six month period. Those that had the added supplement of inulin propionate ester to their meals gained less weight over the course of the term than did those who added inulin alone.

The two studies together show the importance of cultivating the link between diet and gut health. As professor Gary Foster, senior author of the paper from the Department of Medicine at Imperial College notes: “Our previous findings showed that people who ate this ingredient gained less weight - but we did not know why. This study is filling in a missing bit of the jigsaw - and shows that this supplement can decrease activity in brain areas associated with food reward at the same time as reducing the amount of food they eat”.

Dr. Douglas Morrison, author of the paper from the Scottish Universities Environmental Research Centre at the University of Glasgow, emphasizes the importance gut health has on our overall health: “This study illustrates very nicely that signals produced by the gut microbiota are important for appetite regulation and food choice. This study also sheds new light on how diet, the gut microbiome and health are inextricably linked adding to our understanding of how feeding our gut microbes with dietary fibre is important for healthy living.”

The next new diet supplement to hit the shelves may be food for the bacteria living in our guts. "If we add this to foods it could reduce the urge to consume high calorie foods,” said Claire Byrne, a PhD research from the Department of Medicine at Imperial College.



Byrne, C., Chambers, E., Alhabeeb, H., Chhina, N., Morrison, D., Preston, T., Tedford, C., Fitzpatrick, J., Irani, C., Busza, A., Garcia-Perez, I., Fountana, S., Holmes, E., Goldstone, A. and Frost, G. (2016). Increased colonic propionate reduces anticipatory reward responses in the human striatum to high-energy foods. American Journal of Clinical Nutrition, 104(1), pp.5-14. 

EurekAlert!. (2016). Cravings for high-calorie foods may be switched off in the brain by new supplement. [online] Available at: http://www.eurekalert.org/pub_releases/2016-07/icl-cfh070116.php [Accessed 18 Jul. 2016].

Wighton, K. (2016). Cravings for high-calorie foods may be switched off by new food supplement. [online] Www3.imperial.ac.uk. Available at: http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_1-7-2016-10-31-12 [Accessed 18 Jul. 2016].