A new type of food supplement – based on a molecule produced by bacteria in the gut – has been found to reduce. cravings for high-calorie foods, according to scientists from Imperial College London and the University of Glasgow.

Volunteers were asked to drink a milkshake that either contained an ingredient called inulin-propionate ester, or a type of fiber called inulin.

Bacteria in the gut release a compound called propionate when they digest the fiber inulin, which can signal to the brain to reduce appetite. However the inulin-propionate ester supplement releases much more propionate in the intestines than inulin alone.

After drinking the milkshakes, participants underwent an MRI scan, where they were shown pictures of various low or high calorie foods such as salad, fish and vegetables or chocolate, cake and pizza.

When volunteers drank the milkshake containing inulin-propionate ester, they had less activity in areas of their brain linked to reward – but only when looking at the high calorie foods. These areas, called the caudate and the nucleus accumbens, found in the center of the brain, have previously been linked to food cravings and the motivation to want a food.

The volunteers also had to rate how appealing they found the foods. The results showed when they drank the milkshake with the inulin-propionate ester supplement they rated the high calorie foods as less appealing.

In a second part of the study, volunteers were given a bowl of pasta with tomato sauce, and asked to eat as much as they like. When participants drank the inulin-propionate ester, they ate 10 percent less pasta than when they drank the milkshake that contained inulin alone.

Results of the study, published in July edition of the American Journal of Clinical Nutrition, showed 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,” said Professor Gary Frost, senior author of the study from the Department of Medicine at Imperial.

He added that eating enough fiber to naturally produce similar amounts of propionate would be difficult: “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 fiber alone, we would need to eat around 60g a day. At the moment, the UK average is 15g.”