Some people eat when they are hungry and stop when they are not. Others eat until they are full. For that second group, science may soon have a way to help keep them slimmer.

Inulin-propionate ester (IPE) contains propionate, which stimulates the gut to release hormones that act on the brain to reduce hunger. Propionate is produced naturally when dietary fiber is fermented by microbes in the gut and in its first tests in humans, researchers found that the ingredient is effective at preventing weight gain in overweight volunteers.

First, 20 volunteers were given either IPE or inulin, a dietary fiber, and were allowed to eat as much as they liked from a buffet. Those given IPE ate 14 percent less on average, and had higher concentrations of appetite-reducing hormones in their blood.

Credit: Imperial College London

Next, 60 overweight volunteers took part in a 24-week study in which half were given IPE as a powder to add to their food and half given inulin. One out of 25 volunteers given IPE who completed the study gained more than three percent of their body weight, compared with 25 percent given inulin. None of the IPE group gained more than five percent of their body weight, compared with four in the inulin group.

After 24 weeks, the IPE group also had less fat in their abdomens and livers compared with the inulin group. The findings are published today in the journal Gut.

Professor Gary Frost, who led the study at the Department of Medicine at Imperial College London, said, “We know that adults gain between 0.3 and 0.8 kilos a year on average, and there’s a real need for new strategies that can prevent this. Molecules like propionate stimulate the release of gut hormones that control appetite, but you need to eat huge amounts of fiber to achieve a strong effect. We wanted to find a more efficient way to deliver propionate to the gut.

“This small, proof-of-principle study shows encouraging signs that supplementing one’s diet with the ingredient we’ve developed prevents weight gain in overweight people. You need to eat it regularly to have an effect. We’re exploring what kinds of foods it could be added to, but something like bread or fruit smoothies might work well.”

Dr Douglas Morrison, from the Scottish Universities Environmental Research Centre at the University of Glasgow, said, “There is significant interest in how food components like dietary fiber interact with gut microbes to influence health, but much of the evidence we rely upon comes from laboratory and animal studies. It is often difficult to translate these findings directly into successful human interventions.

“Packaging propionate up to more efficiently deliver it to the large intestine has allowed us to make direct observations in humans that propionate may play an important role in weight management. These exciting findings could at last open up new ways to manipulate gut microbes to improve health and prevent disease.”

Citation: E.S. Chambers et al. ‘Effects of targeted delivery of propionate to the human colon on appetite regulation, body weight maintenance and adiposity in overweight adults.’ Gut, 2014. doi 10.1136/gutjnl-2014-307913