Gut 'tasting' could beat poisons

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The human intestine detects potential poisons passing into it - and may take action to reduce the harm they cause.

US researchers have found a link between receptors in the gut which detect bitter foods and higher levels of a digestion-slowing hormone.

The same hormone also reduces appetite - perhaps to stop us eating any more.

The scientists, writing in the Journal of Clinical Investigation, say it means that sweeter-tasting medicines could be more effective.

The whole scientific area of 'nutrient sensing' is really getting quite big Professor Soraya Shirazi-BeecheyUniversity of Liverpool

Humans, and other animals, have evolved to dislike bitter tastes, probably because many natural plant poisons carry these flavours.

The researchers from the University of California at Irvine, led by Dr Timothy Osborne, are suggesting that when we do manage to eat something bitter, another defence mechanism may kick in.

It has been established for some time that the same taste receptors which are found on the tongue, and help us differentiate between sweet and bitter flavours, are found in the gut.

While the tongue-based receptors send a message to the brain, those in the gut are thought to trigger other chemical signals involved in digestion, although these have yet to be fully understood.

The US team found that when the bitter taste receptors in the gut are activated, this leads to the production of a hormone called cholecystokinin.

This is already known to not only slow up "motility", the rate at which food passes through the digestive system from the stomach, but also suppress appetite.

Slow the flow

The researchers believe that keeping potentially poisonous food in the stomach for longer might mean a bigger chance it would be expelled before its ingredients are absorbed.

Additionally, suppressing appetite might mean that less of the poison is eaten.

They are now eyeing the practical uses of their findings - and suggest that some medication might be absorbed more quickly if it was not so bitter tasting.

Professor Soraya Shirazi-Beechey, from the University of Liverpool, led research which proved that the action of "sweet" taste receptors in the gut could actually alter the way that glucose was absorbed into the body.

She said it was "quite reasonable" that bitter receptors might also have an effect on digestion.

"The whole scientific area of 'nutrient sensing' is really getting quite big. This is the first time that the link between bitter taste receptors and this hormone has been made."