Diet rich in fibre reduces risk of severe colon problems, shows research.
"A high-fibre diet reduces the risk of colon problems and that when fibre is lacking, vitamin B3 just may help keep the colon healthy as well," said Vadivel Ganapathy, from Medical College of Georgia at Georgia Regents University (GRU) in the US.
The researchers found that mice lacking the receptor - Gpr109a - were prone to inflammation and cancer of the colon.
Doctors gave mega-doses of vitamin B3 to mice whose healthy colonic bacteria had been wiped out by antibiotics - a frequent occurrence in chronic antibiotic use.
It helped steer immune cells in the colon into a safe, anti-inflammatory mode, according to the study published in the journal Immunity.
"Good bacteria in the colon thrive on fibre and its digestion produces butyrate, a short-chain fatty acid, which naturally activates the receptor," said Nagendra Singh, immunologist at the GRU Cancer Centre.
"To protect your colon, you need this receptor, as well as the fibre and butyrate which activate it," Ganapathy added.
For people who cannot eat high-fibre diets, mega-doses of Vitamin B3 (niacin) may help protect the colon, the scientists suggest.
The colon and intestines are constantly exposed to foreign bacteria that enter the body primarily through the mouth.
The good bacteria, which are essential to digestion and colon health, regularly communicate to immune cells that they are not the enemy and butyrate appears to be a key signal there as well, said the study.