Researchers in Singapore have brewed up a beer containing probiotic bacteria that can improve gut health and boost the immune system.

Food researcher Alcine Chan, 23, experimented for almost a year with a recipe of malt, alcohol, hops and a strain of probiotic bacteria until she got the formula just right.

"The hops are the main ingredient that kills probiotics, so we had to find a way for the probiotics to overcome the hops," Chan said, demonstrating the pre-fermentation process in a laboratory at the National University of Singapore (NUS).