Coconut oil can be used in toothpaste and mouthwash as a germ-fighting ingredient, a new study says.

Earlier research had shown that milk modified with enzymes can reduce the number of bacteria that stick on to the enamel of teeth. This had prompted the researchers from Ireland to investigate other possible food derivatives that can inhibit bacteria growth.

In the study, researchers, from Athlone Institute of Technology (AIT) in Ireland, used natural coconut oil as well as enzyme-treated coconut oil and compared their antimicrobial effects on strains of Streptococcus bacteria that live in the mouth.

They found that coconut oil is effective in destroying most strains of the bacteria and especially Streptococcus mutans - a bacterium that produces acid and is a common cause of tooth decay.

Also, enzyme-treated coconut oil inhibited growth of Candida albicans that causes thrush, a yeast infection characterized by whitish, velvety sores in the mouth and tongue.

According to researchers, 60 to 90 percent of children are affected by tooth decay or cavities.

"Incorporating enzyme-modified coconut oil into dental hygiene products would be an attractive alternative to chemical additives, particularly as it works at relatively low concentrations. Also, with increasing antibiotic resistance, it is important that we turn our attention to new ways to combat microbial infection," said lead author Dr. Damien Brady from Athlone Institute of Technology (AIT).

The study also shed more light on the role of antibacterial activity in the human gut.

"Our data suggests that products of human digestion show antimicrobial activity. This could have implications for how bacteria colonize the cells lining the digestive tract and for overall gut health," said Brady.

"We are currently researching coconut oil and other enzyme-modified foodstuffs to identify how they interfere with the way bacteria cause illness and disease," he added.

The study was presented at the Society for General Microbiology's autumn conference at the University of Warwick.