Kombucha health claims a 'marketing ploy' - dietician

Sales of the fermented drink kombucha have more than doubled in the past year.

There are growing areas devoted to the drink in our supermarkets and there are even breweries and taprooms dedicated to the non-alcoholic drink.

But is there any evidence kombucha can live up to its health benefit claims?

It's fizzy, fermented, flavoured and contains live cultures. Kombucha has been around for thousands of years but recently its popularity has exploded.

"More and more people are becoming aware of kombucha," says New Leaf Kombucha head brewer Derek Hillen.

"It's been around for so long, but in NZ and Australia, US and Europe it's only now sort of coming into our consciousness."

Along with that growing awareness have come the health claims of improved digestion, metabolism, immunity, liver function, heart health and more.

"That's being used as a marketing ploy to promote something that's very hipster," says registered dietician Rajshri Roy.

Latest figures show sales have more than doubled in New Zealand in a year. But is there any scientific evidence of the benefits?

"[There's] no research out there to show these sort of benefits. Even with the studies done on animals, that's not enough and doesn't necessarily translate to humans," Roy says.

Everyone's gut bacteria is different and there's a gap in research so diet experts are warning the fizzy could be a fizzer.

"Also from a dietetic perspective, commercial drinks have a lot of sugar in them, so per serve there are many teaspoons of sugar. There's that to think about too," Roy says.

There is existing research on probiotic, fermented foods such as yoghurt, and sauerkraut. But so far the support for kombucha is anecdotal.

"When people say the scientific evidence doesn't support the ideas that probiotics are good for the body, I say just give science time. Absence of evidence is not evidence of absence," Hillen says.

Everyone has a different kind of flora in their guts and dieticians say until there's more rigorous research available kombucha may simply be a personal matter of trial and error.