Certain beers could be considered “very healthy” thanks to the amount of gut-friendly bacteria they contain, according to scientists specialising in gut health.

Professor Eric Claassen, who works at Amsterdam University, explained that strong Belgian beers, including Hoegaarden, Westmalle Tripel and Echt Kriekenbier, are rich in probiotic microbes that offer a range of health benefits.

Presenting his research at an event held by probiotic drink maker Yakult, Professor Claassen said that unlike most mainstream beers, which go through a single fermentation process, these beers are fermented twice.

The second fermentation not only creates a drier flavour and boosts the strength of the beer, but it also uses a different strain of yeast found in traditional pints. 

This strain of yeast produces acids that kill harmful bacteria in the gut that can make us ill.

More than four million National Trust members will be asked to drink beer to protect Britain’s historic houses and countryside.

The charity has set up a craft beer club through which enthusiasts can obtain hundreds of rare ales from around the country, including five from the Trust’s own brewery.

Letters and emails to members are being prepared and gift packs placed in WH Smiths in town centres with the aim of convincing more than 70,000 people to join.

The club is being run by Delavals, the National Trust’s brewery partner based in Northumberland. It will feed back to the charity a slice of the anticipated £1.1 million a year profit, understood to be up to 10 per cent