Holland & Barrett has been acquired for £1.8billion by a retail investment fund controlled by Russian billionaire Mikhail Fridman.
L1 Retail, an arm of the tycoon's holding company LetterOne, said that it has snapped up the retailer from its parent firm Nature's Bounty, which is owned by private equity giant Carlyle.
The health food and "wellness" retail chain has a number of branches in the North East, including Sunderland, Durham, South Shields, Hartlepool, Newcastle and the MetroCentre.
The fund's managing partner Stephan DuCharme said: "Holland & Barrett is a clear market leader in the UK health and wellness retail market, with attractive growth positions in other European and international markets, and growing online presence, with a leading customer loyalty programme and 10 million active cardholders."
He added that the group will look to take a bigger slice of the growing £10billion health and wellness market, adding that L1 Retail will continue to work with Holland & Barrett chief executive Peter Aldis.
Headquartered in Nuneaton, Holland & Barrett's annual revenues in 2016 exceeded £610million.
Founded in 1870, it is now Europe's largest health food chain, has outlets in more than 1,150 locations and employs a workforce of more than 4,200.
Mr Aldis said: "We have upgraded much of our core store portfolio to concept stores to deliver additional in-store theatre and increased customer engagement.
"New products launched through our ethical sourcing programme have also been a key growth driver."
Led by Mr DuCharme, L1's advisory board is made up of Karl-Heinz Holland and John Walden, the former bosses of Lidl and Home Retail Group respectively.
They are joined by Clive Humby, co-founder of customer data company Dunnhumby.