Carlyle Group has agreed to buy vitamin and nutritional supplements maker NBTY for $3.5bn (€2.7bn), in one of the largest transactions to take a public company private since the credit bubble burst.

NBTY, based in Ronkonkoma, New York, on Long Island, was formerly known as Nature's Bounty and sells products under a variety of brands including Solgar, Rexall and MET-Rx.