The supermarkets' focus on own-label and tertiary brands presented a direct challenge to household brands, they claimed. Any that weren't market leading were particularly vulnerable, they said.
The warning came as Arla announced it was pulling its Anchor Cheddar brand, the fifth-biggest brand in the sector.
"Brands that aren't must-have category number ones are going to lose market share ," said Intangible Business joint MD, Stuart Whitwell.
"Given some companies' debt levels, it wouldn't take much of a downturn in sales to start them struggling. The real danger comes from delisting. Naturally, retailers will put pressure on suppliers to pull lines that aren't performing. They know if they introduce a bargain own-label version of most lines, it'll sell, so they won't hesitate to free up shelf space."
Consumers were increasingly looking for value and highly promoted items, said OC&C Strategy Consultants partner, Chris Outram. "There's scope for 'treat' products, but little middle ground," he said.
However, comfort foods and luxury goods were likely to do well, said experts. Wine, spirits and confectionery brands were among the categories likely to prosper, as consumers turned to affordable luxuries, said Whitwell.