Growth in global sales of functional foods is set to slow as consumers become doubtful over the health claims made for products.
The £36.5bn market is forecast by Datamonitor to grow in value by 5.7% a year for the next five years to £48bn, with 6.1% growth in the US and 4.7% in Europe.
This compares with average annual growth of 7% in the past five years.
The slowdown could be blamed on scepticism of health claims brought on by negative media coverage, said Datamonitor market analyst Michael Hughes.
Some 94.2% of the 5,400 people surveyed in the US, Europe and Asia-Pacific said they were at least a little sceptical about health claims made for food and drink. More than 10% said they were "very sceptical".
"Although consumers are actively seeking food and drinks that optimise performance and reduce the risk of illness, they are becoming less trusting of claims," said Hughes.
"It is essential that manufacturers promote functional foods in a credible and honest way and continue to educate consumers."
Nevertheless, he said market conditions suggested the sector would continue to grow as changing social demographics meant an ageing population and younger shoppers would look for quick health fixes.