The Chime Communications-owned research firm found that consumers trust journalists, pressure groups and campaigners to tell them the truth, over and above those in business and politics.
OLR asked over 1,000 consumers nationwide to rate those most trusted on general and specific issues including the MMR vaccine, GM food, foot-and-mouth and stem cell research.
On MMR, 36 per cent of consumers rated alternative medicine practitioners the most trustworthy, but 26 per cent said they did not trust anybody on the issue.
Health secretary Alan Milburn was only cited by 11 per cent of respondents as a reliable source of information on MMR.
For stem cell research, 62 per cent said they trusted independent scientists, whereas just 13 per cent picked their government counterparts and three per cent chose religious groups.
Greenpeace secured a vote of trust from 30 per cent of consumers on GM crops issues, supermarkets received 14 per cent, while GM food producer Monsanto was deemed trustworthy by just one per cent of respondents.
OLR joint chief executive Viki Cooke said: 'Recent events such as Enron, WorldCom and BSE have meant that there's been an apparent erosion of trust in authority. Before people may have presumed trust but now they have to earn it.'
She added the findings have important implications for PROs, whose clients are becoming less trusted.
'We've got to move away from a culture of spin, because people know the truth can be manipulated - companies and politicians must get involved in dialogue with the public without being patronising,' said Cooke.