More than half of U.S. adults believe advertising for dietary/nutritional supplements are untrustworthy, according to a survey conducted by Thomson Reuters.

The survey asked respondents about their attitudes toward advertising for both prescription medications and dietary supplements. Among those polled, roughly two thirds (65%) had experienced some form of prescription advertising in the past six months and nearly the same percentage (63%) had experienced dietary/nutritional advertising.

Nearly 60% of respondents believe advertising for dietary/nutritional supplements are untrustworthy. Skepticism increases among people with higher income and education.

However, nearly 12% of respondents who had seen, heard or received advertising for a dietary/nutritional supplement were influenced to buy the product.

Conducted by Thomson Reuters and developed in conjunction with National Public Radio, the survey included responses from 3013 participants interviewed from June 1-13, 2010.