Stanford University scientists ... concluded that fruits and vegetables labeled organic were, on average, no more nutritious than their conventional counterparts, which tend to be far less expensive. Nor were they any less likely to be contaminated by dangerous bacteria like E. coli.

The researchers also found no obvious health advantages to organic meats.

Conventional fruits and vegetables did have more pesticide residue, but the levels were almost always under the allowed safety limits, the scientists said. The Environmental Protection Agency sets the limits at levels that it says do not harm humans. ...

The conclusions will almost certainly fuel the debate over whether organic foods are a smart choice for healthier living or a marketing tool that gulls people into overpaying. The production of organic food is governed by a raft of regulations that generally prohibit the use of synthetic pesticides, hormones and additives.

The organic produce market in the United States has grown quickly, up 12 percent last year, to $12.4 billion, compared with 2010, according to the Organic Trade Association. Organic meat has a smaller share of the American market, at $538 million last year, the trade group said.