LA FARGE, Wis. -- They are marketed as healthier and safer, but are organic foods actually either?

A new study from the Stanford School of Medicine concluded no.

There is no disputing the growing popularity of organic foods. Since 1997, the industry has grown about 10 times in size to more than $30 billion in sales last year.

"When you go to the grocery store, the absolute safest and healthiest thing you're going to pick-up will be organic products," said Louise Hemstead, the chief operating officer at Organic Valley foods.

Hemstead says the La Farge-based business is the nation's largest organic food co-op. She says consumer demand for pesticide and herbicide-free products is ever-growing.

"You've got the consistency with the organic rules with how the land is treated, how the animals are treated and the results that come out are in the food," said Hemstead.

The organic foods come at a premium price but promise to be healthier and safer. The Stanford study says otherwise.

Researchers analyzed more than 200 studies involving organic foods and concluded the vitamin content in organic products is similar to that of conventionally grown ones.

The study also says there is no difference in protein or fat content between organic and conventional milk products.

As for pesticides, the study says there is a 30% lower risk for contamination in organic products. However, it also says that pesticide levels for both organic and conventional products almost always fall within allowable safety limits.

"Nutrition and safety are not reasons to buy organic. However, you may have other reasons to buy organic such as personal preference. You may think they taste better or you may have a concern that it's more environmentally appropriate," said Lisa Cimperman, a clinical dietitian.

Hemstead questions the method of the study and its results.

"They're taking studies that are unrelated to each other and then trying to compare those to each other," said Hemstead.

She argues reduced exposure to harmful chemicals can only be a good thing.

"It reduces the risk and when you're looking at reducing risk, go with organic because there is law to support how that product is produced from the ground up."