We are back now with this health news story that’s getting a lot of attention, tonight. It’s about organic foods. People who buy them and pay more for them do it for a lot of reasons, but mostly because they think they are healthier. But are they? Our report from our chief medical editor Dr. Nancy Snyderman.

Reporter: In supermarkets across the country and at farmers’ markets from coast to coast, increasingly, Americans are buying organic. In 1997, U.S. sales of organic foods topped off at $3.6 billion, fast forward to 2010, sales total more than $26 billion.

The reasons?

You want to put something on your table that’s healthy. And straight from the farm is the best place to go.

Whether that’s healthy or not, I don’t know. It makes—it makes eating more interesting.

Reporter: More interesting maybe, but a new Stanford University study concludes that organic foods are no more nutritious than their conventional alternatives.

We didn’t find strong evidence of higher nutritional content in organic foods.

However, we did find differences in the risk of detecting pesticide residues.

Reporter: According to the report, organic produce is 30% less likely to carry pesticide residues than other fruits and vegetables. And organic chicken and pork are 67% less likely to have bacteria resistant to common antibiotics. Nutritionists say it may take years to link pesticides and antibiotics to long term health problems, but they say these are issues we have to consider today.

I really think people should be thinking about knowing where their food comes from, how it’s grown, that it is economically, that it is environmentally sound.

Reporter: According to those who study food purchasing preferences, millennials, those under age 30 are actually driving the trend.

They are choosing to want to eat more pure foods and organics is definitely part of that decision process.

Reporter: While organic farmers and ranchers don’t claim their foods are healthier, more than half of them in a recent poll believe organic is more nutritious. So your best advice, buy local. The shorter the distance between farm to table the better it’s going to be.

And the more nutritious.