LOS ANGELES, CA (Catholic Online) - Researchers from Stanford University and the Veterans Affairs Palo Alto Health Care System discovered that organic options may live up to their claims of lowering exposure to pesticide residue and antibiotic-resistant bacteria.

"People choose to buy organic foods for many different reasons. One of them is perceived health benefits," Dr. Crystal Smith-Spangler, who led the new study, says.

"Our patients, our families ask about, 'well, are there health reasons to choose organic food in terms of nutritional content or human health outcomes?'"

Smith-Spangler and her colleagues reviewed over 200 studies that compared either the health of people who ate organic or conventional foods. They also examined the nutrient and contaminant levels in the foods themselves.

Food in the study included organic and non-organic fruits, vegetables, grains, meat, poultry, eggs and milk.

It must be stressed that the studies didn't specify their standards for what constituted "organic" food - which can cost as much as twice what conventional food costs - the researchers wrote.

In order to qualify, organic farms have to avoid the use of synthetic pesticides and fertilizers, hormones and antibiotics. Organic livestock must also have access to pastures during grazing season, according to United States Department of Agriculture standards.

The majority of U.S. farms use pesticides to ward off bugs and raise animals in crowded indoor conditions with antibiotics in their feed to promote growth and ward off disease.

Surprisingly, Smith-Spangler and her colleagues found there was no difference in the amount of vitamins in plant or animal products produced organically and conventionally. Scientists found that the only nutrient difference was slightly more phosphorus in the organic products.

Organic milk and chicken may also contain more omega-3 fatty acids, they found - but that was based on only a few studies.

More significant differences were found by growing practice in the amount of pesticides and antibiotic-resistant bacteria in food. It was found that more than one-third of conventional produce had detectable pesticide residues, compared to seven percent of organic produce samples. And organic chicken and pork was 33 percent less likely to carry bacteria resistant to three or more antibiotics than conventionally-produced meat.

Smith-Spangler says it is highly unusual for either organic or conventional foods to exceed the allowable limits for pesticides. Therefore, it's unclear whether a difference in residues would have an effect on health.

But Chensheng Lu, who studies environmental health and exposure at the Harvard School of Public Health in Boston, recommends that people consider pesticide exposure in their grocery-shopping decisions.

"If I was a smart consumer, I would choose food that has no pesticides," Lu, who wasn't involved in the new study, says. "I think that's the best way to protect your health."