Stanford Organic Study: Flawed & Simplistic

A recent press release from the Stanford School of Medicine read, "Little evidence of health benefits from organic foods."

The headline could just have easily read, "Despite billions spent on research and subsidies, conventional foods found more dangerous than organic."

The Stanford study was striking in several regards: 1) no new research was conducted — the Stanford team simply reviewed existing studies; 2) the review included research conducted under different sets of organic standards; 3) the review included research conducted prior to 2002, when USDA National Organic Program Regulations took effect; and 4) the review concluded that organic foods consistently contain fewer pesticide residues and antibiotic-resistant bacteria, and significantly higher levels of beneficial nutrients in organic milk.

The Stanford team used a novel and simplistic "risk difference" measurement to compare pesticide residue levels in organic versus non-organic foods, and concluded that organic foods have a risk difference of 30 percent, compared to non-organic foods. This metric is seriously flawed and easily misinterpreted. Let me explain.

The Stanford team found that non-organic foods are likely to contain pesticide residues 37 percent of the time and organic foods 7 percent of the time. Given those percentages, then the risk of exposure to pesticides increases by 81 percent when someone chooses to consume non-organic versus organic foods (37-7/37 = 81 percent). The risk of exposure to pesticide residues increases by 81 percent, not 30 percent.

Further, the Stanford team did not account for synergistic effects of multiple pesticide residues commonly found in non-organic foods, even though USDA pesticide detection data confirms that non-organic foods consistently are contaminated with multiple pesticides, whereas organic foods are often free of pesticide residues. When residues occur in organic foods, they are typically for one compound, rather than multiple compounds.

In examining human health impacts, the Stanford team made no mention of the effects of organic versus non-organic production on the most essential nutrient — water! Research from the University of Minnesota and Washington State has shown that organic practices help protect groundwater from nitrate contamination. Persistent, carcinogenic pesticides are not allowed in organic production, meaning that organic methods help protect drinking water from these contaminants.

The Stanford paper contained no discussion of the health impacts of pesticides on farmers, farmworkers, and rural residents. It has been well established that exposure to agricultural pesticides is associated with an increased risk of prostate cancer, according to the American Journal of Epidemiology. Research has shown that twice as many children of Iowa farmers developed childhood lymphoma as the control population, according to Environmental Health Perspectives.

Argentinean physicians have reported significant increases in birth defects, miscarriages and child cancer in towns surrounded by GMO soybean fields sprayed with glyphosate. In Chaco Province, the rate of birth defects has gone from 19.1 per 10,000 in 1997 to 85.3 per 10,000 in 2008. Cases of child cancer rose from 29 to 40 per year from 1985 to 2001.

The Stanford study contained no discussion of emerging human health research findings related to genetic engineering, the use of which is prohibited in organic production. Researchers in Canada have established that Cry1Ab, a specific type of Bt toxin from genetically modified (GM) crops, has been detected in human and fetal blood samples and crosses the placental barrier, according to Reproductive Toxicology.

French researchers have found side effects linked with GM corn consumption, including kidney and liver damage. Other effects were also noticed in the heart, adrenal glands, spleen and haematopoietic system. Researchers in Indiana have concluded that genetically engineered Bt toxins are found in streams and rivers at least six months after the harvest of Bt corn.

The Stanford paper had no discussion of the human health impacts of livestock growth hormones, which are commonly used in non-organic animal production but are prohibited in certified organic production. It did not address artificial flavors, colors and preservatives, common in non-organic foods but prohibited in organic. Other factors not addressed, all of which have human health implications, include soil health, biologic and genetic diversity, carbon sequestration and climate change, energy use, economic vitality, and food security.

Likely the most favorable outcome of the Stanford study is that it has opened up a conversation about the verified multiple benefits of organic production and the need for expanded research on organic agriculture and human and environmental health.

Land Stewardship Project member Jim Riddle is the organic outreach coordinator for the University of Minnesota's Southwest Research and Outreach Center.