The argument that organic food, including meat, is more nutritious than conventionally grown food has been cast doubt on by new research, based on an analysis of several hundred studies.
The study by Dr Crystal Smith Spangler and others, published in Annals of Internal Medicine (4 Sept), is the most comprehensive meta-analysis to date of existing studies comparing organic and conventional foods. Researchers analysed 237 separate studies which compared the organic foods to conventionally grown foods. They did not find strong evidence that organic foods are more nutritious or carry fewer health risks than conventional alternatives, though consumption of organic foods can reduce the risk of pesticide exposure.
As for what the findings mean for consumers, the researchers said their aim is to educate people, not to discourage them from making organic purchases. “If you look beyond health effects, there are plenty of other reasons to buy organic instead of conventional,” noted lead researcher Dena Bravata, from Standford University. She listed taste preferences and concerns about the effects of conventional farming practices on the environment and animal welfare as some of the reasons people choose organic products.
Professor Alan Dangour of the London School of Hygiene and Tropical Medicine, says like a review he and others conducted in 2009, this latest study “again demonstrates there are no important differences in nutrient content between organic and conventionally produced foods.” It also finds no evidence that organic foods are healthier than conventionally produced foods, he adds.
Organic driven by risk aversion
The majority of people who eat organic food are driven by risk aversion not nutritional superiority, believes Liza Oates, a PhD researcher into the health effects of organic diets and course coordinator of Food as Medicine, Wellness and Complementary and Alternative Medicine for the Master of Wellness Programme at RMIT University in Melbourne.
“Our research shows organic consumers are more interested in what’s not in their food – such as pesticides and antibiotics – than what is. Most also say that the environmental and social benefits of organic food play a key role in their decision to go organic.”
She points to US research that has shown that eating organic food has a dramatic effect on pesticide residues in children. “Substituting non-organic fruits and vegetables with organics for five days resulted in an almost complete reduction in organophosphate pesticide residues. It is this kind of benefit that many organic consumers are looking for when choosing to buy organic food,” says Oates.