Organics are one of the fastest growing sectors in the food market, but are they better for you? After comparing the research on the health effects of organic and conventional foods, Stanford researchers have concluded there is no strong scientific evidence that organic foods contain more of vitamins A, C, and E than conventional foods. However, they did find that compared to conventional foods, organic produce contains more phenol phytonutrients, organic milk contained more healthy omega-3 fatty acids, and that consuming an organic diet may reduce exposure to pesticides and antibiotic-resistant bacteria.
Contrary views make the news
In a meta-analysis of existing research since 1966, the Stanford group combed several research databases to identify and review 17 human studies and 223 studies of nutrient levels in organic and conventional foods. Only 3 of the human studies looked at clinical results and only 1 looked at outcomes between groups based on food type.
The most widely reported findings: organic produce did not contain more vitamins A, C, or E, nor were organic meats any less likely to harbor E. coli bacteria than conventional meats. Other types of bacterial contamination were similar in organic and conventional pork and chicken. However, there were other key results of interest, such as:
Pesticides were detected in 7% of organic produce and 38% of conventional produce, though they were both still under EPA limits.
Compared with children eating conventional diets, children eating organic diets had significantly lower urinary pesticide levels.
Compared with organically raised meat, conventional meat was 33% more likely to be contaminated with three or more antibiotic-resistant bacteria.
Levels of phenols--non-vitamin, non-mineral phytonutrients found in plant foods--were significantly higher in organic than in conventional produce.
Organic milk contained significantly higher levels of beneficial omega-3 fats than conventional.
The authors point out that since "there have been no long-term studies of health outcomes of populations consuming predominantly organic versus conventionally produced food controlling for socioeconomic factors" that their "results should be interpreted with caution because summary effect estimates were highly heterogeneous." In other words, they consist of dissimilar information that isn't easily compared.
Pick your priorities
So what's a health-conscious consumer to do? Ask yourself some of these questions:
Why would a person want to go organic? Organic foods may not contain higher levels of vitamin A, C, and E but many people choose organic for other reasons, such as treatment of animals, environmental factors, and avoiding pesticides. And the researchers did find that organic food contains higher levels of other healthful nutrients, including phenols and omega-3 fats.
What does other research say? Health experts look at existing studies, which are far from perfect. As the authors point out, the expensive, large-scale, long-term, controlled trials needed to prove conclusively that organics do or don't provide measurable health benefits do not exist. There is, however, research that suggests pesticide exposure may be harmful to humans and the environment for a number of reasons.
How much pesticide exposure do I feel comfortable with? Some people feel the EPA's safety standards around acceptable pesticide levels may be too low. As this study showed, even organic produce can be contaminated with pesticides, perhaps due to many pesticides lingering in the environment for decades or to drift from conventional to organic farms. By definition, organics should be pesticide-free, so that issue needs to be addressed separately. In the meantime, organic produce is still far less likely to contain pesticides and, when it does, the levels tend to be lower. If you want to minimize exposure, organic is still your best bet.
How much pesticide exposure seems appropriate for the environment? This study did not address other questions about farming practices. Such as whether workers who manufacture, transport, and apply pesticides are at risk of harm or whether we need to think about the total pesticide burden in our food supply. Pesticides end up somewhere--rivers, streams, and fish--even if not in detectable levels in food.
Does pesticide exposure increase the risk of developing certain diseases? Some research points to neurologic effects of pesticides in susceptible individuals, such as increased risk of Parkinson's disease and attention deficit disorder and other behavior problems in children, and reduced IQ in children born to mothers with measurable pesticide exposures.
Am I comfortable with conventional methods for growing livestock? Large-scale, conventional, factory farming practices have been implicated in the mistreatment and suffering of food animals. If this is a concern for you, more humanely raised meat, much of which is organic, might ease your conscience.
(Ann Intern Med 2012;157: published online Sep 4, 2012)
Suzanne Dixon, MPH, MS, RD, an author, speaker, and internationally recognized expert in chronic disease prevention, epidemiology, and nutrition, has taught medical, nursing, public health, and alternative medicine coursework. She has delivered over 150 invited lectures to health professionals and consumers and is the creator of a nutrition website acclaimed by the New York Times and Time magazine. Suzanne received her training in epidemiology and nutrition at the University of Michigan, School of Public Health at Ann Arbor.
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