Many people buy organic foods thinking they're better for them than their conventional cousins. Yet findings from a new study - the most comprehensive analysis to date - casts doubt on this notion.
According to the Stanford University researchers, there's no nutritional or safety differences between organic and conventional foods dispelling the belief that organic food is always healthier and more nutritious.
Organic foods are grown and harvested without the use of synthetic pesticides and fertilizers, growth hormones, antibiotics, genetically modified organisms, irradiation and artificial additives. Organic livestock are fed organic feed and are given access to the outdoors, fresh air and sunlight.
The review, published yesterday in the Annals of Internal Medicine, reviewed 237 studies - 17 human studies and 223 studies that compared nutrient and contaminant levels (bacterial, fungal and pesticide) in foods grown organically and conventionally.
There were no consistent differences in the vitamin content between organic and conventional produce. Only one nutrient - phosphorus - was higher in organic versus conventional produce. However, because a phosphorus deficiency is rare in North America, this finding is unlikely to be clinically important.
There was also no difference in the fat and protein content between organic and conventional milk.
The analysis did, however, turn up weak evidence that organic produce contains higher levels of phenols, phytochemicals though to have to have numerous health benefits. The review suggested that organic chicken and milk may contain more omega-3 fatty acids than conventional products. (However, most milk studies examined raw, not pasteurized, milk.)
The researchers found meager evidence that conventional foods posed greater health risks than their organic cousins. While organic produce was 30 percent less likely to be contaminated with pesticides than conventional produce, 7 percent of organic food samples contained pesticide residues. The pesticide levels of both types of foods, however, fell within allowable safety limits.
Synthetic pesticide residues that end up on organic produce can come from pesticides used in the past now cycling in the soil or water as well as spray drift from non-organic farms.
While two studies in the review found lower pesticide levels in the urine of children fed organic versus conventional diets, levels of urinary pesticides in both groups of children were below safety thresholds.
There was no difference in bacterial contamination between organic and conventional foods - both were commonly contaminated with Salmonella and Camplyobacter. In fact, the results suggested that organic produce is more likely to be contaminated with E. coli.
Conventional chicken and pork had a higher risk of contamination with bacteria resistant to antibiotics. However, the extent to which antibiotic use for livestock contributes to antibiotic resistant bacteria in people is debated.
These findings don't mean you should stop eating organic foods. There are reasons to choose organic over conventional that go beyond health. Many people find organic food tastes better. Others are concerned about the effect of conventional farming on the environment and animal welfare.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.