Are organic fruits, vegetables and grains better for you? No one disputes that organic foods are lower in synthetic pesticides, though how important that is to your health remains controversial, as long as levels fall below EPA thresholds. But most studies have found little difference between organic and conventionally grown crops in nutritional value.
A new report, however, says organic foods not only have fewer pesticides but also more antioxidant compounds. The findings, published in the British Journal of Nutrition, used a database of 343 previously published studies. The meta-analysis calculated that organic crops contained 18% to 69% higher concentrations of antioxidant compounds, depending on the type of antioxidant. Researchers said consumers who switch to organic fruit, vegetables and cereals would get 20% to 40% more antioxidants.
While the conclusions of this meta-analysis are interesting, says Jeffrey B. Blumberg, PhD, director of Tufts HNRCA Antioxidants Research Laboratory, it is important to keep in mind that there are marked variations within the practices of conventional and organic agriculture and naturally wide ranges in the antioxidant content within and between varieties of the same plant species. Importantly, these results should not suggest that choosing organic produce means you can eat fewer fruits and vegetables!
A FRESH LOOK: Results of the study, funded in part by a British charity that supports organic farming, differ from 2012 Stanford research that found only insignificant differences between organic and conventional produce. That study also found higher pesticide residues in conventional crops, but noted that even those levels remained below safety limits.
Researchers in the latest study said they found the quality and reliability of comparison studies has greatly improved in recent years, leading to the discovery of significant nutritional and food safety differences not detected in earlier studies. Most of the data looked at crops grown in the same area on similar soils. This approach reduces other possible sources of variation in nutritional and safety parameters.
It is worth noting, Blumberg cautions, that this study was of putative nutritional benefits and not of health benefits.
FARMING FACTORS: The scientists speculated that those nutritional benefits might be connected to the way organic crops are produced. A plant on a conventionally managed field will typically have access to high levels of synthetic nitrogen and will marshal the extra resources into producing sugars and starches. As a result, they suggested, the harvested portion of the plant could contain lower concentrations of other nutrients, including antioxidants. Also, without the synthetic chemical pesticides applied on conventional crops, organic plants might produce more phenols and polyphenols to defend against pest attacks.
The researchers also found pesticide residues were three to four times more likely in conventional foods than organic ones, and in much higher quantities-though not above EPA safety limits. Conventional crops also had roughly twice as much cadmium, a toxic heavy metal contaminant, as organic crops.