said to be the largest of its kind, recruited a team of international experts to analyse 343 studies into the compositional differences between organic and conventional crops.The researchers found that organic fruit, vegetables and cereals provide additional antioxidants equivalent to eating between one-two extra portions of fruit and vegetables a day, in addition to significantly lower levels of toxic heavy metals when compared to conventional crops.
“This study demonstrates that choosing food produced according to organic standards can lead to increased intake of nutritionally desirable antioxidants and reduced exposure to toxic heavy metals,” said Newcastle University Professor of Ecological Agriculture and lead researcher of the study, Carlo Leifert.
“This constitutes an important addition to the information currently available to consumers which until now has been confusing and in many cases is conflicting.”
According to the researchers, the study represented the most “extensive analysis of the nutrient content in organic vs conventionally-produced foods ever undertaken,” and that the findings contradict those of the 2009 UK Food Standards Agency (FSA) commissioned study which found that there no significant differences between organic and non-organic crops.
Leifert says that in contrast to the FSA commissioned study which based its conclusions on only 46 publications covering crops, meat and dairy, Newcastle’s meta-analysis is based on data from 343 peer-reviewed publications on the composition difference between organic and conventional crops now available.
“The main difference between the two studies is time,” says Leifert.
“Research in this area has been slow to take off the ground and we have far more data available to us now than five years ago”.
The study found that concentrations of antioxidants such as polyphenolics were between 18-69 percent higher in organically-grown crops. Substantially lower concentrations of a range of the toxic heavy metal cadmium were also detected in organic crops, together with lower nitrogen concentrations - concentrations of total nitrogen were 10 percent, nitrate 30 percent and nitrite 87 percent lower in organic compared to conventional crops.
The study also found that pesticide residues were four times more likely to be found in conventional crops than organic ones.
“The organic vs non-organic debate has rumbled on for decades now but the evidence from this study is overwhelming – that organic food is high in antioxidants and lower in toxic metals and pesticides,” said Leifert.
“But this study should just be a starting point. We have shown without doubt there are composition differences between organic and conventional crops, now there is an urgent need to carry out well-controlled human dietary intervention and cohort studies specifically designed to identify and quantify the health impacts of switching to organic food.”
The study was published in the British Journal of Nutrition and jointly funded by the European Framework 6 programme and the Sheepdrove Trust.
