Organic CROP Quality

Source Information: Baranski et al. (2014) Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analysis. British Journal of Nutrition 112, 794-811.

New study finds significant differences between organic and non-organic CROPS

In the largest study of its kind, an international team of experts led by Newcastle University, UK, has shown that organic crops and crop-based foods are up to 60% higher in a number of key antioxidants than conventionally-grown crops.

Analysing 343 studies into the compositional differences between organic and conventional crops, the team found that a switch to eating organic fruit, vegetable and cereals - and food made from them - would provide additional antioxidants equivalent to eating between 1-2 extra portions of fruit and vegetables a day.

The study, published in the British Journal of Nutrition, also shows significantly lower levels of toxic heavy metals in organic crops. Cadmium, which is one of only three metal contaminants along with lead and mercury for which the European Commission has set maximum permitted contamination levels in food, was found to be almost 50% lower in organic crops than conventionally-grown ones.

Newcastle University's Professor Carlo Leifert, who led the study, says: "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." "This constitutes an important addition to the information currently available to consumers which until now has been confusing and in many cases is conflicting."

New methods used to analyse the data

This is the most extensive analysis of the nutrient content in organic vs conventionally-produced foods ever undertaken and is the result of a groundbreaking new systematic literature review and meta-analysis by the international team.

The findings contradict those of a 2009 UK Food Standards Agency (FSA) commissioned study which found there were no substantial differences or significant nutritional benefits from organic food.

The FSA commissioned study based its conclusions on only 46 publications covering crops, meat and dairy, while Newcastle led meta-analysis is based on data from 343 peer-reviewed publications on composition difference between organic and conventional crops now available.

"The main difference between the two studies is time," explains Professor Leifert, who is Professor of Ecological Agriculture at Newcastle University. "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."

Dr Gavin Stewart, a Lecturer in Evidence Synthesis and the meta-analysis expert in the Newcastle team, added: "The much larger evidence base available in this synthesis allowed us to use more appropriate statistical methods to draw more definitive conclusions regarding the differences between organic and conventional crops."

What the findings mean

The study, started under the European Sixth Framework Programme project QualityLowInputFood and completed with funding from the Sheepdrove Trust, found that concentrations of antioxidants such as important polyphenolics were between 18-69% higher in organically-grown crops.

Numerous studies have linked antioxidants to a reduced risk of chronic diseases, including cardiovascular and neurodegenerative diseases and certain cancers.

Substantially lower concentrations of the toxic heavy metal cadmium were also detected in organic crops (on average 48% lower). Nitrogen concentrations were found to be lower in organic crops. Concentrations of total nitrogen were 10%, nitrate 30% and nitrite 87% less in organic compared to conventional crops. The study also found pesticide residues were four times more likely in conventional crops than organic ones.

Professor Leifert added: "The organic vs non-organic debate has rumbled on for decades now but the evidence from this study is overwhelming -organic food is higher in antioxidants and lower in toxic metals and pesticides."
"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, designed to identify and quantify the health impacts of switching to organic food."

New information on health benefits

Two recent publications reporting results from the Norwegian Mother and Child Cohort study linked the consumption of organic vegetables with a reduced risk of (a) pre-eclampsia (a disease during pregnancy characterized by high blood pressure and of the appearance of protein in the urine) and (b) boys being borne with hypospadia (a male genital deformation). For more information please see:

Torjusen et al. (2014) Reduced risk of pre-eclampsia with organic vegetable consumption: results from the prospective Norwegian Mother and Child Cohort Study. British Medical Journal (BMJ) on line doi 10.1136/bmjopen-2014-006143

Brantsaeter et al. (2015) Organic food consumption during pregnancy and Hypospadias and Cryptorchidism at birth: The Norwegian Mother and Child Cohort Study (MoBa). Environmental Health Perspectives on line, doi 10.1289/ehp.1409518

Contact

Professor Carlo Leifert, Professor of Ecological Agriculture, School of Agriculture, Food and Rural Development, Newcastle University. Tel: 01661-830222/830444 e-mail: teresa.jordon@newcastle.ac.uk