Intermediate 
Organic food has more of the antioxidants linked to better health than regular food, and lower levels of toxic metals and pesticides, according to the most comprehensive scienti c analysis so far. The international team behind the work suggests that switching to organic fruit and vegetables could give the same bene ts as adding one or two portions of the recommended  ve a day fruit and vegetables.
The team, led by Professor Carlo Leifert, concludes that there are statistically signi cant differences, with a range of antioxidants being substantially higher  between 19% and 69%  in organic food. It is the  rst study to demonstrate clear differences between organic and conventional fruits, vegetables and cereals.
The researchers say the increased levels of antioxidants are equivalent to one to two of the  ve portions of fruits and vegetables recommended to be consumed daily and would therefore be signi cant in terms of human nutrition.
The  ndings will add to the controversy over organic food and whether it is better for people. Tom Sanders, a professor of nutrition at Kings College London, said the research did show some differences. But the question is are they within natural variation? And are they nutritionally relevant? I am not convinced. He added, Leifert has had a lot of disagreements with a lot of people. He also said that research showed organic cereals have less protein than conventional crops.
The results of the research are based on an analysis of 343 studies from around the world  more than ever before  which examine differences between organic and conventional fruit, vegetables and cereals. The important thing about this research is that it shatters the myth that how we farm does not affect the quality of the food we eat, said Helen Browning, chief executive of the Soil Association, which campaigns for organic farming.
Leifert and his colleagues conclude that many antioxidants have previously been linked to a reduced risk of chronic diseases, including cardiovascular diseases, neurodegenerative diseases and certain cancers. The researchers also found much higher levels of cadmium, a toxic metal, in conventional crops. Pesticide residues were found on conventional crops four times more often than on organic food.
The research is certain to be criticized: the inclusion of so many studies in the analysis could mean poor-quality work makes the results unreliable. Also, the higher levels of cadmium and pesticides in conventional produce were still far below recommended limits. But, the researchers say cadmium accumulates over time in the body and that some people may wish to avoid this, and that pesticide limits are set individually, not for the cocktail of chemicals used on crops.
A further criticism of the research is that the differences seen may result from different climates, soil types and crop varieties, and not from organic farming. The greatest criticism, however, will be over the suggestions of possible health bene ts. The most recent major analysis, which included 223 studies in 2012, found little evidence. The published literature lacks strong evidence that organic foods are signi cantly more nutritious than conventional foods, it found.
This was also the conclusion of earlier, smaller studies published in 2009 in a scienti c journal and by the UK Food Standards Agency. The 2012 study did note that eating organic food might help people avoid pesticide residues. Sanders said he was not persuaded by the new work. You are not going to be healthier if you eat organic food, he said. What is most important is what you eat, not whether its organic or conventional. Its whether you eat fruit and vegetables at all.
Opinion polls show healthy eating (55%) and avoiding chemical residues (53%) are key reasons given by shoppers for buying organic produce. But, many also say care for the environment (44%) and animal welfare (31%) are important, and also taste (35%). Browning said: This research con rms what people think about organic food. In other countries, there have, for a long time, been much higher levels of support and acceptance of the bene ts of organic food and farming. We hope these  ndings will bring the UK into line with the rest of Europe.