Although people buy organic for several reasons, one is that it is more nutritious and healthier for us—but there’s not been a review of the evidence to see if these beliefs are justified, say researchers from the Nafferton Ecological Farming Group at Newcastle University.

To find out, the researchers analysed 67 previously-published studies that had compared the ingredients of organic and non-organic meat. The difference in levels of omega-3s was significant, they found, and this could be explained by the higher grazing and foraging of organic cattle. Non-organic cattle are fed grain. Charles Benbrook, one of the study’s researchers, said: “It’s not something magical about organic. It’s about what the animals are being fed.”

An earlier study by the same group found that organic fruits and vegetables had higher levels of antioxidants and lower pesticide residues than conventionally-grown crops.