Standing in front of piles of organic produce, shoppers wonder just what those premium prices buy one over and above standard foods. Nutrition-wise, not a lot it seems, with organic farming no more sustainable.

But, when it comes to buying food, it is vital to understand nutrition. London School of Hygiene & Tropical Medicine examined 162 papers comparing organic and conventionally produced food for their report published last week, and concluded there is no evidence backing claims of organic food being more nutritious.

Though, one aspect of why shoppers buy organic food is clear i. e. many buy organic fruit and vegetables as they are not sprayed with pesticides, which are known to cause birth defects, cancer, and endocrine disruption, and even the diabetes epidemic (New Scientist, 13th September 2008, p. 36), but it remains unclear whether conventionally grown fruit and vegetables contain high enough amounts to be a health hazard.

Then, there are issues unrelated to health like energy use. Not using synthetic fertilizers, which are energy-intensive, does make organic farming systems more energy- efficient, however, there is limited pressure on organic farmers to cut emissions.

Soil erosion is another factor, with many organic farms emphasising crop rotation, in part to prevent fields being left uncovered and vulnerable to erosion. However, some organic farmers actually cause erosion by tilling the soil frequently for tackling weeds.

Rather than comparing organic and conventional systems in a simplistic way, we should instead ask how all agriculture can be made more sustainable by boosting bio- diversity, keeping rivers free of certain kinds of pollution and fighting climate change.