There is no evidence that organically produced foods are nutritionally superior to conventionally produced food, a new British survey suggests.

The massive study — covering 50 years worth of data from 162 separate surveys — was funded by the British Food Standards Agency. Carried out by the London School of Hygiene and Tropical Medicine and led by Alan Dangour. It found that organic food has the same nutritional content as conventionally developed foodstuffs.

As of June 30, 2009, producers can choose to stamp their products with this logo if they wish to indicate their products have been certified organic by the CFIA. (CBC)

"There is currently no evidence to support the selection of organically over conventionally produced foods on the basis of nutritional superiority," Dangour said.

The research, published in the American Journal of Clinical Nutrition, found that for 10 out of the 13 nutrient categories analyzed, there were no significant differences between production methods in nutrient content. Conventionally produced crops had significantly more nitrogen, and organically produced crops more phosphorus and higher acidity, but it is unlikely that consuming these nutrients at the levels reported in organic foods would provide any health benefit, the report found.

Organic food proponents have been quick to discredit the study, arguing that it does not take factors such as pesticides, herbicides, pollution, environmental impact and animal welfare into account.

"We're careful not to make nutritional claims about organics," said Laura Telford, national director of the Canadian Organic Growers group. "It's clear to us that there are health benefits to be had from organic food.… Among other things, they carry less toxic residue than conventional food…

"This report misses the mark in that organic food tackles some really big issues like soil fertility."

On June 30, a federal law came into effect which legislates the use of labelling on organic food. Foods that claim to be organic must now pass through a rigorous verification process with independent monitors at every stage, Telford said.

It's been estimated that the organic food industry is worth more than $48 billion worldwide. Prices of organic items are frequently higher than those of conventionally-produced food. But the environmental, social and health benefits of going organic are worth it, Telford argued.

"Flip it around and look at the consequences of not going organic. We've seen since the green revolution that agriculture in Canada has created a number of problems," she said.

The British food agency stressed that the report dealt solely with nutritional issues, and the agency was explicit in stopping short of recommending people avoid organic food entirely.

"This study does not mean that people should not eat organic food," FSA director Gill Fine said. "What it shows is that there is little, if any, nutritional difference between organic and conventionally produced food and that there is no evidence of additional health benefits from eating organic food."