"A small number of differences in nutrient content were found to exist between organically and conventionally-produced crops and livestock, said Dr. Alan Dangour, principal author of the study.
"But these are unlikely to be of any public health relevance."
And he added: "Our review indicates that there is currently no evidence to support the selection of organically over conventionally-produced foods on the basis of nutritional superiority."
Organic food, devoid of additives and produced without chemicals such as fertilisers and pesticides, has become an increasingly popular choice on supermarket shelves in recent years.
But it is typically more expensive than regular foodstuffs, and as such has already been hit by the global recession, making shoppers think twice about paying more for organically-grown vegetables and such like.
The study, commissioned by Britain's Food Standards Agency (FSA) and published in the American Journal of Clinical Nutrition, threatens to deal a new blow to the organic food lobby.
But its supporters underlined other benefits of organic produce, notably for the environment.
"Organic farming is a holistic, integrated approach which conserves soils, encourages biodiversity, eliminates greenhouse gas-intensive nitrogen inputs, conserves genetic diversity, and brings more income to the grower," said Andrew Lee of the Sustainable Development Commission.
"And is very probably healthier to boot," he wrote in a letter to the Guardian newspaper.
Molly Connisbee of the Soil Association said that organic farms have on average 30 percent more species and 50 percent more wildlife like birds, butterflies and bees.
"Other environmental benefits are self-evident -- there's less dangerous waste on organic farms and almost no pesticide use. Artificial nitrogen fertiliser is banned in organic farming, so there's less runoff of nutrients that cause algae blooms in coastal waters," she said.
The British study was based on a review of all studies published over the last 50 years relating to nutritional content and health differences between the two kinds of produce.
