Researchers in England say their review of more than 250 research papers indicates that organic farming improves the nutrition of milk and meat.
They contain 50 per cent more beneficial omega-3 fatty acids than non-organic produce, says the team led by Prof. Carlo Leifert of Newcastle University.
The same team previously worked on a global study of organically-produced crops which found they had up to 60 per cent higher levels of antioxidants than conventionally-grown fruits and vegetables.
Leifert said the research indicates that people could increase their omega-3 intake by choosing organic, or they could maintain their intake of the important fats but eat less meat if they switched.
"Nutritionists do not agree on many things, but they all say we should double our intake of omega-3," he said.
Western diets have been shown to lack these important fats, which are also found in oily fish and have been linked with reducing cardiovascular disease, improved neurological development and better immune function.
The study, published in the British Journal of Nutrition, reviewed 196 papers on milk and 67 on meat and found clear differences between organic and conventional products.
Key findings were in their fatty acid composition, and the concentrations of certain essential minerals and antioxidants.
Chris Seal, professor of food and human nutrition at Newcastle University, said "our study suggests that switching to organic would go some way towards improving intakes of these important nutrients."
The review found organic milk contained 40 per cent conjugated linoleic acid, used as a weight loss supplement and by bodybuilders. It also had slightly higher concentrations of iron, Vitamin E and some carotenoids.