Researchers from Newcastle University and an international team of experts found organic meat also had slightly lower concentrations of two saturated fats linked to heart disease.
While the findings have been criticised by some, Soil Association chief executive Helen Browning said the results showed organic farming methods required all organic farmers to adopt techniques which guaranteed ‘nutritionally different’ foods.
“Following research in 2014 confirming nutritional differences between organic and non-organic crops like fruit and vegetables – we can now say for certain that organic farming makes organic food different,” she said.
Organic meat contains more Omega 3 because organic animals eat a more natural grass-based diet containing high levels of clover.
Clover is used in organic farming to fix nitrogen to enable crops and grass grow, rather than manufactured/chemical fertilisers. Under organic standards, organic cows must eat a 60 per cent fresh grass based diet or hay and silage.
Responding to the report published in the British Journal of Nutrition, Organic Farmers and Growers chief executive Roger Kerr said: “Organic farming systems have long been known to offer substantial benefits to our soils, biodiversity and the wider environment, and now we have further proof that they are great for human health too.
“For the millions of shoppers who already buy organic, this report is clear evidence that it is possible to produce superb food in an environmentally-sensitive and resilient way.”
But Prof Ian Givens, food nutrition expert at the University of Reading, said the report implied ‘a greater change than is nutritionally relevant’.
“Much emphasis is placed on the 56 per cent higher n-3 fatty acid content of the organic milk; but this increase is in the milk fat, not in the whole milk,” said Prof Givens.
“The effect also needs to be assessed in the whole diet. On average we consume about 2.2 g of n-3 fatty acids per day.
“Switching from conventional to organic milk would increase n-3 intake by about 33 mg per day - an increase of only 1.5 per cent in our total diet. Such small changes are unlikely to represent any nutritional or health benefit.”
The research also found organic milk and dairy contained slightly higher concentrations of iron, Vitamin E and some carotenoids.
However, the study revealed organic milk contained less iodine which OMSCo (Organic Milk Suppliers Cooperative) managing director Richard Hampton said the industry had been working to address.
Why is iodine good for you? Read more here
“We initiated projects to boost iodine levels and applied these to our farmer members’ enterprises, and by early 2015 we announced that we’d achieved comparable levels with those in the conventional market,” said Mr Hampton.
“Our latest results have shown that one year on from the initial milestone we’re maintaining those levels.”