The nutritional advantages of organic milk and meat

A large international study has shown that both organic milk and meat contain around 50% more beneficial omega-3 fatty acids than conventionally produced products; however, the scientists have cautioned that more research is needed.

The team reviewed 196 papers on milk and 67 papers on meat and found clear differences between organic and conventional milk and meat, especially in terms of fatty acid composition and the concentrations of certain essential minerals and antioxidants.

“Omega-3s are linked to reductions in cardiovascular disease, improved neurological development and function, and better immune function. But getting enough in our diet is difficult. Our study suggests that switching to organic would go some way towards improving intakes of these important nutrients,” said Chris Seal, Professor of Food and Human Nutrition at Newcastle University.

Importantly, a switch from conventional to organic would raise omega-3 fat intake without increasing calories and undesirable saturated fat. For example, half a litre of organic full fat milk (or equivalent fat intakes from other dairy products like butter and cheese) provides an estimated 16% (39 mg) of the recommended, daily intake of very long-chain omega-3, while conventional milk provides 11% (25 mg).

Other positive changes in fat profiles included lower levels of myristic and palmitic acid in organic meat and a lower omega-3/omega-6 ratio in organic milk. Higher levels of fat-soluble vitamins such as vitamin E and carotenoids and 40% more CLA in organic milk were also observed in the study, which was published in the British Journal of Nutrition.

The study showed that the more desirable fat profiles in organic milk were closely linked to outdoor grazing and low concentrate feeding in dairy diets, as prescribed by organic farming standards.

Newcastle University’s Professor Carlo Leifert, who led the studies, said: “People choose organic milk and meat for three main reasons: improved animal welfare, the positive impacts of organic farming on the environment and the perceived health benefits. But much less is known about impacts on nutritional quality, hence the need for this study.

“Several of these differences stem from organic livestock production and are brought about by differences in production intensity, with outdoor-reared, grass-fed animals producing milk and meat that is consistently higher in desirable fatty acids such as the omega-3s, and lower in fatty acids that can promote heart disease and other chronic diseases.”

The study also found 74% more iodine in conventional milk, which is important information, especially for UK consumers where iodised table salt is not widely available.

The work builds on a previous study by the team — involving experts from the UK, US, France, Italy, Switzerland, Norway and Poland — investigating the composition of organic and conventionally grown crops.

This previous study — also published in the British Journal of Nutrition — showed that organic crops and crop-based foods are up to 60% higher in a number of key antioxidants than conventionally grown crops and contained less of the toxic metal cadmium.

The authors highlight that only a small number of studies have been carried out comparing organic and non-organic meat, and that even significant results may still carry a high level of uncertainty.

“We need substantially more, well-designed studies and surveys before we can accurately estimate composition differences in meat from different farm animals and for many nutritionally important compounds (vitamins, minerals, toxic metal and pesticide residues) as there is currently too little data to make comparisons,” said Professor Leifert.

“However, the fact that there are now several mother and child cohort studies linking organic food consumption to positive health impacts shows why it is important to further investigate the impact of the way we produce our food on human health.”