No selenium, vitamin boost for organic milk, say researchers

Scientists from the Swedish University of Agricultural Scientists analysed the vitamin and selenium content of milk from organically-reared cows and compared it to that of milk from conventionally-reared cows.

They thought they may see some differences since nutrient levels are understood to be directly linked to a cow's diet.

However their findings, presented at the conference of the European Association for Animal Production in Dublin this week, did not support the hypothesis, according to the Irish Independent .

The publication status of the study is not known and the full methodology and results have not been seen by NutraIngredients.com.

But the reported results, taken at face value, lend support to those who argue there is little evidence to support the belief that an organic diet carries intrinsic health benefits.

A review conducted by the British Nutrition Foundation and published in the journal Nutrition Bulletin found that the overall body of science does not support the view organic food is more nutritious than conventionally grown food.

The conclusions were particularly pertinent to fruit and veg, but some interesting light was thrown on organic dairy.

Author Claire Williamson of the British Nutrition Foundation quoted several studies that reported improved nutrient levels for alpha-linolenic acid (ALNA), conjugated linoleic acid, alpha-tocopherol (vitamin E), beta-carotene, and/or a higher proportion of polyunsaturated fatty acids (PUFAs) to monounsaturated fatty acids in the organically produced dairy.

"Although these findings regarding organic milk are interesting, there have been no reports of differences in many other nutrients found in milk, such as calcium, zinc, vitamin B2 or vitamin B12," said Williamson.

"Milk and dairy foods are considered to be an important source of calcium and vitamins B2 and B12, whereas they are not a major source of ALA, vitamin E or beta-carotene, which are found in a variety of other foods."

The results of the Swedish study may only pertain to dairy cattle reared in Sweden, where the diet of cows on both organic and conventional farms is largely made up of grass and clover.

Another study comparing organic and conventional milk from Denmark, where cows are conventionally fed a corn-based diet, found that organic milk had higher levels of vitamins A and E.

The scientists said the differences might be because dairy cows in Sweden tended to be fed mainly on grass and clover, both on organic and conventional farms, whereas in Denmark the diet of conventional cows was largely corn-based.