Dairy: No Selenium, Vitamin Boost For Organic Milk, say researchers
Published:September 4, 2007
Source :Nutra Ingredients
Organic milk was not seen to be richer in vitamins or selenium than conventional milk, found a new study presented this week that contradicts the conclusions of an earlier, similar study.
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 Nutra Ingredients.
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.
As Dr. Stewart notes, the quantity of these nutrients in milk are related to dietary intake. The report should not infer in any way that cows grazing on organic certified pastures are going to give milk with more of the said nutrients in the milk than cows grazing on conventionally maintained pastures of the same quality. The same is true for cows maintained on dried and/or ensiled forages. All that is needed is to fortify the rations to increase these nutrients in the milk.
It may be a mute point for the fat soluble vitamins since more and more skim milk is being consumed and these vitamins are removed from the milk when the fat is separated. It all boils down to the fact that organic milk is no healthier for the consumer than conventional milk, just more expensive and thus less affordable for many.
Vitamin E and beta-carotene levels in milk are directly correlated to intake of those nutrients, whether the cows are fed a conventional ration or an organic-based ration. If any cow is consuming lush, green grass then her fat-soluble vitamin levels will be higher in her milk compared to a cow being fed a ration high in haylage or silage. Alfalfa hay has higher vitamin E (d-alpha-tocopherol) and beta-carotene levels when compared to equal dry matter intakes of silage or haylage.
Milk fat-soluble vitamin levels depend exclusively on dietary intake. Recent research in Sweden suggests that natural vitamin E is deposited at higher levels compared to synthetic vitamin E when fed at equal International Units.
Rob Stuart, Stuart Products, Inc.
Recommend
Reply
Would you like to discuss another topic? Create a new post to engage with experts in the community.