'Organic' milk is poorer in iodine than conventional milk

July 4, 2013
Organic farming animals depend on the mineral content in soil. / Meneer Zjeroen

Milk from organic farms has a lower concentration of elements like zinc, iodine and selenium than milk produced by conventional farming methods. The discrepancy is due to the absence of mineral substances in the diets of the cows reared. According to researchers, animals on organic farms should have their diets supplemented with natural sources of iodine such as seaweed, because it is a very important element for children and pregnant women.

The concentration of nutrients in animal food products is linked to the diets of the animals reared. Conventional production methods provide mineral diet supplements, while in animals depend on the in soil, which may not be sufficient.

For this reason, researchers at the University of Santiago de Compostela compared the mineral and of organic and conventional milk taken from over thirty farms located in the northeast of the Iberian Peninsula.

The results demonstrated that mineral element content in is low compared with conventional milk, although no differences were found in the quantity of such as cadmium, which were also detected in very low concentrations.

"Levels of the elements that are typically supplemented in the diets of livestock in conventional systems – particularly iodine, copper, selenium and zinc – are higher than those found in organic milk," Marta López, researcher at the University of Santiago de Compostela and co-author of the study, explains to SINC.

In the researcher's opinion, the fact that organic milk contains lower levels of elements such as copper and zinc is not a problem because milk is not the primary source of these elements in our diets.

"Iodine is another matter," López goes on to clarify. "The contribution of iodine to our diets in countries like Spain is covered by iodised salt; in other countries, like England, with milk. In Spain the lack of sufficient iodine in some kinds of milk is especially relevant for children, due to the importance of iodine in neurological development, but also to people with diets low in salt."

Iodine is necessary for the metabolism, especially during pregnancy and infancy. Iodine deficiency can cause scurvy, which has historically been a big problem the world over, particularly in populations at a distance from the coast, who did not eat much fish, and so milk and its derivatives were the primary source of iodine.

Seaweed as an alternative source

Nevertheless, according to López, the most relevant aspect of the study is that it brings this limitation to light and enables organic production to be improved. "There are of iodine that can be incorporated into the diet. We are trialling the use of as a source of iodine and have had good results," she affirms.

In addition, the scientists found that mineral content is higher in winter, which is when dietary supplementation is greater, as a result of the reduced availability of grass.

In any case, although one might draw the conclusion that conventional milk is more nutritious in terms of minerals, López is cautious: "Organic milk may have lower content of certain minerals, but it has other properties that are much more beneficial than those of conventional milk."

Explore further: Iodine in bread not enough for pregnant women

More information: F. Rey-Crespo, M. Miranda, M. López-Alonso. "Essential trace and toxic element concentrations in organic and conventionalmilk in NW Spain". Food and Chemical Toxicology 55 (2013) 513–518

Related Stories

Iodine in bread not enough for pregnant women

June 18, 2013
(Medical Xpress)—New research from the University of Adelaide shows that iodised salt used in bread is not enough to provide healthy levels of iodine for pregnant women and their unborn children.

Mild iodine deficiency in womb associated with lower scores on children's literacy tests

April 30, 2013
–Children who did not receive enough iodine in the womb performed worse on literacy tests as 9-year-olds than their peers, according to a recent study accepted for publication in The Endocrine Society's Journal of Clinical ...

Iodine deficiency during pregnancy may adversely affect children's mental development

May 21, 2013
A study of around 1,000 UK mothers and their children, published in The Lancet, has revealed that iodine deficiency in pregnancy may have an adverse effect on children's mental development. The research raises concerns that ...

Researchers urge awareness of dietary iodine intake in postpartum Korean-American women

July 12, 2011
Researchers at Boston University School of Medicine (BUSM) have brought attention to the potential health impacts for Korean and Korean-American women and their infants from consuming brown seaweed soup. Seaweed is a known ...

Recommended for you

Sugar not so sweet for mental health

July 27, 2017
Sugar may be bad not only for your teeth and your waistline, but also your mental health, claimed a study Thursday that was met with scepticism by other experts.

Could insufficient sleep be adding centimeters to your waistline?

July 27, 2017
Adults in the UK who have poor sleep patterns are more likely to be overweight and obese and have poorer metabolic health, according to a new study.

Vitamin E-deficient embryos are cognitively impaired even after diet improves

July 27, 2017
Zebrafish deficient in vitamin E produce offspring beset by behavioral impairment and metabolic problems, new research at Oregon State University shows.

The role of dosage in assessing risk of hormone therapy for menopause

July 27, 2017
When it comes to assessing the risk of estrogen therapy for menopause, how the therapy is delivered—taking a pill versus wearing a patch on one's skin—doesn't affect risk or benefit, researchers at UCLA and elsewhere ...

Blowing smoke? E-cigarettes might help smokers quit

July 26, 2017
People who used e-cigarettes were more likely to kick the habit than those who didn't, a new study found.

Brain disease seen in most football players in large report

July 25, 2017
Research on 202 former football players found evidence of a brain disease linked to repeated head blows in nearly all of them, from athletes in the National Football League, college and even high school.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.