Effect of milk type and processing on iodine concentration of organic and conventional winter milk at retail: Implications for nutrition

Abstract

Milk is the largest source of iodine in UK diets and an earlier study showed that organic summer milk had significantly lower iodine concentration than conventional milk. There are no comparable studies with winter milk or the effect of milk fat class or heat processing method. Two retail studies with winter milk are reported. Study 1 showed no effect of fat class but organic milk was 32.2% lower in iodine than conventional milk (404 vs. 595 μg/L; P<0.001). Study 2 found no difference between conventional and Channel Island milk but organic milk contained 35.5% less iodine than conventional milk (474 vs. 306 μg/L; P<0.001). UHT and branded organic milk also had lower iodine concentrations than conventional milk (331 μg/L; P<0.001 and 268 μg/L: P<0.0001 respectively). The results indicate that replacement of conventional milk by organic or UHT milk will increase the risk of sub-optimal iodine status especially for pregnant/lactating women.

Milk as an Essential Source of Iodine in Latvian Population

“…A higher level of iodine in skimmed milk was found in a study conducted in Spain (Soriguer et al, 2011), but a study from United Kingdom (Payling et al, 2015) and another study from Germany (Kohler et al, 2012) did not find significant differences in iodine concentration between milk types.…”

“…Furthermore, organic milk has been shown to contain less iodine (Rasmussen et al, 2000;Dahl et al, 2003;Bath et al, 2012;Kohler et al, 2012;Payling et al, 2015).…”

Organic vs. Conventional Milk: Some Considerations on Fat-Soluble Vitamins and Iodine Content

“…Concerning iodine contents, it has been observed that in organic milk they are present in concentrations of about 30-40% lower than in conventional milk [34,35]. In this regard, it is worth mentioning the study of Rey-Crespo et al [36] on essential trace elements and some heavy metal residues in organic and conventional milk carried out in Spain, 2013.…”

Are plant‐based milk alternatives putting people at risk of low iodine intake?

“…; Payling et al . ) and UHT milk (Payling et al . ) (reviewed in Chambers ); however, both can still be considered as rich sources of iodine according to the European Commission definition (EC ).…”