Data published in Nutrients indicated that 77% of the pregnant women assessed in the study consumed less than the Recommended Dietary Allowance (RDA) of selenium of 60 micrograms and 89% consumed less than the Adequate Intake (AI) of 70 micrograms per day.
For iodine, data from 201 apparently healthy pregnant women showed that only women who were taking 150 micrograms of iodine per day as a supplement had sufficient levels.
“It may be wise to educate women who plan pregnancy that iodine needs increase already in early pregnancy and to recommend augmentation of their iodine consumption, preferably from seafood and/or seaweed, prior to conception,” wrote researchers from University Medical Center Groningen and Radboud University Medical Center.
“This can also be achieved by taking a 150 micrograms iodine/day supplement, which is in line with the advice of the WHO and ETA [European Thyroid Association].
“The results of this study indicate that selenium should be added to this advice, although the optimal dose and formulation need additional investigation.”
The Iodine Global Network has identified iodine deficiency as prevalent in Europe, especially among pregnant women.
Recent studies also link suboptimal maternal iodine intake during pregnancy with impaired child development, especially in the area of language skills.
Infants are vulnerable to iodine deficiency due to their small thyroidal iodine stores, high thyroxine turnover and high iodine requirements per body weight, compared with other age groups.
In pregnancy, iodine requirements are elevated due to increased thyroid hormone synthesis, transfer of iodine to the foetus, and increased glomerular filtration, resulting in increased urinary losses.
Iodine requirements are also increased during lactation, as iodine is secreted into breast milk and serves as a crucial iodine source to the breastfeeding infant.
Selenium is an essential micronutrient and is considered an antioxidant. The mineral is included in 25 selenoproteins in the body, with diverse roles including immune support, thyroid function, and healthy sperm.
“It has become clear that iodine and selenium interact and that many diseases linked to either iodine or selenium in the past are in reality caused by an iodine–selenium disbalance,” noted the researchers behind the new study.
They explained that seafood would be a good way to increase intake of both iodine and selenium, but it is known that the Dutch are among the lowest consumers of fish and seafood in Europe.
The situation is complicated by Dutch women also known to have low intakes of bread and grains, and the Netherlands 2008 decision to lower iodine levels in salt.
“An alternative is to promote the consumption of seaweed, which is a rich source of both iodine and selenium because of their bioconcentration from seawater,” they stated.
Iodine and selenium supplement should also be considered for women who want to become pregnant, stated the researchers.
“However, the advice to take a supplement during pregnancy disregards the probably equally poor iodine and selenium status of the nonpregnant Dutch population and the interaction of iodine and selenium in the etiology of many diseases,” they concluded.
2022, 14(19), 3936; doi: 10.3390/nu14193936
“Pregnant Dutch Women Have Inadequate Iodine Status and Selenium Intake”
Authors: K.C. Mayunga et al.