
Iodine
Iodine is one of the critical nutrients. To ensure sufficient intake, certain foods and their composition must be taken into account. In this article you will learn the most important facts about iodine and what you can do to get enough of it.
Functions
Since iodine is an essential component of the thyroid hormones T3 and T4, it plays a central role as a regulator of metabolism. T3 influences protein synthesis, basal metabolic rate and has effects on overall metabolism. Iodine is also found in gonads and islet cells, it protects against microorganisms and has a spermicidal effect. In addition, iodine has antioxidant and antiproliferative effects.
Occurrence
The iodine content depends on the content of the soil. Soils near the sea are richer in iodine. Therefore, products from the sea contain larger amounts of iodine. In the case of algae, the content is strongly dependent on the species. Dried algae and seaweed have particularly high levels. There is a danger of too high an intake with a small amount of algae. It is recommended to use products with clear information. Iodised table salt is sometimes used in the food industry. Despite the iodine content in this salt, consumption should be kept within limits.
Metabolism
Iodine is absorbed as iodide or iodate (in table salt) by 95-100% in the small intestine. Possible inhibiting factors are:
- Nitrate content of food (nitrate as a competitor to iodine at the receptors.
- Hardness of the water
- Glucosinolates (in large quantities)
Recommended intake
The recommended intake for adolescents and adults is 200 µg per day. Older persons over 50 years of age need only 180 µg per day. Children are much lower, depending on their age. Pregnant women are recommended 230 µg/day and breastfeeding women 260 µg/day.
Deficiency
A manifest deficiency of iodine can lead to goitre. If in the long term the individual basal metabolic rate falls, a deficiency can lead to hypothyroidism. A deficiency that is only mild leads to an enlargement of the thyroid gland, but this does not yet show any symptoms. In pregnancy, a deficiency can have effects on the embryo or foetus. Miscarriage or stillbirth can occur. This occurs more often in developing countries.
Supply in vegans
Iodine is generally a critical nutrient that does not only affect vegans. The average is well below the recommendation. One should pay attention to the specific sources of iodine.
- iodised table salt
- Seaweed
- Drinking water
- Kelp capsules (150 µg/capsule) if you do not use iodised table salt.
Supplements should only be taken under medical supervision in cases of diagnosed deficiency or insufficient intake.

