Iodine – the best vegan sources for this essential nutrient
Iodine is an essential mineral for human health. It contributes to the formulation of thyroid hormones, which help maintain cell health and metabolic rate, and are necessary for growth during pregnancy and childhood. Some studies have shown that vegans are more likely to be deficient in iodine than meat eaters are. This may be because of a lack of awareness, but, whatever the reason, it is important that anyone following a plant-based diet pays attention to their iodine intake and tries to ensure that they are getting enough from the vegan iodine sources available.
Iodine deficiency can lead to a variety of symptoms including weight gain, fatigue, intolerance to cold temperatures, goitre, and depression. For pregnant and breastfeeding women, iodine deficiency can affect their child’s brain development.
Although the recommended daily intake of iodine is very small – about 150 μg (microgrammes) for adults – there are not many reliable vegan iodine sources. Seaweed can provide high levels of iodine, but the amount contained is highly variable, and there is a risk that regular consumption of seaweed can result in excessive iodine intake, which can be harmful to health. More reliable sources of iodine, which, if consumed regularly, can help make up the required daily intake without risking an excess, are iodized salt and fortified plant milks.
For example, a quarter teaspoon (1.5 g) of Cerebos iodized salt, which is available at some supermarkets in the UK and in other countries, contains 30 μg of iodine, which corresponds to 20% of the recommended daily intake for an adult. Half a carton (500 ml) of any Oatly oat drink (except Oatly Oat Drink Organic) contains 112.5 μg of iodine, which is 75% of the recommended daily intake. Some Alpro oat and soya milks also contain similar amounts of iodine. Since iodine is present in varying amounts in soil, many vegetables and grains also contain iodine, but usually in very small quantities, unlikely to be sufficient to meet recommended daily iodine intake.
Iodine supplements are also available, and many multivitamin and mineral supplements contain iodine. However, excessive iodine intake should be avoided, as it can lead to hypothyroidism – with similar symptoms to those resulting from iodine deficiency (see first paragraph) – or hyperthyroidism, which can give rise to symptoms including anxiety, insomnia, muscle weakness, tiredness, weight loss, and tachycardia.