Food Standards Agency has published the results of a survey measuring the levels of iodine in dairy and seaweed-based foods produced in the UK. The survey concluded that concentrations in these foods do not pose a health concern for consumers, including young children.

Iodine is a trace element found in seawater, rocks and some types of soil. It is naturally present in milk. But concentrations in other foods can be influenced by its presence in animal feed and hygiene products used in the dairy industry.

A total of 350 samples were taken from a range of dairy foods for sale in the UK, including milk (cow, goat and sheep), eggs (duck, goose, hen and quail), cheese, yoghurt and commercial seaweeds. The survey was used to estimate how much iodine people take in when consuming these food groups, and the choice of samples aimed to reflect the range of products available across the UK and their market share.

All samples of cow milk contained low concentrations of iodine (ranging from 0.30 to 1.00mg/kg). A small number of goat and sheep milk samples gave slightly elevated levels of iodine. The highest levels were 1.3mg/kg in goat milk and 4.6mg/kg in sheep milk – though relatively few samples were tested, and the results cannot therefore be regarded as statistically significant.

One sample of seaweed from a supplier in Northern Ireland contained a very elevated level of iodine (2,400mg/kg above the level of detection). FSA Northern Ireland has informed the relevant local authority, which has arranged to carry out further analysis.

Iodine is vital for good thyroid function, which in turn is essential for health. High iodine intake may cause the thyroid gland to become overactive and produce excess thyroid hormones (a disorder called hyperthyroidism). As a result, the thyroid gland enlarges to form goitre. However, levels found in this survey are not likely to cause hyperthyroidism.

The iodine content of milk typically varies from season to season. The raw data of the survey suggests that iodine levels are consistently lower in summer than winter. Similar trends are not seen for eggs.

The Expert Group on Vitamins and Minerals gave guidance on the upper level for total iodine exposure, equivalent to 0.9mg per day for a 60kg adult. Some consumers – particularly children – may exceed the guidance level from normal dietary sources. However, the independent Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) concluded in 2000 that the concentrations of iodine in cow milk are unlikely to pose a risk to health, even in those children who drink a lot.

Reference

Back