Some 300 million people around the world get their potable water from 17,000 desalination plants in 150 countries, including Israel.
Researchers have already shown that depending on desalinated water for drinking that lacks magnesium can raise the risk of heart disease. Now, researchers at the Hebrew University of Jerusalem maintain that its lack of iodine naturally occurring in regular water can cause thyroid gland diseases as well. Iodine deficiency is also the single-most-important cause of preventable intellectual deficiency worldwide.

Some 300 million people around the world get their potable water from 17,000 desalination plants in 150 countries, including Israel, which has the highest percentage of desalinated water consumption in the world.

“There is no doubt that desalination is a blessing. However, we need to be mindful of unintended consequences,” said Dr. Aron Troen from HU’s institute of biochemistry, food science and nutrition in the Robert Smith Faculty of Agriculture, Food and Environment. “Desalination removes minerals from the water and could conceivably diminish intake of minerals such as iodine that serve as essential micro-nutrients,” he added.

“Luckily, any problems with iodine nutrition that might emerge from desalination can be easily and inexpensively remedied by the iodization of table salt. Although this has been implemented for many years in the US and other countries, the Health Ministry has not adopted the practice. “Unlike magnesium, the solution is relatively straightforward – to iodize salt, provided there is legislation for routine population surveillance for iodine intake to ensure that salt iodization does not lead to excessive intake.”

Rough calculation of the potential costs for treatment of iodine-deficient children, if a quarter of the country’s population is mildly deficient, amounts to NIS 1 billion per year, say the researchers.

With a growing population and scarcity of water around the world, seawater desalination is increasingly used to meet rising demand for water. “The increasing reliance on desalination could contribute to an increase in iodine-deficiency disorders, which raises a nutritional and public health issue of a major global concern,” said Troen. “This research supports the urgent need to probe the impact of desalinated water on thyroid health in Israel and elsewhere,” he said.

His recent study, published on the website Public Health Nutrition assessed the connection between iodine intake and thyroid function in a region where drinking water is supplied from iodine-poor desalinated water. Troen found a surprisingly high prevalence of insufficient iodine intake and strong thyroid dysfunction among adults.

The study was conducted in Ashkelon, where five desalination plants produce about 50% of Israel’s water, in collaboration with Dr. Dov Gefel of Barzilai Medical Center in Ashkelon and doctoral student Yaniv Ovadia.

The study has also attracted critical views. Health Ministry associate director-general Prof. Itamar Grotto weighed in on the matter. “The HU research is not based enough on facts,” said Grotto. “We too do similar studies. At this point, there is not enough evidence that in Israel salt should be fortified with iodine. Every country in the world has different conditions.”