TORONTO - There's good news and bad news when it comes to salt. Eat too much and you run the risk of heart disease. But because table salt is fortified with iodine, it helps ward off thyroid problems in adults and development delays in children.
Now, with public-health campaigns urging us to put down the salt shaker, Health Canada will be evaluating the role of iodized salt in maintaining healthy iodine levels, says spokesperson Gary Holub.
Its new guidelines aim to cut the average daily sodium intake from 3,400 milligrams to 2,300 mg by 2016.
Although table salt represents only about 11 per cent of Canadians' daily sodium intake, it provides roughly half the 150 micrograms of iodine adults need each day.
Iodized table salt, introduced in Canada in the 1920s, effectively eliminated iodine deficiencies and the telltale goitres (enlarged thyroid glands) that they caused. Canadians also get iodine from dairy products, such as milk and yogurt, seafood and seaweed.
Mary L'Abbe, a professor at the University of Toronto and vice-chair of Health Canada's Sodium Working Group, says the latest Canadian Health Measures survey examined urinary iodine levels, though the results have not been published. "Once you know what the situation is, governments have the ability to either adjust the levels (of iodine) or the types of foods that it's added to, to basically get it right," she says.
That could mean adding iodine to salt used in processed foods or increasing iodine levels in table salt so that a smaller amount of salt would confer a comparable health benefit.
A few recent studies have looked at sodium and iodine, including one in the American Journal of Hypertension that found dietary salt restriction to be associated with iodine deficiency in women. L'Abbe expects more studies to examine the situation.
"Because we're focusing our efforts on lowering sodium, it's an obvious question to start looking at," she says.
Iodine deficiency -- and in some cases, iodine excess -- can be a critical health issue in developing countries, says Dr. Norm Campbell, a professor of medicine at the University of Calgary and co-chair of a World Health Organization conference on salt reduction, which was held in Calgary earlier this month.
Campbell says sodium-reduction experts are scheduled to meet with iodine experts at another meeting in January to tackle the issue internationally.
