Currently, average iodine intake among Chinese, as previous studies showed, stands at 240 micrograms a day, an "optimal level", he said.

Lei said a sound surveillance network of public iodine intake and iodine deficiency diseases could help health authorities fine-tune the policy.

The amount of iodine added to table salt has been adjusted three times since 1995 according to surveillance results, he added.

"Varied measures are taken according to real local situations," he said, adding that a number of residents in regions like Xinjiang and Tibet still suffer from iodine deficiency.

But in the naturally iodine-rich southeast coastal regions, locals have access to non-iodized salt, he said.

In recent years, there have been media reports linking too much iodine intake to a rise in thyroid diseases, including cancer, in coastal areas. Some have blamed iodized salt for that.

Yang said the link has not been substantiated, citing a lack of long-term cancer surveillance data and complicated factors related to thyroid cancer.

But he said excessive intake of iodine would affect health, resulting in conditions like hyperthyroidism. He cautioned parents against serving "nori", a kind of seaweed, as snacks for children, citing an ultra-high concentration of iodine.

Food rich in iodine includes seaweed, shellfish, saltwater fish and yogurt.