BEIJING, July 26 (Xinhua) -- The Ministry of Health on Monday publicized a draft revision of the national standard of iodine content in edible salt, in which it stated the upper limit should be lowered by half.

The average iodine content would be reduced to between 20-30 mg per kg of edible salt, from the current 20-60 mg, according to the draft.

Iodine intake was "excessive" in five provinces and "above normal" in 16 other provinces, although the national level was "acceptable," the ministry said Monday in a statement explaining the revisions.

Members of the public are invited to make submissions on the draft revision to the ministry via fax and email before Sept. 12.

The ministry said earlier this month iodized salt was still essential in China as benefits of it still outweighed the negatives, citing the results of a nationwide risk assessment on iodine intake.

The assessment was carried out in response to claims by media and medical experts that people in some regions, coastal areas in particular, were taking in excessive amounts of iodine.

Since 1996, iodine has been added in salt across the country because in most parts of the country, the average diet is iodine deficient.

Both iodine deficiency and excessive intake can lead to thyroid diseases.