Thyroid disorder may come back to haunt the nation as non-iodized salt's penetration of the local market is growing, health experts have warned. Imported salt products, which are mostly non-iodized, now have an estimated market share of about 20 percent, making it more possible for people to develop goiters — the enlargement of the thyroid gland — because of insufficient iodine intake, the United Evening News reported yesterday.

A lack of iodine may affect children's brains and learning capabilities, the paper cited health experts as saying.

In the 1960s, goiters were common among schoolchildren in Taiwan, with almost one in five showing symptoms of thyroid hormone imbalance, according to the paper.

With the help of the World Health Organization (WHO), lack of iodine was identified as the cause of the disease, and the state-run salt maker started iodizing its products. The rate of goiters among schoolchildren went to only 4.3 percent in a nationwide survey in 1971.

A recent study conducted by the Department of Health (DOH) shows that between 2004 and 2008, iodine intake by males was sufficient. But data for females suggest the risk of under-consumption.

The paper said that for Taiwanese, iodine chiefly comes from salt. Many people are cutting their salt intake because of concerns over high blood pressure and heart disease.

The wide availability of non-iodized salt may be worsening the situation. Many salt imports are marketed as natural, and many of them are not iodized. Taiwan lifted its salt import ban in January 2004.