Chinese health experts have defended iron-fortified soy sauce as a safe and effective means to tackle anemia, in response to claims it could cause cancer and other health problems.

The dispute erupted following the launch on Oct. 21 of the second phase of soy sauce fortification project, which aims to expand coverage to more people across the country.

Bao Shanfen, an expert in trace elements at the Chinese PLA General Hospital, argued the modified soy sauce could affect the assimilation of other trace elements and harm children's bone growth. Some media reported fears that fortified soy sauce could cause cancer.

According to a statement issued Monday by the Food Fortification Office of Chinese Center for Disease Control and Prevention (China CDC), enriched soy sauce could promote the assimilation of trace elements such as zinc, rather than block them.

It also said the human body had a strong ability to adjust to the intake of iron and to expel excessive iron through metabolism.

Food fortification was an internationally recognized method to solve deficiencies of trace elements, said the statement.

A quarter of the total iron intake of Americans and Canadians came from iron-fortified flour, it said.

"Around 3 to 4 milligrams of iron through soy sauce every day would do no harm to people who are not iron-deficient or anemic," said Huo Junsheng, deputy director of the Food Fortification Office.

"Iron-fortified soy sauce only covers 2 percent of the soy sauce market, and expanding coverage of such products doesn't mean consumers have no choice," said Chen Junshi, director of the Food Fortification Office.

More than 20 percent of Chinese had iron-deficiency anemia, but the rates were much higher for infants under the age of two, people aged over 60 and residents of certain regions, said Chen.

The soy sauce fortification project is administered by the Food Fortification Office of the China CDC and funded by the Global Alliance for Improved Nutrition (GAIN), a Geneva-based foundation dedicated to eliminating malnutrition.

China's soy sauce fortification project was initiated in 2003. The first phrase of the project ended in December 2008.

According to the project overview published on the website of GAIN, data collected from 21 health clinics showed that anemia in women and children dropped by a third after iron was added to soy sauce.

(Xinhua News Agency October 26, 2010)