Residents of northern China and those under the age of 14 may be ingesting more aluminum than healthy, according to the China National Center for Food Safety Risk Assessment.

Ma Ning, an associate researcher at the center, announced the results on Monday of a three-year survey conducted by the center.

The center tested 6,654 samples of 11 food items in 21 areas, including Beijing, Hebei, Henan and Shandong provinces in northern China, and Hainan, Sichuan, Hunan and Jiangxi in the southern area, Ma said.

The survey found excessive aluminum content in all 11 food items, including flour, steamed buns, youbing (deep-fried pancakes) and youtiao (deep-fried breadsticks), which are popular breakfast dishes in China.

The aluminum in the food mainly came from additives, which are commonly used to aid dough fermentation and make food rise, Ma said.

"The aluminum humans take in mainly comes from food. And almost all the aluminum in food comes from aluminous additives," he said.

As a result, people in the northern area have a much higher intake of aluminum than those in the south, as northern residents eat more flour products, according to Yan Weixing, deputy director of the center.

"Dishes made from flour, such as steamed buns, are a staple food for northerners, whereas southerners tend to eat rice," he said.

The survey indicated that people in the north ingested 3.028 milligrams of aluminum per kilogram of body weight each week, exceeding the 2 milligrams per kilogram of body weight considered safe by the Joint FAO/WHO Expert Committee on Food Additives. Residents of the south ingested an average of 0.699 milligrams of aluminum per kilogram of body weight per week. "Animal tests have shown that aluminum can be poisonous to the nervous system, reproductive system and to fetuses. Research has shown that people exposed to an excessive amounts of aluminum can develop osteomalacia and osteoporosis," Ma said.

The survey also found that Chinese residents under the age of 14 ingested more aluminum than considered safe by JECFA.

This may be because they weigh less than older people, so the intake of aluminum per kilogram of body weight may be higher, Ma said.

Another contributing factor is puffed snacks, he said.

More than 20 percent of the aluminum ingested by the survey sample aged 7-10 and 11-14 came from puffed snacks, much higher than for older groups, the results showed.

In May, the National Health and Family Planning Commission and four State-level departments issued a statement that, from July 1, aluminous additives are longer allowed in flour and flour products, except for fried products, such as deep-fried pancakes and breadsticks.

The commission also plans to ban aluminous additives in puffed snacks.

"The new standard, if implemented strictly, will significantly lower the aluminum intake of Chinese people," Ma said.

However, food that is allowed to contain aluminous additives may contain much more than recommended, the survey suggested.

The sampling found an average of 429.7 and 221.9 milligrams of aluminum per kilogram in deep-fried breadsticks and pancakes, two popular Chinese breakfast foods, far exceeding the national standard of 100 milligrams of aluminum per kilogram of food prescribed in 2011.

"Such foods are usually made and sold by street vendors and small workshops. Many such vendors and workshops don't measure how the aluminous additives they should use in the products according to the national standard. Instead, they tend to use such additives casually," said Yan, deputy director of the center.