A total of 60 food samples commonly consumed in China were analyzed for phytate using the anion-exchange method and for calcium, iron, and zinc using atomic absorption spectrophotometry. The foods analyzed included those based on cereal grains and soybean. Phytate contents expressed on a wet weight basis ranged from 0 for foods made from starches to 1878 mg/100 g for dried stick-shaped soybean milk film. The calcium contents were between 2.08 mg/100 g for ground corn and 760.67 mg/100 g for diced fried soybean curd. The lowest values of iron and zinc were 0.04 mg/100 g for Panjin pearl rice cooked with discarding extra water and 0.08 mg/100 g for potato and bean starches, while the highest values of iron and zinc were observed in dried stick-shaped soybean milk film. Although many foods were relatively rich in calcium, zinc, and iron, many also contained a higher level of phytate. Of the 60 food samples, 34 foods had a phytate/calcium molar ratio >0.24, 53 foods had a phytate/iron molar ratio >1, 31 foods had a phytate/zinc molar ratio >15, and only 7 foods had a phytate x calcium/zinc >200. Phytate in foods impair the bioavailability of calcium, iron, and zinc, which to some extent depends upon food processing and cooking methods.

In order to prioritise interventions for micronutrient deficiencies in China, the populations affected by iron and zinc deficiencies were assessed based on data from the 2002 China National Nutrition and Health Survey. The costs and costeffectiveness of supplementation, food diversification and food fortification were estimated using the standard World Health Organization ingredients approach. Results indicated that 30% of children (,2 years), adults (.60 years), pregnant and lactating women, and 20% of women of reproductive age were anaemic, some 245 million people. Approximately 100 million people were affected by zinc deficiency (zinc intake inadequacy and stunting), the majority living in rural areas. Among interventions on iron and zinc deficiency, biofortification showed the lowest costs per capita, I$0.01 (international dollars), while dietary diversification through health education represented the highest costs at I$1148. The costeffectiveness of supplementation, food fortification and dietary diversification for iron deficiency alone was I$179, I$66 and I$103 per disability-adjusted life-year (DALY), respectively. Data for biofortification were not available. For zinc deficiency, the corresponding figures were I$399, I$153 and I$103 per DALY, respectively. In conclusion, iron and zinc deficiencies are of great public health concern in China. Of the two long-term intervention strategies, i.e. dietary diversification and biofortification with improved varieties, the latter is especially feasible and cost-effective for rural populations. Supplementation and fortification can be used as short-term strategies for specific groups. Keywords Micronutrient deficiencyIron Zinc Cost-effectiveness ChinaThe latest World Health Organization (WHO) estimates reveal that undernutrition is an underlying cause of 53% of all deaths in children ,5 years of age 1 . It has been estimated that more than 2 billion of the world's population, nearly all in developing countries, are irondeficient 2,3 . Billions of individuals are also at risk for zinc deficiency 4 . Micronutrient deficiency not only affects the health and development of people 5-9 , but also hinders the social and economic development of countries. It is estimated that the loss in economic productivity due to iron deficiency in China is more than 3.6% of the gross national product 10 .The causes of micronutrient deficiencies include inadequate intakes, impaired absorption and/or utilisation, excessive losses, increased physiological need or the combination of these factors 11 . Insufficient intake and poor bioavailability are major causes in developing countries [12][13][14] . Micronutrient content and bioavailability can be improved by either increasing the quantity of a micronutrient or increasing enhancing factors/decreasing inhibiting factors in foods using different techniques or sources. Strategies for increasing the effective supply of nutrients fall into two categories, supplementation and food-based approaches. Supplementation is the addition of ...

Objective: To assess the phytate intake and molar ratios of phytate to calcium, iron and zinc in the diets of people in China. Design: 2002 China Nationwide Nutrition and Health Survey is a cross-sectional nationwide representative survey on nutrition and health. The information on dietary intakes was collected using consecutive 3 days 24 h recall by trained interviewers. Subjects: The data of 68 962 residents aged 2-101 years old from 132 counties were analyzed. Results: The median daily dietary intake of phytate, calcium, iron and zinc were 1186, 338.1, 21.2 and 10.6 mg, respectively. Urban residents consumed less phytate (781 vs 1342 mg/day), more calcium (374.5 vs 324.1 mg/day) and comparable amounts of iron (21.1 vs 21.2 mg/day) and zinc (10.6 vs 10.6 mg/day) than their rural counterparts. A wide variation in phytate intake among residents from six areas was found, ranging from 648 to 1433 mg/day. The median molar ratios of phytate to calcium, iron, zinc and phytate  calcium/zinc were 0.22, 4.88, 11.1 and 89.0, respectively, with a large variation between urban and rural areas. The phytate:zinc molar ratios ranged from 6.2 to 14.2, whereas the phytate  calcium/zinc molar ratios were from 63.7 to 107.2. The proportion of subjects with ratios above the critical values of phytate to iron, phytate to calcium, phytate to zinc and phytate  calcium/zinc were 95.4, 43.7, 23.1 and 8.7%, respectively. All the phytate/mineral ratios of rural residents were higher than that of their urban counterparts. Conclusions: The dietary phytate intake of people in China was higher than those in Western developed countries and lower than those in developing countries. Phytate may impair the bioavailability of iron, calcium and zinc in the diets of people in China.

Objectives: To assess the intake inadequacy and food sources of zinc of people in China. Design and subjects: Diets of 68 962 subjects aged 2-101 years (urban 21 103, rural 47 859) in the 2002 China National Nutrition and Health Survey were analysed. Dietary intake was assessed using 24-hour recall for three consecutive days. Zinc intake inadequacy was calculated based on values suggested by the World Health Organization. Results: The median zinc intake ranged from 4.9 mg day 21 (urban girls, 2-3 years) to 11.9 mg day 21 (rural males, 19þ years). The zinc density of urban residents (2 -3 to 19þ years) was 5.0-5.3 mg day 21 (1000 kcal) 21 , significantly higher than that of their rural counterparts (4.7-4.8 mg day 21 (1000 kcal) 21 ). Differences in food sources of zinc from cereal grains (27.4-45.1 vs. 51.6 -63.2%) and animal foods (28.4-54.8 vs. 16.8 -30.6%) were found between urban and rural residents. Zinc from vegetables and fruits (8.2 -13.8 vs. 9.7-12.4%) and legumes (1.3 -3.3 vs. 2.5-3.4%) was comparable between urban and rural residents. The proportion of zinc intake inadequacy ranged between 2.8% (urban females, 19þ years) and 29.4% (rural lactating women). Rural residents had higher proportions of zinc intake inadequacy than their urban counterparts. Significantly higher proportions of zinc inadequacy were found in the category of phytate/zinc molar ratio .15 for both rural and urban residents. Conclusions: About 20% of rural children are at risk of inadequate zinc intake, with phytate as a potential important inhibitor. Moreover, lactating women are also considered a vulnerable group.

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