China 's Total Dietary Study Was Applied To Dietary Exposure Assessment

It is the origin pricinple for the new "China National Food Safety Law" to establish the system for food safety risk assessment and risk surveillance. The most importance is the dietary exposure assessment of chemical contaminants. Total Diet Study is considered as a most efficient and effective method to evaluate the dietary intakes of certain chemical substances (e.g. contaminates and nutrients) through the ready to eat diet including water for a group of populations. Total diet studies are designed to measure the average amount of each chemical ingested by different age/sex groups living in a country. These data are necessary to assess whether or not specific chemicals pose a risk to health. In fact, total diet studies can be used as a priority-setting tool to enable risk managers to focus their limited resources on those chemicals, both contaminants and nutrients, that pose the greatest risks to public health. This study expounds the application of total diet study to food safety risk assessment and the establishing process of national food safety standards using dietary exposure assessment of trace elements and the heavey metals as the breakthrough.The main description of methods and results were as following1. The establishement of total diet study procesures.At the4th China TDS, it was the first time using individual food items as refined dietary exposure assessement. In the first part of the study, the detailed procesurs were explained including the priciple of selecting the investigated place, dietary survey method, the aggreation of the food samples, the preparation and the transformation of the diet samples. In addition, a method based on international standard practise with strict quality control was set up to mesure the iodine contents of the food items. The limit of detection was0.75μg/kg.2. The food consumption data of the4th China TDS was released.There hav been conducted the dietary survey twice since1990, but the food consumption data has never to be released systemly. The food consumption data of the two dietary investigations were compared. And the results were as following:1) The English explaination of the13food groups was made to make it possible to campare the food consumption with the other countries;2) The food froups of China TDS were basically similar with those of United Sates, Austrilia and New Zealand. The main differences was that Patato and Patato products was a separate food group as that aggragated to vegetales of the other countries. But infant formulas and takeaway food were not in the consider of China TDS food groups.3) The average total food consumption data was12%increased in2007with that of1990. As69%of the food consumption was raised in South1area.3. The application of TDS to evaluate the dietary intakes of trace elements.(1) For dietary iodine intakes:Iodine deficiency disorders (IDD) were prevalent in China until introduction of universal salt iodization (USI) in1995. Concerns have recently arisen about possible excess iodine intake in this context. To document iodine intake and the contribution from iodized salt in China, we surveyed dietary iodine intake in12provinces during China’s2007Total Diet Study (TDS) and during an additional TDS in four coastal provinces and Beijing in2009. Iodine intake was broken down by age and sex in2009. Average daily iodine and salt intake and the contribution from different food and beverage groups (and in2009, individual items) was measured. Iodine in food cooked with iodized and non-iodized salt was assessed. The iodine intake of a standard male in China averaged425μg/day in2007and325μg/day in coastal areas in2009. These averages were biased by the high intake of a minority of consumers. In2009, iodine intake was above the upper limit in only1-7%of age-sex groups, except amongst children (18-19%); however,20-48%, including31%of adult women consumed less than the recommended daily allowance.63.5%of food iodine was contributed by salt, but24.6%of salt iodine was lost in cooking. Overall salt consumption declined between the surveys. Iodization of salt protects iodine nutrition in China. Average iodine intake is biased up by high intake in a minority. Despite USI, intake remains insufficient among many, including reproductive-age women, placing children at risk. Population monitoring of urinary iodine is recommended. (2) For dietary iron intakes:Considering the difference of dietary iron intake from China national nutrition and health survey and the morbidity of anaemia of China’s population. The hugh deflection may be awared when using calculation results combining the food consumption and the food ingredients in the view of the difference of food iron contents from virous sources. TDS can also be a complementary public health tool to determine population dietary exposure to beneficial substances across the entire diet by analysing main foods prepared asconsumed and pooled into representative food groups. In our study, the dietary iron intake was17.0μg/day. The main food sources were vegetables, grain and legume. Meanwhile, iron intake was lower than the Adequate Intake in about27.8%-82.3%of age-sex groups, the13-19female group was the most serious one. Dietaty iron intake remain insufficient especially among the younger woman, which posed the patencial public health concern of low iron intakes.4. The application of TDS to food safety risk assessment and the establishing process of national food safety standards using dietary exposure assessment of heavey metals.(1)For dietary lead exposure assessment:To assess the dietary lead exposure distribution in different·age-gender population groups of China’s residence by China Total Diet Study combined with the new risk assessment outcome for health reference value withdrew by JECFA. Combined the lead concentrations of diet samples and the food consumption from2007China Total Diet Study, the dietary intakes of lead, distribution of different age-gender population groups and dietary sources were obtained. The dietary lead intakes of different age-gender population groups were48.7-116.7μg/day. Lower age groups were in the concerns of high lead exposure as their MOE were0.1-0.3. The main sources of dietary lead were cereals and vegetables, and could cover57%of total lead intakes. It is of high concerned of lowering the dietary lead intakes of China’s residence, especially infants and children. (2) For dietary cadmium exposure assessment:To assess the dietary cadmium exposure distribution in different age-gender population groups of China’s residence by China Total Diet Study according the new released PTMI of Cd. The dietary cadmium intakes of different age-gender population groups were16.3-36.9μg/kg bw per month. The average, median and95percentile dietary exposure of2-7years old children (%PTMI) were36.9μg/kg bw (147.5%),13.0μg/kg bw(52.1%),226.0μg/kg bw(904.1%) per month; While the average, median and95percentile dietary exposure of8-12years old children (%PTMI) were33.5μg/kg bw(134.0%),12.4μg/kg bw(49.6%),209.0μg/kg bw(839.8%) per month. The main food sources of dietary cadmium were rice, the total contribution is near50%. Therefore lower the concentration of cadmium in rice is the main effort to reduce the detary cadmium intakes.