Daily Intake Study of Food Additives by Age Cohort
based on the Market Basket Method

Overview
The study was conducted as part of the Ministry of Health and Welfare’s efforts inensuring the safety of food additives.
The study group prepared a list of 246 types of food products, and calculated theaverage daily intake of each food type for five age categories: 1-6 year olds (younger
children), 7-14 (older children), 15-19 (youths), 20-64 (adults), and over-64 (older
adults). Based on the list, 9 collaborators (eight local governmental health laboratories
and one university) purchased food products at 9 locations nationwide and classified
them into 7 food categories (I. seasonings and beverages; II. cereals; III. potatoes,
legumes and nuts; IV. fish/shellfish and meat; V. fats/oils and milk/milk products; VI.
sugar and confections/savories; VII. fruits, vegetables and seaweeds). Five collaborators(non-governmental laboratories) analyzed 100 types of compounds (covering 241 foodadditives) in the homogenized samples for the 7 food categories by age category, anddetermined the concentration of each compound, then estimated the intake of eachcompound for each age category.
The intake of many target compounds tended to slightly increase with age. Amongothers, sodium saccharin was particularly noteworthy: the intake was about 10 times
higher for adults and older adults than that for younger children. This result was in
sharp contrast with the intake of xylitol: the intake of older adults was a tenth that ofchildren (younger and older). Thus, this study has found that there is a difference inthe daily intake of some additives between age categories. These results indicate thesignificance of a study by age cohort. The study group considers that continuous study
by age cohort is necessary to obtain more realistic information on food additive intake.
In general, there were no findings that raise safety concerns about of food additives. In
comparison between the estimated intakes and the corresponding acceptable daily
intakes (ADIs), the estimated intakes of all substances but nitrate were below thecorresponding ADIs. For nitrate, most of its intake is derived from natural nitrate1contained in vegetables, and therefore a very small part is considered to be derived fromadditives. Considering several factors, such as the benefits of vegetables as food, ourhistorical eating habits, and the international recognition as given in JECFA’s
assessment, the study group determined that nitrate intake does not pose any problems
with safety at the present stage.
Objective
The study group conducted this study to identify the intake of food additives of theJapanese by age category. It is very important to estimate more accurate intakes toensure food safety and protect public’s health. Japan has extensively conducted intake
studies since the 1980s, using several methods,1-3) including the market basket method.
However, the previous intakes have been estimated as averages for the Japanese public
and the studies have hardly considered age categories.
The Ministry of Health and Welfare evaluates the safety of food additives for the
purpose of safety assurance of additives. Safety evaluations are basically, based on
toxicity data, mainly from animal experiments. The daily intake of food additives andthe acceptable daily intake (ADI) are at the core of theses safety evaluations. It isnecessary to confirm whether the daily intake of each in everyday life is less than its
ADI, which is established for each substance. Japan usually adopts ADIs established by
the Joint FAO/WHO Expert Committee on Food Additives (JECFA)4) or it establishes
the ADIs on its own. Thus, it is necessary to estimate the accurate intake of foodadditives as one pillar of safety evaluations.
After 1965, Japanese dietary habits changed a lot and also diversified. This is due
greatly to increased imported foods and diversified processed foods. These factors,
changes in dietary habits and diversified foods, can greatly affect food additive intake.
Hence, it is necessary to identify the current additive intake for safety evaluation.
In this study, the study group first decided the types of food products, and estimated theconsumptions of these products by age category to obtain basic data for themarket-basket based study. Then, based on the obtained consumption data, they
estimated food additive intakes by age category for 100 compounds covering 241 foodadditives, which were regarded to be identifiable.

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Method
Prior to the implementation of the study, the study group prepared two types ofguidelines and distributed them to the collaborating organizations of this study. These
guidelines are those for purchasing products, etc. and those for preparing samples andconducting analysis.
1. Target Food Additives
Table 1 shows the names of 100 compounds targeted at analysis and the names of 241
individual food additives covered by these compounds. The 241 additives consisted of
199 designated food additives and 42 existing food additives. Some compounds wereanalyzed twice per chemical. Calcium citrate, for example, was measured both on citricacid and calcium. The number of additives has slightly changed since some additives
have been withdrawn from the designated additives after the study finished.
2.

Food Consumption Survey by Age Cohort

The study group used the data from the National Nutrition Survey to estimate the foodconsumption for the five age categories. The National Nutrition Survey is annuallyconducted in November, targeting some 15,000 individuals age of 1 or older taken fromapproximately 6,000 randomly-selected households nationwide5). In 1995, the dietstudy method was revised, and consequently, the study requires the individual-based
food consumptions6). The study group used data up to 1997 (n=41, 548) from 1995,
which were available from the computerized database.
The National Nutrition Survey is based on a unique food numbering system, in which
respective food numbers are assigned to a total of 1,194 types of food products6). Outof these, the four types of foods—“processed food,” “ready-to-eat prepared food,”“restaurant food,” and “school lunch”—are categorized as “mixed dish,” and are treatedas a combination of other “single-item food products” (970 types of food products
appearing in the Standard Table of Food Compositions, including “eggplant” and “soysauce”). In other words, they are broken down into “single food items,” and thenumber and the weight (g) of each food consumed by an individual per day are stored in
the database in the form of a “single-item food consumption card.” 7)

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Using a “single-item food consumption card,” the study group estimated foodconsumption on a particular weekday in November. The information obtained includes
the proportion of people who consumed each of the 970 types of products, the average
consumption by all target people including non-eaters, as well as the average
consumption excluding non-eaters. The study group prepared a list of 246 types offood products representing the 970 types of products to purchase them in a morepractical manner. In preparing the list, nutritionists chose a certain product out ofmultiple similar products, considering actual conditions of consumption (frequency andlevel of consumption), ways of processing, and use standards of food additives. These
246 were then divided into 7 categories (I. seasonings and beverages; II. cereals; III.
potatoes, legumes, and nuts; IV. fish/shellfish and meat; V, oils/fats and milk/milk
products; VI. sugar and confections/savories; VII. fruits, vegetables and seaweeds)8).
The study group calculated the average daily consumption for the 246 types of products
for 5 age categories; 1-6 year olds (younger children: n= 2,620), 7-14 (older children:n= 4,175), 15-19 (youths: n= 2,715), 20-64 (adults; n= 25,281), and over-64 (older
adults; n= 6,757) (Table 2). The average body weight was 15.9 kg for 1-6 year olds,
37.1 kg for 7-14, 56.3 kg for 15-19, 58.7 kg for 20-64, and 53.2 kg for over-64.
3. Purchase of Sample Products, Sample Preparation, Analysis and Report ofStudy Results
The purchase of foods, sample preparation and analysis were based on the guidelines
given in section “Method,” above.
1) Purchase of Sample Products
The 9 organizations (eight local governmental health laboratories and one university),
given in Table 3, purchased products within the areas in which the correspondingorganizations are located, according to Table 2 (Food Consumption Table). These
products were purchased between January 18, 2000 and January 21, 2000. Thereafter,
they were given minimal treatments, such as the removal of soil and fish guts. The
products were numbered serially, marked with colored tapes for category identification,
packed according to category, and sent in a frozen state to the Tama Research Instituteof the Japan Food Research Laboratory.

42) Sample Preparation
The sample preparation was based on the guidelines given above. The Tama ResearchInstitute checked the products received from the nine organizations for food categories,
crushed them separately, and then took the required quantities of samples from theindividual products for each age category, according to the Food Consumption Table.
The collected samples falling under the same category were put all together andhomogenized with an adequate amount of water added (5 age groups x 7 categories = 35
samples). Each homogenized sample was divided into five parts. They are separately
packed in antioxidant-free polyethylene bottles, and frozen. The samples, excluding theparts for the Japan Food Research Laboratory, were sent to four of the five laboratories,
which were responsible for analysis, by frozen-parcel delivery service. The samples
taken for adults were twice as large as those for the other age categories, since they
were also to be used for food additives recovery tests.
3) Analytical Method
Unless there was any particular problem, analysis was based on the Analytical Methods
for Food Additives in Food (2000) published by the MHW9) and the Guidance for Food
Safety Testing−Analytical Methods for Food Additives in Food10). Methods weremodified as necessary. Table 4 gives the organizations which were responsible fortesting and the analytical methods used. These organizations are all designated by the
Minister of Health, Labour and Welfare (designated laboratories) as testing laboratories.
The test data were stored in a computer disk according to the guidelines for purchasing
food products, etc. and sent to the Japan Food Additives Association, by which the data
were refined and compiled. The items reported by the laboratories include thecontents of compounds, the daily intakes of additives, the limits of determination, thelimits of detection, the amounts of compounds added in food additives recovery tests,
and recovery rates by age and food categories.
Results and Discussion
1. Study Results and Estimated Intake
Table 5 shows the estimated daily intakes of food additives by age category. Table 6
shows the ratios of the estimated intakes of individual compounds (only those for which

5the ADIs have been set) to the corresponding ADIs (percent of ADI). Table 7
compares the estimated intakes of adults (20-64 year olds) obtained in this study withthose obtained in other studies (as average intake of the Japanese population).
The intakes estimated in this study were based on the contents of target compounds infood. Hence, for some substances which naturally occur in the natural environment
such as nitrate and phosphoric acid, the amount determined includes not only that used
as an additive, but also that naturally included in foods (amount derived from the naturalenvironment) such as vegetables, fruits and meat. Therefore, the estimated intake arealso the sum of the both.
1) Intake by Age GroupThe results show that there were few differences in intake between age categories formany compounds. However, the intake tended to slightly increase with age, as shown in
Table 5. This study group considered that this trend was attributable to an increase infood consumption with age.
Notable differences in intake between age categories were observed for somecompounds. The intake of sodium saccharin roughly increased with age and wasnearly 10 times higher for adults and older adults than that for younger children. The
sources of this substance were categories IV (fish/shellfish and meat) and VII (fruits,
vegetables and seaweeds). Young people tended to consume the substance more fromcategory IV than from category VII, and adults and older adults from category VII.
The study group considered that the notable difference between age categories wasprobably attributable to the fact that adults and older adults consume a larger quantity ofpickled vegetables. Contrary to saccharin sodium, the daily intake of xylitol was
significantly high for younger children and older children, and it gradually decreased
with age. The intake of older adults was approximately 1/10 that of children (younger
and older). The major source of xylitol was category VI (sugar, savories/confections)for children and category I (seasonings and beverages) for older adults. Xylitol is asweetener with refreshing sweetness and is used in chewing gums and candies, which
probably resulted in the notable difference in the intake level of xylitol between age
categories.
The daily intake of lactic acid was the highest among the targeted compounds for all age

6categories, at 1.5 g for younger children, 2.0 g for older children, 2.2 g for youths, and2.6 g for adults and older adults each. The intakes of the following compounds werealso higher than other compounds: citric acid (2.1 g in adults), phosphoric acid (2.1 g in
adults), and malic acid (1.7 g in adults). The intakes of these compounds tended to belower in the younger age categories.
Table 5 shows the estimated intakes based on the determined levels. If theconcentration of an additive was below the limit of determination, it was regarded to be
zero in calculation. No corrections using the corresponding recovery rates wereapplied to the determined levels, which means that the estimated daily intakes may be aslight underestimate. Table 8 shows the estimated maximum intakes calculated basedon Table 5. In calculation, the corresponding limits of detection were added forcompounds which were not detected, or the corresponding limits of determination wereadded for compounds which were detected but not measurable. Compounds whose
values were different from the corresponding values in Table 5 mean that their contents
were below the corresponding limits of detection. There was no substantial difference
between the estimated maximum intake in Table 8 and the estimated intake in Table 5.
It should be noted that in this study, fresh foods were not prepared/cooked and losses
through preparation processes such as cooking were not taken into account. For fresh
foods which are usually washed or cooked, concentrations of additives or naturalingredients in foods are considered to be reduced through preparation processes.
Hence, actual intakes can be lower than those obtained in this study.
2)

Ratio of Intake to ADI

Nitrate was the only compound whose estimated intake exceeded the ADI. The intakesof all other substances were below the corresponding ADIs, as shown in Table 6.
The intake of nitrate exceeded the ADI for each age category, and the intake for younger
children was estimated at about twice the ADI. The intake for younger children wasless than half that for adults, but the body weight of the younger children was roughly aquarter that of the adults. This helps raise the ratio of nitrate intake to ADI for young
children. According to surveys based on production2) and official food inspections3), theuse amount of nitrate as food additives was 1mg or less, and the nitrate intake derived
from the food additives used is reportedly less than 1% of the ADI. On the other hand,according to the intake surveys using the market basket method under the Health7

Science Research Program1), the intake of nitrate is 232mg, or 125% of the ADI, out of
which more than 80% was derived from fresh foods. In this study by age cohort, all age
groups ingested more than 96% of nitrate from category VII (fruits, vegetables, andseaweed). In short, this study confirmed that nitrate is mostly derived from natural
nitrate contained in vegetables and a limited amount is derived from food additives.
The intake of nitrate has also been assessed by the JECFA. The JECFA mentions in
the WHO Technical Report Series No. 859 11) “…. vegetables are an important potential
source of intake of nitrate. However, in view of the well-known benefits of vegetables
and the lack of data on the possible effects of vegetable matrices on the bioavailabilityof nitrate, the Committee considered it inappropriate to compare exposure to nitratefrom vegetables directly with the ADI and hence to derive limits for nitrate invegetables directly from it.” Hence, considering the benefits of vegetables as food andhistorical Japanese eating habits, nitrate intake does not pose any problems with safety
at this stage. Also, this study did not take account of preparation processes of foods
such as washing and cooking. When vegetables are handled normally, the content of
nitrate could be reduced through such processes and the actual intake would be less than
the intake estimated in this study. Continued study is necessary for more accurate intake
estimation.
The intakes of all other compounds did not exceed the corresponding ADIs for any age
category. The ratios of intakes of individual compounds to the corresponding ADIs
were generally high for young people, and tended to decrease with age. This isbecause the intake does not increase greatly with age while the body weight is lower for
young people. For sodium saccharin and adipic acid, an inverse tendency in the ratio
to the ADI was observed. Sodium saccharin intake accounted for 0.1% of the ADI for
the younger groups (younger children, older children and youths) and 0.3% of the ADI
for the adults groups (adults and older adult); adipic acid intake accounted for 0.3% of
the ADI for younger children and, thereafter gradually increased with age up to 0.7%
for older adults.
The compounds for which the ratio to the corresponding ADI exceeded 10% were
D-α-tocopherol (17.5%), nitrite (11.5%), riboflavin (15.1%), tartaric acid (29.6%),
phosphoric acid (38.4%), aluminum (32.5%), and iron (45.1%) for younger children;and phosphoric acid (16.1%), aluminum (13.1%), and iron (20.1%) for adults.
Among the compounds targeted by this study, those having recommended dietary8allowances established by the MHW12) are β-carotene (as vitamin A), D-tocopherols (asvitamin E), L-ascorbic acids (as vitamin C), thiamin (as vitamin B1), riboflavin (asvitamin B2) calcium, phosphoric acid (as phosphorus), iron and magnesium. For thecompounds for which the ratio of intake to ADI exceeded 10%, as stated above,
comparison was made between the intake and the corresponding recommended dietary
allowance. The intake of D-tocopherols (α, β, γ, and δ) calculated in terms ofD-α-tocopherol was roughly the same as the recommended dietary allowance of vitamin
E in all age categories. On the other hand, the intake of riboflavin was about twice therecommended dietary allowance for the younger groups (1-6 year olds, 7-14 year-olds).
(Note: The tolerable upper intake limit is not established for riboflavin.) Each intakeof iron and phosphoric acid (as phosphorus) tended to be slightly lower than thecorresponding dietary allowance. Neither exceeded the tolerable upper intake limit.
Table 9 indicates the ratios of the estimated maximum intakes, based on Table 8, to thecorresponding ADIs. Few compounds were affected with respect to the ratio of intake to
ADI, except that the ratio was a little over 20% for nitrite and 3-7% for sulfite.
3)

Comparison with Estimated Intake by Other Methods

Previous intake studies for additives in Japan have been based on three methods: themarket basket method1); the method based on production2); and the method based on
official inspections which is used for a limited number of additives3). These study
results have been reported as average intake levels for the Japanese population, while
this study has determined intake levels by age category. Table 7 compares theestimated intakes in adults (20-64 year olds) obtained from this study with the estimatedintakes (averages for the Japanese population) from the three study methods mentioned
above.
The results from this study were very close to those from the market-basket study
conducted from 1995 to 1996 1). The study group determined that this was because thesame market basket method was used, despite differences in the time of study and age
category used. When compared with the results from the three methods for use
categories, Table 7 shows that results from this study were almost the same forseasonings and dietary supplements, slightly higher for acidifiers, and slightly lower for
preservatives. When compared with the production method2), results from this study
were slightly higher for additives naturally occurring in food (additives in category B),

9but lower for additives not naturally occurring in food (additives in category A).
When compared with the official-inspection method 3), the results from this study weregenerally lower. The study group assumed that this trend was based on the following
reasons: the official-inspection method targeted mainly food products in which additives
are permitted, and sample products were separately analyzed by product and it waseasier to determine levels.
In this study, the following additives were targeted for the first time:
nordihydroguaiaretic acid, naringin, hesperidine, kojic acid, asparagine, glutamine,
cystine, and hydroxyproline. No ADIs have been established for these food additives.
The intake of glutamine was the highest among these substances, andnordihydroguaiaretic acid, naringin, and kojic acid were not detected.
2.

Basic Data for Food Additive Analysis

As basic data, Tables 10-1 through 10-5 show the additive intakes for individual foodcategories by age category. Table 5 shows compiled data based on Table 10. Tables
11-1 through 11-5 indicate the concentrations of food additives in the consumed foodproducts for individual food categories by age category. The intake levels given in
Table 10 were obtained by multiplying the concentrations given in Tables 11-1 through11-5 by the consumptions of the corresponding food products by food category. Table
12 gives the limits of detection confirmed using food products for adults (20-60 yearolds), Table 13 the limits of determination, Tables 14-1 through 14-5 the contents offood additives in food products calculated using the corresponding limits of detection or
the corresponding limits of determination, and Table 15 recovery ratios. The recovery
ratios were slightly lower for some food categories. This is probably based on thefollowing reasons: Microanalysis was required, unlike food additive analysis which is
generally conducted according to food product, and recovery tests were conducted on
samples of a considerably low concentration. No corrections were made to thedetermined levels of additives in the samples.
3. Comparison of Determined Values by Collaborative StudyIn this program, a confirmation study was conducted by the Tokyo Metropolitan
Research Laboratory of Public Health (hereafter referred to as the Tokyo laboratory), on
additives which were regarded to be consumed in considerably large quantities. The

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target additives were saccharine, sorbic acid, propylene glycol and 17 amino acids.
The data were compared with those reported from the corresponding laboratories.
Table 16 shows the values reported by the Tokyo laboratory and the corresponding
laboratories. Determination was basically conducted on samples for adults (20-60 yearolds) of certain food categories. Food categories IV and VII were used for saccharine,
categories IV and VI for sorbic acid, categories I and II for propylene glycol. For
category II intended for propylene glycol, samples for older adults (over-64 year olds)
were used. For amino acids, category IV (viscous food group) and category III(non-viscous food group) were used.
In general, there was no significant difference in value between the Tokyo laboratory
and the corresponding laboratories, with some exceptions. The differences observed
for some samples were considered to be attributable to viscosity of the samples.
1. For saccharin in categories IV and VII and sorbic acid in categories IV and VI,
similar results were obtained from the Tokyo laboratory and the corresponding
laboratory.
2. For propylene glycol in category I for adults, similar results were obtained from twolaboratories. For category II for older adults, however, the level obtained from theTokyo laboratory was 17µg/g, whereas that obtained from the other laboratory was
46µg/g. This is considered to be attributable to the lack of uniformity in samples due
to viscosity. Even though the samples may have appeared to be uniform, the study
group assumed that they were nonuniform.
3. For amino acids in category IV (viscous samples) and category III (non-viscous
samples), the Tokyo laboratory and the corresponding laboratory exchanged samples
and determined the quantities. No significant differences were observed in theirresults for glutamic acid and glycine, which are considered to be most frequently
used among food additives.
Judging from the above findings, the results from the Tokyo laboratory and thecorresponding laboratories were almost the same. However, there was the difference invalue which was assumed to be attributable to viscosity. More caution is required insample preparation to ensure uniformity for viscous samples.

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4. Conclusion
The study group estimated the intakes of 100 compounds, covering 241 additives, basedon the market basket method. This study was characterized by the intake estimation offood additives by age cohort (5 categories), based on food consumption by age cohort.
There were no findings that raise safety concerns about the intake of food additives.
However, the study has confirmed that there are the clear differences in the consumptionof food between age categories. The study group considers that the differences in foodconsumption can give rise to differences in the intake of food additives. It is not
appropriate to make conclusions based on the study alone, since no other intake studies
have been conducted by age cohort. However, it is still significant to have first
confirmed that additive intake differs by age category, in considering food safety in the
future. Given that the differences in dietary patterns between age categories may be
growing the need to consider the difference in the intake of food additives between age
categories is likely to heighten. Therefore, it is necessary to continuously conduct intake
studies by age cohort in order to collect information on the presence or absence ofadditive residues and annual changes in additive intake. Future studies should focus on
the intake of nitrate and additives whose intakes are extremely high in certain age
groups. The study group hopes that continued studies can help to more accurately
identify the current situation regarding Japanese additive intakes, and thereby contributeto safety assurance for food additives by providing adequate grounds for establishingadditive standards.

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