Last updated on 31 August 2000

Food Standards Agency UK - 1997 Total Diet Study-Fluorine, Bromine and Iodine (Number 05/00)

Food Survey Information Sheet

Key Facts

  • The Total Diet Study provides information on dietary exposures of the general UK population to nutrients and contaminants. This survey was undertaken to investigate fluorine, bromine and iodine in the Total Diet Study samples collected in 1997.
  • Iodine concentrations are similar to those found in recent surveys.
  • Levels of fluorine and bromine were consistent with previous data where available.
  • Dietary exposures to fluorine, bromine and iodine were calculated to see if there were any risks to health from the levels of these elements found in the UK diet. The estimated population average exposure to iodine was 0.25 mg/day, which is within the range of previous estimates (1995, 0.21 mg/day; 1991, 0.17 mg/day; 1985, 0.28 mg/day). Estimated exposures to fluorine (population average, 1.2 mg/day) are similar to those estimated for 1978-1980 (1.8 mg/day).
  • The estimated exposures were considered by the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT). It concluded that the estimated exposures to bromine and iodine are unlikely to pose a risk to health. It will consider the estimated exposures to fluorine when the findings of a review of fluorine by the Expert Group on Vitamins and Minerals are available.

Summary

Concentrations of three halogens (fluorine, bromine and iodine) analysed in the 1997 Total Diet Study (TDS) are reported and have been used to estimate dietary exposures of UK consumers to these elements. Samples for the 20 TDS food groups were obtained from 20 towns in the UK in 1997 and analysed in 1998/99 for fluorine, bromine and iodine. These samples were also analysed for the elements aluminium, arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, tin and zinc and the results of those analyses were reported in December 1999 by the Ministry of Agriculture, Fisheries and Food (MAFF)/Department of Health Joint Food Safety and Standards Group (JFSSG) in Food Surveillance Information Sheet No.191.1

The JFSSG had considered iodine in recent surveys,1, 2but had not considered fluorine recently and had not looked at bromine before. This survey provides up-to-date baseline data for these two elements.

Background

Halogens in food
As with metals and other elements, the halogens are present naturally in food as a result of their presence in the environment, for example, in seawater, soils and rocks.3-7They may also be present as a result of human activities. For example, fluorine may be released from the smelting of aluminium ores. Iodine compounds are used in the dairy industry to sterilise cows' teats and milking tanks and may be added as nutritional supplements to animal feeds.8,9Sodium bromate may be used in the malting process to inhibit sprouting in grains. This may contribute to bromine levels in foods produced from malted ingredients treated in this way - for example, beer. The bromine present in the final product as a result of this use is in the form of bromide rather than bromate. The halogen elements in food are of interest because of their potential effects on health.

Fluorine
No essential function for fluorine has been proven in humans. However, it may have a role in bone mineralisation as it forms calcium fluoroapatite in teeth and bone and is known to protect against dental caries.10, 11As no physiological requirement for fluorine has been established, guidelines on nutritional requirements have not been set. However, due to fluorine's role in the prevention of dental caries, some water supplies in the UK are fluoridated to achieve levels of 1 mg/l.10

Bromine
The physiological function of bromine is unclear and there are no recommendations for optimum dietary intakes in any species. The Committee on Medical Aspects of Food Policy (COMA) has concluded that as bromine is ubiquitous in the environment, it is unlikely that any deficiency would occur in humans.10

Iodine
Iodine is an essential nutrient required for the synthesis of thyroid hormones. The most well known iodine deficiency disorder (IDD) is enlargement of the thyroid gland (goitre). Iodine deficiency can also result in a wide range of mental, psychomotor and growth abnormalities as well as increased infant mortality.12-14

To protect against iodine deficiency, the COMA has recommended a Reference Nutrient Intake (RNI) for adults of 0.14 mg/day and for children between 0.05 mg/day to 0.14 mg/day.10 (The RNI is defined as an amount of a nutrient that is sufficient, or more than sufficient, for about 97 per cent of people in a group. If average intake of a group is at the RNI, then the risk of deficiency in the group is very small.) In comparison, the upper bound average iodine intake for the general UK population estimated from the results of this study was 0.25 mg/day, and that estimated from the 1995 TDS was 0.21 mg/day.15

Although iodine deficiency is of concern, there are also health concerns associated with high levels of iodine in the diet. Excessive exposure to iodine can inhibit the function of the thyroid gland and produce symptoms of iodine deficiency (e.g. goitre, impaired brain function).16 To help protect against the toxic effects of excessive iodine exposure, the Joint Expert Committee on Food Additives of the Food and Agriculture Organization and the World Health Organization (JECFA) has recommended a Provisional Maximum Tolerable Daily Intake (PMTDI) of 0.017 mg/kg bodyweight (b.w.)/day (equivalent to 1.0 mg/day for a 60 kg person).17 The PMTDI is an estimate of the amount of a substance that can be ingested over a lifetime without appreciable risk.

The Food Standards Agency undertakes regular surveys to obtain information on the concentrations of metals and other elements in food. This information, together with food consumption data, is used to estimate dietary exposures and assess the safety of foods consumed in the UK.

Prior to the establishment of the Food Standards Agency, iodine had been investigated regularly by JFSSG, both in the TDS and in surveys of specific foods such as milk to keep estimates of exposures up to date.2,15,18-20 However, JFSSG had not investigated fluorine in food since a survey published in 1984,21 and had not determined bromine in foods before. This survey was undertaken to obtain up-to-date information specifically on these elements in the diet.

Total Diet Study
The TDS is an important part of the Food Standards Agency's surveillance programme for chemicals in food. It has been carried out on a continuous annual basis since 1966 (by JFSSG and MAFF prior to the establishment of the Agency). Results from the TDS are used to estimate dietary exposures of the general UK population to chemicals in food, such as nutrients and contaminants, to identify trends in exposure and make assessments on the safety and nutritional quality of the food supply.22

The design of the UK Total Diet Study has been described in detail elsewhere, but basically involves 119 categories of food combined into 20 groups of similar foods for analysis.22,23The relative proportion of each food category within a group reflects its importance in the average UK household diet and is based on an average of three previous years of consumption data from the National Food Survey.24 Foods are grouped so that commodities known to be susceptible to contamination (e.g. offals, fish) are kept separate, as are foods which are consumed in large quantities (e.g. bread, potatoes, milk).22,23

Analyses for metals and other elements in the TDS are generally carried out every three years. However, 1997 was the first year that the halogens fluorine and bromine had been considered in the TDS. Iodine has been analysed in earlier TDSs. The foods making up the 20 groups analysed for the halogens were obtained from retail outlets in 20 locations throughout the UK. Samples are transported to one centre where they are prepared and cooked (where necessary) according to normal domestic practice. After preparation, the constituents of each group are thoroughly homogenised and frozen until analysis.

Each food group obtained from each location (i.e. a total of 400 samples) in the 1997 TDS was analysed for fluorine, bromine and iodine. The mean (average) concentrations from the 20 samples of each food group were used together with data on the consumption of these food groups to make estimates of dietary exposure for either the average UK household (i.e. population exposure estimates) or for individual adult consumers (i.e. consumer exposure estimates). Population exposure estimates are compared with those from previous years to identify trends in exposures. Consumer exposure estimates are compared with appropriate exposure guidelines (e.g. PMTDIs) where available, to assess the safety of foods consumed by the general UK population.

It was intended that the halogen chlorine would also be determined in these samples. However, it was not possible to obtain reliable data for chlorine due to unforeseen analytical problems.

Brand Names
Brand names are not available as TDS samples are composites of a number of different foods and it is not possible to relate results to individual items.25

Methodology

Sample preparation
Individual components of the TDS food groups were purchased from retail outlets in 20 towns across the UK in 1997 and prepared as for consumption, including cooking where appropriate, before being combined into one of 20 foods groups.22,23The 400 individual TDS samples analysed in this study were prepared and homogenised by the Institute of Food Research (Norwich).

Analytical method
Samples were analysed for fluorine, bromine and iodine by the Central Science Laboratory (CSL). The analytical methods used in this survey determined the total concentration of fluorine, bromine or iodine in the food tested, irrespective of the chemical forms in which the elements were present.

Bromine and iodine were treated and analysed in the same way but fluorine analysis followed a different method. All elements underwent a pre-treatment step prior to analysis and every test batch included reference materials, reagent blanks and a spiked reagent blank for recovery estimate purposes.26

Pre-treatment
Bromine and iodine
A 0.5 g (dry weight or equivalent wet weight) aliquot of each test material was heated with 25 per cent tetramethyl ammonium hydroxide (TMAH) solution. The cooled digests were then made up to 10 ml with de-ionised water. Enzymatic hydrolysis was carried out on the Bread and Cereals food groups before digestion in order to ensure the release of bromine and iodine from protein binding.

Fluorine
Fluorine was diffused as hydrogen fluoride at room temperature in the presence of perchloric acid saturated with hexamethyldisiloxane.27 The released fluoride was absorbed into a trapping layer of sodium hydroxide, which was then dried, dissolved in water and the fluoride content determined by ion chromatography. Enzymatic hydrolysis was carried out on solid foodstuffs before diffusion in order to release fluoride from protein binding.

Quantitative analyses
Bromine and iodine
Bromine and iodine concentrations were determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) using a Perkin-Elmer Elan 6000 spectrometer. Sample aliquots (50 microlitre) were flow-injected using an automated system. Calibration standards and spike solutions were prepared from commercially available standard solutions. An aliquot of one of the mid-range calibration standards was measured at the end of each analytical run for quality assurance.

Fluoride
The sodium hydroxide extracts were neutralised by passing them through Dionex Onguard-H cartridges, and analysed by ion exchange high performance liquid chromatography (HPLC) using a conductivity detector. Calibration standards and spike solutions were prepared from a commercially available standard solution.

Details of the methods of analysis and quality control procedures have been reported previously,27,28and also given in the contractors' final report for the survey26 which is available to the public from the MAFF library (see Further Information for details).

Quality Control
CSL participates in and has consistently demonstrated a satisfactory performance in the appropriate rounds in FAPAS (Food Analysis Performance Assessment Scheme) and is accredited by UKAS (United Kingdom Accreditation Scheme) for iodine and bromine measurements in food extracts. The method for fluorine has been submitted to UKAS for accreditation. The quality control criteria followed for this survey were as follows:

  • Four certified reference materials (CRMs) were analysed with every batch of samples for bromine and iodine [i.e. NIST (National Institute of Standards and Technology) 1547 Peach Leaves, NIST 1549 Non-fat Milk Powder, NIST 8418 Wheat Gluten and IAEA (International Atomic Energy Authority) A13 Freeze Dried Animal Blood]. For fluoride determinations, MC (Ministry of Commerce, China) GBW8752 Prawn CRM was used with every batch of samples for fluorine analysis.
  • Each analytical batch included at least one calibration standard which was measured as a sample at the end of the run. The value produced by the re-measured standard had to be within 20 per cent of the initial value. For fluorine analysis, the asymmetry of the calibration standard used to monitor instrument drift was also recorded. If the value fell outside the range 0.75 to 1.25, the analytical column was replaced or cleaned and the asymmetry checked again before the column was used with an analytical batch.
  • All data were corrected for spike recovery using spiked reagent blanks.
  • Limits of detection (LODs) were defined as 3 times the standard deviation of the signal from reagent blanks after correction for sample weight and dilution. The LODs for fluorine, bromine and iodine are shown in Table 1.

Repeatability
All samples were analysed duplicate in separate batches. The RSD for duplicate measurements had to be less than 20 per cent or lower than the limit of determination, whichever was greater. If results did not meet this criterion, a full re-analysis was carried out on a new extract and digest.

Dietary exposure estimates
Two types of dietary exposures have been estimated from the results of the 1997 TDS for fluorine, bromine and iodine:

1. Population exposure estimates.
These are based on household consumption data from the National Food Survey which is updated every year and so reflects changes in consumption patterns. These are compared with similarly derived estimates from previous TDSs to follow trends in dietary exposures of the general UK population.

2. Adult consumer exposure estimates.
These are estimates of dietary exposures for adults who eat average amounts of each food group (i.e. mean consumers) and those who eat significantly more than average [i.e. upper range (97.5th percentile) consumers] and are based on consumption data from the National Diet and Nutrition Survey of British Adults (Adults Survey).29 Exposure estimates (both mean and 97.5th percentile) of adult consumers are used for comparison with exposure guidelines to assess risk to consumers.

The estimation of both these types of dietary exposure is discussed in more detail below.

Population exposure estimates
The quantities of foods that make up the TDS and the relative proportion of each food are largely based on an average of the available data from three previous years of the National Food Survey and are updated annually.24 For example, to determine the amounts of foods making up the 1997 TDS, and average consumption data from the 1993, 1994 and 1995 National Food Survey were used. Multiplying the amounts of foods consumed (based on consumption data from the appropriate years of the National Food Survey) by the corresponding mean concentrations of the halide elements detected in each TDS food group gives an estimate of population average exposure (covering both adults and children) for that year. These estimates can be used to follow trends in exposure as they take into account changes both in consumption of the various foods making up the general diet and in the concentrations of the halogen elements in these foods.

Concentrations of the halogen elements in the 1997 TDS samples are shown in Table 2. Population average exposures based on these concentrations and consumption data from the National Food Survey are shown in Table 3.

Adult consumer exposure estimates
Exposures to fluorine, bromine and iodine for average and high level (97.5th percentile) adult consumers were estimated using the average concentrations in each food group and consumption data from the British Adults Survey.30

Consumer exposure estimates are less suitable for following trends in exposure than population estimates as they are based on consumption data from the Adults Survey which was carried out only once in 1986 and 1987 and is not updated annually (although preliminary work on a new survey of adults is underway).30They do not therefore take into account changes in consumption patterns and only reflect changes in concentrations of the halogen elements. However, consumer exposure estimates do take into account exposures by individuals rather than the population as a whole and also identify those who consume above average amounts of food (i.e. 97.5th percentile consumers). These estimates therefore provide more accurate assessments of dietary exposures of individual consumers than population exposure estimates for comparison with exposure guidelines.

Unless stated otherwise, the average concentrations and dietary exposures reported in this Food Surveillance Information Sheet are all upper-bound values. This means that for samples in which an element was not detected, it has been assumed that concentration of the element in that sample is equal to the LOD for that element. Dietary exposures are estimated from upper bound average concentrations to ensure that exposures are not underestimated but they may overestimate exposure to some extent.

Results

The average concentrations of fluorine, bromine and iodine found in each food group from the 20 locations in the 1997 TDS for the halide elements are shown in Table 2. Population average exposures and exposures for average and 97.5th percentile adult consumers are shown in Table 3.

In general, relatively high concentrations of all three elements were found in the Fish group compared with the other food groups. This is as expected and reflects the relative abundance of these elements in the marine environment.

Interpretation

Fluorine
Analytical measurements were made on the concentration of the fluoride ion, after treating samples to convert any fluorine present, in whatever form, into the fluoride ion. The results have been reported in terms of total fluorine in the food samples. The method does not provide any information on which fluorine-containing compounds were present in the foods.

The highest average fluorine concentrations were found in the Fish group (1.9 mg/kg), the Beverages group (1.1 mg/kg) and the Oils and fats group (0.52 mg/kg). The lowest average fluorine concentration of 0.05 mg/kg was found in the Milk, Other vegetables and Green vegetables groups (Table 2).

The concentrations above are generally lower than those in similar food groups reported by MAFF in 1984 for selected samples from Total Diet Studies in 1978,1979 and 1980.21 However, it should be noted that prior to 1981, individual food items in the TDS were combined into only 9 food groups compared with 20 food groups in TDSs from 1981 onwards. This means that direct comparisons cannot be made between results for samples from TDSs before 1981 with those from subsequent years.

There is no evidence from these results of a relationship between the fluorine concentrations in the samples from this study and whether or not the drinking water supply in the area from which the samples were collected is fluoridated. This is as expected since the foods making up the TDS samples may not have been produced in the town in which they were purchased. In addition, TDS samples are prepared centrally using deionised water with a negligible fluoride content, so the fluorine levels found in the TDS samples will not reflect any contribution from the use of drinking water which would take place in domestic food preparation by consumers. This is considered further below.

Fluorine concentrations from this survey are similar to those found in the 1990/1991 New Zealand Total Diet Survey (NZTDS) for those food groups which are similar for both surveys.3 For example, results from the NZTDS were 0.2 mg/kg for the Dairy group compared with 0.16 mg/kg in this survey and 0.4 mg/kg in the Oils and fats group compared with 0.52 mg/kg in this survey.

Fluorine was found to be higher in the Beverages group in this survey (1.1 mg/kg) than the NZTDS (0.4 mg/kg),3 while the Nuts group in the NZTDS contained more than twice the average fluorine concentration than the corresponding group in the 1997 UK TDS (0.55 mg/kg versus 0.16 mg/kg respectively). Only two food groups from a Canadian study30 could be directly compared with this study and both were similar. The fluorine concentrations in the Beverages group in the Canadian study were 1.2 mg/kg compared with 1.1 mg/kg in this study. Concentrations in the Fish group were 2.1 mg/kg in the Canadian study and 1.9 mg/kg in this study.

Comparisons between TDSs in different countries should be viewed with caution since the types of foods, their preparation and the general design of the studies varies between countries. This is especially important for beverages, for which the fluorine content will be strongly influenced by the amount of tea included, as tea is known to be rich in fluoride. Furthermore, it is not clear whether upper bound average concentrations are used in TDSs from other countries.

Bromine
The highest average bromine concentrations were found in the Nuts group (25.8 mg/kg), the Fish group (6.7 mg/kg) and the Offals group (0.55 mg/kg). The Beverage group had the lowest average bromine concentration (0.1 mg/kg) (Table 2).

Bromine concentrations from this survey can be compared with those found in samples originally used in the 1990/91 Japanese Total Diet Survey (for those food groups which are similar for both surveys).5 For example, results for the Japanese TDS in 1991 were 19 mg/kg for the Fats and Oils group compared with 2.8 mg/kg in this survey and 15 mg/kg in the Leafy/Green vegetables group compared with 3.5 mg/kg in this survey. Results were not available from the Japanese TDS for the Fish and shellfish groups or the Fruits group in 1991. However, in the 1990 Japanese TDS, the bromine concentration for the Fish and shellfish group was 12 mg/kg compared with 6.7 mg/kg in this study, and for the Fruits group, 12 mg/kg compared with 0.71 mg/kg in this study. It is not known whether the data from the Japanese TDS samples are upper bound average concentrations. The types and proportions of individual foods included in each group will also have differed between the two studies.

Iodine
The highest average iodine concentrations were found in the Fish (1.3 mg/kg), Egg (0.48 mg/kg) and Milk groups (0.32 mg/kg) (Table 2).

Iodine concentrations were similar to those foods tested in a 1994 survey of iodine in British foods and diets18 where similar food groups were analysed. Iodine concentrations were determined in several selected foods including 31 individual fish and fish product samples. The average iodine concentration was 0.78 mg/kg compared with 1.3 mg/kg in this survey. Four types of nuts were also analysed in the earlier study and had an average iodine concentration of 0.15 mg/kg compared with 0.25 mg/kg for the Nuts group in this survey.18

Iodine was also analysed in TDSs in 199118,31 and 1995.15 Iodine concentrations in most of the food groups in this survey are similar to those found in the earlier TDSs. However, exceptions are found in the Meat products group where the concentration of iodine has dropped from 0.85 mg/kg in the 1991 TDS to 0.13 mg/kg in this survey. This may be due to the cessation of the use of the iodine-containing food colouring erythrosine in meat products (this use is not permitted under the Colours in Food Regulations 1995).32 The greatest increases in iodine concentrations from the 1991 TDS were found in the Beverages group (less than 0.001 mg/kg) compared with this survey (0.03 mg/kg) and the Nuts group (0.066 mg/kg in the 1991 TDS compared with 0.25 mg/kg in this survey). Despite these variations in the iodine concentrations in individual food groups, there has been no consistent change in estimates of the total population average iodine exposure since 1985 (Table 4).

Iodine is present naturally in cow's milk but concentrations of iodine in milk can also be influenced by the presence of iodine in animal feed and/or from hygiene products used in the dairy industry, for example as cow teat sterilants and equipment sanitisers.8,9The JFSSG undertook several surveys of iodine in cows' milk.2,15,19,20 The average iodine concentration in milk found in this survey (0.32 mg/kg) is very similar to that found in the 1995 TDS (0.3 mg/kg)15, a 1995/96 milk survey (0.3 mg/kg)20 and a 1998/99 survey of individual samples of cows' milk (0.31 mg/kg).2 These results are, however, higher than the average iodine concentrations found in the 1991 TDS (0.17 mg/kg)18,32 and a 1990/91 survey of cows' milk (0.15 mg/kg).18 These results are discussed in detail in JFSSG Food Surveillance Information Sheet No. 198 - Iodine in Milk.2

Iodine results from this survey can also be compared with some of the food groups in a study of Chinese total diets, again where the food groups in the two studies are similar.33 Iodine concentrations for the Milk group, the Fish group and the Fruit group in the two studies were very similar. Iodine concentrations were much higher in the Potato group (0.48 mg/kg) and about twice as high in the Egg group 0.92 mg/kg in the Chinese study than this survey (Potatoes, 0.07 mg/kg; Eggs, 0.48 mg/kg).33 Iodine concentrations from this survey are generally higher in similar food groups than those from the New Zealand TDS. The only similar result was in the Fresh fruit group where the iodine concentration was 0.032 mg/kg in the NZTDS and 0.04 mg/kg in this survey. Again, differences in survey design, the individual foods included and in reporting will have contributed to these differences between the results of the UK TDS and diet studies in other countries, as well as genuine differences in iodine exposures between countries.

Dietary exposures
Estimates of the population average exposure and the exposures for average and high-level (97.5th percentile) adult consumers for each element are shown in Table 3 and provide up-to-date data for these elements against which risk to consumers has been assessed. Results for each element are discussed individually below.

Fluorine
The average population exposure estimate to fluorine from this study is 1.2 mg/day, to which the beverages contributed 1.0 mg/day, or 85 per cent of the total. This is as expected and reflects the relatively high concentrations of fluorine in tea. This estimate does not include the contribution of fluoride in water used to make tea, which is discussed below.

The population average exposure from this study, 1.2 mg/day, is similar to that of 1.8 mg/day from a 1984 study based on a selection of samples from the 1978, 1979 and 1980 TDSs.21 However, any comparison between these studies should be made with caution because the earlier estimate is based on only a selection of samples from three years TDSs and also because individual foods in TDSs prior to 1981 were combined into only 9 food groups compared with 20 groups in TDSs from 1981 onwards.

The estimated adult exposures to fluorine can be compared with exposures from the New Zealand TDS3 and the Canadian study.30 Exposures to fluorine estimated for adults in the NZTDS (2.65 mg/day) and the Canadian study (1.76 mg/day) were both greater than in this UK survey (0.94 mg/day). However, this may be due to differences in the method of calculation as well as any differences in consumption patterns and fluorine levels in the two countries.

Fluorine in drinking water
Drinking water can also be a significant source of exposure to fluorine. Most of the drinking water in the UK contains naturally occurring fluorine present at concentrations of lower than 0.7 mg/l. The Water Supply (Water Quality) Regulations 1989 set a limit of 1.5 mg/l of fluoride in drinking water. About 10 per cent of the UK population receive drinking water that has been fluoridated to levels of 1 mg/l. The average consumption of drinking water in the UK is about 1 litre/day, and for high-level consumers such as those drinking a lot of tea, about 2 litres day. If it is assumed that this water is from a fluoridated supply, this would result in an additional exposure to fluorine from drinking water of 1 mg/day for average consumers and 2 mg/day for high-level consumers.

Bromine
The average population exposure to bromine was 3.6 mg/day with the main contributors being Milk (22 per cent), Bread (14 per cent) and Miscellaneous cereals (11 per cent). No previous data are available for comparison with this survey, but the results from this survey provide up-to-date baseline data for bromine.

Iodine
The average population exposure to iodine in the 1997 TDS was 0.25 mg/day. This is within the range of estimates from TDSs in previous years: 1985, 0.28 mg/day;18 1991, 0.17 mg/day; and 1995, 0.21 mg/day15 (Table 4). This comparison shows that while there is some variation in estimates of iodine exposure in different years, there is no consistent trend over time.

The estimated average adult exposure to iodine (0.24 mg/day) is higher than that from the New Zealand TDS (0.1 mg/kg)3 and to a lesser extent the Chinese TDS (0.17 mg/day).33 Again, differences between studies mean comparisons should be viewed with caution.

All the estimated iodine exposures from this study, including that for high-level adult consumers, are below the JECFA PMTDI for iodine of 0.017 mg/kg bodyweight/day, which is equivalent to 1.0 mg/day for a 60 kg person.

Implications for consumers
The estimated exposures to halogens were considered by the Chief Medical Officer for England's advisory committee, the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT). It concluded that the estimated exposures to bromine and iodine are unlikely to pose a risk to health. It also commented that information on the chemical forms of these elements in food would assist in risk assessment. The Committee will consider the estimated exposures to fluorine when the findings of a review of fluorine by the Expert Group on Vitamins and Minerals are available. The COT's full statement on this survey is given in Annex 1.

The COT recently considered exposures to iodine by consumers of cows' milk based on the results of a JFSSG survey of iodine in cows' milk collected in 1998 and 1999. Estimated total dietary exposures to iodine by adults were well within exposure guidelines, but some younger children consuming above average amounts of milk could exceed the guideline, particularly in winter when iodine concentrations are higher. The COT concluded that the concentrations of iodine in cows' milk are unlikely to pose a risk to health, even in those children who are high level consumers. However, it added that further studies were needed on iodine in the diet. Full details of this survey and the COT's statement were published in JFSSG Food Surveillance Information Sheet No. 198 - Iodine in Milk.2

Conclusions

This survey has provided up-to-date information on the concentrations of fluorine, bromine and iodine in the typical UK diet and on consumers' exposures to these elements against which the risk to consumers and any future trends can be assessed. Estimated dietary exposures to fluorine and iodine were similar to estimates from previous years. The COT advised that exposures to iodine and bromine are unlikely to pose a risk to health. It will consider fluorine when the findings of a review of fluorine by the Expert Group on Vitamins and Minerals are available.

Actions
A research project to investigate the different forms (species) of iodine in cows' milk, infant formulae and the influence of iodine-based sterilants (iodophors) used in the dairy industry is being carried out for the Food Standards Agency by CSL. The results will be made available when the study is completed.

Glossary of terms

COT: Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment
JECFA: Joint Expert Committee on Food Additives of the Food and Agriculture Organization of the United Nations and the World Health Organization
LOD: Limit of Detection
PMTDI: Provisional Maximum Tolerable Daily Intake
PTWI: Provisional Tolerable Weekly Intake
TDS: Total Diet Study

Summary of units

kilogram (kg): one thousand grams
milligram (mg): one thousandth of a gram
microgram: one millionth of a gram
mg/kg: milligrams per kilogram (equivalent to parts per million)
mg/day: milligrams per day
microgram/day: micrograms per day

References

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Further Information

Further information on this survey can be obtained from:
Dr Patrick Miller
Food Standards Agency
Contaminants Division
PO Box 31037
Room 238, Ergon House
London SW1P 3WG
Tel: +44 (0) 20 7238 5751
Fax: +44 (0) 20 7238 5331

Email: patrick.miller@foodstandards.gsi.gov.uk

Further copies of this Information Sheets may be obtained from:
Food Standards Agency
Information Centre
PO Box 31037
Room 303b, Ergon House
London SW1P 3WG
Tel: +44 (0) 20 7238 6223
Fax: +44 (0) 20 7238 6330
E-mail: information.centre@foodstandards.gsi.gov.uk

Copies of the COT statement on the results of this survey can be obtained from:
Ms Akosua Adjei
COT Secretariat
PO Box 30077
Room 651C, Skipton House
80 London Road
London SE1 6XZ
Tel: +44 (0) 20 7972 5023
Fax: +44 (0) 20 7972 5134
E-mail: akosua.adjei@foodstandards.gsi.gov.uk

A copy of the final report of this survey has been placed in the FSA Library, Aviation House, 125 Kingsway, London, WC2B 6NH, UK; Tel. No. +44 (0) 20 7276 8181. If you wish to consult a copy please contact the Library giving at least 24 hours notice or alternatively copies can be obtained from the library: a charge will be made to cover photocopying and postage.