Duplicate diets

Fe in duplicate diet samples ETAAS NIST SRM 1567, Wheat flour Van Cauwenbergh et al. 1997... 

Adult Females N=114 0.03 Duplicate diet study Ayr, Scotland EPA analysis Sherlock et al. 1982... 

Slope factors for the blood lead contribution from diet in adults can be obtained from an experimental study (Cools et al. 1976) and a duplicate diet study (Sherlock et al. 1982). These slope factors range from 0.027 to 0.034 pg/dL blood per pg lead intake/day (EPA 1986a). The data from the duplicate diet infant study by Ryu et al. (1983) were reanalyzed to derive a slope factor of 0.24 pg/dL blood per pg/day lead intake (EPA 1990e). 

This value is only slightly higher than the estimated lead intake of 54 pg/day found in a Canadian 24-hour duplicate diet study conducted during 1981. The average lead content of the 10 food groups used in the Canadian study ranged from 0.088 pg/g for drinking water to 0.654 pg/g for cheese (Dabeka et al. 1987). 

Dabeka RW, McKenzie AD, Lacroix GMA. 1987. Dietary intakes of lead, cadmium, arsenic and fluoride by Canadian adults A 24-hour duplicate diet study. Food Addit Contam 4 89-102. 

Lacey RF, Moore MR, Richards WN. 1985. Lead in water, infant diet and blood The Glasgow duplicate diet stud. Sci Total Environ 41 235-257. 

Sherlock JC, Quinn MJ. 1986. Relationship between blood and lead concentrations and dietary lead intake in infants The Glasgow Duplicate Diet Study 1979-1980. Food Addit Contam 3 167-176. 

Stanek K, Manton W, Angle C, et al. 1998. Lead consumption of 18- to 36-month-old children as determined from duplicate diet collections nutrient intakes, blood lead levels, and effects on growth. Journal of the American Dietetic Association 98(2) 155-158. 

There is also effort to develop practical ways of measuring intake of additives. The direct measurement of intake continues to be problematical. Duplicate diet studies require a lot of resources, and there are not enough analytical methods available to test for all the additives of interest. Total diet studies, also known as market basket studies, provide a very general picture which can be a useful start to more detailed work on intake, but they too suffer from the same shortage of analytical methods. Biomarker studies are currently problematical. It is difficult to identify metabolites that are both unique to particular additives and can be readily measured in urine. The estimation of additive intake by calculation is still the preferred method, although it requires a large amount of information on both additive levels in food and much data on food consumption. The latter is difficult to obtain without using a lot of resources - many of us have very varied diets ... 

Considering the migration possibilities of such chemicals from their original products, complex studies were performed for classical plasticizers such as DEHP or DBP to evaluate the relevance of each pathway to human exposure assessments. Therefore, the total exposure of adults of such plasticizers was evaluated by quantifying the target substances in duplicate diet portions (collected daily over 7 consecutive days), and also by measuring indoor air and dust concentrations [129]. The results indicate that dietary exposure is the dominant... 

Ritchie MR, Morton M8, Deighton N, Blake A, Cummings JH. Plasma and urinary phyto-oestrogens as biomarkers of intake validity by duplicate diet analysis. Br. J. Nutr. 91, 447 57, 2004. 

Diary studies are used to determine in detail the consumption of a particular part of a diet. A population consuming above-average amounts of food that provides the main source of exposure to a contaminant can be identified using questionnaires. A record of the type and weight of food eaten, and the source, is then kept in a purpose-made diary by participants in the study. Representative samples of foods eaten are then analysed and the data combined. An extension of this approach is exemplified by the duplicate diet study, in which as exact a replicate as possible of all food consumed is collected for analysis. 

Duplicate diet studies of people living in areas where exposure to lead from other sources is known to be low have provided some valuable information. The mean dietary lead exposure to women was estimated to be 0.31 mg/week and the mean lead exposure to children as 0.11 mg/week.12 These studies included the contribution from drinking water. In areas with elevated levels of lead in tap water, estimated lead intakes of both adults and children are found to be higher and, in a small percentage of cases, above the PTWI. 

However, the results of duplicate diet studies have shown that there are localised high intakes by consumers in certain areas or by consumers of certain foods. In the old mining village of Shipham in Somerset, UK, where the cadmium levels in some vegetable samples were more than 1 mg/kg, the dietary exposure to cadmium of the study population was about double the average weekly dietary intake and some individuals exceeded the PTWI for cadmium.19... 

Cf - Concentration (C) in the food (f) item Measurement in individual food items or composite duplicate-diet samples pg/kg... 

Wf- Weight (W) of food (f) item consumed Measured in duplicate-diet sample kg/day... 

A United States study examined the aggregate exposures of preschool children to chlorpyrifos and its degradation product, 3,5,6-trichloro-2-pyridinol (TCP) (Morgan et al., 2005). Samples that were collected included duplicate diet, indoor and outdoor air, urine, solid and liquid food, indoor floor dust, play area soil, transferable residues, and surface wipes (hand, food preparation, and hard floor). Generally, levels of chlorpyrifos were higher than levels of TCP in all media, except for solid food samples. For these samples, the median TCP concentrations were 12 and 29 times higher than the chlorpyrifos concentrations at homes and day-care centres,... 

There is still much ongoing debate on the validity of the different approaches to perform dietary analysis (single food analysis, duplicate diet analysis, total diet, and total mixed diet analysis) to provide an adequate answer to nutritional questions. The approach followed in this study has proven useful for the assessment of the actual dietary intake of trace metals that may be lost and/or added during the preparation of meals. The measurements done on cooked samples prepared according to the Italian local traditions provides an assessment of the actual concentrations of trace elements uptaken by the population through the diet. 

The longest balance study measuring manganese was conducted by Tipton et al. (28) who collected duplicate diets and all urinary and fecal excreta of two men for 347 days. The self-chosen diets of the two men contained an average of 3.3 and 5.5 mg Mn/day and produced positive balances of 0.8 and 2.5 mg/day, respectively. 

Food Additives and Contaminants 20, No.4, April 2003, p.317-24 ESTIMATED DAILY INTAKE OF PLASTICIZERS IN 1-WEEK DUPLICATE DIET SAMPLES FOLLOWING REGULATION OF DEPH-CONTAINING PVC GLOVES IN JAPAN Tsumura Y Ishimitsu S Saito I Sakai H Tsuchida Y Tonogai Y... 

One of the most sophisticated approaches is the duplicate diet method where for every item consumed an identical amount of the item is put aside for analysis at a later date. This approach enables all sources of the substance of interest to be included and gives a realistic and arguably the most accurate way of obtaining an exposure assessment. This is a good way of examining at-risk groups, but it is expensive. The interpretation of the data beyond the... 

Haxton J, Lindsay DG, Hilsop JS, et al. 1979. Duplicate diet study on fishing communities in the United Kingdom Mercury exposure in a "critical group.6 Environ Res 18 351-368. 

Sherlock JC, Lindsay DG, Evans WH, et al. 1982. Duplication diet study on mercury intake by fish consumers in the United Kingdom. Arch Environ Health 37(5) 271-278. 

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