Dietary surveys

Generation of data on the nutrient content of agricultural products and foods forms the basis for estimating nutrient intakes of populations via dietary surveys, nutritional labelling for consumer protection, nutrition education for consumer food choice, home and institution menu planning and food purchase, and for research in nutrient requirements and metabolism, toxicant chemical composition is used to assess effects of farm management practices, crop culture, and food processing on chemical content and implications for human health. 

Foods derived from cocoa beans have been consumed by humans since at least 460 to 480 AD, presumably with no major health effects. Most chocolate is consumed in the form of chocolate confectionery. On the basis of USDA dietary survey data, 12% of the population consumed chocolate confectionery at least once in three days with an average intake of 50.5 g... 

Another Commonwealth government agency also involved in residue monitoring is the Market Basket Survey within ANZFA. This agency is responsible for the Australian Total Dietary Survey that estimates the total dietary burden of pesticides and contaminants. This agency examines levels in food purchased from retail outlets in all capital cities throughout a calendar year. In this way, ANZFA is able to estimate the residues contained in the average Australian diet. 

The AHS, a collaborative research effort between the National Cancer Institute of the National Institutes of Health and EPA, is a prospective occupational study of 89,658 pesticide appliers and their spouses in Iowa and North Carolina assembled between 1993 and 1997 to evaluate risk factors for disease in rural farm populations (Blair et al. 2005). It is being conducted in three phases—phase I (1993-1997), phase II (1999-2003), and phase III (2005)—and includes only limited biomonitoring. Data are gathered with questionnaires to determine pesticide use and exposures, work practices, and other relevant exposures from buccal cell collection with dietary surveys and with interviews to determine updated pesticide exposures (Agricultural Health Study 2005). 

These are estimates of dietary exposure to inorganic contaminants for individuals who eat average amounts of food (i.e. mean consumers) and those who eat more than average (i.e. upper range (97.5th percentile) consumers) and are based on consumption data from the UK National Adult Dietary Survey (NADS).4 They are calculated using the mean upper bound concentrations of specific contaminants in each food group and the consumption data from the NADS. Consumer exposure estimates are less suitable for following trends in exposure than population estimates as they are based on consumption data from the NADS which was carried out only once in 1986 and 1987 and is not updated... 

In 1991 the UK Committee on Toxicology (COT) set a tolerable daily intake value (TDI) of 0.3 mg/kg body weight/day for DEHA. One year later, in 1992, a urinary biomarker study was reported for DEHA in a limited population exercise in the UK. A skewed distribution was determined with a median value of 2.7 mg/day and this confirmed by an independent route, the earlier estimates of DEHA intake made using dietary survey data. 

Australian foods are monitored on the basis of the National Residue Surveys and Australian Market Basket Surveys (now Total Dietary Survey). Only a low percentage of OCP residues have been detected in animal fats since 1996 and none in grains since 1992. Elevated intakes of residues (e.g. dieldrin and HCB) occurred in the early 1970s, which have since declined at approximately first-order kinetics to much lower and generally acceptable levels of intake in the 1990s. 

Australian market basket survey (now known as Total Dietary Survey)... 

TABLE 9.5. Estimated Intakes by Infants (4-6 Years) of Cd, Hg, and Pb Using Age-Specific Consumption Data from the Danish Dietary Survey for the 2000-2002 Period... 

For a 4-6-year-old child however, the mean and 95th percentile of Pb intakes estimated on the basis of age-specific consumption data from the 2000-2002 dietary survey (Table 9.5) correspond to 13 and 20 percent of the PTWI value, respectively. 

The caloric levels of these diets varied considerably, partially because of differences In experimental design. In general, zinc Intake Increased as caloric Intake Increased, resulting In a more narrow range for the zinc densities of the diets—4.1 to 8.8 mg per 1,000 calories—than for the total zinc levels. In all of the studies, the research methods Involved chemical analysis of dietary composites. Few estimates of zinc Intake have been calculated from tables of zinc concentrations In food, even though this approach Is less complex and less costly. Calculation of zinc Intake from dietary survey data has been hindered by the limited proportion of the many foods available In the market place that have been analyzed for zinc. 

Relatively few dietary surveys of nutrient intakes of vegetarians have Included a calculation of zinc Intakes. Handbook analytical values for zinc contents of a wide variety of food substances have only recently become available which may in part account for this omission. 

Marr, J.W., Individual dietary surveys Purposes and methods. World Rev. Nutr. Diet., 13 (1971) 105. 

Plasma and urinary levels of pantothenic acid have been measured in dietary surveys as well as in controlled studies of the vitamin deficiency. One fairly recent study with human subjects involved the feeding of a pantothenic acid-free diet for 9 weeks. The urinary pantothenic acid levels (4-6 mg/day) in vitamin-sufficient subjects were roughly half that of the intake (10 mg/day). With consumption of the vitamin-free diet, urinary pantothenic acid levels gradually declined to about 0.8 mg/day over the 9-week period (Fry et ai., 1976). Both urinary and blood serum levels of pantothenate have been used to assess dietary status. Values from urinary measurements seem to be somewhat better correlated with intake of this vitamin, than blood measurements data (Berg, 1997). 

Having conducted a dietary survey, an epidemiologist may be able to correlate the risk for certain diseases with certain dietary habits. To inspire and guide the activities of research scientists epldeiTiloJogists often try to correlate the risk for disease with the actual chemical constituents of the diet. The connection between food eating habits and these chemicals is made possible by using food tables. The most comprehensive food table available is Hundbook No. S Composition of Foods, Rato, Processed and Prepared, written by the U.S. Department of Agriculture (USD A). 

Integrated aggregate exposure monitoring programs (e.g., concurrent product use surveys, dietary surveys, and exposure media measurements). 

Percentage of respective group reporting fish consumption during the CSFII 3-day dietary survey period in 1989-1991b ... 

The recommended dietary intake for adults is 0.9mg/day. This is close to the lower limit of l.Omg/day found in dietary surveys and has led to suggestions that marginal copper depletion could be found in the U.S. population. The tolerable upper limit is lOmg/day. ... 

It is now proposed, after review of Chinese and New Zealand supplementation studies, that the RDA for selenium is set at 55 jiig/day for adults. On this basis, dietary surveys in North America do not indicate that selenium deficiency is likely in the general population. However, in many countries in Europe, intakes are now dose to or below 55(tg/day, and selenium dietary provision may now be suboptimal. ... 

A number of nitroso compounds, A-nitrosamines among them, are potent carcinogens. The most common carcinogenic nitrosamines, found mainly in protein food, are A-nitroso-dimethylamine (NDMA), A-nitroso-diethylamine (NDEA), A-nitroso-pyrrolidine (N-Pyr), and A-nitroso-piperidine (N-Pip). These compounds supposedly increase the risk of colon, rectum, stomach, pancreas, and bladder cancers. Nitrosamines are most prevalent in cured meats, but have also been detected in smoked fish, soy protein foods dried by direct flame, and food-contact elastic nettings. Dietary surveys indicated weekly mean intakes of these compounds amounting to about 3 pg per person (Anon., 1988 Cassens, 1995). In addition, the precursors of nitrosamines, especially nitrate, are abundant in some leafy and root vegetables (Table 14.1). 

The dietary allowances proposed In the USA are, for infants 0-1 years, 3-5 mg/day children 1-10 years 10 mg/day males and females 11-51 + 15 mg/day pregnant women 20 mg/day and lactating women 25 mg/day. (Recommended Dietary Allowances 1980). Some countries have adopted these allowances while others like Canada, Australia, GDR and the USSR suggest lower amounts in the range 8-15 mg/day, with addition of up to -(-13 mg/day for lactating women. The policy in the UK is to make no particular recommendation since dietary surveys do not suggest that there is a widespread lack of zinc in the average diet. 

Data from the National Dietary Survey based on a food frequency questionnaire (FFQ). Dahl et al., (2003a). 

Johansson, L. and Solvoll, K. (1999). National Dietary Survey among Men and Women, 16—79 Years. Publication No. 2. Norwegian National Council of Nutrition and Physical Activity, Oslo, Norway. 

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