Nutrition and consumers
Part 1 Nutrition and consumers
What consumers eat A. Trichopoulou and A Naska, University of Athens 2.1 Introduction Documenting and monitoring dietary patterns are priorities in nutritional epi demology, in the planning of national food and nutrition policies and in the evaluation of nutrition education strategies. Early efforts in documenting dietary patterns were focused on identifying the specific nutrients that may be respon sible for effects on people's health, but recently research has expanded towards tudying patterns of food intake. Food data are often derived from Food Balance Sheets, providing information on food supply at the population level Household Budget Surveys, which collect data on food availability in the household, based on nationally representative samples of households specifically designed Individual Dietary Surveys, providing information on the food intake of free-living indiv In section 2. 1 of the present chapter, food data sources are presented and com- mented upon, with emphasis on the dietary information collected. Section 2.2 provides an overview of individual dietary surveys undertaken in Europe, during e last 20 years, and discusses the factors that need to be taken into considera tion before data from varied sources are combined and compared. European studies(DAFNE, EPIC, MONICA and SEnECA)that allow for international comparisons are also presented and the section concludes with examples of European studies designed to address specific, nutrition-related research ques- tions. Based on currently available data, the last section of the chapter describes dietary patterns in Europe and attempts to identify socio-demograpl responsible for the disparities observed
2 What consumers eat A. Trichopoulou and A. Naska, University of Athens 2.1 Introduction Documenting and monitoring dietary patterns are priorities in nutritional epidemiology, in the planning of national food and nutrition policies and in the evaluation of nutrition education strategies. Early efforts in documenting dietary patterns were focused on identifying the specific nutrients that may be responsible for effects on people’s health, but recently research has expanded towards studying patterns of food intake. Food data are often derived from: • Food Balance Sheets, providing information on food supply at the population level. • Household Budget Surveys, which collect data on food availability in the household, based on nationally representative samples of households. • specifically designed Individual Dietary Surveys, providing information on the food intake of free-living individuals. In section 2.1 of the present chapter, food data sources are presented and commented upon, with emphasis on the dietary information collected. Section 2.2 provides an overview of individual dietary surveys undertaken in Europe, during the last 20 years, and discusses the factors that need to be taken into consideration before data from varied sources are combined and compared. European studies (DAFNE, EPIC, MONICA and SENECA) that allow for international comparisons are also presented and the section concludes with examples of European studies designed to address specific, nutrition-related research questions. Based on currently available data, the last section of the chapter describes dietary patterns in Europe and attempts to identify socio-demographic factors responsible for the disparities observed
8 The nutrition handbook for food processors 2.2 Dietary components and health The availability of food in Europe has never been as good as in recent decades Affluent though European countries are, sub-groups of populations experience he deficiency of minerals and micronutrients that play a vital role in health and development(Serra-Majem, 2001). A significant proportion of European infants and children are today experiencing a low dietary intake of iodine and iron (Trichopoulou and Lagiou, 1997a; WHO, 1998). The iodine deficiency leads to several disorders collectively referred to as lodine Deficiency Disorders (IDD) with goitre(hyperplasia of thyroid cells), cretinism(mental deficiency) and severe brain damage being the most common. It is estimated that IDD may affect approximately 16%o of the European population. Furthermore, inadequate levels of folate have been implicated with a rise in the blood homocysteine levels, leading possibly to increased risk of cardiovascular disease(CVD).European policies address such deficiencies either by recommending the consumption of foods rich in the implicated micronutrients or with supplementation policies(e.g. iodised salt, flour supplemented with folic acid) The general increase, however, in the quantity and variety of food available has mostly been accompanied by the emergence of degenerative conditions such as CVD, various types of cancer, non-insulin dependent diabetes mellitus, obesity osteoporosis and hypertension. Documenting and monitoring dietary patterns has therefore become a priority in the formulation of dietary recommendations and the planning of national food, nutrition and agricultural policies (Societe francaise de Sante Publique. Health and Human Nutrition, 2000) However, there are questions that emerge early in the formulation of a nutri tion and food policy: these concern the nature of the best diet and the objectives of an ideal diet. With respect to chronic nutrition-related conditions, most of our existing knowledge relies on evidence accumulated mainly in relation to the two most common categories of disease, cardiovascular disease and cancer with respect to CVD, there is strong evidence that the intake of vegetables, pulses reduces the risk, although there is no agreement to what extent the apparent protection is conveyed by fibre, homocysteine-reducing folic acid, antioxidant compounds in vegetables and fruits, the high quantities of olive oil that usually accompany high intake of vegetables and legumes, or the comple mentary reduced consumption of red meat and lipids of animal origin(Willett, 1994,1998) The mainstream view on the effects of macronutrients on CVD is that dietary ipids high in saturated fatty acids and especially trans-fatty acids increase the risk. On the contrary, polyunsaturated fatty acids and some long chain n-3 fatty acids have beneficial effects. Monounsaturated lipids, overwhelmingly present in olive oil, also act beneficially by reducing the disadvantageous low density lipoprotein cholesterol (LDL-C) and increasing the protective high density lipoprotein cholesterol(HDL-C)(Mattson and Grundy, 1985; Mensink and Katan, 1987). Complex carbohydrates do not adversely affect the risk for CV nd their effect on HDL-C is less favourable than that of monounsaturated lipid
2.2 Dietary components and health The availability of food in Europe has never been as good as in recent decades. Affluent though European countries are, sub-groups of populations experience the deficiency of minerals and micronutrients that play a vital role in health and development (Serra-Majem, 2001). A significant proportion of European infants and children are today experiencing a low dietary intake of iodine and iron (Trichopoulou and Lagiou, 1997a; WHO, 1998). The iodine deficiency leads to several disorders collectively referred to as Iodine Deficiency Disorders (IDD), with goitre (hyperplasia of thyroid cells), cretinism (mental deficiency) and severe brain damage being the most common. It is estimated that IDD may affect approximately 16% of the European population. Furthermore, inadequate levels of folate have been implicated with a rise in the blood homocysteine levels, leading possibly to increased risk of cardiovascular disease (CVD). European policies address such deficiencies either by recommending the consumption of foods rich in the implicated micronutrients or with supplementation policies (e.g. iodised salt, flour supplemented with folic acid). The general increase, however, in the quantity and variety of food available has mostly been accompanied by the emergence of degenerative conditions such as CVD, various types of cancer, non-insulin dependent diabetes mellitus, obesity, osteoporosis and hypertension. Documenting and monitoring dietary patterns has therefore become a priority in the formulation of dietary recommendations and the planning of national food, nutrition and agricultural policies (Société Française de Santé Publique. Health and Human Nutrition, 2000). However, there are questions that emerge early in the formulation of a nutrition and food policy: these concern the nature of the best diet and the objectives of an ideal diet. With respect to chronic nutrition-related conditions, most of our existing knowledge relies on evidence accumulated mainly in relation to the two most common categories of disease, cardiovascular disease and cancer. With respect to CVD, there is strong evidence that the intake of vegetables, fruits and pulses reduces the risk, although there is no agreement to what extent the apparent protection is conveyed by fibre, homocysteine-reducing folic acid, antioxidant compounds in vegetables and fruits, the high quantities of olive oil that usually accompany high intake of vegetables and legumes, or the complementary reduced consumption of red meat and lipids of animal origin (Willett, 1994,1998). The mainstream view on the effects of macronutrients on CVD is that dietary lipids high in saturated fatty acids and especially trans-fatty acids increase the risk. On the contrary, polyunsaturated fatty acids and some long chain n-3 fatty acids have beneficial effects. Monounsaturated lipids, overwhelmingly present in olive oil, also act beneficially by reducing the disadvantageous low density lipoprotein cholesterol (LDL-C) and increasing the protective high density lipoprotein cholesterol (HDL-C) (Mattson and Grundy, 1985; Mensink and Katan, 1987). Complex carbohydrates do not adversely affect the risk for CVD and their effect on HDL-C is less favourable than that of monounsaturated lipids 8 The nutrition handbook for food processors
What consumers eat 9 (Mensink and Katan, 1987). Refined carbohydrates substantially affect post- prandial hyperglycemia and they appear to accentuate insulin resistance. With respect to other nutrients, there is converging, but not yet conclusive, evidence that moderate alcohol intake, vitamin E and folic acid are inversely associated with the risk of coronary heart disease(CHD)( Gaziano et al, 1993; Stampfer et al, 1993; Robinson et al, 1998). Salt intake, on the contrary, contributes to the elevation of blood pressure levels in susceptible individuals and thus to the crease of CVD risk(Beilin et al, 1999). The evidence on the role of specific dietary factors in cancer aetiology has en critically summarised in recent reviews(Willett and Trichopoulos, 1996 Willett, 2000). With respect to food groups, vegetable consumption, and perhaps less definitely fruit consumption, have a beneficial effect on a broad spectrum of human cancer types. Among macronutrients, animal protein intake has been reported to increase the risk for colorectal cancer, while intake of saturated fat is positively associated with endometrial, prostate, colorectal, lung and kidney cancer. Although the percentage of calories from dietary lipids does not appear related to colon cancer, greater risks have been seen with higher consumption of red meat, possibly suggesting that factors other than dietary lipids per se may be important. Fibre intake, on the contrary, appears to protect against cancer of the pancreas and the large bowel. There are also indications of a protective role of monounsaturated lipids against breast cancer(Trichopoulou, 1995). Concerning micronutrients the evidence is largely insufficient. Recent studies indicate an inverse association of lycopene(Gann et al, 1999), selenium(Yoshizawa et al, 1998)and vitamin E(Tzonou et al, 1999)with prostate cancer, folic acid in rela- tion to colon and breast cancers( Giovannucci et al, 1998); while beta-carotene supplements have been found to be ineffective against lung cancer risk (Hennekens et al, 1996) Consumption of large quantities of alcoholic beverages, particularly in con- junction with tobacco smoking, has been reported to increase the risk of cancer in the upper respiratory and digestive tract, whereas alcoholic cirrhosis frequently leads to liver cancer. There are also data suggesting that intake of smaller quan- tities of alcohol may be linked to the occurrence of breast and colorectal cancer. Among added substances, only salt appears to be an important contributor to stomach cancer. Moreover, intake of salty fish very early in life has been linked to the occurrence of nasopharyngeal cancer in Southern Asia. Finally, in Central Asia and Southern America the intake of very hot drinks has been found to increase the risk of esophageal cancer(Kinjo et al, 1998) Many of the early efforts have been focused on identifying specific dietary components that may be responsible for effects on people's health. Evaluating the effects of specific foods and nutrients, rather than integral dietary patterns, on disease illustrates how shifting from the empirical evidence may increase uncer- tainty. Dietary exposures are unusually complex and strongly intercorrelated Current data suggest that apparently favourable effects cannot be exclusively attributed to specific components and in several instances these components may act synergistically( Gerber et al, 2000). Consequently, instead of focusing only
(Mensink and Katan, 1987). Refined carbohydrates substantially affect postprandial hyperglycemia and they appear to accentuate insulin resistance. With respect to other nutrients, there is converging, but not yet conclusive, evidence that moderate alcohol intake, vitamin E and folic acid are inversely associated with the risk of coronary heart disease (CHD) (Gaziano et al, 1993; Stampfer et al, 1993; Robinson et al, 1998). Salt intake, on the contrary, contributes to the elevation of blood pressure levels in susceptible individuals and thus to the increase of CVD risk (Beilin et al, 1999). The evidence on the role of specific dietary factors in cancer aetiology has been critically summarised in recent reviews (Willett and Trichopoulos, 1996; Willett, 2000). With respect to food groups, vegetable consumption, and perhaps less definitely fruit consumption, have a beneficial effect on a broad spectrum of human cancer types. Among macronutrients, animal protein intake has been reported to increase the risk for colorectal cancer, while intake of saturated fat is positively associated with endometrial, prostate, colorectal, lung and kidney cancer. Although the percentage of calories from dietary lipids does not appear related to colon cancer, greater risks have been seen with higher consumption of red meat, possibly suggesting that factors other than dietary lipids per se may be important. Fibre intake, on the contrary, appears to protect against cancer of the pancreas and the large bowel. There are also indications of a protective role of monounsaturated lipids against breast cancer (Trichopoulou, 1995). Concerning micronutrients the evidence is largely insufficient. Recent studies indicate an inverse association of lycopene (Gann et al, 1999), selenium (Yoshizawa et al, 1998) and vitamin E (Tzonou et al, 1999) with prostate cancer, folic acid in relation to colon and breast cancers (Giovannucci et al, 1998); while beta-carotene supplements have been found to be ineffective against lung cancer risk (Hennekens et al, 1996). Consumption of large quantities of alcoholic beverages, particularly in conjunction with tobacco smoking, has been reported to increase the risk of cancer in the upper respiratory and digestive tract, whereas alcoholic cirrhosis frequently leads to liver cancer. There are also data suggesting that intake of smaller quantities of alcohol may be linked to the occurrence of breast and colorectal cancer. Among added substances, only salt appears to be an important contributor to stomach cancer. Moreover, intake of salty fish very early in life has been linked to the occurrence of nasopharyngeal cancer in Southern Asia. Finally, in Central Asia and Southern America the intake of very hot drinks has been found to increase the risk of esophageal cancer (Kinjo et al, 1998). Many of the early efforts have been focused on identifying specific dietary components that may be responsible for effects on people’s health. Evaluating the effects of specific foods and nutrients, rather than integral dietary patterns, on disease illustrates how shifting from the empirical evidence may increase uncertainty. Dietary exposures are unusually complex and strongly intercorrelated. Current data suggest that apparently favourable effects cannot be exclusively attributed to specific components and in several instances these components may act synergistically (Gerber et al, 2000). Consequently, instead of focusing only What consumers eat 9
10 The nutrition handbook for food processors on nutrients within foods, research has expanded towards studying patterns of food intake(Trichopoulos et al, 2000) 2.3 Sources of dietary data As mentioned earlier. food data are often derived from Food Balance Sheets that provide information on food supply at the popula tion level Household Budget Surveys that collect data on food availability in the house- hold, based on nationally representative samples of households the food intake of free-living individuals, over a specified time pena specifically designed Individual Dietary Surveys that provide information on 2.3.1 Food balance sheets The food balance sheets(FBSs)assembled by the Food and Agriculture Organ isation(FAO)describe the current and developing structure of the national dietary patterns, in terms of the major food commodities that disappear from the national markets(www.fao.org).Afoodbalancesheetiscompletedatnationallevel,on he basis of the annual food production, imports and exports, changes in stock and the agricultural and industrial uses within a country. When these have been taken into account, the remaining quantities represent the food that can be assumed to have been available for human consumption in that country(Kelly et al, 1991). Since 1949, FBSs are regularly collected on a world-wide basis and, in spite of their limitations, countries with no routine information on the food consump- tion of their population and those interested in comparing their national dietary patterns with those of other populations have traditionally used them(Helsing, 1995) International comparisons based on the time series FBS data, in conjunction with information from other sources, can help to indicate trends in the food avail able to the overall population of one country in relation to others, and have thus been used for ecological correlations of food patterns with the morbidity and mor tality of nutrition-related diseases. The user of these data, however, should bear in mind their constraints and interpret comparisons with due caution(Southgate, 1991). The accuracy of recording differs considerably between countries and commodities. Although data on their own food production are collected in some countries, these sources of information can be largely under-recorded. Waste and food given to pets may also be sources of error, since they are considerably depen dent on time, cultures and type of commodities. Lastly, the conversion of food- stuffs into nutrient equivalents by the application of factors derived from various ources must be prudently treated
on nutrients within foods, research has expanded towards studying patterns of food intake (Trichopoulos et al, 2000). 2.3 Sources of dietary data As mentioned earlier, food data are often derived from: • Food Balance Sheets that provide information on food supply at the population level. • Household Budget Surveys that collect data on food availability in the household, based on nationally representative samples of households. • specifically designed Individual Dietary Surveys that provide information on the food intake of free-living individuals, over a specified time period. 2.3.1 Food balance sheets The food balance sheets (FBSs) assembled by the Food and Agriculture Organisation (FAO) describe the current and developing structure of the national dietary patterns, in terms of the major food commodities that disappear from the national markets (www.fao.org). A food balance sheet is completed at national level, on the basis of the annual food production, imports and exports, changes in stocks and the agricultural and industrial uses within a country. When these have been taken into account, the remaining quantities represent the food that can be assumed to have been available for human consumption in that country (Kelly et al, 1991). Since 1949, FBSs are regularly collected on a world-wide basis and, in spite of their limitations, countries with no routine information on the food consumption of their population and those interested in comparing their national dietary patterns with those of other populations have traditionally used them (Helsing, 1995). International comparisons based on the time series FBS data, in conjunction with information from other sources, can help to indicate trends in the food available to the overall population of one country in relation to others, and have thus been used for ecological correlations of food patterns with the morbidity and mortality of nutrition-related diseases. The user of these data, however, should bear in mind their constraints and interpret comparisons with due caution (Southgate, 1991). The accuracy of recording differs considerably between countries and commodities. Although data on their own food production are collected in some countries, these sources of information can be largely under-recorded. Waste and food given to pets may also be sources of error, since they are considerably dependent on time, cultures and type of commodities. Lastly, the conversion of foodstuffs into nutrient equivalents by the application of factors derived from various sources must be prudently treated. 10 The nutrition handbook for food processors
What consumers eat 11 2.3.2 Household budget surveys The household budget surveys(HBSs) are periodically conducted by the National Statistical Offices of most European countries in nationally representative samples of households. By recording the values and quantities of household food purchases, the HBSs can adequately depict the dietary patterns prevailing in rep resentative population samples. Moreover, the concurrent recording of demo- graphic and socio-economic characteristics of the household members may allow exploratory analyses on the evaluation of their effects on dietary choices. One of the main advantages of the multi-purpose HBSs is their periodic undertaking by Governmental Services, making them a readily available and thus an afford- able source of dietary information in developed and developing countries lou,1992) The HBSs can be thought of as occupying a position between the FBSs and the specially designed individual food consumption surveys. Like food balance sheets, the HBSs allow intercountry comparisons on a regular basis but, moving from total population to household level, they further allow the calculation of both the mean and the distribution of food availability within the population and specific subgroups(Trichopoulou et al, 1999) Issues of comparability can be raised when using HBS data for international omparisons. The data collection methodology is uniform enough to allow such comparisons, but the food information recorded in the various countries may be of different forms and levels of detail. The methodology, however, for address ing these discrepancies has been developed in the context of the DAta Food NE yorking ( DAFNE) project(Lagiou et al, 2001; Friel et al, 2001). However, since HBSs are not primarily designed to collect nutritional information, the food data bear limitations, which need to be considered when they are used for nutritional purposes(van Staveren et al, 1991; Southgate, 1991; Trichopoulou, 1992). The its should be bor In most cases, no records are collected on the type and quantity of food items ind beverages consumed outside the home Information on food losses and waste, food given to pets, meals offered to guests, use of vitamin and mineral supplements and the presence of pregnant or lactating women is not consistently collected Data are collected at household level and estimation of the individuals intake requires the application of stochastic statistical models Information on nutrient intake is not readily available. Nevertheless, appro- priate conversion factors based on food composition tables are developed for converting quantity data into nutrients Despite their limitations, the HBSs provide a resource for the conduct of a vide range of nutritional analyses. They also constitute a reasonable alternative to specially designed individual-based nutrition surveys for most Mediterranean and central/eastern European countries. HBS data could help highlight issues uch as differences in dietary patterns(Byrd-Bredbenner et al, 2000), high risk population groups on account of their nutritional habits, relationships between
2.3.2 Household budget surveys The household budget surveys (HBSs) are periodically conducted by the National Statistical Offices of most European countries in nationally representative samples of households. By recording the values and quantities of household food purchases, the HBSs can adequately depict the dietary patterns prevailing in representative population samples. Moreover, the concurrent recording of demographic and socio-economic characteristics of the household members may allow exploratory analyses on the evaluation of their effects on dietary choices. One of the main advantages of the multi-purpose HBSs is their periodic undertaking by Governmental Services, making them a readily available and thus an affordable source of dietary information in developed and developing countries (Trichopoulou, 1992). The HBSs can be thought of as occupying a position between the FBSs and the specially designed individual food consumption surveys. Like food balance sheets, the HBSs allow intercountry comparisons on a regular basis but, moving from total population to household level, they further allow the calculation of both the mean and the distribution of food availability within the population and specific subgroups (Trichopoulou et al, 1999). Issues of comparability can be raised when using HBS data for international comparisons. The data collection methodology is uniform enough to allow such comparisons, but the food information recorded in the various countries may be of different forms and levels of detail. The methodology, however, for addressing these discrepancies has been developed in the context of the DAta Food NEtworking (DAFNE) project (Lagiou et al, 2001; Friel et al, 2001). However, since HBSs are not primarily designed to collect nutritional information, the food data bear limitations, which need to be considered when they are used for nutritional purposes (van Staveren et al, 1991; Southgate, 1991; Trichopoulou, 1992). The following points should be borne in mind: • In most cases, no records are collected on the type and quantity of food items and beverages consumed outside the home. • Information on food losses and waste, food given to pets, meals offered to guests, use of vitamin and mineral supplements and the presence of pregnant or lactating women is not consistently collected. • Data are collected at household level and estimation of the individuals’ intake requires the application of stochastic statistical models. • Information on nutrient intake is not readily available. Nevertheless, appropriate conversion factors based on food composition tables are developed for converting quantity data into nutrients. Despite their limitations, the HBSs provide a resource for the conduct of a wide range of nutritional analyses. They also constitute a reasonable alternative to specially designed individual-based nutrition surveys for most Mediterranean and central/eastern European countries. HBS data could help highlight issues such as differences in dietary patterns (Byrd-Bredbenner et al, 2000), high risk population groups on account of their nutritional habits, relationships between What consumers eat 11
12 The nutrition handbook for food processors diet and morbidity/mortality data Lagiou et al, 1999)and dietary intakes of addi tives and contaminants 2.3.3 Individual dietary surveys The specially designed individual dietary surveys (IDSs) primarily aim at the col- lection of information on the food intake of free-living individuals over a speci fied period. The individual surveys, when intakes of the subject are recorded as dequately as possible, are expected to provide evidence on the food quantities consumed and to allow the calculation of both the mean and the distribution of food and nutrient intake among the whole or segments of the population The methods used to assess individual intake can be broadly divided into two generic categories(Willett, 1998): Recall methods of sporadic or habitual diet. They can be limited to the pre vious 24 hours(24-hour dietary recall), where subjects are asked to recall everything they consumed the previous day, or to a diet history referring to a broader and less precisely defined time period using food frequency methods Record methods of daily intake, where subjects are required to keep records of everything they eat and drink for one(24-hour food record) or more days The 7-day weighed record is the one commonly used The quantification of foods consumed and the selection of items to be included in the food list, in the case of closed lists, are critical components of data col lection. standard. natural and household units three-dimensional food model photographs, drawings of foods and geometric shapes are often used for docu henting portion sIzes. Recall methods, in comparison to the record ones, do not require literacy; they re not expected to cause alterations in the eating behaviour of the subject, since the information is collected after the fact; and they have minimal respondent burden. Nevertheless, recall methods are subject to respondents'memory, a limi- tation not present in food records. In recent surveys, dietary recalls are collected using computer software programmes that allow data to be uniformly collected by prompting interviewers to ask all the necessary questions, and may further reduce the cost of data collection and processing. The food records and the 24-hour recall may be used to estimate the absolute intake of energy, macronutrients and some vitamins and minerals that are com- monly found in the food supply. Both methods are frequently used in describing the mean intake of aggregated food groups and in validating food frequency ques tionnaires. These short-term methods are completely open ended, they accom- modate any food or food combination reported by the subject and they allow recording information at various levels of detail including the type of food, the food source, the food processing and preparation methods. They are therefore particularly useful for estimating intakes of culturally diverse populations. One gle day of intake, however, is highly unlikely to be representative of usual
diet and morbidity/mortality data (Lagiou et al, 1999) and dietary intakes of additives and contaminants. 2.3.3 Individual dietary surveys The specially designed individual dietary surveys (IDSs) primarily aim at the collection of information on the food intake of free-living individuals over a speci- fied period. The individual surveys, when intakes of the subject are recorded as adequately as possible, are expected to provide evidence on the food quantities consumed and to allow the calculation of both the mean and the distribution of food and nutrient intake among the whole or segments of the population. The methods used to assess individual intake can be broadly divided into two generic categories (Willett, 1998): • Recall methods of sporadic or habitual diet. They can be limited to the previous 24 hours (24-hour dietary recall), where subjects are asked to recall everything they consumed the previous day, or to a diet history referring to a broader and less precisely defined time period using food frequency methods. • Record methods of daily intake, where subjects are required to keep records of everything they eat and drink for one (24-hour food record) or more days. The 7-day weighed record is the one commonly used. The quantification of foods consumed and the selection of items to be included in the food list, in the case of closed lists, are critical components of data collection. Standard, natural and household units, three-dimensional food models, photographs, drawings of foods and geometric shapes are often used for documenting portion sizes. Recall methods, in comparison to the record ones, do not require literacy; they are not expected to cause alterations in the eating behaviour of the subject, since the information is collected after the fact; and they have minimal respondent burden. Nevertheless, recall methods are subject to respondents’ memory, a limitation not present in food records. In recent surveys, dietary recalls are collected using computer software programmes that allow data to be uniformly collected, by prompting interviewers to ask all the necessary questions, and may further reduce the cost of data collection and processing. The food records and the 24-hour recall may be used to estimate the absolute intake of energy, macronutrients and some vitamins and minerals that are commonly found in the food supply. Both methods are frequently used in describing the mean intake of aggregated food groups and in validating food frequency questionnaires. These short-term methods are completely open ended, they accommodate any food or food combination reported by the subject and they allow recording information at various levels of detail including the type of food, the food source, the food processing and preparation methods. They are therefore particularly useful for estimating intakes of culturally diverse populations. One single day of intake, however, is highly unlikely to be representative of usual 12 The nutrition handbook for food processors
What consumers eat 13 intake. For this reason the collection of multiple days of intake is required in rder to estimate as adequately as possible the subjects' usual intake Food frequency questionnaires are food lists of differing length and the infor- mation collected can refer either to the frequency of consuming certain foods and beverages, or to both the frequency and estimates of the portions consumed. The underlying principle of the food frequency method is that the average long-term diet reflects the conceptually important exposure, and therefore makes the food frequency questionnaires the method of choice for measuring dietary exposures in epidemiological studies. In constructing a food frequency questionnaire. careful attention must be given to the format of the food frequency section, the selection of foods that will be included in the food list and the clarity of the ques tions. Food frequency questionnaires can be administered to large population groups; they can be applied as interviews or in a self-administered form and are relatively easy and less time consuming to complete when compared to other dietary assessment methods. It should, however, be borne in mind that food fre- quency questionnaires including a restricted food list may result in reducing the true variance of intake For most investigations of nutritional epidemiology, the relative ranking of individuals according to their food and nutrient intakes is adequate for deter mining correlations of relative risks. In such cases, food frequency questionnaires constitute the primarily selected dietary assessment method. In situations however, when the aim is to compare the nutrient intakes of various population or to evaluate compliance with dietary recommendations, estimates of the absolute energy and macronutrient intakes may be required In such instances, records or 24-hour recalls are generally the methods of choice(Willett, 1998) 2.4 Dietary data in Europe: national surveys A number of European countries have carried out national dietary surveys. Table 2.1 summarises basic information on the various ldss that have been undertaken in 20 European countries during the last 20 years. The surveys are often designed to document the dietary patterns of the genera population or segments of it and possibly to identify groups at nutritional risk. In other instances, the primary aim is to address country-specific objectives. The selection of the dietary survey method depends on a number of different factors and investigators may frequently have to compromise according to the specific objectives of the survey and the inherent cost of setting it up When the option of running international comparisons using these data is raised, a number of methodological constraints emerge. It can directly be noted that a variety of dietary assessment methods are used, making it difficult to accomplish comparability at the international level ( Friedenreich, 1994). The dif- ferences in the data collection methodology are reflected in the type and accu racy of the data collected. Some dietary surveys, usually those conducted with food frequency questionnaires, collect data on the intake of particular food
intake. For this reason the collection of multiple days of intake is required in order to estimate as adequately as possible the subjects’ usual intake. Food frequency questionnaires are food lists of differing length and the information collected can refer either to the frequency of consuming certain foods and beverages, or to both the frequency and estimates of the portions consumed. The underlying principle of the food frequency method is that the average long-term diet reflects the conceptually important exposure, and therefore makes the food frequency questionnaires the method of choice for measuring dietary exposures in epidemiological studies. In constructing a food frequency questionnaire, careful attention must be given to the format of the food frequency section, the selection of foods that will be included in the food list and the clarity of the questions. Food frequency questionnaires can be administered to large population groups; they can be applied as interviews or in a self-administered form and are relatively easy and less time consuming to complete when compared to other dietary assessment methods. It should, however, be borne in mind that food frequency questionnaires including a restricted food list may result in reducing the true variance of intake. For most investigations of nutritional epidemiology, the relative ranking of individuals according to their food and nutrient intakes is adequate for determining correlations of relative risks. In such cases, food frequency questionnaires constitute the primarily selected dietary assessment method. In situations, however, when the aim is to compare the nutrient intakes of various populations or to evaluate compliance with dietary recommendations, estimates of the absolute energy and macronutrient intakes may be required. In such instances, records or 24-hour recalls are generally the methods of choice (Willett, 1998). 2.4 Dietary data in Europe: national surveys A number of European countries have carried out national dietary surveys. Table 2.1 summarises basic information on the various IDSs that have been undertaken in 20 European countries during the last 20 years. The surveys are often designed to document the dietary patterns of the general population or segments of it and possibly to identify groups at nutritional risk. In other instances, the primary aim is to address country-specific objectives. The selection of the dietary survey method depends on a number of different factors and investigators may frequently have to compromise according to the specific objectives of the survey and the inherent cost of setting it up. When the option of running international comparisons using these data is raised, a number of methodological constraints emerge. It can directly be noted that a variety of dietary assessment methods are used, making it difficult to accomplish comparability at the international level (Friedenreich, 1994). The differences in the data collection methodology are reflected in the type and accuracy of the data collected. Some dietary surveys, usually those conducted with food frequency questionnaires, collect data on the intake of particular foods, What consumers eat 13
Table 2.1 Specially designed dietary surveys undertaken in the general population of 20 European countries during the last 20 years. Sample size Survey Population Dietary Countr Name of the survey Years of data collection (number of assessment individuals) Gender Age(yrs) Austrian Study on 1991-1994 2173 F+M 6-18 7 day record Nutritional Status 1993-1997 2065 F+M19-65 (ASNS diet history 1995,1998 F+m elde 7 day record Belgium Belgian Interuniversity 1980-1985 10971 F+M I day recor Research on Nutrition and health ( BIRNH Croati Croatian Study on 1997-1998 348 F+M12-14 recall and Schoolchildren’s Nutrition Dietary Habits in Denmark 303 F+M 15-80 diet history National Dietary Survey 1995 F+M 1-80 7 day record National Continuous 2000-2002 1500( F+M 4-75 7 day record Dietary Survey Finland Dietary Survey of Finnish 1992 186 25-64 3 day record 1997 25-64 24 hour recall (FINDIET National Food diet history Consumption Survey 993-1994 7 day record (ASPCC) 1993-1994 7 day record Individual National Food 1998-1999 7 day record Consumption Surveys 1985 F+M15+ (INCA
14 The nutrition handbook for food processors Table 2.1 Specially designed dietary surveys undertaken in the general population of 20 European countries during the last 20 years. Sample size Survey Population Dietary Country Name of the survey Years of data collection (number of Gender Age (yrs) assessment individuals) method Austria Austrian Study on 1991–1994 2 173 F + M 6–18 7 day record Nutritional Status 1993–1997 2 065 F + M 19–65 24 hour recall, (ASNS) diet history 1995, 1998 78 F + M Elderly 7 day record Belgium Belgian Interuniversity 1980–1985 10 971 F + M 25–74 1 day record Research on Nutrition and Health (BIRNH) Croatia Croatian Study on 1997–1998 348 F + M 12–14 24 hour recall and Schoolchildren’s food frequency Nutrition questionnaire Denmark Dietary Habits in Denmark 1985 2 242 F + M 15–80 diet history National Dietary Survey 1995 3 098 F + M 1–80 7 day record National Continuous 2000–2002 1 500 (2000) F + M 4–75 7 day record Dietary Survey Finland Dietary Survey of Finnish 1992 1 861 F + M 25–64 3 day record Adults 1997 2 862 F + M 25–64 24 hour recall (FINDIET) 290 F + M 65–74 France National Food 1985–1995 1 778 F + M 18–62 diet history Consumption Survey 1993–1994 1 229 F + M 18+ 7 day record (ASPCC) 1993–1994 1 500 F + M 2–85 7 day record Individual National Food 1998–1999 1 018 F + M 3–14 7 day record Consumption Surveys 1 985 F + M 15+ (INCA)
Table 2.1 Continued Sample size Survey Population Dietary Name of the survey Years of data collection (number of individuals) Gender Age(yrs) method Germany National Nutrition Survey 1985-1989 24632 F+M 4-70+ in former West germany National Health Survey in 1991-1992 1897 F+ former East Germany German Nutrition Survey 199 4030 F+M 18-79 First hungarian 1985-1988 16641 +M15-60+ Two 24 hour recalls Representative Nutrition and food frequency Hungarian Randomised 1992-1994 F+M1860+ Three 24 hour recalls and food frequency Iceland Icelandic National 1990 1240 F+M15-80 diet history Ireland Irish National Nutrition 1990 1214 F+M 8-18 North-South food 1998 1379 F+M18-64 7 day record Italy INN-CA 1994-1996 3600 F+M0-94 7 day record Lithuania Baltic Nutrition and Health 1997 2183 20-65 24 hour recall and food frequency Netherlands Dutch National Food 1987-1988 5898 F+M 1-79 2 day record 1992 6218 F+M 192 2 day record 1997-1998 6250 F+M1-97 2 day record Norway National Dietary Survey 1993-1994 31 F+M food frequency NORKOST 1997 F+M food frequency National Dietary Survey 1993 1705 F+M food frequency 1564 18 1999 2400 F+M 6 and 12 food frequency month 1999 2010 F+M
What consumers eat 15 Germany National Nutrition Survey 1985–1989 24 632 F + M 4–70 + 7 day record in former West Germany National Health Survey in 1991–1992 1 897 F + M 18–79 diet history former East Germany German Nutrition Survey 1998 4 030 F + M 18–79 diet history Hungary First Hungarian 1985–1988 16 641 F + M 15–60 + Two 24 hour recalls Representative Nutrition and food frequency Survey questionnaire Hungarian Randomised 1992–1994 2 559 F + M 18–60 + Three 24 hour recalls Nutrition Survey and food frequency questionnaire Iceland Icelandic National 1990 1 240 F + M 15–80 diet history Nutrition Survey Ireland Irish National Nutrition 1990 1 214 F + M 8–18 + diet history Survey North-South Food 1998 1 379 F + M 18–64 7 day record Consumption Survey Italy INN-CA 1994–1996 3 600 F + M 0–94 7 day record Lithuania Baltic Nutrition and Health 1997 2 183 F + M 20–65 24 hour recall and Survey food frequency questionnaire Netherlands Dutch National Food 1987–1988 5 898 F + M 1–79 2 day record Consumption Survey 1992 6 218 F + M 1–92 2 day record 1997–1998 6 250 F + M 1–97 2 day record Norway National Dietary Survey 1993–1994 3 144 F + M 16–79 food frequency among Adults questionnaire (NORKOST) 1997 2 672 F + M 16–79 food frequency questionnaire National Dietary Survey 1993 1 705 F + M 13 food frequency 1 564 18 questionnaire 1999 2 400 F + M 6 and 12 food frequency months questionnaire 1999 2 010 F + M 2 food frequency questionnaire Table 2.1 Continued Sample size Survey Population Dietary Country Name of the survey Years of data collection (number of Gender Age (yrs) assessment individuals) method