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XNN001 Measures of dietary exposure in groups

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  • Information on the food supply in a country, the proportion of that food that is available for use by the population, their access to food and actual food intakes is critical to a national food and nutrition monitoring system and to underpin public health policies.Four critical areas for data collection for monitoring system are:Food supply – availability of foodstuffs and the composition of Australian foodsFood purchasing/ acquisition – expenditure on food, types of food purchased, prices and quantities bought, food securityFood and physical activity behaviours – detailed information on food and nutrient intakes and measures of physical activityNutritional status – biochemical measuresAustralia does not currently have such a formal system in place; difficult to address following questions: Is the food supply adequate and accessible to all? Is the composition of food changing? How much food are we eating? Are food habits changing? How? What are current nutrient intakes? Who takes food supplements? How does this change nutrient intakes? Have physical activity patterns changed? Will these changes increase or decrease the risk of diet-related disease? Are these risks different for different groups?
  • informs governments, the Codex Alimentarius Commission and other relevant institutions, as well as the public, on levels and trends of contaminants in food, their contribution to total human exposure, and significance with regard to public health and tradObvious differences between clusters - (example in next slide)
  • What if we want to compare the foods available for consumption between countries?Comparison between countries can be derived from food balance sheets, however a more comprehensive set of diets has been compiled by WHO.GEMS/Food – Estimates regional dietary patterns of raw and semi-processed food commodities Compares diets across 13 regions (FAO food balance sheets for 1997 – 2001 for 183 countries)Twenty key foods investigated.Groups of countries based on consumption create ‘clusters’. Obvious differences between cluster.GEMS/Foods provide information regarding broad trends over time and differences between regions. However, in order to assess differences in amounts of food consumed and nutrient content within a country, records of actual food consumption are required.
  • Cluster M (Aus, NZ, USA, Canada, Argentina, Chile, Uruguay) - high consumption of meat & cereal based products Clusters G & L (Asia-Pacific) - higher in cereal foods, nuts & oil seeds & seafood but lower in animal products such as meat, milk & animal fats than M
  • To compare trends in ‘apparent’ food consumption over time: Still an estimate as not measuring actual intake at the household levelApparent Consumption Data Derived by ABS in way similar to food balance sheets, however reporting is not limited to primary produce Not used for all food products e.g. if there was a better way of deriving consumption or for foods for which all components of the equation were not available (some milk products, beer, eggs, wine, cheese etc)Gives overall trends & correlationsData is useful in nutrition planningLong term data minimizes daily & seasonal variationsLarge sample populations increase validity of conclusionsNo placebo effectNo participant error
  • Very crude estimates with many limitations and errorspossibility of significant unreported trade across national boundaries
  • ABS Household Expenditure Survey – food available not actual food consumed nor nutrients consumedHousehold food expenditureability to get data on volumes purchased increases participant burdenallows for analysis of trends over timecomparisons of expenditure patterns b/n households from different areas, households with different composition & households with different levels of income
  • How do we investigate food intakes over time?
  • Proxy interviews for 24 hr recall for 2-4y.o.; 5-11y.o. own data with assistance10% did 2nd 24 hr recallsee text Table 10.3 & p161-162can see food changes + then nutrient changes
  • NUTTAB is the electronic version of the ‘Composition of Foods, Australia’ seriesKey point to note – data on Australian fruits and vegetables over 20 years oldMost data comes from analysed samples, however some data are sourced from overseas food com tables, supplied by food industry, taken from labels or calculated using a recipe approach. Provide best information currently possible, however figures should be considered representative rather than absolute values as basic foods show considerable variation in nutrient composition.Values may also vary depending on – methods of analysis, food sampling procedures, forms in which food is analysed and data reporting methods.
  • RDIs are derived from estimates of the physiological requirements of population sub-groups, specified by age, gender and physiological state. With the exception of energy the amounts are greater than the average physiological requirements for each group and include allowances for differences in the absorption and metabolism of nutrients between individuals of the same age, gender and physiological state.
  • Open link – show students where nutrient reference values are. Let them know that they need to use this for their food analysis assignment!
  • Will need to ask Kell what this slide is for.EAR - Daily nutrient level estimated to meet the requirement of half the healthy individuals in a life stage/gender group (ie median value)RDI - Average daily dietary level sufficient to meet the nutrient requirements of NEARLY ALL (97-98%) healthy individuals in a life stage & gender groupAI - Average daily intake based on observed or experimentally-determined approximations or estimates of nutrient intake by a group of apparently healthy people that are assumed to be adequateUL - Highest level of continuing daily nutrient intake likely to pose no adverse health effects in almost all individuals
  • Transcript

    • 1. XNN001
    • 2.  Four critical areas for data collection include  Currently no formal monitoring system in place in Australia Food supply Food purchasing and acquisition Food and physical activity behaviours Nutritional status
    • 3.  To calculate „available food for consumption‟ – Food balance sheets  Information on amounts of food (raw commodities) available for consumption per year Food available for use = production + imports – exports Food available for consumption = production + imports – exports – industrial use – animal use  Important – food available for consumption does NOT tell us how much food is actually eaten! Food supply Food purchasing and acquisition Food and physical activity behaviours Nutritional status Food supply
    • 4.  Global Environment Monitoring System - Food Contamination Monitoring and Assessment Programme (GEMS/Food)  WHO Initiative  Assesses & monitors food contaminants, their contribution to human exposure, & significance for public health and trade  WHO 13 cluster diets, that have been created to cover average food consumption in 13 regions  Twenty Key Foods Investigated  Groups of countries based on consumption create „clusters‟.
    • 5.  Cluster M (Aus, NZ, USA, Canada, Argentina, Chile, Uruguay)  Clusters G & L (Asia-Pacific)
    • 6.  To compare food trends within Australia Apparent food consumption data Apparent consumption = (commercial production + estimated home production + imports + opening stocks) (exports + usage for processed foods + non- food usage + wastage + closing stocks) MINUS
    • 7.  food balance sheets ◦ food available, not food consumed ◦ national average, not individual/sub-group specific  apparent consumption data ◦ not used for all foods  Overall – no ongoing, regular and comprehensive system for monitoring food supply and food availability
    • 8.  Very crude estimates with many limitations and errors  Possibility of significant unreported trade across national boundaries  In UK FBS estimates 30-35% higher than those from household budget surveys ie seems to overestimate intake 10
    • 9.  Retail food sales- provide information on: ◦ type of foods purchased ◦ amount purchased ◦ population level consumption ◦ not measuring actual consumption of individuals
    • 10.  Household food expenditure ◦ budget surveys ◦ provides data on amount of money/proportion of income spent on food by different kinds of households ◦ provides weighting figures for CPI (Consumer Price Index) ◦ not measuring foods or nutrients
    • 11.  Food prices  Provide information on: ◦ Trends in the relative affordability of various food items over time  accessibility ◦ The Consumer Price Index ◦ May not be relevant to rural or low-income households  Household surveys  Provide information on: ◦ Expenditure esp. food ◦ Relative quantities of different types of foods purchased by different kinds of households ◦ BUT NOT FOR nutrition monitoring purposes (although it could & relate it to income, geographic location, composition)
    • 12. Reliable trends in food intake over time can only be established from data collected using the same survey design & food intake methodology. Can achieve this via the aid of national dietary surveys (of intakes)– to provide information on average intake of population 1995 National Nutrition Survey National Health Survey
    • 13.  NNS 1995 ◦ 13,858 Australians > 2 years of age ◦ Conducted using 24hr recalls in the home  This method allowed a large number of people to be included  The decision was made to use this method to allow comparison with other studies (1983 & 1986 NNS) ◦ Most recent National Nutrition Survey for which data available  NNPAS 2011 – 2012 ◦ ABS ◦ 24-hour recalls, similar methodology ◦ First real opprotuniy for comparison
    • 14.  Provide information on: ◦ Likely impact of changes to food regulation ◦ Levels of additives & contaminants in the food supply ◦ Need for, & impact of, fortification of foods
    • 15.  Used to: ◦ Convert information about food intake to nutrient intake  Contain: ◦ Nutrient data that is an average of nutrients in a particular sample of foods & ingredients, determined at a particular time  Need to: ◦ Be current ◦ Match the food supply NOTE: The nutrient composition of foods & ingredients can vary substantially over different batches, & between brands because of a number of factors including: • Changes in season • Processing practices • Ingredient source
    • 16. http://www.foodstandards.gov.au/consumerinformation/n uttab2010/  Contains data for approx 2600 foods available in Australia and up to 245 nutrients (online and electronic versions)  Includes separate files for vitamin D, amino acids, indigenous foods and trans fats  Uses: ◦ A guide to the nutrient content of Australian foods for nutrition research and to assist consumers to make healthy food choices ◦ An education tool for schools and universities
    • 17.  Limitations: ◦ Food supply changes quickly ◦ Biological variation of foods ◦ Single values representing range ◦ Incomplete data – missing foods & nutrients ◦ Bioavailability not considered ◦ Potential measurement & data entry error ◦ Relate to food supply of that country
    • 18.  „RDI‟s‟  1991 – 2006  Now replaced with the Nutrient Reference Values (NRVs)
    • 19. 1991-2006 “The levels of essential nutrients considered, in the judgement of the NHMRC, on the basis of scientific knowledge to be adequate to meet the known nutritional needs of practically all healthy people.” i.e. they apply to group, not individual, needs
    • 20.  RDIs were often misused to assess dietary adequacy of individuals & even foods  To overcome this, many countries have now moved to a system of reference values which retains the concept of the RDI but also attempts to identify the average requirements needed by individuals
    • 21.  „Nutrient Reference Values for Australia & New Zealand Including Recommended Dietary Intakes  Released in 2006 by NHMRC http://www.nhmrc.gov.au/PUBLICATIONS/syno pses/n35syn.htm
    • 22.  Retain the concept of the RDI ◦ Provide more complete information for decision making about nutritional status of individuals and groups  Outline the levels of intake of essential nutrients considered to be adequate to meet the known nutritional needs of practically all healthy people for prevention of deficiency states.  The document can be used by health professionals to assess the likelihood of inadequate intake in individuals or groups of people.
    • 23.  There are different NRV values for different nutrients: Nutrient Reference Values EAR Estimat ed Averag e Require ment AI Adequa te Intake RDI Recom mende d Dietary Intake UL Upper Limit of Intake EER Estimat ed Energy Require ment SDT Sugges ted Dietary Target AMDR Accepta ble Macronu trient Distribu tion Range
    • 24.  Developed using reference (standard) body weights for different age groups  Estimated Energy Requirements (EERs) include physical activity level (PAL) consideration but refer to standardized weight for age  Adults well above and below the reference standard will have slightly different nutrient requirements (use RDI)
    • 25. Macronutrients, water & fibre • Protein • Dietary Fat • Carbohydrate • Dietary Fibre • Total water Vitamins • Thiamin • Riboflavin • Niacin • Vitamin B6 • Vitamin B12 • Folate • Pantothenic acid • Biotin • Choline • Vitamin A • Vitamin C • Vitamin D • Vitamin E • Vitamin K Minerals • Calcium • Phosphorus • Zinc • Iron • Magnesium • Iodine • Selenium • Molybdenum • Copper • Chromium • Manganese • Fluoride • Sodium • Potassium
    • 26.  Daily nutrient level estimated to meet the requirement of half the healthy individuals in a life stage/gender group (i.e. median value)  Uses: Individuals: use to examine the probability that usual intake is inadequate Groups: use to estimate the prevalence of inadequate intakes within a group
    • 27.  Average daily dietary level sufficient to meet the nutrient requirements of NEARLY ALL (97-98%) healthy individuals in a life stage & gender group  Uses: Individuals: usual intake at or above this level has a low probability of inadequacy Groups: DO NOT USE TO ASSESS GROUPS
    • 28.  Average daily intake based on observed or experimentally-determined approximations or estimates of nutrient intake by a group of apparently healthy people that are assumed to be adequate  Used when an RDI can not be determined  Uses: Individuals: can be used as a goal for individual intake but use with caution if nutrient level is based on median intakes of healthy populations Groups: if mean intake is at or above this level, a low prevalence of inadequacy is likely
    • 29.  Highest level of continuing daily nutrient intake likely to pose no adverse health effects in almost all individuals  Uses: Individuals: usual intake above this level may place an individual at risk of adverse effects from excessive nutrient intake Groups: use to estimate the % of the population at potential risk of adverse effects from excessive nutrient intake
    • 30. NRV Individuals Groups EAR Use to determine probability usual intake is inadequate Use to estimate prevalence of inadequate intakes within group RDI Usual intake at or above this level has a low probability of inadequacy DO NOT USE TO ASSESS INTAKES OF GROUPS AI Usual intake at or above has a low probability of inadequacy. When AI is based on median intakes of healthy population, interpret with caution. Mean usual intake at or above this level implies a low prevalence of inadequate intake. When AI is based on median intakes of healthy population, interpret with caution. UL Usual intake above this level may place individual at risk of adverse effects from excessive intake Use to estimate % of population at potential risk of adverse effects from excessive nutrient intake
    • 31. EAR RDI UL AI Riskofexcess EAR estimated average requirement, AI adequate intake, RDI recommended dietary intake, UL upper limit
    • 32.  SDTs – Suggested Dietary Targets  AMDRS – Acceptable Macronutrient Distribution Ranges
    • 33.  Applicable to adolescents over 14 years and adults  A daily average intake from food and beverages for certain nutrients that may help in prevention of chronic disease  For most nutrients, the recommendation is based on the 90th centile of current population intake
    • 34. Cover: ◦ Vitamin A, C, E ◦ Selenium ◦ Folate ◦ Sodium/potassium ◦ Dietary fibre ◦ Long chain omega 3 fats (DHA:EPA:DPA)
    • 35.  Estimate of the range of intake for each macronutrient for individuals which would allow for an adequate intake of all the other nutrients whilst maximising general health outcomes  Expressed as % energy  Applicable to adolescents over 14 years and adults
    • 36.  Protein ◦ 15-25% of energy intake ◦ 10% required to cover physiological needs but not Fe, Mg etc  Fat ◦ 20-35% of energy intake ◦ <10% of energy intake from saturated and trans fat ◦ 4-5 – 10% energy from omega 6 (linoleic acid) ◦ 0.4-0.5 – 1% energy from omega 3 (alpha-linolenic acid)  Carbohydrate ◦ 45-65% of energy intake ◦ Predominately from low energy density, low GI foods
    • 37.  Recommendations: % of total energy ◦ Carbohydrate 45 – 65 ◦ Protein 15 – 25 ◦ Fat 20 – 35%  saturated fat ≤10  mono-unsaturated fat ≥10
    • 38.  Recommendations (‘guidelines’) which encourage healthy lifestyles that will minimise the risk of the development of diet related diseases within the Australian population  Highlight the groups of foods and lifestyle patterns that promote good nutrition and health  Available in ‘Eat for Health’ publication
    • 39.  Focus on: ◦ Contribution of core foods & major sources of energy (fat, starch & sugar) to the overall diet  Provide: ◦ A practical way of informing consumers about food choices that are consistent with current dietary recommendations ◦ Separate guidelines for adults and children & adolescents
    • 40.  Outlines how many serves a person should have of each food group based on their: ◦ age ◦ gender ◦ body size (to a degree) ◦ activity level (to a degree)  Provides examples of what a serve is.
    • 41.  Summarise current nutrition knowledge  Trigger more comprehensive education programs  Represent best consensus of scientific knowledge  For use by healthy adults  Apply to whole diet not to individual foods  Guidelines are meant to be complementary not separate items  Not appropriate for cross cultural issues or unusual habits
    • 42.  Possible limitations: ◦ Has a large breads & cereals section which, if consumed as refined grains, may be detrimental to health &/or weight ◦ Does not give varying recommendations for varying energy needs & physical activity levels ◦ Does not address food sustainability and security or account for impact of rising food prices
    • 43.  Plate/pie shaped rather than a pyramid  Based on 5 food groups  bread, cereal, rice, pasta, noodles  vegetables, legumes  Fruit  milk, yoghurt, cheese  meat, fish, poultry, eggs, nuts, legumes  Each section represents proportions of that food group eaten in 1 day – not 1 meal
    • 44. Water – key messages  8 glasses or 2L of water every day  More required when physically active & in hot weather  All fluids, other than alcohol, contribute Extra foods – key messages  Choose these sometimes or in small amounts  Not essential to provide nutrients the body needs  Guide allows them to be considered in the context of selecting a healthy eating pattern