FAO Food Balance Sheets: Overview of Methodology, Uses in Health Research, and an Analysis of NZ Data

Abstract

Food Balance Sheets (FBSs) constructed by the Food and Agricultural Organization (FAO) illustrate the food supply and utilization pattern of a country over time, and are the only source of standardized food supply data available for multiple countries over many years. However, there are questions about the details of the FBS methodology, their use in health research, and the reliability of the data. Thus, the aim of this research was to describe in detail the FAOFBSs methodology and its uses in health research, and undertake analysis of New Zealand FBS data to describe national food and nutrient availability between 1961 and 2011. Methods The research was divided into three parts as follows: - A comprehensive appraisal of available published and online information on FBS methodology, components, and data sources. This was supplemented by direct requests for further information from FAO representatives. In addition, sources of data for New Zealand’s FBSs were specifically examined. - A systematic review of published literature to identify common uses of FBS in health research. - Analysis of per capita trends in New Zealand food and nutrient availability over time for six major food groups, energy, protein and fat. Findings - Data collected for FBSs comprise three main categories: supply (total food supply of a country), utilization (food available to consumers) and per capita supply (food available per person). The FAO sends questionnaires to relevant organizations within participating countries to complete every year. FAO-FBSs balance raw data using formulas, extraction rates or food composition factors to obtain all values of food commodities in FBS, and then undertake standardization. The final FBSs are made available on the FAO website. - 119 eligible studies (all study designs) were included in the systematic literature review and divided into five categories of FBS data use: within-country analysis of food groups, nutrient availability and/or dietary trends (n=17), inter-country, regional or global comparison of food groups, nutrient availability and/or dietary trends (n=45), comparison of FBSs with other national sources of dietary data (n=7), association between FBS dietary factors and mortality or health outcomes (n=45) and modelling studies (n=5) - Key recommendations based on the findings of the literature review were: FBS data should be averaged over several years, caution should be exercised regarding the quality of FBS data because the published values depend on the reliability of input data, and results of analyses using FBS data should ideally be reported as nutrient densities (e.g. expressed per 1000kcal), trends, and percentage energy or ratios rather than absolute values. - Statistics New Zealand is the major source of data for the New Zealand FBS. Over the past 50 years, increases in per capita supply were seen for vegetables and fruits: 600g/day (1961-63) to 800g/day (2009-11); wine and other alcoholic beverages: 0.5g alcohol/day (1961-63) to 2.4 and 2g alcohol/day (2009-11); poultry: 8g/day (1960s) to around 100g/day (2011); sugar: 127.3g/day (1961-63) to 138g/day (2009-11), and vegetable fats and oils: 2g/day (1960s) to 21.5g/day (2009-11). Decreases in per capita supply were seen for milk: 500g/day (1961-63) to 300g/day (2009-11) and butter: 50g/day (1961-63) to 27g/day 92009-11). Per capita supply of energy was stable between 12000-14000kJ/day (1961-2011). Conclusions FBSs are a valuable source of population-level dietary data for national and international epidemiological studies when reported and analysed appropriately. Regarding NZ diet, although significant improvements for certain food groups were seen, the increase in availability of sugar and the stable energy trend is worrying to the continued increase in the obesity rates.