DIETARY TRENDS - ESTIMATES FROM FOOD-SUPPLY AND SURVEY DATA

Objective: To illustrate methodological issues involved in estimating dietary trends in populations using data obtained from various sources in Australia in the 1980s and 1990s. Methods: Estimates of absolute a nd relative change in consumption of selected food items were calculat ed using national data published annually on the national food supply for 1982-83 to 1992-93 and responses to food frequency questions in tw o population based risk factor surveys in 1983 and 1994 in the Hunter Region of New South Wales, Australia. The validity of estimated food q uantities obtained from these inexpensive sources at the beginning of the period was assessed by comparison with data from a national dietar y survey conducted in 1983 using 24 h recall. Results: Trend estimates from the food supply data and risk factor survey data were in good ag reement for increases in consumption of fresh fruit, vegetables and br eakfast food and decreases in butter, margarine, sugar and alcohol. Es timates for trends in milk, eggs and bread consumption, however, were inconsistent. Conclusions: Both data sources can be used for monitorin g progress towards national nutrition goals based on selected food ite ms provided that some limitations are recognized. While data collectio n methods should be consistent over time they also need to allow for c hanges in the food supply (for example the introduction of new varieti es such as low-fat dairy products). From time to time the trends deriv ed from these inexpensive data sources should be compared with data de rived from more detailed and quantitative estimates of dietary intake.