Development of a food frequency questionnaire in Koreans.

We describe the development of a data-based food frequency questionnaire (FFQ) to determine the relationship between dietary intakes and diseases among Koreans. A total of 224 individuals were recruited to participate in a three-day dietary record survey. In all, 596 food items were consumed. The intakes of 20 nutrients including energy, protein, fat, carbohydrate, vitamins, minerals, and crude fibre were calculated for each food item by multiplying the weight of food consumed by its nutrient content. Some foods, consumed less than five times in a total of three days, were deleted from the preliminary food item list. The number of foods accounting for up to 90 cumulative percentage contribution to nutrient intake was 314. One hundred and seventy seven foods that accounted for up to 0.90 cumulative multiple regression coefficients and 90 cumulative percentage contribution were then selected. By grouping foods, 94 food items were finally included in the questionnaire: Grains and their products (15 food items), potatoes and starch (4), seeds (1), soybean, soybean products and other beans (4), vegetables (22), mushrooms (2), fruits (13), meats (7), eggs (1), fish (7), shellfish (4), other fish (2), seaweed (2), milk and dairy products (4), and beverages (6). Intake frequencies were classified into eight categories. Portion size was determined from food consumption reports in the three-day records. The mean percentage coverage of the 20 nutrient intakes by the developed FFQ was 82.4%. This questionnaire may be useful for ranking diet-related risk factors in Koreans.