COMPARISON OF 2 DIETARY METHODS - 24-HOUR RECALL AND SEMIQUANTITATIVEFOOD FREQUENCY QUESTIONNAIRE

BACKGROUND: Methods of dietary collection at an individual level inclu de various procedures with different estimates of food, energy and nut rients intakes. The aim of this study was to compare two dietary metho ds widely used in nutritional epidemiology: a 24-hour recall and a sem iquantitative food frequency questionnaire. METHODS: One hundred and f ifty five people selected at random from the population of the Valle d e Aran (Lerida, Spain) were surveyed. Nutritional intake information w as obtained from both methods. RESULTS: The frequency method overestim ated all the nutrient intakes only before adjustment by energy intake, except for cholesterol. After adjustment by energy intake estimations from both questionnaires were very similar; the percentages of energy supplied by proteins, fatty acids and carbohydrates were very similar , too; the polyunsaturated/monounsaturated fatty acid ratios, were alm ost the same. Results show a level of correlation between the question naires that ranger from 0.81 to 0.23. Nutrients that showed the highes t crude correlation between both questionnaires were alcohol, energy, carbohydrates, sodium and iodine (R greater than or equal to 0.7) whil e vitamins C, B-1, B-6, B-12, and A, niacine, folic acid, iron, phosph orus and potassium showed the lowest (R less than or equal to 0.5). En ergy adjusted correlations were quite different to unadjusted ones par ticularly for lipids, monounsaturated fatty acids, carbohydates, fiber , cholesterol, zinc and sodium, for which a lower coefficient was calc ulated after adjustment, and vitamins B-2, B-6, C, D and potassium, fo r which a higher coefficient was estimated after energy adjustment. CO NCLUSIONS: Both methods make similar assessments when adjusting for ca loric intake, but food frequency questionnaire tends to overestimate f ood consumption.