Correlation between estimated food intake and energy expenditure measured trough the doubly labeled water method in independent older persons

Abstract

Increased incidence of non-transmissible chronic diseases is correlated with dietary pattern in the elderly population. Thereafter, research on dietary patterns is essential to prevent and treat these diseases. There are no standard methods to assess diet in elderly, and underreport of food intake has been described by many authors. Semi-quantitative food intake frequency questionnaires have not been studied in the elderly population. History questionnaire has been considered the best assessment in the literature, but, frequently, it is correlated to inaccurate energy intake report. The implementation of biomarkers to assess real intake allows the evaluation of the accuracy of food intake questionnaires. This project is aimed to compare the estimation of food intake in healthy elderly through a semi-quantitative frequency questionnaire and history questionnaire and to correlate reported energy intake with total energy expenditure assessed through the doubly labeled water technique. In the same way, nitrogen balance, assessed through the measurement of nitrogen excretion, will be analyzed to assess adequacy of protein ingestion reports. 100 voluntaries will be studied, with age ranging from 60 to 70 years old. History and semi-quantitative frequency questionnaire will be applied. Anthropometric (weight, height, body mass index) and body composition assessment through bioimpedance will be performed. In the second stage of the project, 40 subjects will be selected, representing the four quartiles of body fat mass percentage. Resting energy expenditure will be measured through indirect calorimetry and total energy expenditure will be measured through the doubly labeled water technique, according to Schoeller and colleagues. Urine will be collected to quantify nitrogen balance. The intention of this study is to determine which methods of dietary intake assessment are more accurate in the elderly population. Also, total energy expenditure of the elderly Brazilian population has not, so far, been investigated through accurate methods as the doubly labeled water. This research will provide essential tools for future studies of food intake in the Brazilian older population. (AU)