Research in Medicine

Background : Under-reporting of energy intake is a common problem among nutrition-related epidemiological studies. The aim of the present study was to determine the effect of under-reporting of energy intake on the estimate of nutrient intake.

 Materials and methods : 901 subjects aged >16 years were enrolled. Food intake was assessed using a 24-hour food recall questionnaire. Basal metabolic rate was determined according to the age, sex, and weight. Then, the ratio of energy intake to basal metabolic rate (EI/BMR) was calculated. The ratio of <1.35 was considered as under-reporting and the ratio of 1.35-2.39 within the normal limit. To adjust the effect of Results : Under-reporting was revealed in 31% of the subjects, and was more common among females, (40% females vs. 19% males, p<0.01). The mean age of females who under-reported was significantly lower than the normal-reporting females (32±13 vs. 35±14 years, p<0.05) however, the age difference between the two groups was not significant in men. The absolute intake of macro and micronutrients, (except B2 in females and B6 and zinc in both sexes), was lower in under-reporting subjects however, following adjustment there was no significant difference between the two sexes.

Conclusion : Results have revealed that under-reporting affects the estimate of nutrient intake, thus, in studies aiming to find the association between a chronic disease and a nutrient, we suggest adjustment for energy intake in under-reporters.