Within-and between-individual variation in energy and macronutrients intake by elderly women in Mexico

Inter and intraindividual intake variance is a factor in evaluating the nutritional risk of individual subjects and in the assessment of nutritional risk in prospective studies. Several studies have shown that inter and intraindividual variance depends on the population studied. However, in Mexico there are no reported data of inter and intraindividual variance in different high risk population groups. The purpose of the present study was to determine the inter and intraindividual variance in retired non-institutionalized teachers over 60 years of age in the city of Tijuana, BC, Mexico. Four-day dietary records were conducted on 38 women between 60 and 94 years of age. All the participants were trained to weigh and register their food before and after each meal. Two working days and two weekend days were randomly selected and included for each participant. The dietary registry was then checked by one researcher and each subject to complete or adjust for any misunderstanding. There were 152 days recorded, by Nutritionist IV software program, with the addition of different foods and meal combinations from other composition tables, or estimating equivalent foods according to their nutritional content. Inter and intraindividual variation coefficients were calculated for energy and nutrient content (protein, carbohydrate, fat, cholesterol and fiber). The calculation of the estimated number of days required to provide a true mean consumption for calories, carbohydrate, fat, protein, cholesterol and dietary fiber was also conducted. The intraindividual coefficient variation was found to be 26.9 for energy, 30.5 for carbohydrate, 39.4 protein, 43.3 fat, 49.0 fiber, and 62.0 for cholesterol. This study suggests that the number of dietary days needed to estimate the mean intakes at the 95% confidence level, within 30% of the true mean intake, is 3 days for energy, 4 days for carbohydrate, 7 for protein, 8 for fat, 10 for fiber, and 16 days for cholesterol.