OBJECTIVE: Quantitative assessment of nutrient intake requires knowing how much of the nutrient is needed for the normal functions of the individual and his or her habitual intake. Nutrient requirements vary between individuals; the assumed coefficient of variation is 10 to 15%. Individual intake is subject to variation of daily intake, which is known as intrapersonal variability. Currently, information on intrapersonal variation in the literature refers to the American population. This study has two objectives: 1) determine the intrapersonal standard deviation of nutrient intake for the Brazilian population that can be used for calculating the adequacy of nutrient intake; and 2) offer theoretical values that support decision making in clinical practice regarding the adequacy of nutrient intake selected by an individual, based on standard deviations and with three levels of reliability. METHODS: Data from teenagers, adults and elderly individuals who participated in the population-based health survey done in the city of São Paulo were used. These individuals (n=865) answered a 24-hour recall, replicated in a subsample of 294 individuals. These data were used for calculating the standard deviation using random effects models. RESULTS: The estimated coefficients varied from 40% for zinc to 127% for vitamin C. CONCLUSION: The standard deviations can be used for the assessment of quantitative intake adequacies of vitamin E, pyridoxine, thiamin, riboflavin, calcium, magnesium, iron, zinc, folate and niacin. Hence, one more element for nutritional status diagnosis is made available for clinical assessment.
Nutrition assessment; Eating; Nutritional requirements; Nutrients
