Vitamin intake and status in a group of subjects from the Gubbio area Italy.

beta-Carotene, retinol, niacin, riboflavin, thiamin intake and blood nutritional status beta-carotene, retinol, and alpha-tocopherol) were investigated in a group of 79 subjects (35 males and 44 females) of 30 years and over, living in three rural hamlets in the Gubbio area (Central Italy) to see if there were any differences in nutrient intake using different methods of dietary assessment and if there was a relationship between vitamin intake and status. Vitamin intakes were assessed by three different methods: dietary history, two-day weighed record and two-day duplicate-portion chemical analysis. Vitamin content of duplicate diets was assessed by semiautomated HPLC methods. Plasma vitamin status was assessed by semi-automated isocratic straight-phase HPLC methods. The three methods of dietary assessment were compared using the Student's paired t-test and Wilcoxon-Mann-Whitney test. Between the two days weighed record and diet history, significant differences were observed for beta-carotene and thiamin. Between the two-day weighed record and chemical analysis, significantly differences were found for beta-carotene, riboflavin and thiamin. Between diet history and chemical analysis, significant differences were obtained for beta-carotene, riboflavin and thiamin. The t-test analysis showed different results according to sex and age. Plasma vitamin status using the current cut-off criteria showed some deficiencies for beta-carotene. As on other occasions no correlation was observed between data from diet history, weighed record and chemical analysis of duplicate portions and the corresponding blood vitamin levels for the whole group of subjects.