Folate, vitamin B6 and B12: the relationship between serum homocysteine concentration and dietary intake and status of vitamins among adolescents of Indaiatuba, São Paulo.

Author(s)

Josiane Steluti

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Saúde Pública (FSP/CIR)
• Defense date: 2010-08-24

Examining board members

Dirce Maria Lobo Marchioni; Vania D'Almeida; Ligia Araujo Martini

• Advisor: Dirce Maria Lobo Marchioni

Abstract

Introduction: Folate and the metabolically related B vitamins are intimately connected with metabolic pathways of homocysteine (hcy). Epidemiologic studies have shown that increased total homocysteine concentration is an independent predictor for a number of human diseases, especially, cardiovascular diseases. Objective: to investigate the dietary intake and status of folate, related B-vitamin, and the relationship to total homocysteine concentration among adolescents. Methods: A cross-sectional study was conducted among adolescents, both genders, aged 16 to 19 years, in a public school of Indaiatuba, São Paulo. Dietary intake was measured using three-day dietary record. The energy and nutrients were computed using Nutrition Data System for Research software. The usual intake and prevalence of inadequate by EAR cut-point method were estimated using PC-SIDE, version 1.0. Biochemical analyses were determined according the methods recommended by the scientific literature. All statistical analyses were performed using STATA, version 10.0. A two-tailed p value <0.05 was considered significant. Results: The study was conducted among 99 adolescents, 58 (58.6%) were girls, mean age of 17.6 (SD 0.9) years old. The means of folate, B6 and B12 vitamins status were of 9.2 (SD 3.4) ng/ml, 18.7 (SD 5.1) nmol/L and 397.5 (SD 188.4) pg/ml, respectively. The proportion of adolescents with folate, B6 and B12 intakes above the recommendation was 15.2%, 10.2%, e <1%, respectively. The foods that more contributed for folate intake were French bread (23.1%), pasta (9.7%) and beans (8.2%). For B6 intake rice (9.9%), chicken (5.7%) and meat (4.2%). For B12 intake, meat without fat (16.4%) whole milk (15%) and meat with fat (12.3%). The mean of hcy was 15.4 (SD 10.2) µmol/L in boys and 8.2 (SD 2.2) µmol/L in girls. In boys, 25% of them showed values of serum hcy concentration upper to 15 µmol/L and, means of folate and vitamin B12 decreased according of serum hcy tercil (p<0.005). Conclusions: The prevalence of inadequate intake of folate, vitamin B6 and B12 were low, possibly due to improved access and availability of food, including processed foods that contain the fortified flour with folic acid as ingredient. However, the beans, a component of the Brazilians usual dietary pattern, are founded as important contributors of folate intake. The total homocysteine levels were higher in boys when compared with girls. In boys, folate and vitamin B12 status were decreased significantly with trend among different tercile serum homocysteine concentration. (AU)

• FAPESP's process: 08/02102-7 - Folate, B6 e B12 vitamins: dietary intake, blood levels and the relationship with serum homocysteine concentration in adolescents of Indaiatuba, São Paulo, Brazil
• Grantee: Josiane Steluti
• Support Opportunities: Scholarships in Brazil - Master