Serum homocysteine and folate concentrations among a US cohort of adolescents before and after folic acid fortification.

OBJECTIVE: We assessed serum homocysteine (tHcy) and folate concentrations among US adolescents before and after fortification of cereal-grain products with folic acid, and associations with demographic, behavioural and physiological factors. DESIGN: Observational study conducted among participants of a randomized trial. SETTING: The Child and Adolescent Trial for Cardiovascular Health (CATCH) study. SUBJECTS: Adolescents (n 2445) in grades 8 (pre-fortification, mean age 14 years) and 12 (post-fortification, mean age 18 years). RESULTS: Average serum concentrations of tHcy, folate and vitamin B6 increased by 17 %, 16 % and 14 %, respectively, while serum concentrations of vitamin B12 decreased by 11 % post-fortification. Folic acid fortification provided, on average, an additional intake of 118 µg folate/d. Male sex (P < 0.0001) and white race (P = 0.0008) were associated with significantly greater increases in tHcy concentration, while increases in BMI (P = 0.006) and serum folate concentration (P < 0.0001) were associated with significant decreases in tHcy concentration. Female sex (P < 0.0001), non-smoking (P < 0.0001), use of multivitamins (P < 0.0001) and higher dietary intake of folate (P = 0.001) were associated with significantly greater increases in serum folate concentrations. From grade 8 to grade 12, the upward age trend in serum tHcy concentration was uninterrupted in its course (P > 0.50); whereas serum folic acid concentration showed a downward trend that incurred a discrete jump upward (17 % higher; P < 0.0001) with fortification. These trends differed significantly for males v. females (P < 0.001 for interaction). CONCLUSIONS: Fortification had a significant impact on improving folate status but not serum tHcy concentrations among US adolescents.

Serum homocysteine is related to food intake in adolescents: the Child and Adolescent Trial for Cardiovascular Health.

BACKGROUND: An understanding of the relation in adolescents between serum homocysteine and foods rich in vitamin B-6, vitamin B-12, and folate is important because high homocysteine concentrations in childhood and adolescence may be a risk factor for later cardiovascular disease. However, little is known about the relation between food intake and homocysteine in adolescents. OBJECTIVE: Five years after national folic acid fortification of enriched grain products, cross-sectional relations between food intake and serum homocysteine concentrations were examined in 2695 adolescents [x age: 18.3 (range: 15-20) y] enrolled in the Child and Adolescent Trial for Cardiovascular Health. DESIGN: A nonfasting blood specimen was analyzed for serum homocysteine, folate, and vitamins B-6 and B-12. Dietary intake was assessed by using a food-frequency questionnaire. Multiple regression analyses were used to evaluate the relation of intakes of whole grains, refined grains, fruit, vegetables, dairy products, red and processed meats, and poultry with serum homocysteine concentrations after adjustment for demographic characteristics, lifestyle factors, and food intake. RESULTS: Serum homocysteine concentrations were lower with greater intakes of whole grains (P for trend = 0.002), refined grains (P for trend = 0.02), and dairy foods (P for trend <0.001); were higher with greater intake of poultry (P for trend = 0.004); and were not related to intakes of fruit, vegetables, or red or processed meat. After additional adjustment for serum B vitamins, the relations of serum homocysteine with most food groups were attenuated. CONCLUSION: These observational findings suggest a beneficial effect of whole-grain, refined-grain, and dairy products on serum homocysteine concentrations in an adolescent population.

Do trends in physical activity, sedentary, and dietary behaviors support trends in obesity prevalence in 2 border regions in Texas?

OBJECTIVE: The aim of the study was to compare the change in energy balance-related behaviors from 2000-2002 to 2004-2005 between 2 Texas regions with distinct patterns in obesity prevalence (decrease in the El Paso region [EP] and leveling off in the Rio Grande Valley region [RGV]) and to determine the role of the behaviors in the difference in obesity prevalence between the regions. DESIGN: Cross-sectional measurements of the School Physical Activity and Nutrition Study. SETTING: Elementary schools. PARTICIPANTS: 3,949 children (9-10 years). VARIABLES MEASURED: Body mass index (objectively measured) and behaviors (self-assessed). ANALYSIS: Probability and post-stratification weighting procedures and mediation analysis. RESULTS: Compared to students in the RGV, students in the EP experienced a smaller decrease in sports team participation, an increase in regular meal consumption, and an increase in the frequency of milk/yogurt, cereal, sweet snacks, and frozen dessert consumption between measurement periods. Prevalence of frequent television viewing was lower in the EP. The lower body mass index in the EP was associated with regular meal consumption, and higher milk/yogurt and sweet snack consumption. CONCLUSIONS AND IMPLICATIONS: Improvement of physical activity, sedentary behaviors, and healthful diet, but not unhealthful diet like sweet snack consumption, seem to be related to the decrease in obesity in the EP.