Can an increase in dietary fibre improve the folate status of women?

Despite accumulating evidence linking suboptimal folate status with increased risk of neural tube defects (NTD), North American women are not consuming the recommended amount (400 ug) of folate. It has been recognized that large quantities of folate are produced by intestinal bacteria, and more recently others have shown that bacterially synthesized folate can be absorbed. Given that dietary fibre stimulates microbial growth, the purpose of this study was to assess whether an increase in fibre (as nonstarch polysaccharides), improves the folate status of women. Two-hundred and twenty-four female adolescents (14-19 yrs) were recruited via advertisements in local newspapers, schools and community groups. Threeday weighed dietary records revealed a median (Q1, Q3) fibre intake of 11.6 (8.1, 16.3} g/day with intakes ranging from 2.7 to 40.8 g/day. Median (Q1, Q3) dietary folate intake was 192.1 (137.9, 269.2) ug/day, reflecting a range of intakes from 36 to 458 ug/day. Biochemical assessment of folate status resulted in median (Q1, Q3) serum folate and serum homocysteine concentrations of 11.3 (3.4, 16.1) nmol/L and 5.7 (4.7, 6.7) nmol/ml, respectively. Analysis of covariance revealed that fibre had a significant impact on serum folate concentrations (p-0.012). Furthermore, each 1 gram increase of dietary fibre was associated with a 1% increase in serum folate concentrations. In conclusion, an increase in dietary fibre may provide an additional strategy to increasing the folate nutrition of women. (Supported by NSERC).