Evaluation of the significance of dietary folate from wild vegetables in Vietnam.

Data on the overall dietary folate intakes among high-risk groups in poor countries is very limited. Vegetables are considered good sources but the evaluation of their contribution is hampered by the lack of data on folate concentrations in many traditional foods. Data on the analysis of folate concentrations in 16 wild vegetables used in the Mekong Delta and the Central Highlands in Vietnam and an evaluation of the relative importance of different foods in folate intakes of women is presented. Vegetable samples were collected in four study villages, blanched and frozen samples were transported to Sweden for analysis. Freeze-dried samples were analysed for total folate quantification using a commercial radio protein binding assay. Daily folate intakes among women were estimated from 7-day food frequency interviews with 213 women. The folate concentration in the vegetable samples ranged from 10 to 96 microg/100 g. The mean estimated daily folate intake among the 213 women in the study areas was 251 microg. Vegetables contributed approximately one-third of the daily folate intake, of which 72% and 42%, respectively, in the two regions was from wild vegetables. A majority of the women (87%) got some dietary folate from wild vegetables and nearly one-third had mean daily folate intakes of > 50 microg from such hidden food sources. The evaluation of dietary folate is complicated by data gaps in food composition tables, the unreliability of existing food data, variations between methods used for folate analysis and limited understanding of the bioavailability of food folate.