Folate is an important B vitamin in the daily diet. It is not known to what extent naturally occurring folates in the mixed diet is bioavailable. Knowledge on to what extent the natural folates are absorbed would be best studied in a population that is not exposed to any folate fortificant. The aim of the present study was to study the bioavailability of dietary 5-methyl tetrahydrofolate (5-MTHF) in a whole day??s mixed diet relative to supplemental 5-MTHF in a selected Indian population. A dietary survey (n=200) conducted in South India, revealed a mean total intake of folate of 277+ 92.3 μg/day (which is nearly 3 times higher than the current Indian Recommended Dietary Intake set to 100 μg/day) based on the actual analysis of foods collected from a typical diet using a trienzyme technique followed by the microbiological assay. Further, the individual folate forms present in the foods were also analysed using a newly developed Liquid Chromatography Tandem Mass Spectrometry LC-MS/MS). Quantification of folates was performed using internal standards. Good linearity was observed between 2-100 ng/Injection (Injection volume-100 μL, R2: 0.98) that was suitable for analysis of foods (cereal, pulse, vegetables, milk based preparations and fruit) and blood samples (serum folate and erythrocyte folate) for use in bioavailability study. The folate intakes were reported to be higher (429+ 68.7 μg/day) when the individual foods from the diet were analysed using the LC-MS/MS technique when compared to the values generated using microbiological assay. LC-MS/MS analysis revealed that the Indian diets were predominant in 5-MTHF and the important sources being cereals, pulses and vegetables. 22 human volunteers, aged 18-25 years were recruited in India to study the bioavailability of 5-MTHF. A randomized trial (12 weeks) was designed, where the subjects consumed 400 g 5-MTHF/day in the form of as supplemental drink or an experimental diet (400 g/day) consisting predominantly 5-MTHF (90%). Relative bioavailability of 5-MTHF was calculated by comparing the responses to food folate in relation to supplemental 5-MTHF, as indicated by the biomarkers. The relative bioavailability of food folate predominant in 5-MTHF was 41% based on serum folate indicator and 47% based on erythrocyte folate status. A mean increase of 60% was observed in the erythrocyte folate levels of the subjects consuming diets predominant in 5-MTHF in 12 weeks. Diets predominant in 5-MTHF have a good potential in improving the folate status of the population.
| Identifer | oai:union.ndltd.org:ADTP/257651 |
| Date | January 2008 |
| Creators | Vishnumohan, Shyamala, Chemical Sciences & Engineering, Faculty of Engineering, UNSW |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | http://unsworks.unsw.edu.au/copyright, http://unsworks.unsw.edu.au/copyright |
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