| 1. |
- Maunder, Peter, et al.
(författare)
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The synthesis of folic acid, multiply labelled with stable isotopes, for bio-availability studies in human nutrition
- 1999
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Ingår i: Journal of the Chemical Society-Perkin Transactions 1. - : Royal Society of Chemistry (RSC). - 0300-922X .- 1364-5463. ; :10, s. 1311-1323
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Tidskriftsartikel (refereegranskat)abstract
- Two different methods for the synthesis of folic acid, which are suitable for the incorporation of compounds multiply labelled with stable isotopes, are described. The first method is based on the use of a novel reductive amination to link 2-acetylamino-4-hydroxy-6-formylpteridine with p-aminobenzoyl-L-glutamic acid. The second method is based on the penultimate formation of an amide bond between N-2-acetyl-N-10-trifluoroacetylpteroic acid and dimethyl L-glutamate. Both methods have been used to transform [C-13(6)]aniline into folic acid, labelled with [C-13(6)] in the p-aminobenzoate moiety, and [3,3,4,4-H-2(4)]-L-glutamic acid into folic acid, labelled with [H-2(4)] in the glutamate moiety. Doubly labelled [C-13(6), H-2(4)]-p-aminobenzoyl-L-glutamate has also been prepared by the former method.
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| 2. |
- Bouckaert, Kimberley P, et al.
(författare)
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Critical evaluation of folate data in European and international databases : recommendations for standardization in international nutritional studies.
- 2011
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Ingår i: Molecular Nutrition & Food Research. - : Wiley. - 1613-4125 .- 1613-4133. ; 55:1, s. 166-180
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Tidskriftsartikel (refereegranskat)abstract
- SCOPE: The objective was to perform an inventory and critical evaluation of folate data in selected European and international databases. The ultimate aim was to establish guidelines for compiling standardized folate databases for international nutritional studies.METHODS AND RESULTS: An ad hoc questionnaire was prepared to critically compare and evaluate folate data completeness, quantification, terminologies, and documentation of 18 European and international databases, and national fortification regulations. Selected countries participated in the European Prospective Investigation into Nutrition and Cancer project and European Food Information Resource Network (EuroFIR). Folate completeness was generally high. "Total folate" was the most common terminology and microbiological assay was the most frequently reported quantification method. There is a lack of comparability within and between databases due to a lack of value documentation, the use of generic or non-appropriate terminologies, folate value conversions, and/or lack of identification of synthetic folic acid.CONCLUSION: Full value documentation and the use of EuroFIR component identifiers and/or INFOODS tagnames for total folate ("FOL") and synthetic folic acid ("FOLAC"), with the additional use of individual folates, will increase comparability between databases. For now, the standardized microbiological assay for total folate and HPLC for synthetic folic acid are the recommended quantification methods.
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| 3. |
- Finglas, Paul M, et al.
(författare)
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Use of an oral/intravenous dual-label stable-isotope protocol to determine folic acid bioavailability from fortified cereal grain foods in women.
- 2002
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Ingår i: Journal of Nutrition. - 0022-3166 .- 1541-6100. ; 132:5
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Tidskriftsartikel (refereegranskat)abstract
- Folic acid fortification, mandatory in the United States, is currently being considered by the UK. The hypothesis that the matrix of some cereal-product vehicles may result in low fortificant bioavailability was tested using a dual oral/intravenous (i.v.) isotopic-label approach, which was evaluated concurrently. Fifteen women received 225 microg oral folate (capsules, fortified white bread and fortified branflakes), mainly as folic acid labeled with (13)C on 6 carbons of the benzoyl ring ((13)C(6)-PteGlu), followed by i.v. injection of 100 microg folic acid labeled with (2)H on 4 hydrogens of the glutamic acid group ((2)H(4)-PteGlu). The urinary excretion ratio (UER) in intact folate of the percentage of labeled oral dose excreted divided by the percentage of i.v. dose excreted was used as the primary index of absorption. The geometric mean (95% confidence interval) UER for folic acid capsules was 3.68 (1.90, 7.14) at 24 h and 2.18 (1.24, 3.83) at 48 h. Because these were significantly in excess of 1.0, indicative of 100% absorption of the oral dose, it was concluded that oral and i.v. labeled folic acid are handled differently by the body and that "absolute" absorption cannot be calculated. Compared with the 48-h UER for folic acid capsules, the "relative" 48-h UER for white bread and branflakes was 0.71 and 0.37, respectively, indicating that some cereal-based vehicles may inhibit absorption of fortificant. However, even the validity of this "relative" approach is questioned.
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| 4. |
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| 5. |
- Nicolas, Geneviève, et al.
(författare)
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Compilation of a standardised international folate database for EPIC.
- 2016
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 193, s. 134-140
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the methodology applied for compiling an "international end-user" folate database. This work benefits from the unique dataset offered by the European Prospective Investigation into Cancer and Nutrition (EPIC) (N=520,000 subjects in 23 centres). Compilation was done in four steps: (1) identify folate-free foods then find folate values for (2) folate-rich foods common across EPIC countries, (3) the remaining "common" foods, and (4) "country-specific" foods. Compiled folate values were concurrently standardised in terms of unit, mode of expression and chemical analysis, using information in national food composition tables (FCT). 43-70% total folate values were documented as measured by microbiological assay. Foods reported in EPIC were either matched directly to FCT foods, treated as recipes or weighted averages. This work has produced the first standardised folate dataset in Europe, which was used to calculate folate intakes in EPIC; a prerequisite to study the relation between folate intake and diseases.
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