| 1. |
- Büttner, Barbara E, et al.
(författare)
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Effect of type of heat treatment of breastmilk on folate content and pattern.
- 2014
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Ingår i: Breastfeeding Medicine. - : Mary Ann Liebert Inc. - 1556-8253 .- 1556-8342. ; 9:2, s. 86-91
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Breastmilk is the recommended aliment for preterm infants. Milk banks provide donated breastmilk for the neonatal care of preterm infants when mother's own milk is not is available. To avoid pathogen transmission, donated breastmilk is heat-treated according to different procedures before administration. There is varying information on the effect of heat treatment on folate in breastmilk. Sufficient folate intake, however, is essential for normal growth and brain development. This study determined and compared the effects of different heat treatments on breastmilk folate content and pattern of individual folate forms.MATERIALS AND METHODS: Donated Swedish breastmilk samples were heat-treated according to three procedures: two low temperature treatments (57°C, 23 minutes; 62.5°C, 12 minutes) and a rapid high temperature treatment (heating to 73°C in boiling water). The folate content and pattern were determined before and after treatment by high-performance liquid chromatography.RESULTS: The folate content in 38 untreated Swedish breastmilk samples was 150±46 nmol/L. Two different folate vitamers were detected: 5-methyltetrahydrofolate (78±7%) and tetrahydrofolate (22±7%). Heat treatment affected only tetrahydrofolate stability and decreased folate content by 15-24%; however, the effects on folate content did not differ among the investigated heat treatment procedures.CONCLUSIONS: Folate losses during heat treatment of human milk were considered acceptable. Yet, native folate content of heat-treated, non-fortified breastmilk supplied only 25% of the recommended daily intake for preterm infants.
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| 2. |
- Büttner, Barbara E, et al.
(författare)
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Quantification of isotope-labeled and unlabeled folates and folate catabolites in urine samples by stable isotope dilution assay.
- 2013
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Ingår i: International Journal for Vitamin and Nutrition Research. - : Hogrefe Publishing Group. - 0300-9831 .- 1664-2821. ; 83:2, s. 112-121
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Tidskriftsartikel (refereegranskat)abstract
- Dual-label stable isotope dilution assays for the simultaneous quantification of isotopologic folates in clinical samples offer the perspective for differentiating between unlabeled folates from endogenous body pools and administered [13C5]-labeled folates from a test dose when performing bioavailability trials. In contrast to intact folates, this methodology could hitherto not be applied to the quantification of the folate catabolites, p-aminobenzoyl glutamate and p-acetamidobenzoyl glutamate. In this study, [2H4]-p-aminobenzoyl glutamate, [2H4]-p-acetamidobenzoyl glutamate, and unlabeled p-acetamidobenzoyl glutamate were synthesized. The synthesis of the [2H4]-labeled compounds started at unlabeled p-aminobenzoic acid. For the formation of p-acetamidobenzoyl glutamate, p-aminobenzoyl glutamate was acetylated. The new substances were applied successfully in stable isotope dilution assays for the simultaneous quantification of the [13C5]-labeled and unlabeled folate catabolites, p-aminobenzoyl glutamate and p-acetamidobenzoyl glutamate, along with the predominant folate vitamers in urine. The assays were based on clean-up by strong anion exchange followed by liquid chromatography-tandem mass spectrometry detection. Assay sensitivity was sufficient to detect the folate catabolites in physiologic concentrations. The limit of detection was below 0.4 and 0.3 nmol/100 g for p-aminobenzoyl glutamate isotopologues and p-acetamidobenzoyl glutamate isotopologues in urine, respectively. The successful synthesis of [2H4]-p-aminobenzoyl glutamate, [2H4]-p-acetamidobenzoyl glutamate, and unlabeled p-acetamidobenzoyl glutamate and the implementation of these substances in stable isotope dilution assays allows dual-label designs that provide a more detailed insight into human folate metabolism.
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| 3. |
- Büttner, Barbara E, et al.
(författare)
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Quantification of isotope-labelled and unlabelled folates in plasma, ileostomy and food samples.
- 2011
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 399:1, s. 429-439
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Tidskriftsartikel (refereegranskat)abstract
- New stable isotope dilution assays were developed for the simultaneous quantitation of [(13)C(5)]-labelled and unlabelled 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid, folic acid along with unlabelled tetrahydrofolic acid and 10-formylfolic acid in clinical samples deriving from human bioavailability studies, i.e. plasma, ileostomy samples, and food. The methods were based on clean-up by strong anion exchange followed by LC-MS/MS detection. Deuterated analogues of the folates were applied as the internal standards in the stable isotope dilution assays. Assay sensitivity was sufficient to detect all relevant folates in the respective samples as their limits of detection were below 0.62 nmol/L in plasma and below 0.73 μg/100 g in food or ileostomy samples. Quantification of the [(13)C(5)]-label in clinical samples offers the possibility to differentiate between folate from endogenous body pools and the administered dose when executing bioavailability trials.
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| 4. |
- Öhrvik, Veronica, et al.
(författare)
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Folate bioavailability from breads and a meal assessed with a human stable-isotope area under the curve and ileostomy model.
- 2010
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 92:3, s. 532-538
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Recent data revealed differences in human absorption kinetics and metabolism between food folates and folic acid supplements and fortificant.OBJECTIVE: The objective was to determine folate bioavailability after ingestion of breads or a breakfast meal fortified with either 5-CH(3)-H(4) folate or folic acid by using a stable-isotope area under the curve (AUC) and ileostomy model.DESIGN: In a randomized crossover trial, healthy ileostomists (n = 8) ingested single doses of whole-meal bread that contained ap 450 nmol (200 micro g) of either (6S)-[(13)C(5)]5-CH(3)-H(4) folate or [(13)C(5)]folic acid or a breakfast meal that contained ap 450 nmol (200 micro g) [(13)C(5)]folic acid. We collected blood from the subjects during 12 h postdose for assessment of plasma kinetics. Nonabsorbed folate was assessed from labeled folate contents in stomal effluent 12 and 24 h postdose.RESULTS: The median (range) plasma AUC(0 rarr 12) (AUC from 0 to 12 h after ingested dose) of 66 nmol sdot h/L (34-84 nmol sdot h/L) after ingestion of bread that contained (6S)-[(13)C(5)]5-CH(3)-H(4) folate was significantly greater (P lt 0.001) than that after ingestion of [(13)C(5)]folic acid in fortified bread [28 nmol sdot h/L (15-38 nmol sdot h/L)] and a fortified breakfast meal [26 nmol sdot h/L (15-60 nmol sdot h/L)]. Both labeled doses resulted in increases of plasma [(13)C(5)]5-CH(3)-H(4) folate. However, the kinetic variables C(max) (maximum plasma concentration) and T(max) [time (min) of maximum plasma concentration] varied after ingestion of the different folate forms. The stomal folate content was lt 10% of the ingested dose and did not vary significantly after ingestion of test foods that contained (6S)-[(13)C(5)]5-CH(3)-H(4) folate [median (range): 13 nmol (10-31 nmol)] or [(13)C(5)]folic acid [median (range): 25 nmol (8-42 nmol)] (P = 0.33).CONCLUSIONS: Our data confirm differences in plasma absorption kinetics for reduced folates and synthetic folic acid administered with the test foods. Stomal folate contents indicated almost complete bioavailability of labeled folate from the breads or breakfast meal.
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