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Bile Salt Enhancement of Riboflavin and Flavin Mononucleotide Absorption in Man

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The gastrointestinal absorption of riboflavin and flavin mononucleo- tide (FMN) was determined under control conditions and after oral administration of 600 mg sodium deoxycholate. When the bile salt is given prior to a 30-mg dose of riboflavin there is a 50 to 80% increase in total urinary recovery of apparent ribo flavin. A similar, but less marked, enhancement is observed when the same dose of FMN is given with sodium deoxycholate. Urinary excretion data also suggest an unusually prolonged absorption of riboflavin in the presence of the bile salt. The possibility exists that the bile salt enhancement of riboflavin and FMN absorption may be due to changes in gastrointestinal motility or changes in the permeability of the gastrointestinal membranes to the transport of the vitamins, or both. Other possibilities are also explored.
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... Contrary to earlier studies suggesting that riboflavin was absorbed by processes involving simple diffusion, recent studies have identified the presence of specialized saturable transporters, not only for riboflavin but also for each of the other B vitamins. Coupled with these site-specific transporters, the absorption of riboflavin is generally enhanced in the presence of food owing to a combination of variations in gastric and intestinal motility, bile salt secretion (Jusko et al. 1971;Mayersohn et al. 1969), and changes in splanchnic blood flow. Thus, factors that (a) permit more prolonged contact of dietary riboflavin with the apical surface of the intestinal mucosal cell, (b) increase its solubility within the unstirred water layer, and (c) enhance its translocation and removal from the enterocyte would be expected to increase overall intestinal absorption of riboflavin. ...
... However, total intake recoveries for genistein differed significantly by repeated measures ANOVA ( Table 1). Recoveries of riboflavin in this study are consistent with prior reports [17][18][19][20][21]. The excretion patterns of daidzein and genistein shown in Fig. (1B, C) are consistent with findings from our previous studies [15]. ...
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Historical OverviewChemistryDietary Sources and BioavailabilityAbsorption, Transport and MetabolismBiochemical FunctionsVitamin B2 DeficiencyNutritional AspectsFurther ReadingReferences
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