title: Studies on the bioavailability of the provitamin A carotenoid, beta-carotene, using human exfoliated colonic epithelial cells.
abstract: The possibility of using exfoliated colonic epithelial cells for assessing the bioavailability of beta-carotene was examined. Analysis of exfoliated colonic epithelial cells showed the presence of beta-carotene and vitamin A. The beta-carotene content was significantly lower in cells from stool samples of subjects on a beta-carotene-poor diet than those receiving a single dose of a beta-carotene supplement. Colonic epithelial cells isolated from stool samples collected daily during a wash-out period while the subjects were on a beta-carotene-poor diet showed a steady decrease in beta-carotene content, reaching the lowest value on day 7. Kinetic analysis showed that a single dose of a beta-carotene supplement in the form of spirulina (Spirulina platensis) or agathi (Sesbania grandiflora) after the wash-out period caused an increase in the beta-carotene content after a lag period of 5-7 d, but the vitamin A levels during these periods were not significantly affected. Analysis of plasma beta-carotene concentration also showed similar changes, which correlated with those of exfoliated colonic cells. A relationship between the beta-carotene content of the diet and that of the colonic epithelial cells suggests that analysis of the beta-carotene content in exfoliated human colonic epithelial cells is a useful non-invasive method to assess the bioavailability of provitamin A beta-carotene.
authors.affiliation: Department of Biochemistry, University of Kerala, Trivandrum, India 695 581.
authors.forename: T
authors.initials: T
authors.lastname: Gireesh
authors.forename: P P
authors.initials: PP
authors.lastname: Nair
authors.forename: P R
authors.initials: PR
authors.lastname: Sudhakaran
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000493:pharmacokinetics*; D001067:Appetite Depressants / Q000008:administration & dosage; D001426:Bacterial Proteins / Q000008:administration & dosage; D001682:Biological Availability; D002478:Cells, Cultured; D003106:Colon / Q000378:metabolism*; D004032:Diet; D019587:Dietary Supplements; D004847:Epithelial Cells / Q000378:metabolism*; D005243:Feces / Q000737:chemistry; D006801:Humans; D014975:Lutein / Q000032:analysis; D010758:Phosphorus / Q000008:administration & dosage*; D053545:Spirulina; D014801:Vitamin A / Q000032:analysis; D019207:beta Carotene / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*
chemical_list: D000975:Antioxidants; D001067:Appetite Depressants; D001426:Bacterial Proteins; D019207:beta Carotene; D014801:Vitamin A; D010758:Phosphorus; D014975:Lutein