Vitamin B-6 status indicators decrease in women consuming a diet high in pyridoxine glucoside.
Previous research has shown that the pyridoxine glucoside (PNG) form of vitamin B-6 has a reduced bioavailability compared with pyridoxine, but its effect on vitamin B-6 status has not been assessed. Following an 8-d adjustment period, nine women consumed diets containing a high or low amount of PNG for 18 d each, in a crossover design. The high and low PNG diets provided 1.52 mg/d (8.98 micromol/d) and 1.44 mg/d (8.57 micromol/d) of vitamin B-6, of which 27% and 9% was PNG, respectively. The dietary vitamin B-6 to protein ratio of both diets was 0.017 mg/g. Urinary excretions of 4-pyridoxic acid and total vitamin B-6 were significantly lower (P < 0.05) during the high PNG diet period than when the low PNG diet was consumed. Urinary PNG excretion was equal to about 9% of the total PNG intake during both periods. Plasma total vitamin B-6 (P < 0.01) and red blood cell pyridoxal 5'-phosphate (PLP) (P < 0.05) were significantly lower when the high PNG diet was consumed than during the low PNG diet period. Fecal total vitamin B-6 excretion was significantly higher (P < 0.001) when the high PNG diet was consumed. Women consuming a diet containing a higher percentage of the total vitamin B-6 intake as PNG exhibited a decrease in vitamin B-6 status indicators, consistent with the reduced bioavailability of PNG demonstrated in other studies, equal to a loss of 15-18% of the total vitamin B-6 intake. During the determination of Recommended Dietary Allowances, the reduced bioavailability of PNG and its presence in higher amounts in some diets should be considered.
Hansen
C M
CM
Department of Nutrition and Food Management, Oregon State University, Corvallis 97331, USA.
Leklem
J E
JE
Miller
L T
LT
D000328:Adult; D000818:Animals; D001682:Biological Availability; D018592:Cross-Over Studies; D004032:Diet; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000737:chemistry; D005243:Feces / Q000737:chemistry; D005260:Female; D005960:Glucosides; D006801:Humans; D011732:Pyridoxal Phosphate / Q000032:analysis / Q000097:blood; D011735:Pyridoxic Acid / Q000652:urine; D011736:Pyridoxine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics / Q000494:pharmacology / Q000652:urine; D012044:Regression Analysis
D005960:Glucosides; C022945:5'-O-(glucopyranosyl)pyridoxine; D011735:Pyridoxic Acid; D011732:Pyridoxal Phosphate; D011736:Pyridoxine