Barbara M. Chrisley

Plasma B6 vitamer and 4-pyridoxic acid concentrations of men fed controlled diets

A rapid and sensitive procedure is described for the analysis of all the B6 vitamers and 4-pyridoxic acid in human plasma utilizing reversed-phase high-performance liquid chromatography with ultraviolet and fluorometric detection. Pyridoxal phosphate values obtained by radiometric and chromatographic, ultraviolet and fluorometric, assays were highly correlated as were pyridoxine phosphate values determined using both detectors. Plasma B6 vitamer and 4-pyridoxic acid concentrations of 22 men fed diets containing 0.75-0.98 mg of vitamin B6 daily for eight weeks were in the range of reported values; pyridoxal phosphate was their predominant plasma B6 vitamer. This methodology should be useful in the assessment of vitamin B6 requirements.

Vitamin B-6 status of a group of cancer patients

Abstract The vitamin B-6 status of 12 nonmedicated patients with newly diagnosed malignancies of the oral cavity and thorat, lung, or prostate and bladder and 3 nonhospitalized control subjects was determined by coenzyme stimulation of erythrocyte alanine aminotransferase activities and plasma pyridoxal phosphate levels. The subjects were males except for one female each in the lung and control groups; the mean ages of all groups were about 58 yr. All subjects had smoked for over 25 yr. The status parameter values of the patients with the 3 types of malignancies were similar. The typical vitamin B-6 intakes reported by the cancer patients and control subjects were close to 2 mg daily. All of the cancer patients and none of the control subjects had coenzyme stimulation values indicative of vitamin B-6 inadequacy. Low plasma pyridoxal phosphate concentrations were observed in 67% of the cancer patients and none of the controls. Vitamin B-6 inadequacy was observed in most if not all individuals diagnosed as having cancers of the oral cavity and throat, lung, and prostate and bladder.

Separation and quantification of the B6 vitamers in plasma and 4-pyridoxic acid in urine of adolescent girls by reversed-phase high-performance liquid chromatography.

The vitamin B6 status of seemingly healthy adolescent girls was determined using several accepted and proposed parameters in an effort to establish guidelines for status evaluation. High-performance liquid chromatography-derived plasma B6 vitamers (pyridoxal phosphate, PLP; pyridoxine phosphate. PNP; pyridoxamine phosphate, PMP; pyridoxal, PL; pyridoxine, PN; and pyridoxamine, PM) and 4-pyridoxic acid (4-PA) concentrations and urinary 4-PA levels of 28 white adolescent females, 12-15 years, having radiomonitored plasma PLP concentrations and coenzyme stimulation of erythrocyte alanine aminotransferase activities indicative of adequate status were determined. Mean vitamin B6 and protein intakes were 1.48 mg and 78.3 g. Ranges for plasma B6 vitamer and 4-PA concentrations (nmol/l) were: PLP, 40.9-122.2; PNP, non-detectable (ND)-16.1; PMP, ND-8.1; PL, ND-15; PN, ND-21.9; PM, ND-17.8; and 4-PA, ND-55.7. PLP was the only vitamer found in plasma of all subjects. Urinary 4-PA concentrations ranged from 0.11 to 2.50 mumol/mmol of creatinine. B6 vitamer values of these girls should be of use in the establishment of normal ranges for vitamin B6 status parameters.

Estimated Dietary Intakes of Vitamin B-6

Most of the researchers who have estimated dietary intakes of vitamin B-6 have utilized the composition tables in Home Economics Research Report No. 36 (1). The values given in this bulletin as well as those published by others (2–7) were obtained mainly via microbiological assay, generally Saccharomyces uvarum, ATCC No. 9080. Vitamin B-6 is found mainly bound to the protein portion of foods; however, the vitamin may also be present in food in its free state. Pyridoxal (PL) and pyridoxamine (PM) are the forms of the vitamin usually found in animal products; whereas pyridoxine (ol, PN) is the predominant form in plant products (8). The relative potency of PN, PL, and PM in man has not yet been determined.