The increasing knowledge of the significance of vitamin B₆ in
human metabolic processes has emphasized the importance of developing
reliable means of assessing nutritional status with respect to
this vitamin. One possible approach to this end is the measurement
of pyridoxal phosphate in blood or plasma, particularly since this
phosphorylated...
The bioavailability of vitamin B₆ in four selected foods
(bananas, filberts, soybeans and beef) was determined in five men,
aged 22 to 25 years, who were saturated with pyridoxine. The study
consisted of a five-day adjustment period followed by a 28-day experimental
period. All subjects consumed a constant diet containing...
The purposes of the research presented in this thesis were: (1)
to determine the precision with which it is possible to measure
changes in vitamin B6 compounds in the blood and urine following
oral doses of levels of vitamin B6 (as pyridoxine) which are in the
range of the normal...
Bioavailability (BA) of vitamin B6 (B-6) from foods may be
limited. The knowledge of the BA of B6 from food is important in
that this would help to understand if the B6 present in the diet of
individuals will meet the requirements for this vitamin.
The purpose of this study...
4-Pyridoxic acid is the major metabolite of all forms of
vitamin B₆ in mammalian species. The determination of 4-pyridoxic
acid, therefore, is important in the investigation of vitamin B₆
metabolism and for the establishment of human requirements for the
vitamin.
Although 4-pyridoxic acid is itself fluorescent, Huff and
Perlzweig (1944)...
The effect of dietary glycosylated vitamin B-6 on the bioavailability
of vitamin B-6 was determined in 4 women. A 44-d metabolic-balance diet
study was divided into a preliminary 8-d adjustment period followed by
two 18-d experimental periods. The subjects were divided into two groups
in a crossover design to compare...
Oral contraceptive (OC) users frequently have lower vitamin B₆
status than non-oral contraceptive (NOC) users. However, normal dietary
intake, a possible factor, has not been adequately studied.
Therefore, 26 OC users and 25 NOC users, of college age, were compared
with respect to dietary intake of vitamin B₆ and blood...
Recent studies in men have shown plasma levels of vitamin B-6
and pyridoxal 5'-phosphate (PLP), the active form of vitamin B-6, to
increase with exercise. It was hypothesized that muscle glycogen
phosphorylase might be the source of these increases as this enzyme
has been shown to increase with increasing vitamin...
The purpose of this study was, first, to investigate whether there
is a vitamin B-6 requirement for carnitine synthesis and, second, to investigate
the effect of fasting on vitamin B-6 metabolism. An experimental
group of 72 rats (6 per group) were fed either a vitamin B-6 deficient
diet (-B6) (ad...
The effect of vitamin B-6 (VB6) deficiency in mice on host
susceptibility to primary and secondary Moloney-sarcoma virus
(MSV)-induced tumor growth, cytotoxic activities of T cells,
antibodies and natural killer (NK) cells, and phagocytosis by
macrophages was examined. Five- to six-week old female C57B1/6 mice
were fed 20% casein diets...
Pyridoxal phosphate is a coenzyme in about 50 known enzymatic
reactions. A simple and accurate method for the determination of
pyridoxal phosphate would be desirable because it could provide a
means to assess the nutritional status of vitamin B₆ in the human.
The cyanohydrin methods to determine pyridoxal phosphate appear...
To investigate the responses of healthy adult women to two
levels of vitamin B-6, a seven week two-part experiment was conducted
with five young adults and eight middle-aged subjects. During the
four unsupplemented weeks, dietary vitamin B-6 was 2.3-2.4 mg/day.
In the final three weeks, the same diet was supplemented...
Previous studies have found that smoking may have a negative effect on
vitamin B-6 indices and have demonstrated a possible association between smoking
and depressed plasma pyridoxal-5'-phosphate (PLP) concentration. Individuals with
plasma PLP values below the adequate level of 30 nmoles/L might benefit from
consumption of vitamin B-6 supplements, but...
The purpose of this study was to determine the relationship between the overall
changes in concentration of plasma pyridoxal 5'-phosphate (PLP), red blood cell PLP (rbc
PLP) and plasma glucose during an oral glucose tolerance test (OGTT) in persons with
diabetes mellitus (DM), and to test the hypothesis that the...
The bioavailability of vitamin B-6 from four selected
foods was investigated in five men, aged 22 to 25 years,
who were receiving a pyridoxine supplement. The subjects
received a constant diet containing 1.34 mg of vitamin B-6
throughout this five-week study, except on Saturdays and
Sundays when they ate their...
This investigation was designed to add to present understanding
of vitamin B-6 (B6) metabolism during exercise. Ten women, 5
aerobically trained and 5 untrained, were fed 4 controlled diets: a
moderate carbohydrate (49%) (MCHO) for 2 weeks, a high carbohydrate
(63%) (HCHO) for one week, MCH0+B6 for 2 weeks, and...
Four young trained men were studied during 50 min of continuous
bicycle ergometer exercise [30 min at 60%, 15 min at 80%,
and 5 min at 90% maximal heart rate (MHR)] to elucidate changes
in fuel metabolism resulting from a glycogen depletion-repletion
regimen, and to determine the effect of supplemental...
Previous studies suggest that vitamin B-6 supplementation can alter fuel metabolism during
exercise and plasma amino acid levels at rest. To examine the effect of vitamin B-6
supplementation on plasma fuel substrates and amino acid levels during exercise, five trained
males (age: 29±7; V0₂ max: 54.7±6.2 ml/kg/min) performed two separate...
The status of vitamin B-6 (B6) nutriture of nine
persons (4F;5M) with insulin dependent diabetes mellitus
(IDDM), nine persons (5F;4M) with non-insulin dependent
diabetes mellitus (NIDDM), and 18 control individuals
(9F;9M) was evaluated, using biochemical and dietary
indicators of B6 status. The biochemical indices employed
were plasma concentration of pyridoxal...
This study was designed to evaluate the effect of glucose on plasma pyridoxal 5'- phosphate (PLP) concentration. The objective was to determine whether there was a negative relationship between glucose ingestion and plasma PLP concentration and to evaluate the possible mechanism of decreased PLP after acute glucose ingestion. Seven healthy...
There were two main purposes to this study. The first was to determine the vitamin B-6 and pyridoxine β-glucoside content of selected foods commonly consumed in Malawi. The second was to examine the effect of preparation procedures of foods in Malawi on the content of vitamin B-6 and pyridoxine β-...
The purpose of this study was to monitor coronary responses
occurring in the S-T segment of an electrocardiogram before, during
and after exercise following a "standard" carbohydrate-loading schedule with varied vitamin B-6 supplementation. The study was conducted
using four college-aged males who had been training a minimum of two
years...
Four studies were conducted to evaluate the effect of varying levels of vitamin
B-6 (B6), protein and pyridoxine glucoside (PNG) on B6 status and requirements of
women. In the first two studies, women were fed a constant protein diet and vitamin
B-6 intakes of 0.84 to 2.39 mg/d during 10-...
The effect of pyridoxine (PN) supplementation on lymphocyte
responsiveness was investigated in 15 elderly volunteers (aged
65-81 years) by measuring lymphocyte proliferation to T and B cell
mitogens, lymphocyte subpopulations with monoclonal antibodies
(T3, T4, T8) and plasma pyridoxal 5'-phosphate (PLP) concentration
at pre-supplementation and after 1 and 2 months...
This study examined the effect of vitamin B-6 supplementation and exhaustive
submaximal exercise on plasma catecholamine concentrations, and the relationship
between plasma catecholamines and fuel use, heart rate and oxygen consumption. Five
trained men (age= 18-35 years; V0₂max=53 ml 0₂/kg/min.) participated in two controlled
dietary periods that were identical except...
Trained male cyclists (6 in study 1, 5 in study 2) cycled to exhaustion (EXH) at
75% of VO₂ max twice; once in the non-supplemented (NS) state and once in the vitamin
B-6 (B-6)(20 mg PN) supplemented (S) state. The diet contained 2.3 mg B-6 in study 1
and 1.9...
Two studies were conducted to determine the effect of varying vitamin B-6 (B- 6) status on lymphocyte mitogenic response and pyridoxal 5'-phosphate (PLP) concentration in peripheral blood mononuclear cells (PBMC) in young women. In the first study, women were fed 1 mg/d for the first week and 1.5, 2.1 and...
The objectives of this study were to determine the
peritoneal clearance of vitamin B-6 and to evaluate the
vitamin B-6 and vitamin A status of children with chronic
renal failure undergoing continuous ambulatory peritoneal
dialysis (CAPD). Eight children aged 2 to 18 years
(mean 12) were included in the study....
The purpose of this study was to measure plasma B-6 vitamers, and other factors which may affect the plasma concentrations of these vitamers under extreme physical conditions. Blood samples were drawn from 8 men and 3 women (43.7 ± 8.6 years) 30 minutes prior to the start of a 50-km...
We compared a kinetic method (KM) and a colorimetric method (CM) for
measuring erythrocyte aspartate aminotransferase (EAST) activity. Twenty-three
healthy college students including 7 men and 16 women, aged from 22 to 40 years,
participated in this study. Vitamin B-6 status was assessed by EAST activity
coefficient (EAST-AC), the ratio...
The effect of pyridoxine (PN) supplementation on the activities
of erythrocyte alanine aminotransferase (EAlaAT) and aspartate aminotransferase
(EAspAT) was observed in five men, aged 22 to 25 years.
The subjects received a constant diet containing 1.34 mg of vitamin
B-6 Monday through Friday of each week during this five-week study....
The present study was designed to investigate the
effects of exercise on vitamin B-6 metabolism. Four groups
of subjects (intermittent, college, untrained, and high school)
consisting of nineteen male and two female individuals, participated
in the study. The subjects exercised either on a
bicycle ergometer, by running three 1500 meter...
Research suggests that, in individuals with carpal tunnel syndrome (CTS), low
plasma pyridoxal 5'-phosphate (PLP) concentrations are related to an increased incidence
and severity of symptoms associated with CTS. This study was designed to determine
the relationship between plasma and red blood cell PLP concentrations and the severity
and incidence...
The effect of vitamin B-6 (B-6) status on plasma fatty acids (FA) levels and lipid
metabolism was investigated in this metabolic study. Eight female subjects were fed for 28
days. For the first 7 days, they were fed a constant diet containing 2.10 mg of B-6. For the
rest of...
Serine transhydroxymethylase (STHM), a pyridoxal 5'-
phosphate requiring enzyme is indirectly involved in
pyrimidine deoxynucleotide metabolism. A decrease in the
activity of this enzyme could lead to altered deoxycytidine
(dC) metabolism. This study was undertaken to determine if
a vitamin B-6 deficiency affects dC metabolism. The effect
of a vitamin...
The study was designed to indirectly understand muscle
glycogen utilization during prolonged exercise when either
glucose, fructose, or water is ingested. Eight trained
adult males exercised on a cycle ergometer at 58±7% of V02
max for 2 h on 2-4 occasions. At 0 minutes of exercise and
at 30-minute intervals...
In two studies we tested the effect of vitamin B-6
(B-6) intake on in vitro lymphocyte, proliferation and IL-2
production in healthy young women. In Study I, 6 women were
fed a constant diet containing 0.84 mg (4.96 μmols) of B-6
for 12 d, and 1.24 mg (7.33 μmols) and...
The objectives of this study were a) to determine
if pyridoxine (PN) supplementation increases the rate at
which plasma urea and ammonia return to basal levels,
following exercise, b) to determine, by open circuit
calorimetry, the utilization of carbohydrates, and c) to
further understand vitamin B-6 metabolism during and
following...
This investigation was conducted to determine the
effect of estrogen replacement therapy (ERT) on vitamin B-6
status of postmenopausal women. Nineteen postmenopausal
women served as subjects. Nine (54.7 + 4.7 years) were
taking ERT (experimental group); ten (56.8 + 2.3 years)
were not (control group). For three consecutive days,
subjects...