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Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best?


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Magnesium is an element of great importance functioning because of its association with many cellular physiological functions. The magnesium content of foods is gradually decreasing due to food processing, and magnesium supplementation for healthy living has become increasingly popular. However, data is very limited on the bioavailability of various magnesium preparations. The aim of this study is to investigate the bioavailability of five different magnesium compounds (magnesium sulfate, magnesium oxide, magnesium acetyl taurate, magnesium citrate, and magnesium malate) in different tissues. Following a single dose 400 mg/70 kg magnesium administration to Sprague Dawley rats, bioavailability was evaluated by examining time-dependent absorption, tissue penetration, and the effects on the behavior of the animals. Pharmacokinetically, the area under the curve calculation is highest in the magnesium malate. The magnesium acetyl taurate was found to have the second highest area under the curve calculation. Magnesium acetyl taurate was rapidly absorbed, able to pass through to the brain easily, had the highest tissue concentration level in the brain, and was found to be associated with decreased anxiety indicators. Magnesium malate levels remained high for an extended period of time in the serum. The commonly prescribed dietary supplements magnesium oxide and magnesium citrate had the lowest bioavailability when compared to our control group. More research is needed to investigate the bioavailability of magnesium malate and acetyl taurate compounds and their effects in specific tissues and on behavior.
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Timeline (Bioavailability) of Magnesium Compounds in Hours:
Which Magnesium Compound Works Best?
Nazan Uysal
&Servet Kizildag
&Zeynep Yuce
&Guven Guvendi
&Sevim Kandis
&Basar Koc
Ulas M. Camsari
&Mehmet Ates
Received: 27 December 2017 /Accepted: 13 April 2018
#Springer Science+Business Media, LLC, part of Springer Nature 2018
Magnesium is an element of great importance functioning because of its association with many cellular physiological functions.
The magnesium content of foods is gradually decreasing due to food processing, and magnesium supplementation for healthy
living has become increasingly popular. However, data is very limited on the bioavailability of various magnesium preparations.
The aim of this study is to investigate the bioavailability of five different magnesium compounds (magnesium sulfate, magnesium
oxide, magnesium acetyl taurate, magnesium citrate, and magnesium malate) in different tissues. Following a single dose 400 mg/
70 kg magnesium administration to Sprague Dawley rats, bioavailability was evaluated by examining time-dependent absorption,
tissue penetration, and the effects on the behavior of the animals. Pharmacokinetically, the area under the curve calculation is
highest in the magnesium malate. The magnesium acetyl taurate was found to have the second highest area under the curve
calculation. Magnesium acetyl taurate was rapidly absorbed, able to pass through to the brain easily, had the highest tissue
concentration level in the brain, and was found to be associated with decreased anxiety indicators. Magnesium malate levels
remained high for an extended period of time in the serum. The commonly prescribed dietary supplements magnesium oxide and
magnesium citrate had the lowest bioavailability when compared to our control group. More research is needed to investigate the
bioavailability of magnesium malate and acetyl taurate compounds and their effects in specific tissues and on behavior.
Keywords Magnesium acetyl taurate .Magnesium malate .Magnesium citrate .Magnesium oxide .Magnesium sulfate .
Anxiety .Brain .Muscle
Magnesium is the eight most common element found on our
planet [1]. It is also the fourth most abundant element in ver-
tebrates and the second most common element in the cell
following potassium in eukaryotic cells. There is an average
of 0.4 g/kg (total of 24 g in a 70-kg adult) magnesium in the
human body [2]. Approximately 99% of the total body mag-
nesium is localized in the bone, muscle, and the soft tissue
surrounding them; of which 5060% is found in the bones [3].
One third of the magnesium found in bones tissue act as a
reservoir, regulated to maintain normal blood magnesium
levels [4]. The magnesium content of the bone decreases with
age, leading to a decline in its storage function [1].
Extracellular magnesium constitutes 1% of the total body
magnesium and is mostly found in serum and red blood cells.
Seventy percent of the magnesium in serum is ionized, 20% is
protein-bound, and 10% is bound to anions such as phosphate,
bicarbonate, citrate, and sulfate [3,4].
Magnesium is a vital component of cells, involved in many
physiological functions [2]. It is the most frequently found
metal ion cofactor in enzymatic systems, including DNA/
RNA polymerases and all enzymes functioning in ATP me-
tabolism. In cells, the presence of magnesium is critical for the
stability of polyphosphate compounds. Under normal condi-
tions, biologically active ATP is bound to a magnesium ion [2,
*Nazan Uysal
Medical Faculty, Department of Physiology, School of Medicine,
Dokuz Eylul University, Balcova, Izmir, Turkey
College of Vocational School of Health Services, Schoolof Medicine
Izmir, Dokuz Eylul University, İzmir, Turkey
Department of Medical Biology and Genetics, School of Medicine,
Dokuz Eylul University, Izmir, Turkey
Department of Psychiatry and Psychology, Mayo Clinic,
Rochester, MN, USA
Biological Trace Element Research
4]. ATP metabolism is essential for muscle contraction and
relaxation, normal neurological function, and release of neu-
rotransmitters. Mg affects muscle performance through its
fundamental role in muscle contraction/relaxation and energy
metabolism [5]. The most common manifestation of magne-
sium deficiency is muscular cramps. In addition, it is essential
in the regulation of vascular tone, heart rhythm, platelet-
activated thrombosis, and bone formation [6]. It has been sug-
gested that magnesium deficiency has related with both anx-
iety and depressive disorders. Some studies demonstrated
magnesiums anxiolytic effects in both rodent models and
humans [7].
Approximately 3040% of the dietary magnesium is
absorbed from the digestive tract with a variability between
~ 10 and 65% depending on the physiological need.
Absorption occurs mostly in the small intestine, but also con-
tinues in the colon. In humans, magnesium absorption partic-
ularly occurs in the distal segment of the small intestine; how-
ever, radioisotope-labeled magnesium has been detected in
plasma 1 h after ingestion, indicating that absorption begins
in the upper regions of the small intestine, such as duodenum
and jejunum [8]. The presence of fibers in the diet that can be
fermented by intestinal bacteria increases Mg absorption from
the large intestine [9]. Following absorption from the digestive
tract, magnesium enters the bloodstream. However, the rate of
magnesium transport across cell membranes is not the same in
all tissues of the human body; the rate is higher in the heart,
liver, and kidney and lower in the skeleton, red cells, and brain
[10]. Magnesium easily crosses the blood-brain barrier [2].
The recommended daily dose of magnesium is 310 mg for
women 1930 years of age and 320 mg for women 31+ years
old and 400 mg for men aged 1930 and 420 mg for men 31+
years [11]. Food and water are the major sources of magne-
sium intake. It is abundant in green leafy vegetables, cereals,
nuts, and legumes. Nonetheless, the magnesium content of
foods has decreased in the last century [12,13]. Processed
and refined foods are poor sources of the nutrient, reducing
its content up to 85%. Cooking (especially boiling) also de-
creases the magnesium content in foods [14]. In addition to a
magnesium-poor diet, deficiency can occur secondary to
chronic alcohol usage, lengthy hospitalizations, or chronic
diseases such as type 2 diabetes, obesity, and metabolic syn-
drome. Magnesium uptake can be increased by a magnesium-
rich diet or magnesium supplementation. Decreased intake or
absorption and chronic diseases caused magnesium deficien-
cy, in which taking a dietary supplement becomes necessary.
The magnesium element forms compounds with organic or
inorganic molecules and mostly exists as magnesium salts in
nature. Organic and inorganic compounds are the two main
classes of chemical compounds. With a few exceptions, an
organic compound is defined as containing C-H bonds and
is associated with living organisms and life processes.
Inorganic compounds include salts, metals, minerals, and
other elemental compounds that do not contain carbon and
are not associated with living matter. Production of inorganic
compounds is cheaper and they break down very easily in the
digestive tract. Yet they have a lower absorption rate when
compared to organic substances. When magnesium minerals
are consumed, they are quickly released and free to bind other
compounds such as phytates found in nuts, grains, and some
vegetables. Thus, the resulting new compounds are excreted
without absorption. The unbound magnesium mineral can al-
so irritate the digestive system and cause a laxative effect or
diarrhea [1517].
Information on the bioavailability and efficacy of different
magnesium compounds is limited. The aim of this study is to
investigate the bioavailability of different organic (magnesium
citrate, magnesium acetyl taurate, and magnesium malate) and
inorganic (magnesium oxide and magnesium sulfate) magne-
sium compounds. Magnesium citrate and magnesium oxide
are the most prescribed Mg compounds as dietary supple-
ments. Magnesium acetyl taurate was shown to have an effect
on an experimental cataract model and is also recommended
for the treatment of migraine. Magnesium malate is used in the
treatment of fibromyalgia. We compared the bioavailability of
these widely used magnesium compounds and parenteral us-
age to oral intake.
Materials and Methods
Forty-nine adult outbred male Sprague Dawley rats (Dokuz
Eylul University School of Medicine, Experimental Animal
Laboratory, Izmir, Turkey) were used in this study. All rats
were housed in individual cages with free access to water and
laboratory chow. They were kept in a 12-h light/12-h dark
cycle at constant room temperature (22 ± 1 °C) and humidity
(60%). Dokuz Eylul University School of Medicine Animal
Care Committee approved all experimental procedures.
Rats were divided into six groups: (1) Control group (n=
7), (2) magnesium sulfate (n= 7), (3) magnesium oxide (n=
7), (4) magnesium citrate (n= 7), (5) magnesium acetyl taurate
(n= 7), (6) magnesium malate (n=7).
Experimental Design The details of experiment are summa-
rized in Fig. 1. The effects of magnesium on the body were
investigated 6 h after magnesium administration (400 mg/
70 kgrecommended daily dose for men) [18]. Elementary
magnesium levels of all compounds were calculated and then
dissolved using phosphate-buffered saline (PBS). Also, our
aim was to compare parenteral form with peroral; therefore,
magnesium sulfate was administered intraperitoneally, while
the other magnesium compounds were given orally. The mag-
nesium sulfate group was subject to the experiments 2 h after
Uysal et al.
magnesium administration. All magnesium compounds were
given in 1-ml volume/each rat. Control animals were given the
same volume of PBS orally.
We looked at different tissues to assess the bioavailability
of magnesium. We utilized two established animal anxiety
models to assess the effects of magnesium in the brain tissue:
open-field arena and elevated plus-maze apparatus. The re-
cording and analyses were completed by 4.1.106 version
Noldus Ethovision XT video-tracking system. In order to as-
sess the effects of magnesium in the muscle tissue, we
assessed locomotor activity, muscle strength levels, and motor
coordination. Eight hours after administration of magnesium
[19], blood samples were drawn under carbon dioxide anes-
thesia; later, brain was separated from the cerebellum and
magnesium level was measured in the whole brain. While
measuring Mg in muscle tissue, gastrocnemius was removed
because it contains muscle fibers of type 1 and type 2.
Open-Field Test
This test has been commonly used to assess spontaneous lo-
comotor activity and anxiety. As part of our series of experi-
ments, exploratory behavior of the rodents was evaluated in
the open-field test. The open field consists of an area of 1 ×
1 m surrounded with a wall 50 cm in height, and a video
camera installed 2.5 m above the apparatus. Each rat was
placed in the center of the open field and then locomotor
activity (ambulation) was measured for 5 min in a soundproof
observation room illuminated with controlled light (100 lx)
Elevated Plus Maze
This is another established model for anxiety in rodents. This
test causes anxiety in the animal and therefore is more accurate
for the assessment of anxiety. The elevated plus-maze appara-
tus consists of a central platform (5 cm × 5 cm) with two open
arms (50 cm long, 10 cm wide, and 0.5 cm high borders) and
two closed arms (50 cm long, 10 cm wide with 40 cm high
walls) that were elevated 50 cm above the ground. Rats were
placed on the platform facing the open arm and were observed
for 5 min. The total number of entries into the open and closed
arms as well as the time spent in each arm was measured [21].
Forelimb Grip Strength Measurement
The muscle strength of the subjects was measured using a
muscle strength meter. Rats were lifted from the tail to hold
the device bar with the forearms and then pulled gently from
their tail. The value given by the digital force indicator before
the release of the rod was defined as the grip force. The test
was repeated three times in succession and the highest value
was regarded as the holding force [22].
Rotarod: Assessment of Motor Coordination
The rotarod test device consists of 3-cm diameter cylinders,
separated by panels to prevent animals from seeing each other.
Five animals can be tested at the same time. The speed of the
bar was linearly increased from 4 to 20 rpm for 180 s. The
animals were trained to walk on the accelerating rotarod. Each
walking performance on the rotarod was timed by the counter
until the animal lost balance and fell down [23].
Blood, Brain, and Muscle Tissue Magnesium Levels
Blood, brain, and muscle samples were stored at 85 °C until
they were analyzed. Magnesium level in the brain, plasma,
and muscle tissues was determined by atomic absorption spec-
trophotometry (following microwave oven digestion210
VGP model, East Norwalk, Connecticut, USA), 8 h post ad-
ministration. Magnesium level was measured at different time
points using a Beckman Coulter AU 5800 analyzer (Beckman
Coulter, Brea, CA). Tissue magnesium concentration was cal-
culated per wet weight. Protein analysis was performed as per
manufacturers description of BCA protein assay kit (Cat No
E- BP-500, Elabscience, Wuhan, China). The erythrocyte
magnesium levels were calculated per protein (hemoglobin).
Fig. 1 Timeline of experiments
Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best?
Calculation of the Area Under the Curve
Bioavailability refers to the fraction of drug systemically
absorbed and it can be measured by quantifying area under
the curve (AUC) of a serum concentration against a time plot.
We calculated the AUC of the plot of serum magnesium levels
determined at different time points. (AUC = (C1 + C2)/(t2-
t1) + (C2 + C3)/(t3-t4) + (C3 + C4)/(t5-t4)).
Statistical Evaluation
All statistical procedures were performed by SPSS software
for Windows, Version 11.0 (SPSS, Chicago, IL). Differences
between groups were analyzed using one-way ANOVA with
the Bonferroni post hoc test when a statistically significant
difference was found between groups. Correlations among
groups were calculated using the Pearson correlation analysis.
Results are presented as mean ± S.E.M, where p<0.05 was
considered statistically significant.
All results are summarized in Table 1. In the open-field test,
the magnesium acetyl taurate group demonstrated more activ-
ity in the center of the open-field arena compared to the mag-
nesium sulfate, magnesium oxide, magnesium citrate, and
control groups (p< 0.05 for magnesium sulfate; p<0.001
for the other experimental groups) (Fig. 2a).
The magnesium acetyl taurate group demonstrated more
activity in the open arms of elevated plus-maze test when
compared to the magnesium malate, magnesium citrate, mag-
nesium oxide, and control group rats (p< 0.05 for magnesium
malate and magnesium citrate; p< 0.001 for magnesium ox-
ide, and control groups) (Fig. 2b).
No difference was observed in muscle strength or rotarod
performance between the experimental groups and control
(Fig. 2c, d).
As early as 4 h post administration, blood magnesium
levels were high in rats administered with magnesium malate
(indicating fast intestinal absorption), but no statistical differ-
ence was found between the magnesium malate and magne-
sium acetyl taurate groups. At the eighth hour, blood magne-
sium levels were significantly higher in the magnesium malate
group when compared to all other groups (p<0.001)(Fig.3a).
No difference was observed in erythrocyte magnesium levels
between the experimental and control groups (Fig. 3b).
The area under the magnesium curve is the difference be-
tween all magnesium compounds. Magnesium malatesAUC
is much higher than all other groups (p< 0.0001). Magnesium
acetyl taurate and magnesium sulfates AUC are higher than
magnesium oxide and citrate (both p< 0.0001) (Fig. 3c).
Brain magnesium levels were highest in the magnesium
acetyl taurate group when compared with others (comparison
with magnesium citrate p< 0.05; for other groups p<0.0001)
(Fig. 4a). On the other hand, muscle magnesium levels were
lower in the magnesium acetyl taurate group when compared
with magnesium sulfate, magnesium oxide, magnesium cit-
rate, and control groups (all of p<0.001) (Fig.4b).
We found strong positive correlations between brain mag-
nesium levels and time spent in open arms of the elevated plus
maze (r=0.541,p=0.0001).Wealsofoundintermediateneg-
ative correlations between muscle magnesium levels and dis-
tance in the open-field arena and also open arms of the elevat-
ed plus maze (r=0.446, p=0.005; and r=0.468, p=
0.003, respectively).
This study compared the bioavailability of three organic and
two inorganic (intraperitoneal and peroral) Mg compounds.
Bioavailability was assessed by investigating tissue magne-
sium levels and also evaluated behavioral effects.
To understand the bioavailability of Mg in the brain, we
conducted two established experimental anxiety models for
rodents, and Mg has been previously used with success in
these models in reducing anxiety in rodents. We were able to
demonstrate that among the magnesium preparations we test-
ed, the magnesium acetyl taurate group demonstrated the low-
est anxiety indicators as per open-field test and elevated plus-
maze test markers (by entering more often into the center cells
of the open-field arena and by spending more time in the open
arms of elevated plus-maze test); the magnesium acetyl taurate
group also had the highest Mg concentration in brain tissue
after 8 h, strongly indicating an efficient blood-brain barrier
passage. However, blood and muscle magnesium levels were
low in the magnesium acetyl taurate group when compared to
the other experimental groups. Serum levels were the highest
in the magnesium malate group.
Literature on the bioavailability of various Mg compounds
is limited. To our knowledge, there is no previous study in-
vestigating and comparing the immediate physiological and
behavioral effects of various magnesium preparations and
their corresponding blood/tissue magnesium levels. Most
studies so far have compared the bioavailability of up to three
different magnesium compounds and bioavailability has been
measured through the urinalysis [2426]. After oral adminis-
tration, magnesium is absorbed from the intestines, and in-
creased levels in the blood would not suffice, it would need
to pass through the cell membrane and get inside the cell in
order to participate in normal physiological functions.
Therefore, we have used both peroral and parenteral adminis-
tration of inorganic magnesium supplements. In our experi-
ments, we did not observe any differences between the control
Uysal et al.
group and the inorganic magnesium groups (magnesium ox-
ide and magnesium sulfate), which can be interpreted as the
low bioavailability of these compounds [15,17]. We showed
that the magnesium acetyl taurate (an organic compound)
group had the highest brain magnesium levels, followedclose-
ly by magnesium malate. Magnesium is an essential mineral
for the homeostasis of all living cells. It is a cofactor in over
300 biochemical reactions, regulating nucleic acid and protein
synthesis, ATP synthesis, nerve and muscle cell functions, and
body temperature [2,27]. Magnesium is also important in
psychoneuroendocrine systems that attenuate stress hormone
release and modulate the activity of the hypothalamuspitui-
taryadrenocortical axis [7,28].
Magnesium depletion is associated with affective mood
disorders, anxiety, and depression. It was previously shown
that increased magnesium levels in the brain were associated
with anxiety-related behavior in mice [29]. Magnesium treat-
ment was shown to reduce anxiety in other rodent studies [30,
31]. In Poleszasks study, organic and inorganic magnesium
compounds were compared and while magnesium sulfate did
Control MgSO4 MgAT MgO MgC MgM
Fig. 2 Behavioral test results. aOpen-field test result, percentage of
moving-time in open-field test. Asterisk indicates p< 0.05 compared to
other groups. bElevated plus-maze test result, total entries to open arms
of elevated plus maze. Single asterisk indicates p< 0.001 compared to
control, MgC, MgO, and MgM. Double asterisks indicate p< 0.001
compared to control and MgO. cForelimb grip strength measurement
results. dRotarod test results. MgSO4 magnesium sulfate, MgT
magnesium acetyl taurate, MgO magnesium oxide, MgC magnesium
citrate, MgM magnesium malate
Table 1 Behavioral tests results and tissue and blood magnesium levels in 8 h
Time spend in
middle area (sec)
Time spend
open arms (sec)
Blood Mg
Muscle Mg
(mg/g tissue)
Brain Mg
(mg/g tissue)
Control 5.2 ± 0.2 8.8 ± 1.6 3.3 ± 0.5 327.4 ± 1.4 189.3 ± 1.6
MgSO4 6.3 ± 0.6 38.6 ± 5.6** 3.4 ± 0.3 328.5 ± 2 178.6 ± 3.7
MgAT 11.4 ± 2.1* 39.8 ± 5.5* 3.1 ± 0.7 296.9 ± 8.8* 216.9 ± 2.9*
MgO 5.3 ± 0.7 8.0 ± 0.8 3.2 ± 0.7 326.2 ± 3.4 182.9 ± 1.5
MgC 3.8 ± 0.4 23.2 ± 2.9 3.4 ± 1.1 324.9 ± 2.5 198.8 ± 7.1
MgM 10.0 ± 1.1 21.9 ± 2.5 3.7 ± 0.8* 333.4 ± 5.6 180.6 ± 3.9
*p< 0.05 compared with control; **p< 0.001 compared to control and MgO
Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best?
not affect anxiety, magnesium hydroaspartate (an organic
compound) was shown to decrease anxiety levels in mice
[30]. Consistent with these results, in our study, inorganic
compounds did not affect anxiety either while magnesium
acetyl tauratean organic compoundreduced anxiety.
Other organic magnesium compounds (magnesium citrate
Fig. 3 aSerum magnesium
levels. aTime point
measurements of serum
magnesium levels. Single asterisk
indicates p< 0.001 compared
with control, Double asterisks
indicate p< 0.01 compared to
MgT. bTime point measurements
of erythrocyte magnesium levels.
cPlasma magnesium AUC
calculation results. Single asterisk
indicates p< 0.001 compared to
other groups, Double asterisks
indicate p< 0.001 compared to
control, MgO, MgC, MgT, and
MgM. AUC the area under the
curve, MgSO4 magnesium
sulfate, MgT magnesium acetyl
taurate, MgO magnesium oxide,
MgC magnesium citrate, MgM
magnesium malate
Uysal et al.
and magnesium malate) had no effect on anxiety indicators.
There were differences in the magnesium administration
method of our study and Poleszasks[30]. In Poleszask
et al., all organic magnesium compounds were given intraper-
itoneal. In our study, we mainly used oral administration.
Level in brain tissue was only shown to be increased in the
magnesium acetyl taurate group.
We did not observe any effect on muscle tissue after
magnesium supplementation in the acute period. There are
some reports on magnesium supplementation in fibromy-
algia patients. A magnesium reduction in the muscle cells
of fibromyalgia has previously been reported [32].
Abraham and Flechas treated fibromyalgia patients with
a daily magnesium malate supplementation of 300
600 mg, for 8 weeks, and reported improvement in the
fibromyalgia symptoms of the patients [33]. In our study,
acute magnesium administration did not affect muscle tis-
sue magnesium levels in our magnesium malate group.
of the magnesium malate group when compared to its
controls. Our results support a previous study data dem-
onstrated no correlation between that serum magnesium
level and muscle strength [34]. Magnesium is distributed
to the bone, muscle, and brain tissue after getting into the
bloodstream through the gastrointestinal tract [35].
Therefore, we particularly chose to investigate its bio-
availability in muscle tissue directly and in brain tissue
through its presumed behavioral manifestations.
One limitation of our study is that we could not collect
urine to measure excretion of magnesium. In order for us
to do this, rats must have been kept alone in metabolism
cages for collection of urine. This would have caused
isolation stress and would have likely adversely affected
our behavioral test results. Being able to measure urine
magnesium would have allowed us to calculate the entire
magnesium metabolism.
In our study, we were surprised to find magnesium oxide
and magnesium citrate compoundscommonly prescribed
by doctorshad the lowest bioavailability measured, and in
most cases, no significant difference from the control group
was observed. It is known that magnesium is rapidly separated
from the compound in both of these magnesium forms and
free magnesium quickly binds to many intestinal contents
such as food. During our experiments, our rats had free access
to food; thus, our findings may indicate a lower bioavailability
of the magnesium compound.
Fig. 4 Tissue magnesium levels.
aBrain tissue magnesium levels.
bMuscle tissue magnesium
levels. Asterisks indicate p<0.05
compared to other groups.
MgSO4 magnesium sulfate, MgT
magnesium acetyl taurate, MgO
magnesium oxide, MgC
magnesium citrate, MgM
magnesium malate
Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best?
Today, the reduced nutrient content of foods makes micronu-
trient reinforcement necessary. Magnesium is one of the mi-
croelements that must be taken as supplement if it is deficient
in the body. In this study, we demonstrated that orally admin-
istered magnesium acetyl taurate detected in the brain was
quickly absorbed, able to pass through to the brain easily,
and had measurable effects on anxiety indicators as specifical-
ly evidenced by strong positive correlation between brain
magnesium levels and time spent in open arms of the elevated
plus maze. Another notable findings were that magnesium
taurate levels remained high for a long time in the serum.
We used single dosing (daily recommended dosing) in this
study; dose-dependent responses of these magnesium com-
pounds would require further investigation. In addition, fur-
ther work is needed to explain the effects of these magnesium
compounds on the body of long-term applications.
Compliance with Ethical Standards
The experiments were carried out according to the Guiding Principles in
the Use of Experimental Animals and approved by the Animal Care and
Use Committee of the Dokuz Eylul University, School of Medicine.
Conflict of Interest The authors declare that they have no conflict of
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Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best?
... It participates as a cofactor in more than 600 enzymatic reactions that are mostly dependent on adenosine triphosphate. It intervenes in macronutrient degradation routes, in oxidative phosphorylation, in synthesis of proteins and DNA, in neuromuscular excitability, and in the regulation of parathyroid hormone secretion [1]. Mg is a physiological antagonist of calcium channels, regulates the permeability of membranes through interaction with phospholipids, and affects vessel tone and blood pressure, among others [2]. ...
... A methodological difference among studies was the inclusion of Mg in the diet by formulation of specific feeds with a specific mineral mixture [18,19], or the administration of the dissolved Mg supplement through a flexible cannula directly to the stomach. Even when it was administered by catheter, on one occasion it was dissolved in distilled water [10] and in other cases in phosphatebuffered saline [1,8]. ...
... Uysal et al. [1] more recently studied the bioavailability of different forms of Mg by analyzing its accumulation in different tissues from a single dose of Mg equivalent to the recommended dose in humans (Table 1). They also measured absorption as a function of time and the effect that the different salts could have on animal behavior. ...
Introduction: The market for food supplements is booming due to their increased consumption. European regulations include different ways in which vitamins/minerals are administered, without the consumer being clear if one formulation has advantages over the other. The aim was to compare the bioavailability of different forms of Mg and to analyze the differences between them. Methods: Based on a PICO (Population, Intervention, Comparison, Outcome) research question, a search strategy for Mg bioavailability studies that compared different forms was established for Pubmed, Cochrane, Web Of Science and Scopus databases. 433 studies were found of which 14 were finally selected. Results: Inorganic formulations appear to be less bioavailable than organic and the percentage of absorption is dose dependent. Conclusion: All Mg dietary supplements can maintain the physiological levels of Mg in healthy subjects without prior deficit, although it cannot be assured in older patients, patients with illnesses or with previous sub-physiological levels.
... Currently, several generations of magnesium-containing preparations depending on their pharmacological properties are distinguished (Trisvetova 2012). It was proved that the first-generation drugs, represented by inorganic magnesium compounds, have little effect on the balance of this element in the body (Ates et al. 2019; Uysal et al. 2019). Magnesium oxide, dioxide, carbonate and phosphate exhibit primarily antacid properties, but are not used in correcting magnesium deficiency. ...
... In addition, it has many side effects, such as a metallic taste in the mouth, nausea and vomiting, which limits this way of its introduction. This drug is used mainly parenterally due to its anticonvulsant, vasodilator, se- Second-generation drugs, represented by organic magnesium salts, are well absorbed in the gastrointestinal tract and rarely cause side effects (Gröber et al. 2015;Ates et al. 2019;Gromova et al. 2019). Тhis group of magnesium-containing compounds is represented by such salts as magnesium malate, magnesium gluconate, magnesium orotate, magnesium citrate, magnesium pidolate, and magnesium lactate ( Table 2). ...
... In addition, the chelated form is able to cross the placental barrier and provide fetal nutrition. It is important that such compounds neither affect the gastric acidity nor the digestive processes (Trisvetova 2012;Dadak et al. 2013;Ates et al. 2019). ...
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Introduction : The relevance of the issue of increasing stress resistance is due to a significant deterioration in the mental health of the population caused by the special conditions of the disease control and prevention during the COVID-19 pandemic. Recently, the decisive role in the severity of clinico-physiological manifestations of maladjustment to stress is assigned to magnesium ions. The aim of the work was to study the magnesium importance in the body coping mechanisms under stress for the pathogenetic substantiation of the magnesium correction in an unfavorable situation of disease control and prevention during the COVID-19 pandemic. Materials and methods : The theoretical basis of this scientific and analytical review was an analysis of modern Russian and foreign literature data posted on the electronic portals MEDLINE, PubMed-NCBI, Scientific Electronic Library eLIBRARY.RU, Google Academy, and CyberLeninka. Results and discussion : It was shown that the total magnesium level in the body plays the indicator role of the body functional reserves. Acute and chronic stresses significantly increase the magnesium consumption and cause a decrease in its body content. Magnesium deficiency is one of the main pathogenetic mechanisms of reducing stress resistance and adaptive body reserves. Arising during the COVID-19 pandemic, increased nervous and emotional tension, the lack of emotional comfort and balance can lead to the onset or deterioration of magnesium deficiency, which manifests itself in mental burnout and depletion of adaptive capacities. The inability to synthesize magnesium in the body necessitates including foodstuffs high in magnesium in the population diet during this period. The appointment of magnesium preparations is pathogenetically justified with moderate and severe magnesium deficiency. This therapy should take into account the major concomitant diseases, severity of magnesium deficiency, and a patient’s age. Conclusion : magnesium correction, carried out during the COVID-19 pandemic, will contribute to increasing stress resistance, preventing mental diseases and improving the population’s life quality.
... This review explored also publications on the bioavailability of the different Mg salts in order to identify specificities among pharmaceutical preparations. A number of publications have studied 17 Mg salts in preclinical and clinical conditions [111][112][113][114][115][116][117][118]. Comparison of the oral bioavailability and absorption of different pharmaceutical forms of inorganic and organic Mg salts has been explored in 5 RCTs [113][114][115][116][117] (Table 2). ...
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Background: Magnesium (Mg) is commonly used in clinical practice for acute and chronic pain and has been reported to reduce pain intensity and analgesics consumption in a number of studies. Results are, however, contested. Objectives: This review aims to investigate randomised clinical trials (RCTs) on the effectiveness of Mg treatment on pain and analgesics consumption in situations including post-operative pain, migraine, renal pain, chronic pain, neuropathic pain and fibromyalgia. Results: The literature search identified 81 RCTs (n = 5447 patients) on Mg treatment in pain (50 RCTs in post-operative pain, 18 RCTs in migraine, 5 RCTs in renal pain, 6 RCTs in chronic/neuropathic pain, 2 RCTs in fibromyalgia). Conclusion: The level of evidence for the efficacy of Mg in reducing pain and analgesics consumption is globally modest and studies are not very numerous in chronic pain. A number of gaps have been identified in the literature that need to be addressed especially in methodology, rheumatic disease, and cancer. Additional clinical trials are needed to achieve a sufficient level of evidence and to better optimize the use of Mg for pain and pain comorbidities in order to improve the quality of life of patients who are in pain.
... Small studies showed that magnesium in the aspartate, chloride, citrate, and lactate salt is absorbed almost completely and is more bioavailable than magnesium oxide and magnesium sulfate [204,206]. In general, it has been suggested that absorption of organic magnesium salts is better than the absorption of inorganic compounds, whereas other studies did not find differences between salt formulations [4,200,207,208]. Unabsorbed magnesium salts in general cause diarrhea and laxative effects due to the osmotic activity in the intestine and colon and the stimulation of gastric motility [58]. ...
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Magnesium plays an important role in many physiological functions. Habitually low intakes of magnesium and in general the deficiency of this micronutrient induce changes in biochemical pathways that can increase the risk of illness and, in particular, chronic degenerative diseases. The assessment of magnesium status is consequently of great importance, however, its evaluation is difficult. The measurement of serum magnesium concentration is the most commonly used and readily available method for assessing magnesium status, even if serum levels have no reliable correlation with total body magnesium levels or concentrations in specific tissues. Therefore, this review offers an overview of recent insights into magnesium from multiple perspectives. Starting from a biochemical point of view, it aims at highlighting the risk due to insufficient uptake (frequently due to the low content of magnesium in the modern western diet), at suggesting strategies to reach the recommended dietary reference values, and at focusing on the importance of detecting physiological or pathological levels of magnesium in various body districts, in order to counteract the social impact of diseases linked to magnesium deficiency.
... ATA Mg was also showed to increase magnesium concentration in the brain in a more efficient way than inorganic (oxide or sulfate) and organic compounds (citrate or malate): Uysal et al. (2018) demonstrated that a single dose of Mg acetyltaurate (400 mg/70 kg bw elemental Mg) administrated orally in rats was able to significantly increase Mg concentration in the brain measured by atomic spectrophotometry (216.9 AE 2.9 mg/g compared to 189.3 AE 1.6 mg/g in control rats) which was not the case of the other compounds [28]. ...
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While magnesium deficiency is common and its effects well known on the nervous system, very few studies has been dedicated to the efficiency of magnesium replacement treatments on the central nervous system. In this study, the effects of oral administration of magnesium salts of acetyl-taurinate on the central manifestations of magnesium deficiency is described in rats submitted to low-magnesium diet and in a murine model of Alzheimer's disease. We tested the effect of ATA Mg®, a salt combining magnesium and taurine, on the hippocampus, a critical component of cognition. 7-10-month-old rats were submitted to dietary magnesium deprivation for 64 days. The effect of magnesium deficiency was studied in ex vivo hippocampal slices. We showed that long-term potentiation of synaptic transmission in the hippocampus was significantly improved by the oral administration of ATA Mg® at a dose of 50 mg/kg bw/day, which is comparable to the recommended dose in humans. 7-10-months-old transgenic APP/PS1 mice, a model of Alzheimer's disease, received ATA Mg® during 24 days at a dose of 700 mg/kg bw/day which is the dose used in previous studies demonstrating the positive effect of magnesium supplementation. We showed that long-term potentiation was significantly improved in the treated mice. Moreover, the expression of NR2B subunit of NMDA receptors, known to be involved in synaptic plasticity, was significantly increased in the hippocampus. These results demonstrate the ability of ATA Mg® to improve the symptoms related to chronic magnesium deficiency at the level of the hippocampus suggesting its bioavailability and effectiveness in reaching the central nervous system.
... Besides, there is no consensus on the type of Mg 2+ salt to Nutrients 2021, 13, 320 9 of 16 use. The bioavailability of different Mg 2+ salts has been investigated in depth [131][132][133][134]. Magnesium sulfate, oxide, carbonate, chloride, citrate, malate, acetate, gluconate, lactate, aspartate, fumarate, acetyl taurate, bis-glycinate, and pidolate are all employed in Mg 2+ supplementation. ...
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Magnesium (Mg2+) deficiency is probably the most underestimated electrolyte imbalance in Western countries. It is frequent in obese patients, subjects with type-2 diabetes and metabolic syndrome, both in adulthood and in childhood. This narrative review aims to offer insights into the pathophysiological mechanisms linking Mg2+ deficiency with obesity and the risk of developing metabolic syndrome and type 2 diabetes. Literature highlights critical issues about the treatment of Mg2+ deficiency, such as the lack of a clear definition of Mg2+ nutritional status, the use of different Mg2+ salts and dosage and the different duration of the Mg2+ supplementation. Despite the lack of agreement, an appropriate dietary pattern, including the right intake of Mg2+, improves metabolic syndrome by reducing blood pressure, hyperglycemia, and hypertriglyceridemia. This occurs through the modulation of gene expression and proteomic profile as well as through a positive influence on the composition of the intestinal microbiota and the metabolism of vitamins B1 and D.
... We did not measure its effectiveness at earlier time points and the effectiveness of long-term applications. In our previous study, in which we examined the bioavailability of oral magnesium compounds, we detected that magnesium levels increased gradually due to gastrointestinal absorption in the blood samples taken at 2nd, 4th, and 8th hours [78]. If the pain threshold experiment had been conducted at an earlier time point, the highest plasma concentration would probably not have been achieved. ...
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Magnesium is being investigated in various clinical conditions and has shown to be effective in some chronic pain models. However, it is not clear if oral magnesium use affects pain perception in acute pain. TLR4’s (toll-like receptor) role in pain perception has emerged through its role in immune pathways and ion channels. The aim of this study is to investigate the effect of a single oral dose of magnesium citrate on pain conduction and whether with magnesium, the expression of TLR4 changes in the acute phase. Following a single dose of 66-mg/kg magnesium citrate administration to male Balb-c mice, pain perception (via hot-plate test), motor conduction (via electrophysiological recording, forelimb grip strength, rotarod and open-field tests), and emotional state (via elevated plus maze and forced swim test) were evaluated. In behavioral experiments, the control group was compared with applied magnesium for three different time groups (4, 8, 24 h). TLR4 expression was measured in four groups: control, magnesium (Mg), hot plate (HP), and Mg + HP. Hot plate latency was prolonged in the magnesium group (p < 0.0001) and electrophysiological recordings (p < 0.001) and forelimb grip strength measurement (p < 0.001) determined motor latency. Compared with the untreated hot plate group, TLR4 levels was lower in the brain (p = 0.023) and higher in the sciatic nerve (p = 0.001) in the magnesium-treated hot plate group. Consequently, the study indicated a single dose of magnesium citrate appeared to cause weakening in the transmission and perception of nociceptive pain. TLR4 may act as a regulator in magnesium’s effects on pain perception.
... Hypomagnesemia is usually managed with magnesium salts including magnesium chloride and magnesium citrate [34]. Magnesium sulfate is used orally but this route of drug administration has limitations which can be addressed with transdermal drug delivery systems. ...
Objective In vitro diffusion experiments were performed to assess the permeation of magnesium sulfate across pig skin. Method The mean thickness of the dermatomed porcine skin was 648 ± 12 µm. Magnesium concentration was measured using inductively coupled plasma-optical emission spectroscopy. Transdermal flux of magnesium sulfate across MN-treated and untreated porcine skin was obtained from the slope of the steady-state linear portion of cumulative amount versus time curve. Results Statistical analysis of the results was done with Student’s t-test. The transdermal flux of magnesium sulfate across microneedle-treated porcine skin was 134.19 ± 2.4 µg/cm2/h, and transdermal flux across untreated porcine skin was 4.64 ± 0.05 µg/cm2/h. Confocal microscopy was used to visualize the microchannels created by a solid microneedle roller (500 µm). Conclusion From our confocal microscopy studies, it was evident that the 500 µm long microneedles disrupted the stratum corneum and created microchannels measuring 191 ± 37 µm. The increase in transdermal flux across the microneedle-treated skin was statistically significant compared to that of controls, i.e., without the application of microneedles. With the application of microneedles, the transdermal flux of magnesium permeated over 12 h was approximately 33-fold higher in comparison to passive diffusion across an intact stratum corneum.
Lithium (Li) isotopes are a tracer of silicate weathering processes, but how they react to different components of organic and plant-assisted weathering is poorly known. To examine the effect of organic acids compared to a strong mineral acid (HCl) on Li isotope behaviour, basalt-water weathering experiments were amended with different organic acids (glycine, malic acid, cinnamic acid, and humic acid; 0.01M). The presence of the different acids significantly affects the behaviour of dissolved elemental concentrations (such as Mg, Fe, and Al), both by increasing primary rock dissolution and hindering rates of secondary mineral formation. However, the behaviour of Li isotopes appears unaffected, with all experiments following an almost identical trend of δ⁷Li versus Li/Na. This observation was consistent with a single fractionation factor during the uptake of Li into secondary minerals, yet both calculated saturation states and leaching experiments on the reacted solids indicated that Li was removed into multiple phases, suggesting that the bulk combined fractionation factor barely varied. Of the Li lost from solution in the organic experiments, we estimated that on average 76% went into neoformed clays, 16% into oxides/oxyhydroxides, and 10% into the exchangeable fraction. The fractionations observed for each phase were Δ⁷Liexch-soln = -12.7 ± 1.7‰, Δ⁷Liox-soln = -26.7 ± 0.4‰, and Δ⁷Liclay-soln = -21.6 ± 3.3‰. These fractionations were identical, within error, to those from experiments with organic-free water, implying that the Li isotope behaviour was unaffected by the presence of organic acids in the weathering reaction. This result has interesting consequences for the interpretation of Li isotopes in terms of plant-assisted weathering and the geological record of terrestrialisation. In particular, it appears to imply that seawater Li isotope records can be expected to resolve the integrated effect of plants on weathering fluxes or weathering congruence, rather than being sensitive to specific organic-mediated weathering mechanisms.
Магний является незаменимым катионом организма человека и содержится преимущественно в костях, мышцах и мягких тканях. Магнийсодержащие лекарственные препараты назначаются с учетом клинических и лабораторно-диагностических показателей. В статье уделено внимание биологической роли магния и связанным с ним фармакодинамическим эффектам лекарственных препаратов. Систематизирована информация по показаниям к применению и противопоказаниям, нежелательным реакциям и лекарственным взаимодействиям с позиции причинно-следственных связей, опирающихся на биохимические, фармакодинамические и фармакокинетические особенности соединений магния. Установлено, что соли магния обладают низкой биодоступностью (и зависят от типа соли), всасываются в тонком кишечнике двумя транспортными путями (параклеточный и трансклеточный), а почки оказывают важную роль в поддержании гомеостаза магния. Magnesium is an irreplaceable cation of the human body and it is found mainly in bones, muscles and soft tissues. Magnesium-containing medicines are prescribed on the base of clinical and laboratory diagnostic parameters. The article is focused on the biological role of magnesium and the associated pharmacodynamic effects of medicines. Actual and systematic information about medical use and contraindications, adverse reactions and drug interactions was systematized according to pharmacodynamics and pharmacokinetics of magnesium compounds and cause- effect relationships. It is discovered that magnesium salts have low bioavailability (and depend on the type of salt); they are absorbed in the small intestine by two transport pathways (paracellular and transcellular), and kidneys play an important role in maintaining the magnesium homeostasis.
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Background Information on the bioavailability of the essential mineral Mg2+ is sparse. Objective/Method Evaluation of the present knowledge on factors influencing the bioavailability and intestinal absorption of Mg2+. Results Mg2+ is absorbed via a paracellular passive and a transcellular active pathway that involves TRPM6/7 channel proteins. The bioavailability of Mg2+ varies within a broad range, depending on the dose, the food matrix, and enhancing and inhibiting factors. Dietary factors impairing Mg2+ up-take include high doses of other minerals, partly fermentable fibres (e.g., hemicellulose), non-fermentable fibres (e.g., cellulose, lignin), phytate and oxalate, whereas proteins, medium-chain-triglycerides, and low- or indigestible carbohydrates (e.g., resistant starch, oligosaccharides, inulin, mannitol and lactulose) enhance Mg2+ uptake. The Mg2+ dose is a major factor controlling the amount of Mg2+ absorbed. In principle, the relative Mg2+ uptake is higher when the mineral is in-gested in multiple low doses throughout the day compared to a single, large intake of Mg2+. The type of Mg2+ salt appears less relevant than is often thought. Some studies demonstrated a slightly higher bioavailability of organic Mg2+ salts compared to inorganic compounds under standardized conditions, whereas other studies did not. Conclusion Due to the lack of standardized tests to assess Mg2+ status and intestinal absorption, it remains unclear which Mg2+ binding form produces the highest bioavailability. The Mg2+ intake dose combined with the endogenous Mg2+ status is more important. Because Mg2+ cannot be stored but only retained for current needs, a higher absorption is usually followed by a higher excretion of the mineral.
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Background: Anxiety related conditions are the most common affective disorders present in the general population with a lifetime prevalence of over 15%. Magnesium (Mg) status is associated with subjective anxiety, leading to the proposition that Mg supplementation may attenuate anxiety symptoms. This systematic review examines the available evidence for the efficacy of Mg supplementation in the alleviation of subjective measures of anxiety and stress. Methods: A systematic search of interventions with Mg alone or in combination (up to 5 additional ingredients) was performed in May 2016. Ovid Medline, PsychInfo, Embase, CINAHL and Cochrane databases were searched using equivalent search terms. A grey literature review of relevant sources was also undertaken. Results: 18 studies were included in the review. All reviewed studies recruited samples based upon an existing vulnerability to anxiety: mildly anxious, premenstrual syndrome (PMS), postpartum status, and hypertension. Four/eight studies in anxious samples, four/seven studies in PMS samples, and one/two studies in hypertensive samples reported positive effects of Mg on subjective anxiety outcomes. Mg had no effect on postpartum anxiety. No study administered a validated measure of subjective stress as an outcome. Conclusions: Existing evidence is suggestive of a beneficial effect of Mg on subjective anxiety in anxiety vulnerable samples. However, the quality of the existing evidence is poor. Well-designed randomised controlled trials are required to further confirm the efficacy of Mg supplementation.
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Adipose tissue is considered an endocrine organ that promotes excessive production of reactive oxygen species when in excess, thus contributing to lipid peroxidation. Magnesium deficiency contributes to the development of oxidative stress in obese individuals, as this mineral plays a role as an antioxidant, participates as a cofactor of several enzymes, maintains cell membrane stability and mitigates the effects of oxidative stress. The objective of this review is to bring together updated information on the participation of magnesium in the oxidative stress present in obesity. We conducted a search of articles published in the PubMed, SciELO and LILACS databases, using the keywords ‘magnesium’, ‘oxidative stress’, ‘malondialdehyde’, ‘superoxide dismutase’, ‘glutathione peroxidase’, ‘reactive oxygen species’, ‘inflammation’ and ‘obesity’. The studies show that obese subjects have low serum concentrations of magnesium, as well as high concentrations of oxidative stress marker in these individuals. Furthermore, it is evident that the adequate intake of magnesium contributes to its appropriate homeostasis in the body. Thus, this review of current research can help define the need for intervention with supplementation of this mineral for the prevention and treatment of disorders associated with this chronic disease.
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The kidney has a vital role in magnesium homeostasis and, although the renal handling of magnesium is highly adaptable, this ability deteriorates when renal function declines significantly. In moderate chronic kidney disease (CKD), increases in the fractional excretion of magnesium largely compensate for the loss of glomerular filtration rate to maintain normal serum magnesium levels. However, in more advanced CKD (as creatinine clearance falls <30 mL/min), this compensatory mechanism becomes inadequate such that overt hypermagnesaemia develops frequently in patients with creatinine clearances <10 mL/min. Dietary calcium and magnesium may affect the intestinal uptake of each other, though results are conflicting, and likewise the role of vitamin D on intestinal magnesium absorption is somewhat uncertain. In patients undergoing dialysis, the effect of various magnesium and calcium dialysate concentrations has been investigated in haemodialysis (HD) and peritoneal dialysis (PD). Results generally show that dialysate magnesium, at 0.75 mmol/L, is likely to cause mild hypermagnesaemia, results for a magnesium dialysate concentration of 0.5 mmol/L were less consistent, whereas serum magnesium levels were mostly normal to hypomagnesaemic when 0.2 and 0.25 mmol/L were used. While dialysate magnesium concentration is a major determinant of HD or PD patients' magnesium balance, other factors such as nutrition and medications (e.g. laxatives or antacids) also play an important role. Also examined in this review is the role of magnesium on parathyroid hormone (PTH) levels in dialysis patients. Although various studies have shown that patients with higher serum magnesium tend to have lower PTH levels, many of these suffer from methodological limitations. Finally, we examine the complex and often conflicting results concerning the interplay between magnesium and bone in uraemic patients. Although the exact role of magnesium in bone metabolism is unclear, it may have both positive and negative effects, and it is uncertain what the optimal magnesium levels are in uraemic patients.
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A large section of the North American population is not meeting recommended intakes for magnesium (Mg). Supplementation and consumption of Mg-fortified foods are ways to increase intake. Currently, information on Mg bioavailability from different compounds and their efficacy in improving Mg status is scant. This study compared the relative ability of inorganic and organic Mg compounds to preserve the Mg status of rats when fed at amounts insufficient to retain optimal Mg status. Male Sprague-Dawley rats (n=12/diet group) were fed one of eight test diets supplemented with phytic acid (5 g/kg diet) and low levels of Mg (155 mg elemental Mg/kg diet) from Mg oxide, Mg sulphate, Mg chloride, Mg citrate, Mg gluconate, Mg orotate, Mg malate or ethylenediaminetetraacetic acid disodium Mg salt for five weeks. Rats were also fed three control diets that did not contain added phytic acid but were supplemented with 500 (NMgO, normal), 155 (LMgO, low) or 80 (DMgO, deficient) mg of Mg per kg diet as Mg oxide. Mg concentrations in femur, serum and urine showed a graded decrease in rats fed the control diets with lower Mg. Mg concentrations did not differ (P≥0.05) between rats fed the different test diets. Addition of phytic acid to the diet did not affect the Mg status of the rats. The results indicate that any differences in the Mg bioavailability of the compounds were small and physiologically irrelevant.
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Implies that a balance of the different essential nutrients is necessary for maintaining health. The eight minerals that are usually analysed are Na, K, Ca, Mg, P, Fe, Cu, Zn. A comparison of the mineral content of 20 fruits and 20 vegetables grown in the 1930s and the 1980s (published in the UK Government’s Composition of Foods tables) shows several marked reductions in mineral content. Shows that there are statistically significant reductions in the levels of Ca, Mg, Cu and Na in vegetables and Mg, Fe, Cu and K in fruit. The only mineral that showed no significant differences over the 50 year period was P. The water content increased significantly and dry matter decreased significantly in fruit. Indicates that a nutritional problem associated with the quality of food has developed over those 50 years. The changes could have been caused by anomalies of measurement or sampling, changes in the food system, changes in the varieties grown or changes in agricultural practice. In conclusion recommends that the causes of the differences in mineral content and their effect on human health be investigated.
Background: The role of magnesium in maintaining muscle integrity and function in older adults is largely unknown. Objective: We aimed to investigate the relation between serum magnesium concentrations and muscle performance in older subjects. Design: Data are from the baseline examination conducted between September 1998 and March 2000 of the InCHIANTI (aging in the Chianti area) study, a prospective epidemiologic survey of risk factors for late-life disability. From among 1453 randomly selected community residents completing a home interview, 1138 men (46%) and women (aged 66.7 ± 15.2 y; x̄ ± SD) with complete data on muscle performance and serum magnesium who were not severely cognitively compromised and had no evidence of kidney disease or hypercalcemia were included in the analysis. Muscle performance was evaluated by grip strength, lower-leg muscle power, knee extension torque, and ankle extension isometric strength and was normalized for age and body mass index (BMI) within each sex. Results: After adjustment for age, sex, BMI, laboratory variables, presence of chronic diseases, muscle area, muscle density, and physical activity level, serum magnesium concentrations were significantly associated with indexes of muscle performance, including grip strength (β = 2.0 ± 0.5, P = 0.0002), lower-leg muscle power (β = 8.8 ± 2.7, P = 0.001), knee extension torque (β = 31.2 ± 7.9, P < 0.0001), and ankle extension strength (β = 3.8 ± 0.5, P < 0.0001). Conclusions: The serum magnesium concentration is an independent correlate of muscle performance in older persons. Whether magnesium supplementation improves muscle function remains to be shown.