Nephrol Dial Transplant (2013) 28: 716–723
doi: 10.1093/ndt/gfs170
Advance Access publication 4 July 2012
Original Articles
1
Moosa Salehi1,
Department of Nutrition, Shiraz School of Health and Nutrition,
Shiraz University of Medical Sciences, Shiraz, Iran,
Zahra Sohrabi1,
2
1
Maryam Ekramzadeh ,
Health Policy Research Center, Shiraz University of Medical
Sciences, Shiraz, Iran,
3
2
Mohammad Kazem Fallahzadeh ,
Shiraz Transplant Research Center, Shiraz University of Medical
Sciences, Shiraz, Iran and
Maryam Ayatollahi3,
4
3
Bita Geramizadeh ,
Shiraz Nephro-Urology Research Center, Shiraz University of
Medical Sciences, Shiraz, Iran
Jafar Hassanzadeh1
and Mohammad Mahdi Sagheb4
Keywords: anorexia, antioxidants, nutrition assessment, trace
elements, uremia
Correspondence and offprint requests to: Mohammad
Mahdi Sagheb; E-mail: saghebf@gmail.com
†
The authors declare that the results presented in this
paper have not been published previously in whole or
part, except in the abstract form.
ferritin and transferrin as well as the subjective global assessment (SGA) score, malnutrition–inflammation score (MIS)
and hemoglobin (Hb) levels were measured at the baseline
and at the end of the treatment phase. The primary outcome
was a change in the nutritional status measured by the SGA
score from the baseline towards the end of the treatment
phase of the study.
Results. The SGA score and MIS decreased significantly in
the selenium group compared to the placebo group
(P < 0.001 for both). Moreover, serum levels of MDA decreased significantly in the selenium group compared with
increasing levels in the placebo group (P < 0.001). Selenium supplementation also hindered an increase in IL-6
levels compared with the placebo group (P = 0.016). There
were no significant differences between the selenium and
placebo groups in terms of changes in serum levels of lipoproteins, HSCRP, homocysteine, ferritin and transferrin
or Hb levels.
A B S T R AC T
Background. Malnutrition is highly prevalent in hemodialysis (HD) patients. These patients have high levels of oxidative
stress and inflammation which can subsequently induce malnutrition. Selenium levels have been found to be decreased in
HD patients. As selenium deficiency leads to oxidative stress
and inflammatory response, the aim of this study was to
evaluate the effects of selenium supplementation on oxidative
and inflammatory markers and the nutritional status of HD
patients.
Methods. In this randomized double-blind placebo-controlled trial, 80 patients on stable HD for at least 3 months
without any acute illness or active infections were randomly
allocated to two equal groups to receive one selenium (200
µg) or placebo capsule daily for 12 weeks. Serum levels of
lipoproteins, malondialdehyde (MDA), interleukin-6 (IL-6),
high-sensitivity C-reactive protein (HSCRP), homocysteine,
© The Author 2012. Published by Oxford University Press on
behalf of ERA-EDTA. All rights reserved.
716
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Selenium supplementation improves the nutritional status of
hemodialysis patients: a randomized, double-blind, placebocontrolled trial†
INTRODUCTION
(i)
The patients in the first group received one capsule of
selenium in the form of selenium yeast (200 µg) daily
for 12 weeks.
(ii)
The patients in the second group received one capsule
of placebo daily for 12 weeks.
Blocked randomization with a fixed block size of four was
performed by one of the investigators who had no clinical involvement in the study using Random Allocation Software
[17]. All selenium and placebo capsules were provided by
Shiraz School of Pharmacy in prepacked bottles numbered
for each patient according to the randomization sequence.
Each patient was assigned to an order number and received
the selenium or placebo in the corresponding prepacked
bottles. The placebo and selenium capsules were completely
similar in size, weight, color and taste. All of the patients,
clinical investigators, including the one who administered
SGA questionnaires, and other health care staff were blinded
to the treatment assignment.
Selenium has a narrow window of the therapeutic index.
The maximum recommended allowance dose for selenium is
400–450 µg/day. As the baseline selenium levels of the
patients were not measured in this study, in order to maintain the patients’ safety and reduce the chance of selenium
toxicity, the dose of selenium supplementation was chosen to
be 200 µg/day. Moreover, in support of choosing this dose, a
3-month treatment of HD patients with the same dose of oral
selenium has been demonstrated to be safe and effective in
restoring levels of selenium and in attenuating oxidative
DNA damage in a study by Zachara et al. [18].
SGA is a comprehensive nutritional assessment tool that
has several strengths: it is inexpensive and rapid to conduct,
can be easily implemented in different disciplines, needs no
laboratory evaluation and has been shown to be valid and
M AT E R I A L S A N D M E T H O D S
This randomized, double-blind, placebo-controlled, two-arm
parallel trial was done in accordance with the Declaration of
Helsinki and Good Clinical Practice guidelines. The Ethics
Committee of Shiraz University of Medical Sciences reviewed
and approved the protocol of this study. Eligible participants
were 18- to 80-year-old patients who were under regular HD
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Selenium for malnutrition in hemodialysis patients
ORIGINAL ARTICLES
Malnutrition or insufficient protein-calorie intake is highly
prevalent in hemodialysis (HD) patients [1]. Protein-energy
wasting and inflammation are concurrent conditions in HD
patients and are associated with poor prognosis [1]. Hence,
the term malnutrition–inflammation complex syndrome
(MICS) was used to comprise both malnutrition and inflammation, regardless of the original causes [1, 2]. MICS is considered as one of the main causes of atherosclerotic
cardiovascular disease (CVD), hospitalization and increased
mortality in HD patients [1].
Among the contributing factors to the pathogenesis of
MICS in HD patients, high oxidative stress is considered to
be one of the most important ones [3, 4]. High oxidative
stress in HD patients results from increased production of
oxidative compounds and impaired antioxidant defense
mechanisms [5–7]. Selenium is an essential trace element
with known antioxidant properties [8, 9]. It acts as a cofactor
for the reduction in important antioxidant enzymes like glutathione peroxidase [10]. Several studies have demonstrated
that HD patients have low levels of selenium compared with
healthy controls, and deficiency of this trace element may
contribute to increased oxidative stress and inflammation in
HD patients [10–13]. Furthermore, strong positive correlations between levels of selenium and nutritional markers
such as serum albumin have been reported [14, 15]. Therefore, selenium deficiency may also contribute to malnutrition
in HD patients [11]. So far, a few small non-controlled trials
have shown the efficacy of selenium supplementation in reducing oxidative stress markers in HD patients [6]. However, no
clinical study has ever evaluated the efficacy of selenium supplementation on improving clinical outcomes such as malnutrition in these patients. Therefore, we performed this trial to
evaluate the efficacy of selenium supplementation on improving the nutritional status of HD patients. Furthermore, to
delineate its possible mechanisms of action, we evaluated the
effects of selenium supplementation on serum levels of malondialdehyde (MDA) as a surrogate marker for oxidative
stress and on serum levels of interleukin-6 (IL-6) and highsensitivity C-reactive protein (HSCRP) as surrogate markers
for inflammation.
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in Faghihi Hospital Hemodialysis Center for 3 months or
more. Exclusion criteria were pregnancy, taking antioxidant
supplements including vitamin E, vitamin C, lipoic acid,
omega-3 fatty acids, soy extracts and green-tea preparations
or immunosuppressive medications within 2 months prior to
enrollment in the study, hospitalization in the previous
month before the onset of the trial, or having active infection.
Sample size was determined according to the subjective
global assessment (SGA) score in a previous study in malnourished HD patients [16]. A sample size of 25 patients per
group was obtained with a mean difference of 0.8, an SD of 1
and a probability of 80% at the predetermined level of
α = 0.05. While considering 15 dropouts in each group, the
final sample size was determined to be 40 patients per group.
After screening all of the 280 patients under regular HD
in Faghihi Hospital Hemodialysis Center, 80 stable patients
were found to be eligible for enrollment and gave their informed consent to participate in this trial. These participants
were dialyzed three times a week by low-flux dialyzer with
polysulfone/polyamide membranes, reverse osmosis purified
water and bicarbonate-containing dialysate. These patients
were randomly assigned in a 1:1 ratio into two groups:
Conclusions. This study shows that selenium may be an effective complementary supplement for reducing the severity
of malnutrition in HD patients through alleviating oxidative
stress and inflammation.
ORIGINAL ARTICLES
SA, Belgium ELISA kits for IL-6; Biomerica, CA, USA
ELISA kits for PTH; Axis Shield, UK ELISA kits for homocysteine; IBL, Germany ELISA kits for HSCRP and ferritin); intra- and interassay coefficients of variation were 4.2
and 4.4%, 2.8 and 5.1%, 7 and 9%, 4.1 and 5.8%, and 7.8
and 7.6%, respectively. Other parameters were measured
with standard automated techniques. Adverse events were
inspected by clinical staff in each dialysis session during
the treatment phase of the trial.
Statistical analyses were done using SPSS version 15 (SPSS
Inc., Chicago, IL) statistical software package. Normally distributed data were compared between two groups by an independent sample t-test; skewed data were compared by the
Mann–Whitney U-test and categorical data such as sex by χ 2
test. P-values <0.05 were considered statistically significant.
The primary outcome of this trial was an absolute change in
nutritional statuses of patients measured by the SGA score
from the baseline to the end of the treatment phase of the
study in an intention-to-treat population.
This trial is registered with Clinicaltrial.gov, number
NCT01147354, where the trial protocol could be accessed.
R E S U LT S
Eligible participants were recruited from March 2009 to June
2009. As demonstrated in the flow diagram of the study
(Figure 1), during the treatment phase of the study, 11
patients were excluded in the selenium group and 4 in the
placebo group. The reasons for these exclusions are mentioned in the flow diagram. Baseline demographic and laboratory characteristics of patients in both groups are
demonstrated in Table 1; no statistically significant differences were observed between these two groups in terms of
baseline characteristics. All of the enrolled patients were
under regular treatment with erythropoietin and intravenous
iron based on our regional HD guideline.
The changes in measured parameters during the treatment phase of the study are mentioned in Table 2. SGA
scores and MIS decreased in the selenium group while
these scores increased in the placebo group; when changes
in these scores were compared between the two groups, decrements in SGA scores and MIS in the selenium group
were significantly different from the corresponding increments in the placebo group (P < 0.001 for both). Likewise,
a decrement in serum levels of MDA was significantly
different from the corresponding increment in the placebo
group (P < 0.001). Moreover, serum levels of IL-6 increased
in both groups; however, this increment was significantly
lower in the selenium group (P = 0.016). Changes in other
parameters were not significantly different between two
groups.
The frequency of serious adverse events and other adverse
events in patients is demonstrated in Table 3. Other adverse
events occurred in the first 2 weeks of treatment, and none of
them was bothersome enough to compel the patients to quit
the treatment.
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M. Salehi et al.
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reliable in HD patients [19, 20]. Despite these advantages, it
should be appreciated that the status of visceral proteins such
as albumin is not well assessed by SGA. To compensate for
this problem, the malnutrition–inflammation score (MIS) has
been developed that incorporates the serum laboratory
markers of malnutrition with SGA and is suggested to be a
better indicator of MICS [19, 21, 22]. Therefore, in this study,
the nutritional statuses of all patients were assessed by both
SGA and MIS. At the baseline, the questions of the SGA
questionnaire were read to the patients and completed in
person by the main investigator of this study who is an
experienced nutritionist working with HD patients regularly. The questions of SGA questionnaire were also asked
by the same person at the end of the treatment phase. Furthermore, the physical examinations were done by the same
person at the baseline and at the end of the treatment
phase. The SGA questionnaire inquired about any changes
in weight (during the preceding 6 months and 2 weeks),
dietary intake, gastrointestinal symptoms, functional
capacity and an assumed metabolic demand of the underlying disease. The physical examination consisted of loss of
subcutaneous fat, muscle wasting and the presence of
ankle/sacral edema. Each of these features were rated as A,
B or C separately to indicate the degree of malnutrition.
Then, the SGA classifications were converted to numerical
equivalents: a score of <10 points was regarded as wellnourished; 10–17 points, at risk for malnutrition or mildly
to moderately malnourished; and more than 17 points, severely malnourished [23]. MIS consisted of four sections
(nutritional history, physical examination, BMI and laboratory values) and 10 components. The first three sections
included five components adopted from the original SGA
and the fourth MIS section included two laboratory values:
serum albumin and transferrin. Each component had four
levels of severity, from 0 (normal) to 3 (severely abnormal).
The sum of all 10 MIS components ranged from 0
(normal) to 30 (severely malnourished); a higher score reflected a more severe degree of malnutrition and inflammation [21].
Before the onset of the treatment and after the end of the
treatment phase of the study, 10 cc blood samples were taken
from each patient. The blood was taken from the patient’s
arm used for HD cannulae just before the beginning of the
HD session. The serum was separated by centrifugation at
3000 g/min for 5 min and stored at −70°C. Serum levels of
MDA (µmol/L), IL-6 ( pg/mL), HSCRP (μg/mL), ferritin (ng/
mL), transferrin (μg/dL), homocysteine (μmol/L), calcium
(mg/dL), phosphate (mg/dL), parathyroid hormone (PTH)
( pg/dL), albumin (g/dL), blood urea nitrogen (BUN) (mg/
dL) and creatinine (mg/dL) as well as hemoglobin (Hb) levels
(g/dL) were measured in all patients at the baseline and at
the end of the treatment phase of the study.
Serum concentrations of MDA were measured by the
modified thiobarbituric acid method (spectrophotometric
method); the intra- and interassay coefficients of variation
were 5.5 and 5.9%, respectively [24]. Serum levels of IL-6,
PTH, homocysteine, HSCRP and ferritin were measured
using highly sensitive ELISA kits (DIAsource Immunoassays
Our study, for the first time, demonstrated the efficacy of selenium supplementation in improving the nutritional status of
HD patients. This effect is probably mediated by inhibiting
oxidative stress and inflammation.
High oxidative stress and generalized inflammation are
implicated in the pathogenesis of several complications of
HD like atherosclerotic CVD, anemia and malnutrition [3, 7,
25]. This high oxidative stress in HD patients results from an
imbalance between pro- and antioxidant factors [6, 7].
Among defense mechanisms against oxidative injury, selenium-dependent enzymes like glutathione peroxidase are
the most important ones [5, 8, 25]. There are several reports
on the deficiency of selenium and its dependent enzymes in
HD patients [5, 12, 13, 26]. Furthermore, low levels of selenium in HD patients have been reported to be associated
with increased inflammatory markers [27]. There are also
reports on a possible association of selenium deficiency with
increased risk of malnutrition in HD patients evidenced by
significant positive correlations found between low levels of
selenium and of nutritional markers such as serum albumin,
total muscle mass, triceps skin-fold and mid-arm muscle circumference [11, 14, 15, 26, 28]. Although few interventional
studies have demonstrated the beneficial effects of selenium
supplementation on reducing oxidative stress markers or increasing the activity of antioxidant enzymes in HD patients
[28–32], the potential efficacy of selenium supplementation
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Selenium for malnutrition in hemodialysis patients
ORIGINAL ARTICLES
in improving clinical outcomes like malnutrition in these
patients has not been evaluated in any randomized controlled
trial so far.
In our study, a decrease in serum levels of MDA in the
selenium group was significantly higher than placebo. In an
interventional study by Ardalan et al. [32], selenium and
vitamin E administration to HD patients prevented the iron
infusion-induced increase in serum levels of MDA. In another
interventional study by Koenig et al. [31], selenium supplementation decreased plasma levels of MDA and increased
levels of antioxidant enzymes like glutathione peroxidase in
HD patients. Furthermore, in a recent interventional study,
Zachara et al. [18] have demonstrated that HD patients have
higher oxidative DNA damage in white blood cells compared
with healthy controls, and selenium supplementation could
significantly dampen this damage. Moreover, in our study, an
increase in serum levels of IL-6 levels was significantly lower in
the selenium group than placebo. By regulating the expression
of selenoprotein genes, selenium has been shown to inhibit the
activation of nuclear factor kappa B (NF-κB) signaling
pathway and therefore decrease the production of inflammatory cytokines such as IL-6 [33, 34]. Therefore, based on the
findings of our study, the observed beneficial effect of selenium
supplementation on improving the nutritional status of HD
patients may be partly mediated by the inhibition of oxidative
damage and inflammation. However, in this study, changes in
serum levels of other inflammatory markers such as HSCRP
were not significantly different between two groups. These
DISCUSSION
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F I G U R E 1 : Flow diagram of the trial.
Table 1. Baseline demographic characteristics and measured parameters in patients
Demographic characteristics and
measured parameters in patients
Selenium
Placebo
P-value
Number
40
40
—
17 (42.5)a
17 (42.5)
—
Diabetic nephropathy
14 (35)
11 (27.5)
Renal stone
1 (2.5)
0 (0)
Polycystic kidney disease
0 (0)
1 (2.5)
Pyelonephritis
2 (5)
1 (2.5)
Glomerulonephritis
1 (2.5)
1 (2.5)
Unknown
5 (12.5)
9 (22.5)
Age (years)
50 ± 15.4
55 ± 13
NS
Gender (female)
24 (60)
20 (50)
NS
BMI (kg/m )
22.86 ± 4.07
22.37 ± 3.52
NS
Daily Kt/V
1.42 ± 0.26
1.34 ± 0.17
NS
Creatinine (mg/dL)
7.75 ± 2.6
8.5 ± 4.11
NS
BUN (mg/dL)
64.04 ± 21.3
64.9 ± 28.9
NS
Calcium (mg/dL)
8.12 ± 1.1
8.13 ± 0.89
NS
Phosphorus (mg/dL)
5.25 ± 1.8
5.64 ± 1.6
NS
PTH (pg/dL)
84.9 (8.85, 318.97)
96.7 (25.97, 221.6)
NS
Albumin (g/dL)
4.43 ± 0.69
4.1 ± 1.06
NS
SGA score
12 (9, 18)
11 (8.25, 12)
NS
MIS
9 (4.25, 14.75)
8 (5, 10)
NS
MDA (µmol/L)
11.83 ± 3.02
11.56 ± 2.9
NS
IL-6 (pg/mL)
33.55 (8.37, 53.45)
14.55 (0.5, 53.17)
NS
HSCRP (μg/mL)
4.5 (1.72,19.97)
6.7 (2.75, 26.77)
NS
TG (mg/dL)
104.53 ± 58.59
121.5 ± 60.73
NS
Total cholesterol (mg/dL)
155.81 ± 33.77
163.5 ± 39.31
NS
LDL (mg/dL)
88.09 ± 27.88
89.45 ± 34.3
NS
HDL (mg/dL)
46.08 ± 17.1
49.75 ± 14.21
NS
Homocysteine (μmol/L)
23.7 ± 10.38
24.45 ± 8.25
NS
Ferritin (ng/mL)
819.4 (439.95, 1180)
838.9 (468.52, 1048.5)
NS
Total iron binding capacity (μg/dL)
315 (204, 454)
303 (147, 474.75)
NS
Hb (g/dL)
9.94 ± 2.28
10.4 ± 2.22
NS
Causes of ESRD (frequency)
Hypertensive nephropathy
NS, not significant.
Categorical data are expressed as number (%), continuous data with normal distribution as means ± SDs and continuous data with
skewed distribution as median (IQR).
a
differences may reach significance levels in studies with larger
sample sizes and longer durations.
In addition to its antioxidant and anti-inflammatory properties, the observed beneficial effects of selenium on the
nutritional status may be attributed to its effects on the digestion and absorption of fat, nutrient utilization, decreasing
ketone bodies (as appetite suppressants) and improving
insulin effects [35–38].
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ORIGINAL ARTICLES
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2
Table 2. Effect of selenium supplementation on levels of measured parameters in patients
Placebo group
P-value
SGA score
−3.89 ± 3.2 [−5.13 to
−2.65]a
1.35 ± 3.01 [0.3–2.4]
<0.001
MIS
−4.17 ± 4.2 [−5.81 to
−2.54]
0.7 ± 3.71 [−0.58 to 2]
<0.001
MDA (µmol/l)
−1.2 (−3.17, −0.45) [−2.41
to −1.16]
0.6 (0.01, 2.22) [0.47–1.86]
<0.001
IL-6 (pg/mL)
6.05 (−20.4, 50.8) [−61.4 to
89.68]
22.95 (0.92, 1978.2)
[336.33–1218.3]
0.016
HSCRP (μg/mL)
−0.85 (−2.47, 5.25) [−1.99
to 16.46]
1.3 (−17.7, 4.52) [−13.69 to
5.08]
NS
TG (mg/dL)
14.5 (−2.5, 54.25) [3.06–
50.55]
23 (−12, 54) [−7.25 to
36.28]
NS
Total cholesterol(mg/dL)
−13.7 ± 50.4 [−34.09 to
6.63]
−8.02 ± 59.6 [−28.51 to
12.45]
NS
LDL (mg/dL)
−15.2 ± 45.27 [−33.5 to
3.07]
−5.44 ± 53.86 [−23.94 to
13.06]
NS
HDL (mg/dL)
7.7 ± 26.1 [−2.16 to 17.7]
0.69 ± 23.5 [−7.26 to 8.64]
NS
Homocysteine (μmol/L)
−6.04 ± 9.04 [−9.48 to
−2.59]
−2.75 ± 10.02 [−6.14 to
0.64]
NS
Ferritin (ng/mL)
23 (−107, 216.45) [−26.67
to 168.58]
−31.4 (−153.65, 124.35)
[−194.55 to 38.5]
NS
Total iron-binding capacity
(μg/dL)
−15 (−276, 103.5)
[−322.35 to −0.74]
6 (−177, 162) [−88.11 to
128.17]
NS
Hb (g/dL)
−0.23 ± 2.04 [−1.01 to
0.53]
−0.14 ± 2.29 [−0.9 to 0.62]
NS
Albumin (g/dL)
0.61 ± 1.14 [0.17–1.05]
0.4 ± 1.09 [−0.01 to 0.81]
NS
NS, not significant.
a
Continuous data with normal distribution are expressed as means ± SDs [95% confidence interval] and continuous data with skewed
distribution as median (IQR) [95% confidence interval].
Table 3. Adverse events in patients
Adverse events
Serious adverse events
Other adverse events
Selenium group
a
Placebo group
Death due to myocardial
infarction
2
2
Death due to
cerebrovascular accident
1
0
Dyspepsia and abdominal
pain
2
3
Nausea and vomiting
2
0
a
Number of patients with adverse events.
The beneficial effect of selenium supplementation on
the nutritional status of patients with chronic diseases was
also observed in a randomized interventional study by
Federico et al. [39]; in this interventional study,
aggravation of the nutritional status was prevented in
patients with cancer of the digestive tract who received selenium and zinc supplementation compared with those
who received placebo.
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ORIGINAL ARTICLES
Selenium group
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Measured parameters
AC K N O W L E D G E M E N T S
This study was funded by a Grant from Shiraz University of
Medical Sciences, Shiraz, Iran. We would like to thank Dr
Nasrin Shokrpour for English review of this article.
C O N F L I C T O F I N T E R E S T S TAT E M E N T
None of the authors has any conflict of interest to declare.
(See related article by Thompson and Tonelli. Selenium for
malnutrition in hemodialysis patients: have we considered all
of the elements? Nephrol Dial Transplant 2013; 28: 498–500.)
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ORIGINAL ARTICLES
CVD is the main cause of mortality in HD population
[4, 6]. Malnutrition, inflammation and oxidative stress are
all proposed to contribute to the pathogenesis of CVD in
HD patients through mediation of vascular injury and
endothelial dysfunction [4, 6, 40]. Surrogate markers of
malnutrition and inflammation such as MIS, SGA score
and serum levels of IL-6 have been demonstrated to be
correlated with the prospective mortality rate in HD
patients in several studies [21, 22, 41, 42]. Moreover, antioxidant therapies like vitamin E and N-acetylcysteine have
been shown to be effective in reducing CVD events in
HD patients [43, 44]. Therefore, selenium supplementation that has been demonstrated to be effective in hampering
the
surrogate
markers
of
malnutrition,
inflammation and oxidative stress in our study could
potentially reduce CVD and its resultant mortality in HD
patients. However, this claim needs to be further evaluated in future studies with larger sample sizes and longer
durations.
Selenium has a low therapeutic index, and toxicity may
occur with its high-dose supplementation; adverse effects
of selenium toxicity include brittle hair and nails and their
loss, dermatitis, pulmonary edema, neurotoxicity, nausea
and vomiting [12, 45]. Except for gastrointestinal disturbances in few patients, none of the other adverse effects of
selenium toxicity was observed in this trial. A few cardiovascular deaths also occurred in both selenium and
placebo groups; however, these deaths are probably due to
higher prevalence of CVDs in HD population. The low incidence of adverse events in this study may be due to the
administration of lower dose of selenium (200 µg/day)
compared with its maximum allowance dose (400–450 µg/
day) [12]. Other trials which used similar doses of selenium in HD patients also did not report the adverse
events of selenium toxicity [18, 30, 32]. However, due to
short duration and low sample size of these trials as well
as our trial, selenium supplementation in HD patients
could not be claimed safe.
The main limitation of our study, and interpretation of its
results, is the lack of the selenium measurement at the baseline and at the end of the treatment phase. Without measuring these levels, it is not known to what extent the differences
in the baseline selenium levels might have impacted the
therapeutic effect of the selenium supplementation; therefore,
it is impossible to say that the selenium supplementation was
actually successful. Low sample size and short duration are
other limitations of our study.
In conclusion, our study for the first time demonstrated
the efficacy of selenium supplementation in improving the
nutritional status of HD patients in short term. This perceived effect may be mediated by hampering oxidative
stress and inflammation. Therefore, selenium supplementation may be considered as an addition to the current
therapeutic remedies for malnutrition in HD patients.
However, further multicenter trials with larger sample
sizes are needed to confirm its efficacy and safety in the
long term and also to delineate its possible mechanisms of
action.
723
Selenium for malnutrition in hemodialysis patients
ORIGINAL ARTICLES
Received for publication: 29.1.2012; Accepted in revised form: 6.4.2012
Downloaded from https://academic.oup.com/ndt/article/28/3/716/1812238 by guest on 05 November 2022
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