Chromium and parenteral nutrition.
Studies involving patients on total parenteral nutrition (TPN) led to conclusive
documentation of the essential role of Cr in human nutrition. These patients
developed severe diabetic symptoms including glucose intolerance, weight
loss, impaired energy utilization, and nerve and brain disorders that were
refractory to insulin. After addition of Cr to TPN fluids, diabetic symptoms
were alleviated, and exogenous insulin was no longer required. Cr intake
by healthy subjects consuming average Westernized diets is suboptimal; if
these subjects experience severe physical trauma or other forms of stress,
Cr status may be overtly compromised. Recommendations for daily Cr supplementation
of 10-20 micrograms for patients on short-term TPN (< or = 1-3 mos) appear
to be adequate. Stable patients on long-term TPN may receive ample Cr from
that present in TPN fluids. Because of the variable nature of contaminating
Cr, Cr intake and losses of TPN patients should be monitored.
Nutrition. 1995 Jan-Feb;11(1 Suppl):83-6
Effect of chromium supplementation
on glucose tolerance and lipid profile.
OBJECTIVES: To investigate chromium status of the adult population in the western
region of Saudi Arabia and the possibility of using serum chromium status measurement
as indicator of this status. METHODS: The effect of chromium supplement on
glucose tolerance and lipid profile was studied in 44 normal, free living adults.
200mg chromium/day as CrCL3 or a placebo was given in a double blind cross-over
study, with 8 weeks experimental periods. Fasting, 1 hour and 2 hour post glucose
challenge (75 g of glucose) glucose, serum fructosamine, total cholesterol,
high-density lipoprotein-cholesterol, triglycerides, chromium and dietary intakes
were estimated at the beginning and the end of each stage. RESULTS: Mean serum
chromium increased significantly after supplement (P<.001) indicating proper
absorption of the element. Supplement did not effect the total cholesterol,
however, the mean high-density lipoprotein-cholesterol level was significantly
increased (P<.001), the mean triglycerides levels significantly decreased
(P<.001), and the mean fructosamine level significantly decreased (P<.05).
In addition, chromium supplement effected 1 hour and 2 hour post glucose challenge
glucose levels in subgroups of subjects with 2 hour glucose level > 10%
above or below fasting level and significantly differing to it (P<.05 in
both cases), by decreasing or increasing them significantly (P<.05 in all
cases) so that the 2 hour mean became not significantly different to the fasting
mean. Since no significant changes in weight, dietary intake or habits were
found, and placebo had no effect, all noted biochemical changes were attributed
to chromium. CONCLUSION: Improved glucose control, and lipid profile following
chromium supplement suggests the presence of low chromium status in the studied
population. However, serum chromium could not be recommended for use as an
indicator of chromium status as subjects with widely varying levels responded
favorably to the chromium supplement.
Saudi Med J. 2000 Jan;21(1):45-50
Beneficial effects of chromium in
people with type 2 diabetes, and urinary chromium response to glucose
load as a possible indicator of status.
No reliable method for the estimation of chromium (Cr) status is available
yet. The aim of this study is to investigate the possibility of using urinary
Cr response to glucose load as an indicator of Cr status. Seventy-eight non-insulin-dependent
diabetes mellitus patients, were divided randomly into two groups and given
Cr supplements as brewer's yeast and CrCl3 sequentially with placebo in between,
in a double-blind, crossover design of four stages, each lasting 8 wk. At the
beginning and end of each stage, subjects were weighed, their dietary data
and drug dosage recorded, and blood and urine samples collected for analysis
of glucose and urinary chromium (fasting and 2 h post-75-g glucose load) and
fructosamine. The mean urinary Cr after the glucose load was significantly
higher than the fasting mean at zero time (p<0.01). However, only 52 of
the patients showed an obvious increase; the others showed a slight decrease
or no change. Both supplements caused a significant increase in the means of
urinary Cr and a significant decrease in the means of glucose and fructosamine.
Only those subjects responding to Cr supplement by improved glucose control
showed an increase in post-glucose-load urinary Cr over fasting level, after
the supplement but not at zero time. Therefore, it was concluded that urinary
Cr response to glucose load could be used as an indicator of Cr status.
Biol Trace Elem Res. 2002 Feb;85(2):97-109
Antioxidant effects of chromium supplementation
with type 2 diabetes mellitus and euglycemic subjects.
To determine the effects of chromium (Cr) supplementations on oxidative stress
of type 2 diabetes and euglycemic (EU) subjects, adult having HbA(1C) values
of <6.0% (EU), 6.8-8.5% (mildly hyperglycemic, MH), and >8.5% (severely
hyperglycemic, SH) were supplemented for 6 months with 1000 microg/day of Cr
(as Cr yeast) or with a placebo. In the beginning, the levels of the plasma
Cr in the MH and SH groups were 25-30% lower than those of the EU subjects.
The values of thiobarbituric acid reactive substances (TBARS) and total antioxidative
status (TAS) of the MH and SH groups were significantly higher than those of
the EU ones. Following supplementations, the levels of plasma TBARS in the
Cr groups of MH and SH groups were significantly decreased (the inverse was
found in the EU) and showed no significant changes in the placebo group. The
levels of plasma TAS in the Cr groups of EU and MH were significantly decreased
(the inverse was found in the SH) and showed no significant changes in the
placebo group. No significant difference was found in the antioxidant enzyme
(superoxide dismutase, glutathione peroxidase, catalase) activities during
supplementations. These data suggest that Cr supplementation was an effective
treatment strategy to minimize increased oxidative stress in type 2 diabetes
mellitus patients whose HbA(1C) level was >8.5%, and the Cr in EU groups
might act as a prooxidant.
J Agric Food Chem. 2004 Mar 10;52(5):1385-9
Concentrations of seven trace elements
in different hematological matrices in patients with type 2 diabetes
as compared to healthy controls.
This study aimed to compare the trace element status of patients with type
2 diabetes (n = 53) with those of nondiabetic healthy controls (n = 50). The
concentrations of seven trace elements were determined in the whole blood,
blood plasma, erythrocytes, and lymphocytes of the study subjects. Vanadium
and iron levels in lymphocytes were significantly higher in diabetic patients
as compared to controls (p < 0.05 for iron and p < 0.01 for vanadium).
In contrast, lower manganese (p < 0.01) and selenium (p < 0.01) concentrations
were detected in lymphocytes derived from patients with type 2 diabetes versus
healthy subjects. Furthermore, significantly lower chromium levels (p < 0.05)
were found in the plasma of diabetic individuals as compared to controls. Trace
element concentrations were not dependent on the degree of glucose control
as determined by correlation analysis between HBA1c versus metal levels in
the four blood fractions. In summary, this study primarily demonstrated that
trace element levels in lymphocytes of patients with type 2 diabetes could
deviate significantly from controls, whereas, in general, no considerable differences
could be found when comparing the other fractions between both patient groups.
Therefore, it seems reasonable to analyze metal levels in leukocytes to determine
trace element status in patients with type 2 diabetes and perhaps in other
diseases.
Biol Trace Elem Res. 2001 Mar;79(3):205-19
Chromium and insulin resistance.
Since as early as the 50s of the last century, it has been known that chromium
is essential for normal glucose metabolism. Too little chromium in the diet
may lead to insulin resistance. However, there is still no standard against
which chromium deficiency can be established. Nevertheless, chromium supplements
are becoming increasingly popular. Various systematic reviews have been unable
to demonstrate any effects of chromium on glycaemic regulation (possibly
due partly to the low dosages used), but there is a slight reduction in body
weight averaging 1 kg. In a double-blind randomised placebo-controlled trial
in a Chinese population with type-2 diabetes mellitus, supplementation with
1000 micrograms of chromium led to a fall in the glycosylated haemoglobin
level (HbA1c) by 2%. Toxic effects of chromium are seldom seen; recently,
however, the safety of one of the dosage forms of chromium, chromium picolinate,
has been questioned. One should be aware that individual patients with type-2
diabetes mellitus may have an increased risk of hypoglycaemic episodes when
taking chromium supplements as self-medication.
Ned Tijdschr Geneeskd. 2004 Jan 31;148(5):217-20
The effects of LDL reduction and
HDL augmentation on physiologic and inflammatory markers.
Cholesterol plays an important role in atherogenesis. Oxidized low-density
lipoprotein cholesterol is harmful to arteries whereas high-density lipoprotein
cholesterol appears to have beneficial properties on vascular function. There
is increasing evidence that inflammation is also involved in the atherogenic
process. Inflammation accelerates atherosclerosis and promotes thrombogenesis,
and inflammatory biomarkers have been correlated with cardiovascular risk.
There is now evidence that lowering low-density lipoprotein and raising high-density
lipoprotein cholesterol have beneficial effects on inflammation that might
contribute to the reduction in clinical cardiovascular events with currently
available lipid-altering therapies. New therapeutic strategies are being designed
to inhibit specific aspects of the inflammatory system that contribute to the
initiation and progression of atherosclerosis.
Curr Opin Cardiol. 2003 Jul;18(4):295-300
New perspectives on the use of niacin
in the treatment of lipid disorders.
Therapy with niacin (nicotinic acid) is unique in that it improves all lipoprotein
abnormalities. It significantly reduces low-density lipoprotein cholesterol,
triglyceride, and lipoprotein(a) levels, while increasing high-density lipoprotein
cholesterol levels. This makes niacin ideal for treating a wide variety of
lipid disorders, including the metabolic syndrome, diabetes mellitus, isolated
low high-density lipoprotein cholesterol, and hypertriglyceridemia. Niacin-induced
changes in serum lipid levels produce significant improvements in both coronary
artery disease and clinical outcomes. Niacin is currently available in 3 formulations
(immediate release, extended release, and long acting), which differ significantly
with respect to their safety and efficacy profiles. Immediate-release niacin
is generally taken 3 times a day and is associated with adverse flushing, gastrointestinal
symptoms, and elevations in blood glucose levels. Long-acting niacin can be
taken once daily and is associated with significantly reduced flushing, but
its metabolism increases the risk of hepatotoxic effects. Extended-release
niacin, also given once daily, has an absorption rate intermediate between
the other formulations and is associated with fewer flushing and gastrointestinal
symptoms without increasing hepatotoxic risk.
Arch Intern Med. 2004 Apr 12;164(7):697-705
Niacin for dyslipidemia: considerations
in product selection.
The efficacy and safety profiles of various forms of niacin for treating dyslipidemia
are described. Niacin is well recognized for treating dyslipidemia in adults
and has been shown to be effective in reducing coronary events. It has a broad
range of effects on serum lipids and lipoproteins, including lowering total
cholesterol, low-density-lipoprotein (LDL) cholesterol, and triglycerides.
Niacin is the most effective lipid-modifying drug for raising high-density-lipoprotein
(HDL) cholesterol levels and has been shown to lower Lp(a) lipoprotein. Niacin
reduces triglycerides and very-low-density-lipoprotein and LDL cholesterol
synthesis, primarily by decreasing fatty acid mobilization from adipose tissue.
Niacin appears to raise HDL cholesterol by reducing hepatic apolipoprotein
A-l clearance and enhancing reverse cholesterol transport. Niacin is metabolized
through a conjugation or nicotinamide pathway. Standard immediate-release niacin
is metabolized primarily through the conjugation pathway, which results in
a high frequency of flushing. Long-acting niacin is metabolized through the
nicotinamide pathway, which results in less flushing but increases the risk
of hepatotoxicity. Extended-release niacin has a more balanced metabolism and
causes fewer of both types of adverse effects. Improved serum lipid levels
during niacin therapy have been associated with clinical and angiographic evidence
of reduced coronary artery disease, especially when combined with statins.
Niacin is particularly useful for managing high triglyceride and low HDL cholesterol
levels as well as the lipid abnormalities associated with metabolic syndrome,
including those commonly encountered in patients with diabetes. Several niacin
products are available with significant differences in their safety and efficacy
profiles. Health care providers must consider the differences between agents
when recommending niacin for dyslipidemia treatment.
Am J Health Syst Pharm. 2003 May
15;60(10):995-1005
Vanadate improves cardiac function
and myocardial energy metabolism in diabetic rat hearts.
Vanadium mimicking the metabolic effects of insulin is known to decrease serum
glucose levels and to influence glucose metabolism in diabetes mellitus. However,
it is unclear whether vanadium ameliorates the metabolic disorder in diabetic
hearts causing myocardial dysfunction. The purpose of this study was to assess
the effects of vanadium on cardiac performance and energy metabolism in diabetic
rat hearts. Four groups of Wistar rats were studied: untreated control rats
(group C, n = 8). vanadate-treated rats (group V, n = 10), untreated diabetic
rats (group DM, n = 9) induced by streptozotocin. and vanadate-treated diabetic
rats (group DMV, n = 8). Vanadate-treated rats drank a 1.5 mM sodium orthovanadate
(Na3VO4) solution during a 4 week diabetic condition. Hearts were perfused
with Krebs-Henseleit buffer after the diabetic duration. After the maximum
left ventricular dP/dt and cardiac efficiency were calculated, the myocardial
contents of ATP and creatine phosphate (P-Cr) and myocardial energy metabolism
were assessed by cytosolic phosphorylation potential. Peak positive and negative
dP/dt, and cardiac efficiency decreased significantly in group DM compared
with group C, while there were no significant differences between groups C
and DMV. The myocardial contents of ATP (micromol/g wet heart) and P-Cr (micromol/g
wet heart), and cytosolic phosphorylation potential (M(-1)) increased from
2.72 +/- 0.46. 1.45 +/- 0.58. and 3,530 +/- 1,220 in group DM to 3.88 +/- 0.76,
3.81 +/- 1.36, and 11,200 +/- 2,400 in group DMV, respectively. It is concluded
that vanadium restored the production of high energy phosphates in the myocardium
and improved myocardial dysfunction by regulating metabolic processes in diabetic
rat hearts.
Jpn Heart J. 2003 Sep;44(5):745-57 |