Chromium
Increases Insulin Internalization
Evans GW & Bowman TD. J Inorg Biochem (1992 Jun) 46(4):
243-50
The effects of chromium chloride, chromium nicotinate,
and chromium picolinate on insulin internalization in cultured
rat skeletal muscle cells was examined. Insulin internalization
was markedly increased in cells cultured in a medium that
contained chromium picolinate and the increased internalization
rate was accompanied by a marked increase in the uptake
of both glucose and leucine. The effect was specific for
chromium picolinate since neither zinc picolinate nor any
of the other forms of chromium tested was effective. The
increased insulin internalization rate may result from an
increase in membrane fluidity since chromium picolinate
and to a lesser extent, chromium nicotinate, increased the
membrane fluidity of synthetic liposomal membranes.
Longevity Effect of Chromium Picolinate
McCarty MF. Med Hypotheses (1994 Oct) 43(4): 253-65
The first rodent longevity study with the insulin-sensitizing
nutrient chromium picolinate has reported a dramatic increase
in both median and maximal lifespan. Although the observed
moderate reductions in serum glucose imply a decreased rate
of tissue glycation reactions, it is unlikely that this
alone can account for the substantial impact on lifespan;
an effect on central neurohormonal regulation can reasonably
be suspected. Recent studies highlight the physiological
role of insulin as a modulator of brain function. I postulate
that aging is associated with a reduction of effective insulin
activity in the brain, and this contributes to age- related
alterations of hypothalamic functions that result in an
'older' neurohormonal milieu; consistent with this possibility,
diabetes leads to changes of hypothalamic regulation analogous
to those seen in normal aging. Conversely, promoting brain
insulin activity with chromium picolinate may help to maintain
the hypothalamus in a more functionally youthful state;
increased hypothalamic catecholamine activity, sensitization
of insulin- responsive central mechanisms regulating appetite
and thermogenesis, and perhaps trophic effects on brain
neurons may play a role in this regard. Since both the pineal
gland and thymus are dependent on insulin activity, chromium
may aid their function as well. Thus, the longevity effect
of chromium picolinate may depend primarily on delay or
reversal of various age-related changes in the body's hormonal
and neural milieu. A more general strategy of hypothalamic
'rejuvenation' is proposed for extending healthful lifespan.
Chromium and other insulin sensitizers may enhance glucagon
secretion: implications for hypoglycemia and weight control.
Med Hypotheses (ENGLAND) Feb 1996, 46 (2) p77-80
Increased pancreatic beta-cell secretory activity usually
is associated with decreased alpha-cell activity; stimulated
beta-cells release gamma-aminobutyric acid, which hyperpolarizes
alpha-cells, inhibiting glucagon release. Thus, insulin
secretion and glucagon secretion are usually inversely coupled.
This suggests that chromium and other insulin-sensitizing
modalities increase glucagon secretion. Such an effect might
play a role in the documented therapeutic activity of supplemental
chromium and biguanides in reactive hypoglycemia, and might
also be of benefit to dieters.
Effects of chromium picolinate supplementation on body
composition: A randomized, double-masked, placebo-controlled
study
Current Therapeutic Research - Clinical and Experimental
(USA), 1996, 57/10 (747-756)
To examine the effect of chromium picolinate (CrP) on body
composition, a randomized, double-masked, placebo-controlled
study was conducted. A total of 154 patients received either
a placebo or 200 microg or 400 microg of CrP per day. Subjects
were asked to consume at least two servings of a protein/carbohydrate
nutritional drink a day that contained the different amounts
of CrP. Subjects were free-living and were not provided
with weight loss, dietary, or exercise guidance. Body composition
was measured before and after the 72-day test period by
using underwater testing (displacement method) with residual
lung volumes determined by helium dilution. On completion
of the posttest, a body composition improvement (BCI) index
was calculated for each subject by adding the loss of body
fat and gain in nonfat mass and subtracting fat gained and
lean lost. Analysis of the prestudy data revealed that there
were no significant differences in body composition between
the three groups. After the test period, both the 200-microg
and 400-microg groups had significantly higher positive
changes in BCIs compared with placebo. A single-factor analysis
of variance weighted linear trend was also highly significant.
No significant differences in BCI were found between the
200- and 400-microg groups. Supplementation with a minimum
of 200 microg/d of chromium (as CrP) can lead to significant
improvement in body composition.
Chromium improves insulin response to glucose in rats.
Metabolism (UNITED STATES) Oct 1995, 44 (10)
The effects of chromium (Cr) supplementation on insulin
secretion and glucose clearance (KG) during intravenous
glucose tolerance tests (IVGTTS) were assessed in rats with
impaired glucose tolerance due to dietary Cr deficiency.
Male Wistar rats were maintained after weaning on a basal
low-Cr diet containing 55% sucrose, 15% lard, 25% casein.
American Institute of Nutrition (AIN)-recommended levels
of vitamins, no added Cr, and an altered mineral content
as required to produce Cr deficiency and impaired glucose
tolerance. The Cr-supplemented group ([+Cr] n = 6) were
provided with 5 ppm Cr as CrCl3 in the drinking water, and
the Cr-deficient group ([-Cr]n = 5) received purified drinking
water. At 12 weeks on the diet, both groups of rats were
hyperinsulinemic (+Cr, 103 +/- 13; -Cr, 59 +/- 12 microU/mL)
and normoglycemic (+Cr, 127 +/- 7; -Cr, 130 +/- 4 mg/dL),
indicating insulin resistance. After 24 weeks, insulin levels
were normal (+Cr, 19 +/- 5; -Cr, 21 +/- 3 microU/mL) and
all rats remained normoglycemic (+Cr, 124 +/- 8; -Cr, 131
+/- 6 mg/dL). KG values during IVGTTS were lower in -Cr
rats (KG = 3.58%/min) than in +Cr rats (KG = 5.29%/min),
correlating with significantly greater 40-minute glucose
areas in the -Cr group (P < .01). Comparisons of 40-minute
insulin areas indicated marked insulin hyperresponsiveness
in the -Cr group, with insulin-secretory responses increased
nearly twofold in -Cr animals (P < .05). Chromium deficiency
also led to significant decreases in cyclic adenosine monophosphate
(cAMP)-dependent phosphodiesterase (PDE) activity in spleen
and testis (P < .01). In these studies, Cr deficiency
was characterized by both beta-cell hypersecretion of insulin
and tissue insulin resistance that were associated with
decreased tissue levels of cAMP PDE activity.
Enhancing central and peripheral insulin activity as a
strategy for the treatment of endogenous depression--an
adjuvant role for chromium picolinate?
Med Hypotheses (ENGLAND) Oct 1994, 43 (4)
Depression is often associated with insulin resistance,
owing to cortisol overproduction; conversely, many studies
suggest that diabetics are at increased risk for depression.
Recent evidence indicates that insulin is transported through
the blood-brain barrier and influences brain function via
widely distributed insulin receptors on neurons. These receptors
are particularly dense on catecholaminergic synaptic terminals,
and, while effects are variable dependent on brain region,
several studies indicate that insulin promotes central catecholaminergic
activity, perhaps by inhibiting synaptic re-uptake of norepinephrine.
Additionally, it is well known that insulin enhances serotonergic
activity in increasing blood-brain barrier transport of
tryptophan. Since impaired monoaminergic activity in key
brain pathways is believed to play an etiological role in
depression, techniques which promote effective insulin activity,
both centrally and peripherally, may be therapeutically
beneficial in this disorder. This may rationalize anecdotal
reports of improved mood in clinical depressives and diabetics
receiving the insulin-sensitizing nutrient chromium picolinate.
This nutrient, perhaps in conjunction with other insulin-sensitizing
measures such as low-fat diet and aerobic exercise training
(already shown to be beneficial in depression), should be
tested as an adjuvant for the treatment and secondary prevention
of depression.
Homologous physiological effects of phenformin and chromium
picolinate.
Med Hypotheses (ENGLAND) Oct 1993, 41 (4)
The insulin-sensitizing drug phenformin, in addition to
its clinical utility in type II diabetes, has been reported
to lower blood lipids, reduce body fat, enhance cellular
immunity, and--in rodents--to increase mean lifespan and
retard the development of growth of cancer. Initial studies
with the insulin-sensitizing nutrient chromium picolinate
indicate that it aids glucose tolerance in type II diabetes,
lowers elevated LDL cholesterol, reduces body fat while
increasing lean mass, and--in rats--increases median lifespan.
These effects are thus analogous to those reported for phenformin;
chromium picolinate should be tested to determine whether
it likewise has a favorable impact on cellular immunity
and cancer risk. The ability of both phenformin and chromium
picolinate to increase lifespan suggests that age-related
insulin resistance may play a profound role in the aging
process. It may not be coincidental that caloric restriction--the
best documented technique for increasing lifespan--markedly
increases insulin sensitivity. Safe, appropriate measures
for promoting lifelong insulin sensitivity include a low-fat
diet, exercise training, and supplemental chromium picolinate.
Chromium in human nutrition: a review
J Nutr (UNITED STATES) Apr 1993, 123 (4)
This review summarizes the results of 15 controlled studies
supplementing defined Cr (III) compounds to subjects with
impaired glucose tolerance. Three of these (3-4 mumol Cr/d
for 2 mo) produced no beneficial effects: serum glucose,
insulin and lipid concentrations remained unchanged. The
remaining 12 interventions improved the efficiency of insulin
or the blood lipid profile of subjects (ranging from malnourished
children and healthy middle-aged individuals to insulin-requiring
diabetics). In addition, three cases of impaired glucose
tolerance after long-term total parenteral alimentation
responding to Cr supplementation have been reported. Chromium
potentiates the action of insulin in vitro and in vivo;
maximal in vitro activity requires a special chemical form,
termed Glucose Tolerance Factor and tentatively identified
as a Cr-nicotinic acid complex. Its complete structural
identification is a major challenge to chromium research.
The development and validation of a procedure to diagnose
chromium status is the second challenge. Such a test would
allow the assessment of incidence and severity of deficiency
in the population and the selection of deficiency in the
population and the selection of chromium-responsive individuals.
The third challenge is the definition of chromium's mode
of action on parameters of lipid metabolism that have been
reported from some studies but not others. Future research
along these lines might establish whether chromium deficiency
is a factor in the much discussed "Syndrome X"
of insulin resistance. (49 Refs.)
Use of the artificial beta cell (ABC) in the assessment
of peripheral insulin sensitivity: effect of chromium supplementation
in diabetic patients.
Gen Pharmacol (ENGLAND) 1984, 15 (6)
The artificial beta cell (ABC), a closed-loop insulin delivery
system, was used to determine insulin sensitivity. Progressively
increasing glucose loads were administered after initial
stabilization of the blood glucose at euglycemic levels
such that the serum C-peptide was suppressed. The amount
of insulin required to maintain euglycemia was considered
a measure of sensitivity to insulin. Six stable maturity
onset diabetics were studied before and after supplementation
with chromium-rich brewer's yeast. All patients demonstrated
an increase in sensitivity to insulin as indicated by a
decrease in the fasting blood glucose concentration and
a decrease in insulin requirement during the glucose challenge
(P less than 0.02). The data obtained support the hypothesis
that chromium or some other factor(s) present in brewer's
yeast potentiates the peripheral effects of insulin. It
remains to be established whether this effect occurs at
the receptor or post-receptor level.
Effects of dietary chromium picolinate supplementation
on growth, carcass characteristics, and accretion rates
of carcass tissues in growing-finishing swine.
J Anim Sci (UNITED STATES) Nov 1995, 73 (11)
An experiment was conducted to evaluate the effects of
chromium picolinate (CrP) on growth performance, carcass
composition, and tissue accretion rates in pigs from 27
to 109 kg BW. Seven littermate sets of Yorkshire-Hampshire
barrows, individually penned, were fed a fortified, corn-soybean
meal basal diet (.95% lysine from 27 to 55 kg; .80% lysine
from 55 to 109 kg) supplemented with 0 or 200 micrograms/kg
of Cr from CrP. Addition of CrP increased (P < .09) ADG
but did not affect ADFI or feed: gain ratio. Average and
10th rib backfat and longissimus muscle area were not affected
by Cr supplementation. The right side of the carcass was
physically dissected into muscle, fat, bone, and skin. Additionally,
five pigs were killed for determination of initial body
composition. Dietary CrP addition increased (P < .02)
the percentage of muscle and decreased (P < .06) the
percentage of fat. Total gain of dissected bone and skin
were not different between treatments, but CrP increased
(P < .06) the total gain of dissected muscle and decreased
(P < .02) the total gain of dissected fat. Also, CrP
increased the daily accretion rates of muscle (P < .05)
and bone (P < .03) and decreased the daily accretion
rate of fat (P < .05). The left side of the carcass was
ground for determination of water, protein, lipid, and ash.
The addition of CrP to the diet increased the percentage
(P < .09) and accretion rate (P < .09) of water and
increased the percentage (P < .004), total gain (P <
.02), and accretion rate (P < .02) of protein while decreasing
(P < .04) the percentage of lipid. Pigs fed CrP also
had a decreased (P < .004) percentage of lipids in the
dissected carcass muscle. Water, protein, and ash from the
dissected muscle were not different between treatments.
These results suggest that CrP supplementation throughout
the entire growing-finishing phase increases the total gain
and accretion rate of muscle while decreasing the total
gain and accretion rate of fat. This results in carcasses
with an increased percentage of muscle and decreased percentage
of fat.
Anabolic effects of insulin on bone suggest a role for
chromium picolinate in preservation of bone density.
Med Hypotheses (ENGLAND) Sep 1995, 45 (3) p241-6
Activation of osteoclasts by parathyroid hormone (PTH)
is mediated by PTH stimulation of osteoblasts, and is dependent
on a PTH-induced rise in protein kinase C activity. Physiological
levels of insulin reduce the ability of PTH to activate
protein kinase C in osteoblasts, suggesting that insulin
may be a physiological antagonist of bone resorption. In
addition, insulin is known to promote collagen production
by osteoblasts. These findings imply that efficient insulin
activity may exert an anabolic effect on bone, and rationalize
the many clinical studies demonstrating reduced bone density
in Type I diabetes. Recently, the insulin-sensitizing nutrient
chromium picolinate has been found to reduce urinary excretion
of hydroxyproline and calcium in postmenopausal women, presumably
indicative of a reduced rate of bone resorption. This nutrient
also raised serum levels of dehydroepiandrosterone-sulfate,
which may play a physiological role in the preservation
of postmenopausal bone density. The impact of chromium picolinate
(alone or in conjunction with calcium and other micronutrients)
on bone metabolism and bone density, merits further evaluation
in controlled studies. (69 Refs.)
Effect of chromium picolinate on growth, body composition,
and tissue accretion in pigs.
J Anim Sci (UNITED STATES) Jul 1995, 73 (7) p2033-42
An experiment was conducted to evaluate the effect of dietary
chromium picolinate (CrP) on growth and body composition
of pigs. Twenty-four barrows (three from each of eight litters)
were randomly allotted within litter to one of three treatments:
1) basal (B) diet from 19.1 to 106.4 kg BW (Control); 2)
B from 19.1 to 57.2 kg BW and then B + 200 ppb of chromium
as CrP from 57.2 to 106.4 kg BW (CrP-F); and 3) B + 200
ppb of chromium as CrP from 19.1 to 106.4 kg BW (CrP- GF).
Average daily gain and ADFI were reduced (P < .08) and
first rib fat thickness was increased (P < .08) in pigs
fed CrP-GF compared with pigs fed the Control diet. Specific
gravity of the carcass was not affected (P .10) by treatment.
Tenth rib fat was reduced (P < .01) in pigs fed CrP-F
compared with pigs fed CrP-GF, and percentage of muscle
was increased in pigs fed CrP-F (P < .09) compared with
pigs fed either the Control or CrP-GF diets. Leaf fat (P
< .05) and lung weights (P < .08) were reduced in
pigs fed CrP-F compared with pigs fed CrP-GF. As determined
by physical-chemical separation, pigs fed CrP-GF had an
increased (P < .07) percentage of intermuscular fat compared
with pigs fed the Control or CrP-F diets. Pigs fed CrP-F
had a lesser (P < .07) percentage of total fat and a
greater (P < .07) percentage of muscle than pigs fed
the Control or CrP-GF diets. As determined by mechanical-chemical
separation, pigs fed CrP-F had a greater (P < .10) percentage
of moisture than pigs fed the Control diet and a lesser
(P < .10) percentage of fat and a greater (P < .06)
percentage of ash than pigs fed the Control or CrP-GF diets.
Pigs fed CrP-GF had an increased (P < .04) daily fat
accretion compared with pigs fed CrP-F. Sensory and shear
force values were not affected by CrP, with the exception
that meat from pigs fed CrP-GF had a greater (P < .10)
shear force value than meat from pigs fed CrP-F. These results
suggest that dietary supplementation of CrP in the finishing
phase of pig production may increase muscle and decrease
fat deposition; however, not all measures of muscling or
fatness were improved by CrP.
Longevity effect of chromium picolinate--'rejuvenation'
of hypothalamic function?
Med Hypotheses (ENGLAND) Oct 1994, 43 (4) p253-65
The first rodent longevity study with the insulin-sensitizing
nutrient chromium picolinate has reported a dramatic increase
in both median and maximal lifespan. Although the observed
moderate reductions in serum glucose imply a decreased rate
of tissue glycation reactions, it is unlikely that this
alone can account for the substantial impact on lifespan;
an effect on central neurohormonal regulation can reasonably
be suspected. Recent studies highlight the physiological
role of insulin as a modulator of brain function. I postulate
that aging is associated with a reduction of effective insulin
activity in the brain, and this contributes to age-related
alterations of hypothalamic functions that result in an
'older' neurohormonal milieu; consistent with this possibility,
diabetes leads to changes of hypothalamic regulation analogous
to those seen in normal aging. Conversely, promoting brain
insulin activity with chromium picolinate may help to maintain
the hypothalamus in a more functionally youthful state;
increased hypothalamic catecholamine activity, sensitization
of insulin-responsive central mechanisms regulating appetite
and thermogenesis, and perhaps trophic effects on brain
neurons may play a role in this regard. Since both the pineal
gland and thymus are dependent on insulin activity, chromium
may aid their function as well. Thus, the longevity effect
of chromium picolinate may depend primarily on delay or
reversal of various age-related changes in the body's hormonal
and neural milieu. A more general strategy of hypothalamic
'rejuvenation' is proposed for extending healthful lifespan.
Effects of chromium picolinate on beginning weight training
students.
Int J Sport Nutr (UNITED STATES) Dec 1992, 2 (4) p343-50
Changes in body weight (BW), a sum of three body circumferences
(sigma C), a sum of three skinfolds (sigma SF), and the
one-repetition maximum (1RM) for the squat (SQ) and bench
press (BP) were examined in 59 college-age students (37
males [M], 22 females [F]) over a 12-week weight lifting
program. Using a double-blind protocol, half of the students
were given 200 micrograms/day chromium (Cr) in the form
of chromium picolinate (CrPic) while the other half received
a placebo (P). Therefore four groups were randomly formed:
F-CrPic (n = 12), F-P (n = 10), M-CrPic (n = 18), and M-P
(n = 19). All groups had significant increases in sigma
C and significant decreases in sigma SF. No treatment effects
were seen for the strength measurements, although the males
experienced greater absolute increases. The only significant
treatment effect found was due to the F-CrPic group gaining
more BW (p = 0.0048) than the other three groups. It was
concluded that CrPic supplementation had a greater effect
on the females than on the males.
Nutritional ergogenic aids: chromium, exercise, and muscle
mass.
Int J Sport Nutr (UNITED STATES) Sep 1991, 1 (3) p289-93
Athletes who want to develop muscle mass have sought various
ways to reach this goal. We are all too familiar with the
abuse of anabolic steroids and growth hormone. Given the
concern for such abuses, athletes and coaches are seeking
new and safer means to achieve the same end. Within the
last couple of years, advertisements for chromium supplements
have been prominently displayed in body-building and strength-training
magazines. These supplements are purported to be a safe
alternative to anabolic steroids and are said to promote
an increase in muscle mass. This brief review will focus
on the theoretical basis for believing that chromium supplements
will increase muscle mass, and on the current research regarding
the relationship of chromium and exercise.
Efficacy of chromium supplementation in athletes: emphasis
on anabolism
Int J Sport Nutr (UNITED STATES) Jun 1992, 2 (2) p111-22
As the biologically active component of glucose tolerance
factor (GTF), the essential trace mineral chromium is now
being marked to athletes. GTF potentiates insulin activity
and is responsible for normal insulin function. Thus, insulin's
effects on carbohydrate, fat, and protein metabolism are
dependent upon the maintenance of adequate chromium stores.
Due to excessive chromium loss and marginal chromium intake,
athletes may have an increased requirement for chromium.
Therefore, in some circumstances the dietary supplementation
of a chromium compound may be efficacious. The restoration
and maintenance of chromium stores via supplementation would
promote optimal insulin efficiency, necessary for high-level
athletic performance. However, potential anabolic effects
of enhanced insulin function would likely be marginal, and
reports of short-term anabolic increases from the supplementation
of an organic chromium compound need to be confirmed. (87
Refs.)
Chromium and other insulin sensitizers may enhance glucagon
secretion: Implications for hypoglycemia and weight control
Medical Hypotheses (United Kingdom), 1996, 46/2 (77-80)
Increased pancreatic beta-cell secretory activity usually
is associated with decreased alpha-cell activity; stimulated
beta-cells release gamma-aminobutyric acid, which hyperpolarizes
alpha-cells, inhibiting glucagon release. Thus, insulin
secretion and glucagon secretion are usually inversely coupled.
This suggests that chromium and other insulin-sensitizing
modalities, by down-regulating beta-cell activity, may increase
glucagon secretion. Such an effect might play a role in
the documented therapeutic activity of supplemental chromium
and biguanides in reactive hypoglycemia, and might also
be of benefit to dieters.
Age-related decreases in chromium levels in 51,665 hair,
sweat, and serum samples from 40,872 patients - Implications
for the prevention of cardiovascular disease and type II
diabetes mellitus
Metabolism: Clinical and Experimental (USA), 1997, 46/5
(469-473)
This report shows, for the first time using modern analytical
techniques, highly significant age-related decreases in
chromium levels in 51,665 hair, sweat, and serum samples
obtained from 40,872 patients referred by their physicians
to an independent medical research clinic and laboratory
(r = -. 598 to -. 762, P < .0001 for all correlations).
Males were found to have significantly lower mean chromium
levels than females (P < .05 to .0001). There was good
correlation between chromium levels in hair, sweat, and
serum (r = 536 to .729, P < .0001 for all correlations),
indicating that hair and sweat chromium levels are valid
additions to the serum levels in assessing chromium status.
Chromium measurements in sweat, hair, and serum were performed
using graphite furnace atomic absorption spectrophotometry.
The influences that age-related decreases in chromium levels
might have on increasing the risk to develop age-related
impaired glucose metabolism, disordered lipid metabolism,
coronary heart disease, arteriosclerosis, and type II diabetes
mellitus are outlined, and the role that refined carbohydrates
play in the development of compromised chromium status is
presented.
Chromium oligopeptide activates insulin receptor tyrosine
kinase activity
Biochemistry (USA), 1997, 36/15 (4382-4385)
A possible new mechanism for the amplification of insulin
receptor tyrosine kinase activity in response to insulin
has been identified. The chromium-containing oligopeptide
low molecular weight chromium-binding substance (LMWCr)
does not effect the tyrosine protein kinase activity of
rat adipocytic membrane fragments in the absence of insulin;
however, insulin- stimulated kinase activity in the membrane
fragments is increased up to 8- fold by the oligopeptide.
Using isolated rat insulin receptor, LMWCr has been shown
to bind to insulin-activated insulin receptor with a dissociation
constant of circa 250 pM, resulting in the increase of its
tyrosine protein kinase activity. The ability of LMWCr to
stimulate insulin receptor tyrosine kinase activity is dependent
on its chromium content. The results appear to explain the
previously poorly understood relationship between chromium
and adult-onset diabetes and cardiovascular disease.
Effect of chromium nicotinic acid supplementation on selected
cardiovascular disease risk factors
Biological Trace Element Research (USA), 1996, 55/3 (297-305)
The effects of daily supplemental chromium (200 microg)
complexed with 1.8 mg nicotinic acid on plasma glucose and
lipids, including total cholesterol, HDL cholesterol, LDL
cholesterol, and triglycerides, were assessed in 14 healthy
adults and 5 adults with noninsulin-dependent diabetes mellitus
(NIDDM) using a double-blind crossover study with 8-wk experimental
periods. Eight of the 14 healthy subjects and all 5 subjects
with NIDDM also underwent an oral glucose tolerance test
with assessment of 90 min postprandial plasma glucose and
insulin concentrations. No statistically significant effects
of chromium nicotinic acid supplementation were found on
plasma insulin, glucose, or lipid concentrations, although
chromium nicotinic acid supplementation slightly lowered
fasting plasma total and LDL cholesterol, triglycerides,
and glucose concentrations, and 90-min postprandial glucose
concentrations in individuals with NIDDM.
Chromium picolinate supplementation improves cardiac metabolism,
but not myosin isoenzyme distribution in the diabetic heart
Journal of Nutritional Biochemistry (USA), 1996, 7/11 (617-622)
Because chromium (Cr) containing compounds are thought
to improve glucose homeostasis, we hypothesized that chromium
picolinate (CrP) could partially reverse diabetes-induced
damage to cardiac tissue. Young, adult female rats were
fed either a basal diet (CONT), a basal diet containing
no CrP and made diabetic (DIAB-CONT), or a basal diet containing
600 ng/g of CrP (3 times the suggested daily chromium intake)
and made diabetic (DIAB-CrP). Diabetes was induced by a
single streptozotocin injection, 55 mg/kg i.p. After 8 weeks
animals were sacrificed, hearts removed, and spectrophotometrically
analyzed for citrate synthase (CS), hexokinase (HK), and
beta hydroxyacyl CoA dehydrogenase activity (HOAD). Cardiac
myosin isoenzymes were separated from crude myofibril extracts
by PAGE electrophoresis. Diabetes did not alter CS activity
relative to the CONT group, but did significantly (P <
0.05) reduce HK and HOAD activity and expression of the
high ATPase myosin isoenzyme VI. In contrast, DIAB-CrP animals
displayed normal HK activity and greater HOAD activity relative
to CONT animals. Surprisingly, the addition of CrP to the
diet further reduced expression of the VI myosin isoenzyme.
These results demonstrate thet dietary CrP supplementation
has diverse effects on the subcellular properties of the
diabetic heart. The functional impact of these CrP-induced
changes remains to be defined.
Vitamin and mineral deficiencies which may predispose to
glucose intolerance of pregnancy
Journal of the American College of Nutrition (USA), 1996,
15/1 (14-20)
There is an increased requirement for nutrients in normal
pregnancy, not only due to increased demand, but also increased
loss. There is also an increased insulin resistant state
during pregnancy mediated by the placental anti-insulin
hormones estrogen, progesterone, human somatomammotropin;
the pituitary hormone prolactin; and the adrenal hormone,
cortisol. If the maternal pancreas cannot increase production
of insulin to sustain normoglycemia despite these anti-insulin
hormones, gestational diabetes occurs. Gestational diabetes
is associated with excessive nutrient losses due to glycosuria.
Specific nutrient deficiencies of chromium, magnesium, potassium
and pyridoxine may potentiate the tendency towards hyperglycemia
in gestational diabetic women because each of these four
deficiencies causes impairment of pancreatic insulin production.
This review describes the pathophysiology of the hyperglycemia
and the nutrient loss in gestational diabetes and further
postulates the mechanism whereby vitamin/mineral supplementation
may be useful to prevent or ameliorate pregnancy-related
glucose intolerance.
[The effect of chromium picolinate on the liver levels
of trace elements]
Nutr Hosp (SPAIN) Nov-Dec 1995, 10 (6) p373-6
Chromium picolinate has been implicated as a lipid and
carbohydrate reducing agent, and therefore it may be a valuable
adjunct to the treatment and prevention of diabetes and
heart disease. This compound is inexpensive and apparently
nontoxic. In this work, we have determined the influence
of its administration (100, 200, 500 micrograms Cr/ml, for
7 and 21 days) on hepatic content of Zn, Mn, Cu and Fe of
male Wistar rats. The results show a variation of the levels
of these elements after the administration of chromium picolinate,
although the differences are only significantly (p <
0.01) in the case of Mn. This influence is dose-dependent,
occurring at a decrease of 72% in the group treated with
500 micrograms/ml (Pic-500) respect to the content of control
group.
Anabolic effects of insulin on bone suggest a role for
chromium picolinate in preservation of bone density.
Med Hypotheses (ENGLAND) Sep 1995, 45 (3) p241-6
Activation of osteoclasts by parathyroid hormone (PTH)
is mediated by PTH stimulation of osteoblasts, and is dependent
on a PTH-induced rise in protein kinase C activity. Physiological
levels of insulin reduce the ability of PTH to activate
protein kinase C in osteoblasts, suggesting that insulin
may be a physiological antagonist of bone resorption. In
addition, insulin is known to promote collagen production
by osteoblasts. These findings imply that efficient insulin
activity may exert an anabolic effect on bone, and rationalize
the many clinical studies demonstrating reduced bone density
in Type I diabetes. Recently, the insulin-sensitizing nutrient
chromium picolinate has been found to reduce urinary excretion
of hydroxyproline and calcium in postmenopausal women, presumably
indicative of a reduced rate of bone resorption. This nutrient
also raised serum levels of dehydroepiandrosterone-sulfate,
which may play a physiological role in the preservation
of postmenopausal bone density. The impact of chromium picolinate
(alone or in conjunction with calcium and other micronutrients)
on bone metabolism and bone density, merits further evaluation
in controlled studies. (69 Refs.)
Beneficial effect of chromium supplementation on serum
triglyceride levels in NIDDM.
Diabetes Care (UNITED STATES) Dec 1994, 17 (12) p1449-52
OBJECTIVE--To investigate the effect of chromium picolinate
supplementation on the lipid profile of the predominantly
Hispanic population of non-insulin-dependent diabetes mellitus
(NIDDM) patients in San Antonio, Texas.
RESEARCH DESIGN AND METHODSóA prospective, double-blind,
placebo-controlled, crossover study was performed on 14
men and 16 women. Initially, each patient was randomly assigned
to receive either chromium picolinate or placebo for 2 months.
This initial treatment phase was followed by a 2-month washout
period. Subjects were then crossed-over and received the
alternate capsule for an additional 2 months. Fasting blood
glucose, HbA1c, and serum lipids were compared at the end
of each treatment phase.
RESULTS--Twenty-eight of the originally enrolled 30 patients
completed the study. There were no adverse reactions to
chromium reported. There were no differences noted between
the control and chromium-treated subjects in glucose control,
high-density lipoprotein cholesterol levels, or low-density
lipoprotein cholesterol levels. Triglyceride (TG) levels
were reduced significantly (17.4%; P < 0.05) during the
2 months of chromium supplementation.
CONCLUSIONS--Ours is the first report of a significant
reduction in serum TGs in a group of NIDDM patients treated
with chromium. The low cost and excellent safety profile
of chromium make it an attractive lipid-lowering agent for
this population. Long-term studies are needed to determine
if the short-term changes in plasma lipids can be sustained.
Insulin resistance in Mexican Americansóa precursor
to obesity and diabetes?
Med Hypotheses (ENGLAND) Oct 1993, 41 (4) p308-15
Mexican Americans appear to have a strong genetic predisposition
to insulin resistance, android obesity, and type II diabetes,
apparently as a function of Native American genetic heritage.
Theoretical considerations suggest that insulin resistance
may be a primary factor that plays a causative role in the
induction of both obesity and diabetes. Measures which promote
optimal insulin sensitivity--chromium picolinate, brewer's
yeast, soluble fiber supplements, metformin, very-low-fat
diet, exercise training--may have value for preventing,
treating, or retarding the onset of obesity and diabetes,
and merit clinical evaluation in this regard. Correction
of insulin resistance may also lessen cardiovascular risk,
in part by reducing LDL cholesterol and improving risk factors
associated with Syndrome X. These comments are likely to
be valid for other Native American groups at high risk for
diabetes.
An expanded concept of "insurance" supplementation--broad-spectrum
protection from cardiovascular disease.
Med Hypotheses (ENGLAND) Oct 1981, 7 (10) p1287-1302
The preventive merits of "nutritional insurance"
supplementation can be considerably broadened if meaningful
doses of nutrients such as mitochondrial "metavitamins"
(coenzyme Q, lipoic acid, carnitine), lipotropes, and key
essential fatty acids, are included in insurance supplements.
From the standpoint of cardiovascular protection, these
nutrients, as well as magnesium, selenium, and GTF-chromium,
appear to have particular value. Sophisticated insurance
supplementation would likely have a favorable impact on
many parameters which govern cardiovascular risk--serum
lipid profiles, blood pressure, platelet stability, glucose
tolerance, bioenergetics, action potential regulation--and
as a life-long preventive health strategy might confer substantial
benefit.