chromium picolinate supplementation and resistive training by
older men: effects on iron-status and hematologic indexes.
Campbell WW; Beard JL; Joseph LJ; Davey SL; Evans WJ
Donald W Reynolds Department of Geriatrics, University of Arkansas
for Medical Sciences, Little Rock 72205-7199, USA.
Am J Clin Nutr, 66(4):944-9 1997 Oct
chromium competes with iron for binding to transferrin, and high-dose
chromium supplementation has been hypothesized to adversely affect
iron status. This study examined the effects of chromium picolinate
supplementation on hematologic indexes and selected indexes of
iron status in 18 men aged 56-69 y who participated in an introductory
resistive training program. The men were randomly assigned (double-blind
design) to groups (n = 9) that consumed either 17.8 mumol Cr/d
(924 micrograms Cr/d) as chromium picolinate or a low-chromium
placebo for 12 wk while engaging in resistive training twice
weekly (3 sets of 8-12 repetitions at 80% of one repetition maximum
for 5 exercises). Hematocrit, hemoglobin, red blood cell (erythrocyte)
count, mean corpuscular volume, mean corpuscular hemoglobin,
mean corpuscular hemoglobin concentration, red blood cell distribution
width, platelet count, and mean platelet volume were within normal
clinical ranges and were unchanged by either chromium picolinate
supplementation or resistive training. Resistive training decreased
total-iron-binding capacity from 38.4 +/- 9.3 to 27.3 +/- 5.6
mumol/L (P < 0.0001) and increased transferrin saturation
from 35.7 +/- 16.3% to 45.4 +/- 16.9% (P = 0.050). chromium picolinate
supplementation did not influence these responses. Serum iron
concentrations and serum ferritin concentrations were unchanged
by either resistive training or chromium picolinate supplementation.
These data suggest that high-dose chromium picolinate supplementation
for 12 wk did not influence hematologic indexes or indexes of
iron metabolism or status in older men. The decrease in total-iron-binding
capacity and increase in transferrin saturation (%) with resistive
training are largely opposite to changes associated with iron
depletion and suggest a novel effect of resistive training on
[Effect of chromium yeast and chromium picolinate on body composition
of obese, non-diabetic patients during and after a formula diet
Bahadori B; Wallner S; Schneider H; Wascher TC; Toplak H
Ambulanz f ur Diabetes und Stoffwechsel der Medizinischen Universit
atsklinik, Graz, Osterreich.
Acta Med Austriaca, 24(5):185-7 1997
The objective of this study was to assess the effects of chromium
yeast and chromium picolinate on lean body mass during and after
weight reduction with a very-low-calorie diet. 36 obese (BMI
33.7 +/- 5.4 kg/m2), non-diabetic patients aged 45 +/- 6 years
undergoing a 8-week very-low-calorie diet followed by a 18-week
maintenance period. During the whole 26 week treatment period
subjects received either placebo or chromium yeast (200 micrograms/d)
or chromium-picolinate (200 micrograms/d) in a double-blind manner.
Body weight was measured as BMI and body composition after calculation
from skinfold thickness. As a result all three groups showed
comparable weight loss after 8 and 26 weeks. Lean body mass was
reduced in all groups after 8 weeks. However, after 26 weeks
chromium picolinate supplemented subjects showed increased lean
body mass (p < 0.029) whereas the other treatment groups still
had reduced lean body mass. chromium picolinate, but not chromium
yeast, is able to increase lean body mass in obese patients in
the maintenance period after a very-low-calorie diet without
counteracting the weight loss achieved.
chromium supplementation and resistance training: effects on
body composition' strength' and trace element status of men [see
Lukaski HC; Bolonchuk WW; Siders WA; Milne DB
US Department of Agriculture' Agricultural Research Service'
Grand Forks Human Nutrition Research Center' ND' USA.
Am J Clin Nutr, 63(6):954-65 1996 Jun
The effects of 8 wk of daily chromium supplementation (3.3-3.5
mumol as chromium chloride or chromium picolinate) or placebo
(0.1 mumol Cr) and weight training were examined in 36 men in
a double-blind design. Strength' mesomorphy' fat-free mass' and
muscle mass increased with resistance training independently
of chromium supplementation (P < 0.0001). Protein' magnesium'
zinc' copper' and iron intakes equalled or exceeded the recommended
dietary allowance (RDA) or estimated safe and adequate daily
dietary intake (ESADDI) during training and did not change significantly
from pretraining intakes (P > 0.05). chromium supplementation
increased the serum chromium concentration and urinary chromium
excretion without a difference as a result of the chemical form
of chromium (P < 0.05). Resistance training was associated
with a significant decrease (P < 0.05) in serum ferritin'
total-iron-binding capacity' transferrin saturation' the ratio
of enzymatic to immunoreactive ceruloplasmin' and plasma copper'
independently of chromium supplementation. However' transferrin
saturation was decreased more with chromium picolinate supplementation
(24%) than with chromium chloride or placebo (10-13%). Compared
with pretraining values' urinary magnesium excretion increased
(P < 0.05) and urinary zinc output tended to decrease during
the first 4 wk of resistance training and then returned to baseline
values for the final 4 wk' which suggests an adaptation in mineral
excretion in response to weight training. These findings suggest
that routine chromium supplementation has no beneficial effects
on body- composition change or strength gain in men. Whether
chromium supplementation of individuals with diminished chromium
nutriture facilitates propitious changes in body structure and
function remains to be determined.
Effects of chromium picolinate on body composition.
Trent LK; Thieding-Cancel D
Naval Health Research Center' San Diego' CA 92186-5122' USA.
J Sports Med Phys Fitness, 35(4):273-80 1995 Dec
OBJECTIVE: This study explored the efficacy of chromium picolinate
as a fat-reduction aid for obese individuals enrolled in a physical
exercise program. EXPERIMENTAL DESIGN: The study employed a double-blind'
placebo-controlled protocol and lasted for 16 weeks. SETTING:
The physical conditioning programs were conducted on Navy bases
(gymnasium' athletic field' etc.) and met a minimum of three
times per week for at least 30 minutes of aerobic exercise. PARTICIPANTS:
Participants were healthy' active-duty Navy personnel (79 men'
16 women) who exceeded the Navy`s percent body fat standards
of 22% fat for men' 30% for women. Mean age was 30.3 years; racial
distribution was 76% white' 16% black' and 8% other. Comparisons
between the 95 study completers and the 109 dropouts revealed
no significant differences in demographics or baseline percent
body fat. INTERVENTIONS: Bottles of capsules containing either
400 micrograms chromium picolinate or a placebo were distributed
to the designated individuals by their fitness program coordinator.
Participants took one capsule per day and kept a log of their
daily exercise activities. They also completed a pre-post questionnaire
concerning their health and lifestyle habits. MEASURES: Primary
outcome measures were percent body fat' body weight' and lean
body mass. Percent body fat was computed from body circumference
measurements and height. Analyses controlled for diet and exercise.
RESULTS: At the end of 16 weeks' the group as a whole had lost
a small amount of weight and body fat. However' the chromium
group failed to show a significantly greater reduction in either
percent body fat or body weight' or a greater increase in lean
body mass' than did the placebo group. CONCLUSIONS: It was concluded
that chromium picolinate was ineffective in enhancing body fat
reduction in this group and could not be recommended as an adJuvant
to Navy weight-loss programs in general.
Department of Pharmacology and Therapeutics' University of South
Florida College of Medicine' USA.
J Fla Med Assoc, 83(1):29-31 1996 Jan
chromium picolinate is a dietary supplement gaining in popularity
among Americans' especially those seeking a weight-reduction
program. Although the mechanism(s) responsible for the purported
actions of chromium picolinate have not been thoroughly investigated'
studies suggest that the biochemical' physiological' and behavioral
actions of chromium picolinate may be a consequence of the effects
of picolinic acid on the central nervous system. Analogues of
picolinic acid have been shown to induce profound alterations
in the metabolism of serotonin' dopamine' and norepnephrine in
brain. Thus' caution should be used with chromium picolinate
supplements especially by individuals prone to behavioral disorders.
chromium picolinate supplementation for diabetes mellitus.
Fox GN; Sabovic Z
Mercy Health System-Northern Region Family Practice Residency,
Toledo, Ohio 43624, USA. firstname.lastname@example.org
J Fam Pract, 46(1):83-6 1998 Jan
chromium picolinate is a widely available nutritional supplement
marketed for a plethora of afflictions. There is some evidence,
including results from human studies, that it has a role in glucose
homeostasis. We report the case of a 28-year-old woman with an
18-year history of type 1 diabetes mellitus whose glycosylated
hemoglobin (Hb A1c) declined from 11.3% to 7.9% 3 months after
initiation of chromium picolinate, 200 micrograms 3 times daily.
chromium picolinate continues to fall squarely within the scope
of "alternative medicine," with both unproven benefits
and unknown risks. It deserves closer scrutiny with additional
prospective, randomized, double-blind, placebo-controlled trials
to evaluate its efficacy in improving outcomes in patients with
diabetes. A brief review of the literature was done to assist
physicians who are being called upon to counsel and treat patients
who are engaging in alternative therapies.
Lack of toxicity of chromium chloride and chromium picolinate
Anderson RA; Bryden NA; Polansky MM
Nutrient Requirements and Functions Laboratory' Beltsville Human
Nutrition Research Center' U.S. Department of Agriculture' ARS'
Maryland 20705-2350' USA.
J Am Coll Nutr, 16(3):273-9 1997 Jun
OBJECTIVE: To evaluate the safety of chromium (Cr) as a nutrient
supplement. Several recent studies have reported beneficial effects
of supplemental Cr at levels higher than the upper limit of the
suggested intake for Cr. Trivalent Cr is considered relatively
nontoxic but some recent unconfirmed studies have questioned
its toxicity. We evaluated the toxicity of Cr chloride and a
more bioavailable form of trivalent Cr' Cr tripicolinate. METHODS:
Harlan Sprague Dawley rats (4 weeks of age) were fed a stock
diet to which was added 0' 5' 25' 50 or 100 mg of Cr per kg of
diet as chloride or picolinate. Fasting blood samples were taken
at 11 and 17 weeks and animals sacrificed at 24 weeks of age.
Lack of toxicity was demonstrated by blood and histological measurements.
chromium incorporation into tissues was determined by graphite
furnace atomic absorption. RESULTS: There were no statistically
significant differences in body weight' organ weights or blood
variables among all the groups tested at 11' 17 and 24 weeks.
Blood variables measured were glucose' cholesterol' triglycerides'
blood urea nitrogen' lactic acid dehydrogenase' transaminases'
total protein and creatinine. Histological evaluation of the
liver and kidney of control and animals fed 100 mg/kg Cr as Cr
chloride or picolinate also did not show any detectable differences.
Liver and kidney Cr concentrations increased linearly for both
the Cr chloride and picolinate fed animals. CONCLUSIONS: These
data demonstrate a lack of toxicity of trivalent Cr' at levels
that are on a per kg basis' several thousand times the upper
limit of the estimated safe and adequate daily dietary intake
for humans. Animals consuming the picolinate supplemented diets
had several-fold higher Cr concentrations in both the liver and
kidney than those fed Cr chloride.
chromium and exercise training: effect on obese women.
Grant KE; Chandler RM; Castle AL; Ivy JL
Department of Kinesiology and Health Education' University of
Texas at Austin 78712' USA.
Med Sci Sports Exerc, 29(8):992-8 1997 Aug
chromium supplementation may affect various risk factors for
coronary artery disease (CAD) and non-insulin-dependent diabetes
mellitus (NIDDM)' including body weight and composition' basal
plasma hormone and substrate levels' and response to an oral
glucose load. This study examined the effects of chromium supplementation
(400 micrograms.d-1)' with or without exercise training' on these
risk factors in young' obese women. chromium picolinate supplementation
resulted in significant weight gain in this population' while
exercise training combined with chromium nicotinate supplementation
resulted in significant weight loss and lowered the insulin response
to an oral glucose load. We conclude that high levels of chromium
picolinate supplementation are contraindicated for weight loss
in young' obese women. Moreover' our results suggest that exercise
training combined with chromium nicotinate supplementation may
be more beneficial than exercise training alone for modification
of certain CAD and NIDDM risk factors.
Elevated intakes of supplemental chromium improve glucose and
insulin variables in individuals with type 2 diabetes.
Anderson RA; Cheng N; Bryden NA; Polansky MM; Cheng N; Chi J;
Beltsville Human Nutrition Research Center, U.S. Department of
Agriculture, Maryland 20705-2350, USA. email@example.com
Diabetes, 46(11):1786-91 1997 Nov
chromium is an essential nutrient involved in normal carbohydrate
and lipid metabolism. The chromium requirement is postulated
to increase with increased glucose intolerance and diabetes.
The objective of this study was to test the hypothesis that the
elevated intake of supplemental chromium is involved in the control
of type 2 diabetes. Individuals being treated for type 2 diabetes
(180 men and women) were divided randomly into three groups and
supplemented with: 1) placebo, 2) 1.92 micromol (100 microg)
Cr as chromium picolinate two times per day, or 3) 9.6 micromol
(500 microg) Cr two times per day. Subjects continued to take
their normal medications and were instructed not to change their
normal eating and living habits. HbA1c values improved significantly
after 2 months in the group receiving 19.2 pmol (1,000 microg)
Cr per day and was lower in both chromium groups after 4 months
(placebo, 8.5 +/- 0.2%; 3.85 micromol Cr, 7.5 +/- 0.2%; 19.2
micromol Cr, 6.6 +/- 0.1%). Fasting glucose was lower in the
19.2-micromol group after 2 and 4 months (4-month values: placebo,
8.8 +/- 0.3 mmol/l; 19.2 micromol Cr, 7.1 +/- 0.2 mmol/l). Two-hour
glucose values were also significantly lower for the subjects
consuming 19.2 micromol supplemental Cr after both 2 and 4 months
(4-month values: placebo, 12.3 +/- 0.4 mmo/l; 19.2 micromol Cr,
10.5 +/- 0.2 mmol/l). Fasting and 2-h insulin values decreased
significantly in both groups receiving supplemental chromium
after 2 and 4 months. Plasma total cholesterol also decreased
after 4 months in the subjects receiving 19.2 micromol/day Cr.
These data demonstrate that supplemental chromium had significant
beneficial effects on HbA1c, glucose, insulin, and cholesterol
variables in subjects with type 2 diabetes. The beneficial effects
of chromium in individuals with diabetes were observed at levels
higher than the upper limit of the Estimated Safe and Adequate
Daily Dietary Intake.
A prediction of chromium(III) accumulation in humans from chromium
Stearns DM; Belbruno JJ; Wetterhahn KE
Department of Chemistry' Dartmouth College' Hanover' New Hampshire
FASEB J, 9(15):1650-7 1995 Dec
It has been proposed that 90% of American`s diets are deficient
in the trace essential mineral chromium. Several chromium(III)
dietary supplements are currently available to alleviate this
deficiency. We show here that the same pharmacokinetic models
that have been used to quantitate absorption of chromium(III)
in humans predict that ingested chromium(III) will accumulate
and be retained in human tissues for extended periods. Calculations
were carried out with the popular supplement chromium picolinate
as an example' but may be applied to any chromium(III) complex.
Results from these calculations were compared to clinical data
obtained from chromium(III) absorption/retention studies in humans.
The models predict that chromium(III) can accumulate in human
tissues to reach the levels at which DNA damage has been observed
in animals and in vitro. The use of chromium supplements for
extended periods or in excess dosages should be reevaluated in
terms of these established models because the possible long-term
biological effects of chromium accumulation in humans are poorly
The effect of chromium picolinate on the liver levels of trace
Aguilar MV; Jorge AM; Mateos CJ; Garc]ia J; Laborda JM; Meseguer
I; Mart]inez-Para MC; Gonz]alez MJ
Departamento de Nutrici]on y Bromatolog]ia' Facultad de Farmacia'
Universidad de Alcal]a de Henares' Espa~na.
Nutr Hosp, 10(6):373-6 1995 Nov-Dec
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 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, 45(3):241-6 1995 Sep
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.
Nutritional factors influencing the glucose/insulin system: chromium.
Nutrient Requirements and Functions Laboratory, United States
Department of Agriculture, Beltsville, Maryland 20705-2350, USA.
J Am Coll Nutr, 16(5):404-10 1997 Oct
chromium (Cr) improves the glucose/insulin system in subjects
with hypoglycemia, hyperglycemia, diabetes and hyperlipemia with
no detectable effects on control subjects. chromium improves
insulin binding, insulin receptor number, insulin internalization,
beta cell sensitivity and insulin receptor enzymes with overall
increases in insulin sensitivity. There have been several studies
involving Cr supplementation of subjects with NIDDM and/or lipemia
and most have reported beneficial effects of Cr on the glucose/insulin
system. In a recent study, Chinese subjects with NIDDM were divided
into three groups of 60 subjects and supplemented with placebo,
100 or 500 micrograms of Cr as chromium picolinate 2 times per
day for 4 months. Improvements in the glucose/insulin system
were highly significant in the subjects receiving 500 micrograms
twice per day with less or no significant improvements in the
subjects receiving 100 micrograms twice per day after 2 and 4
months. In summary, Cr is involved in the control of the glucose/insulin
system and the amount, and likely form of chromium, are critical
when evaluating the role of chromium in this system.
The effectiveness of long-term supplementation of carbohydrate,
chromium, fibre and caffeine on weight maintenance.
Pasman WJ; Westerterp-Plantenga MS; Saris WH
Department of Human Biology, Maastricht University, The Netherlands.
Int J Obes Relat Metab Disord, 21(12):1143-51 1997 Dec
OBJECTIVE: To investigate whether supplementation of carbohydrate,
chromium, dietary fibre and caffeine is effective for maintenance
of weight-loss in the long-term. DESIGN: A longitudinal, double-blind,
randomly assigned intervention study of 16 months with supplementation
of either 50g of carbohydrates (CHO), 200 micrograms chromium-picolinate
(Cr-Pic), 20g of soluble fibre plus 100 mg caffeine (CHO+) or
50g of plain CHO, for 16 months besides a very low energy diet
(VLED) during the first two months. SUBJECTS: Thirty-three female
obese subjects (age, 34.8 +/- 7.0 y; body weight (BW): 85.5 +/-
10.0 kg; body mass index (BMI) 31.2 +/- 3.7 kg.m-2) participated,
13 subjects were supplemented with CHO+, 11 subjects were supplemented
with CHO and 9 subjects served as a control group. MEASUREMENTS:
SW, body composition, energy intake and blood parameters were
measured before the VLED (0), after the VLED at 2 months (2),
and at 4, 10 and 16 months. RESULTS: The amount and course of
relapse of BW was equal for the supplemented and control groups.
The average regain at 16 months (the weight gained as a percentage
of the total weight loss during the VLED) was 66.1 +/- 81.2%,
and was not different between the groups. No differences in body
composition were found between the groups at 16 months. The CHO
supplements resulted in significantly elevated energy percentage
(En %) intake of CHO daily, in both supplemented groups, although
this did not result in less regain. Pearson correlation analysis
for all subjects revealed that the more fat consumed, the more
regain was found at 16 months (r = 0.41, P < 0.05). A high
CHO consumption was correlated with less regain (r = -0.40, P
= 0.05). Furthermore, chromium intake did not result in significant
changes in blood parameters and body composition. CONCLUSION:
Although additional supplementation of CHO, chromium, dietary
fibre and caffeine intake did not affect BW, the En % CHO daily
was increased significantly. Our results indicate that a high
En% intake of CHO and a low En% intake of fat daily is beneficial
for prevention of weight regain.
Effect of chromium picolinate on growth' body composition' and
tissue accretion in pigs.
Boleman SL; Boleman SJ; Bidner TD; Southern LL; Ward TL; Pontif
Department of Animal Science' Louisiana State University Agricultural
Center' Baton Rouge 70803' USA.
J Anim Sci, 73(7):2033-42 1995 Jul
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.
Effects of dietary chromium picolinate supplementation on growth'
carcass characteristics' and accretion rates of carcass tissues
in growing-finishing swine.
Mooney KW; Cromwell GL
Department of Animal Sciences' University of Kentucky' Lexington
J Anim Sci, 73(11):3351-7 1995 Nov
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 lipid 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.
chromium picolinate modulates rat vascular smooth muscle cell
intracellular calcium metabolism.
Moore JW; Maher MA; Banz WJ; Zemel MB
Departments of Nutrition and Medicine, The University of Tennessee,
Knoxville, TN 37996-1900, USA.
J Nutr, 128(2):180-4 1998 Feb
We have previously shown that insulin attenuates vasoconstriction,
accelerates both vascular relaxation and [Ca2+ i recovery from
pressor agonist-induced Ca2+ loads, and stimulates Ca2+-ATPase
gene expression in rat and human vascular smooth muscle cells
(VSMC). Moreover, these functions are impaired in VSMC from both
insulin resistant and insulinopenic rats, suggesting that hypertension
in insulin resistant states may result, in part, from impaired
insulin-regulation of VSMC Ca2+ transport. Accordingly, we have
now evaluated the effect of improving cellular insulin sensitivity
with chromium picolinate (CrPic) on regulation of VSMC Ca2+ transport.
Cultured VSMC from rats were grown from passage to confluence
in the presence or absence of 1 &mgr;mol/L CrPic, maintained
in a quiescent medium for 24 h and incubated with or without
insulin (10(-8) mol/L) for the final 2 h. Cells were then harvested
and RNA and protein extracted for Northern and Western blot analysis,
respectively. Insulin caused a significant stimulation of plasmalemmal
Ca2+-ATPase mRNA and protein (P < 0.05). A comparable stimulation
of the mRNA and protein levels was caused by CrPic in the absence
of insulin (P < 0.05), while the CrPic + insulin treatment
caused a greater percentage stimulation of the Ca2+-ATPase mRNA
level than either separate treatment (P < 0.05). Fluorometric
analysis of the rate of [Ca2+ i recovery following stimulation
with arginine vasopressin support these findings: insulin caused
an 83% increase, CrPic caused a 35% increase and insulin + CrPic
caused a 133% increase in [Ca2+ i recovery rate. These data suggest
that CrPic may be an effective modality to reduce VSMC [Ca2+
i loads and thereby reduce peripheral vascular resistance in
insulin resistant states.