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Chromium picolinate may favorably influence the vascular risk associated with smoking by combating cortisol-induced insulin resistance.

Smoking promotes insulin resistance and other features - excepting hypertension - of the insulin resistance syndrome; these effects appear to reflect chronic nicotine exposure. The adverse impact of smoking on insulin function may be a prominent mediator of the excess vascular risk associated with smoking. Although the mechanistic basis of nicotine-induced insulin resistance remains to be clarified, increased secretion of ACTH and cortisol seems likely to play an important role in this regard. It is therefore intriguing to note that supplemental chromium picolinate has been reported to have a rapid and substantial favorable impact on glycemic control in patients with corticosteroid-induced diabetes. In dexamethasone-treated rats, high doses of this compound have been shown to markedly improve insulin sensitivity. Thus, if these initial reports are confirmable, ample intakes of bioactive chromium may have the potential to reverse the negative influence of corticosteroids on insulin signaling. Such an effect might have utility not only for smokers, but for others in whom chronic up-regulation of the hypothalamic-pituitary-adrenal axis compromises vascular health. The impact of chromium picolinate on smoking- or nicotine-induced insulin resistance merits study.

Adrenocorticotropic Hormone↗

Lack of mutagenicity of chromium picolinate in the hypoxanthine phosphoribosyltransferase gene mutation assay in Chinese hamster ovary cells.

Chromium picolinate (CrPic, Chromax) is a dietary supplement that is stable and more bioavailable than other commercially available forms of chromium. Chromium supplementation is known to enhance the action of insulin, particularly in insulin resistance and type 2 diabetes mellitus. A previous study reported that CrPic produced increases in mutations of the hypoxanthine phosphoribosyltransferase (Hprt) gene in Chinese hamster ovary (CHO) cell mutation tests. This study, however, evaluated CrPic produced by the testing laboratory and used an atypical 48 h exposure period for this test system. The current study evaluated the mutagenic potential of the most widely utilized commercial form of CrPic in CHO/Hprt mutation tests following International Conference on Harmonisation (ICH) Guidelines (+/-S9 metabolic activation with a 5h exposure) in addition to repeating the test with a 48 h exposure period -S9 activation. CrPic was suspended in dimethyl sulfoxide (DMSO) up to a concentration of 50 mg/mL; exposures were conducted under conditions in which precipitate was not evident and under conditions in which some precipitate of CrPic was visually evident in the cell culture medium at the highest concentrations (500 microg/mL). The concentrations evaluated for mutagenicity ranged from 15.6 to 500 microg/mL (+S9 and -S9) for the 5 h exposure and 31.3-500 microg/mL for the 48 h exposure (-S9). Only a slight degree of cytotoxicity was seen in the standard tests up to the limit of solubility in the medium. Toxicity, i.e., cloning efficiency < or =50% of the solvent control, but no mutagenic increases were observed at 500 microg/mL following a 48 h exposure period. The results of these studies showed that CrPic was non-mutagenic in two independent CHO/Hprt assays and in an assay using a 48 h exposure period.

Animals↗

Effectiveness of chromium in atypical depression: a placebo-controlled trial.

BACKGROUND: Chromium picolinate (CP) has been reported to benefit patients with symptoms of atypical depression. METHODS: A placebo-controlled, double-blind, pilot study of CP was conducted in 15 patients with DSM-IV major depressive disorder, atypical type. Patients received 600 micro g of CP or matching placebo (PBO) for 8 weeks. RESULTS: Seven (70%) CP and zero (0%) PBO patients met responder criteria (p =.02). Other outcomes were consistent with greater effect of CP. Three patients on CP failed to show any improvement. Chromium picolinate was well tolerated. CONCLUSIONS: Chromium picolinate shows promising antidepressant effects in atypical depression. Its mechanism of action may relate to 5HT2A downregulation, increased insulin sensitivity, or to other effects.

Adult↗

Separation of no-carrier-added 52Mn from bulk chromium: a simulation study for accelerator mass spectrometry measurement of 53Mn.

53Mn radionuclide (T(1/2) = 3.7 x 10(6) y) is produced through the interaction of cosmic rays. Measurements of concentrations of 53Mn in rocks might help to understand Earth surface processes that occurred in time periods not accessible with other cosmogenic nuclides. Only accelerator mass spectrometry (AMS) can determine such ultratrace levels of 53Mn. The main interference in the detection of 53Mn by AMS is its stable isobar 53Cr, which is roughly approximately 10(12) times more abundant in nature. A prerequisite of any AMS measurement of 53Mn in geological samples is therefore chromium separation by an efficient chemistry. Thus, we have developed a method for the separation of chromium and manganese by using a radiometric simulation. The separation procedure was monitored by 51Cr (T(1/2) = 27.70 d) and 52Mn (T(1/2) = 5.59 d) as the corresponding radiotracers for chromium and manganese, respectively. The separation studies were performed by a liquid-liquid extraction technique using trioctylamine (TOA) diluted in cyclohexane. A high separation factor (approximately 16 000) for Mn and Cr can be obtained at optimal conditions of 0.8 M TOA and 9 M HCl. The developed method has been found equally applicable for real geological samples such as manganese crusts, lava, and sediment samples. Therefore, the method offers an important tool to improve 53Mn measurements by AMS.

Journal Article↗

Chromium complexes of an isomeric N-donor ligand, 2-[(N-arylamino)phenylazo]pyridine: amination reactions, X-ray structure, and redox properties.

The chromium chemistry of two positional isomers of the ligand 2-[(N-arylamino)phenylazo]pyridine (HL(1)and HL(2)) are described. While the ligand HL(1) coordinates as a bischelating tridentate N,N,N-donor, [L(1)](-), with deprotonation of the amine nitrogen, its isomer HL(2) coordinates as a neutral bidentate N,N-donor. The amine nitrogen in this case remains protonated. Thus the reaction of CrCl(3).nH(2)O with HL(1) produced the brown cationic complex, [Cr(L(1))(2)](+), [1](+). The representative X-ray structure of [1a](ClO(4)) is reported. The two azo nitrogens of the anioinc tridentate ligand approach the metal center closest with Cr(1)-N(azo) av 1.862(6) A. There is a significant degree of ligand backbone conjugation in the coordinated ligands, which resulted in shortening of the C-N distances and also in lengthening of the diazo (N=N) distances. Two synthetic approaches for the synthesis of chromium complexes of HL(2) are investigated. The first approach is based on the substitution reaction, wherein all the coordinated CO ligands of Cr(CO)(6) were completely substituted by the three bidentate HL(2) ligands to produce a violet complex [Cr(HL(2))(3)]. The second approach is based on para-amination reaction of coordinated 2-(phenylazo)pyridine (pap). Thus the reaction of an inert complex, [CrCl(2)(pap)(2)], with ArNH(2) yields a mixed ligand complex, [CrCl(2)(pap)(HL(2))], 3. In this reaction one of the two coordinated pap ligands in [CrCl(2)(pap)(2)] undergoes amination at the para carbon (with respect to the diazo function) to yield HL(2) in situ. This metal-promoted transformation is authenticated by the X-ray structure determination of a representative complex, [CrCl(2)(pap)(HL(2a))], 3a. Notable differences in bond distances along the ligand backbones of the two coordinated ligands in 3a indicate different levels of metal-ligand overlap in this complex. All the chromium complexes of HL(2) are characterized by their intense blue-violet color. The frequencies of the visible range transitions in these complexes linearly correlate with the Hammett's substitution constant. Intraligand charge-transfer transitions in the visible region are believed to be responsible for the intense color. Redox properties of all these complexes are reported.

Journal Article↗

Syntheses, Structures, FAB Mass Spectra, and Magnetic Properties of Chromium Chalcogenide Cluster Complexes [Cr(6)Se(8)(PEt(3))(6)], [Cr(6)Se(8)(H)(PEt(3))(6)], and [Cr(6)S(8)(H)(PEt(3))(6)].

Chromium selenide cluster complexes [Cr(6)Se(8)(PEt(3))(6)] (1) and [Cr(6)Se(8)(H)(PEt(3))(6)] (2) were prepared by the reaction of anhydrous chromium dichloride, Na(2)Se(x)(), and triethylphosphine in methanol. A similar procedure except for the use of NaS(x)()H in place of Na(2)Se(x)() gave a sulfide cluster complex [Cr(6)S(8)(H)(PEt(3))(6)] (3). The partly deuterated derivative [Cr(6)S(8)(D)(0.8)(H)(0.2)(PEt(3))(6)] (4) was prepared for comparison. An extra hydrogen atom in 2-4 has been confirmed by FAB mass spectra. The reactivity and structural studies have indicated that it is at the center of the Cr(6) octahedral cluster. The molecular structures of 1 and 2 have been determined by X-ray structure analyses. Crystallographic data: [Cr(6)Se(8)(PEt(3))(6)] (1) (226 K), triclinic, P&onemacr;, a = 12.887(2) Å, b = 25.332(7) Å, c = 12.061(3) Å, alpha = 111.23(2) degrees, beta = 108.25(2) degrees, gamma = 109.86(2) degrees, Z = 2; [Cr(6)Se(8)(H)(PEt(3))(6)].2THF (2) (293 K), rhombohedral, R&thremacr;, a = 17.384(4) Å, c = 19.768(4) Å, Z = 3. The Cr-Cr bond distances of 2 are 0.13-0.16 Å shorter than those of 1, indicative of bonding interaction between the insterstitial hydrogen and the six chromium atoms in 2. The number of cluster valence electrons for 1 is 20 while that for 2 and 3 is 21. Magnetic measurements (2-330 K for 1, 2.5-330 K for 2, and 4.5-330 K for 3) have shown that the number of unpaired spins in the ground state for 1 is zero while that for 2 and 3 is one.

Journal Article↗

Electron Spin Relaxation in Chromium-Nitrosyl Complexes.

A new method to prepare Cr(NO)(H(2)O)(5)(2+) from dichromate and NH(2)OH is reported. The chromium nitrosyls Cr(NO)(EHBA)(+) and Cr(NO)(EHBA)(2) (EHBA = 2-ethyl-2-hydoxybutyrate) were prepared by a literature reaction and characterized by continuous wave electron paramagnetic resonance and two-pulse electron spin echo spectroscopy at X-band. The g values are characteristic of a single unpaired electron in a predominantly d(xy)() orbital. In fluid and glassy solutions Cr(NO)(EHBA)(2) is a mixture of cis and trans isomers. Rotation of the methyl groups in the EHBA ligands causes an increased rate of spin echo dephasing at temperatures between 40 and 120 K. For the EHBA complexes echo envelope modulation is observed at temperatures below about 40 K that is attributed to inequivalent coupling to protons of the slowly rotating methyl groups. Both the effect of the methyl rotation on spin echo dephasing and the depth of the proton modulation are dependent on the number of ethyl groups in the ligand, and thus the spin echo experiments provide confirmation of the number of EHBA ligands in the complexes. The spin-lattice relaxation rates for the chromium-nitrosyl complexes at temperatures near 100 K are similar to values reported previously for Cr(V) complexes, which also have a single unpaired electron in a predominantly d(xy)() orbital. For Cr(NO)(H(2)O)(5)(2+), Cr(NO)(EHBA)(+), and Cr(NO)(EHBA)(2) the dominant contribution to spin-lattice relaxation between 12 and 150 K is the Raman process with a Debye temperature, theta(D), of 110-120 K. For Cr(NO)(CN)(5)(3)(-) the data are consistent with a Raman process (theta(D) = 135 K) and a contribution from a local mode, which dominates above about 60 K. The formally low-spin d(5) chromium nitrosyl complexes relax about 5 orders of magnitude more slowly than low-spin d(5) Fe(III) porphyrins, which is attributed to the absence of a low-lying excited state.

Journal Article↗

A Nucleophilic Chromium(V) Dioxo Radical Anion.

Treatment of Cr(NRAr)(3) (R = C(CD(3))(2)CH(3) or tert-butyl, Ar = 2,5-C(6)H(3)FMe) with oxygen gives the purple chromium(VI) complex O(2)Cr(NRAr)(2) in 83% purified yield. Upon one-electron reduction with cobaltocene, the d(1) dioxo cobaltocenium salt [CoCp(2)][O(2)Cr(NRAr)(2)] was isolated in 89% yield. The dioxo anion displays solid-state magnetic behavior consistent with a Curie-Weiss paramagnet with one unpaired electron. The chromium(V) dioxo [CoCp(2)][O(2)Cr(NRAr)(2)] acts as a nucleophile toward ClSiPh(3), ClC(O)Ph, and MeOTf to afford the monooxo complexes OCr(OSiPh(3))(NRAr)(2) (86% yield), OCr[OC(O)Ph](NRAr)(2) (34% yield), and OCr(OMe)(NRAr)(2) (76% yield), respectively. Two of these rare examples of monooxo chromium(V) derivatives, OCr(OSiPh(3))(NRAr)(2) and OCr[OC(O)Ph](NRAr)(2), were structurally characterized and display Cr-O(oxo) distances of 1.611(6) and 1.588(3) Å, respectively. The benzoate complex features an eta(1)-carboxylate ligand. All of the monooxo complexes show three peaks in their (2)H NMR spectra consistent with isomers arising from restricted rotation about the Cr-N bonds. Two of the complexes, O(2)Cr(NRAr)(2) and OCr(OSiPh(3))(NRAr)(2), were examined by cyclic voltammetry.

Journal Article↗

Kinetic and thermodynamic acidities of pentacarbonyl(cyclobutenylidene)chromium complexes. Effect of antiaromaticity in the conjugate anion. An experimental and computational study.

The deprotonation of pentacarbonyl[(3-diethylamino-2,4-dimethyl)cyclobut-2-ene-1-ylidene]chromium (1d) and pentacarbonyl[(3-diethylamino-4-methyl-2-phenyl)cyclobut-2-ene-1-ylidene]chromium (1e) leads to antiaromatic conjugate anions by virtue of their being cyclobutadiene derivatives. Rate constants for the deprotonation of 1d and 1e by P2-Et and pKa values were determined in acetonitrile. Gas-phase B3LYP calculations of 1d, 1e, and their respective conjugate anions, using a generalized basis set, were also performed. Furthermore, for purposes of comparison with carbene complexes of similar structures, but having conjugate anions that are not antiaromatic, corresponding calculations were performed on pentacarbonyl[3-diethylamino-2,5-dimethyl)cyclopent-2-ene-1-ylidene]chromium (5), [dimethylamino(methyl)carbene]pentacarbonylchromium (3a), and [dimethylamino(iso-propyl)carbene]pentacarbonylchromium (3b) and their respective conjugate anions, and solution-phase pKa and kinetic measurements were carried out for 3a and 3b. Major points of interest include the effect of antiaromaticity on the kinetic and thermodynamic acidities of 1d and 1e, the large effect of the phenyl group on the gas-phase acidity of 1e, the strong attenuation of the acidities and the effect of the phenyl group in acetonitrile, and the position of the C=C double bonds in the cyclobutadiene ring of the conjugate anion of 1e.

Journal Article↗

Mechanism of selective oxidation of organic sulfides with Oxo(salen)chromium(V) complexes

The selective oxidation of organic sulfides to sulfoxides by oxo(salen)chromium(V) complexes in acetonitrile is overall second-order, first-order each in the oxidant and the substrate. The rate constant, k(2), values of several para-substituted phenyl methyl sulfides correlate linearly with Hammett sigma constants and the rho values are in the range of -1.3 to -2.7 with different substituted oxo(salen)chromium(V) complexes. The reactivity of different alkyl sulfides is in accordance with Taft's steric substituent constant, E(S). A mechanism involving direct oxygen atom transfer from the oxidant to the substrate rather than electron transfer is envisaged. Correlation analyses show the presence of an inverse relationship between reactivity and selectivity in the reaction of various sulfides with a given oxo(salen)chromium(V) complex and vice versa. Mathematical treatment of the results shows that this redox system falls under strong reactivity-selectivity principle (RSP).

Journal Article↗

Kinetic studies of chromium (VI) binding to carboxylic acid- and methyl ester-functionalized silica/water interfaces important in geochemistry.

Real-time kinetic measurements of hexavalent chromium binding to fused silica surfaces functionalized with carboxylic acid and methyl ester terminal groups are performed in situ using resonantly enhanced surface second harmonic generation (SHG) at pH 7 and 300 K. These functional groups were chosen because of their high abundance in humic acids and related biopolymers. Kinetic measurements are conducted in the submonolayer regime using chromate solution concentrations ranging from 1 x 10(-6) to 2 x 10(-5) M. The adsorption rates were analyzed using the standard Langmuir model and the Frumkin-Fowler-Guggenheim model. The desorption kinetics are consistent with a first-order process. These results indicate that hexavalent chromium mobility in carboxylic acid- and ester-rich soil environments increases with decreasing chromate concentrations. Based on the measured half-lives of the adsorbed Cr(VI) species, remobilization of bound hexavalent chromium due to natural or anthropogenic events that lower the chromate concentration in the aqueous phase can occur within minutes.

Adsorption↗

Effect of synthesis parameters on the chromium content and catalytic activities of mesoporous Cr-MSU-x prepared under acidic conditions.

A series of chromium-incorporated MSU-x mesoporous molecular sieves were synthesized under different templates, initial Si/Cr molar ratios, aging times, and temperatures in acid solution. The synthesis was performed by using sodium silicate, chromium nitrate, and nonionic poly(ethylene oxide) surfactant as the source of silicone, metal, and the template, respectively. The Cr-MSU-x products were analyzed by inductively couple plasma-optical emission spectrometry to determine the actual Cr content and were characterized by X-ray diffraction, N(2) adsorption-desorption, scanning electron microscopy, high-resolution transmission electron microscopy, diffuse reflectance UV-visible, X-ray adsorption near-edge spectroscopy, and temperature-programmed reduction techniques. The Cr species were mostly formed as Cr(VI) in tetrahedral coordination. Two kinds of Cr(VI) species with different reduction abilities were distinguished. The catalytic activities of Cr-MSU-x in the dehydrogenation of ethane to ethylene with CO(2) were investigated at the same time. The synthesis parameters explored strongly influence the chromium content in Cr-MSU-x and, subsequently, the catalytic activities. The Cr-MSU-x synthesized with Si/Cr = 20, aging at 25 degrees C for 22 h, and templating by fatty alcohol polyoxyethylene ether gave the best activities, resulting in 58.0% ethane conversion and 92.1% ethylene selectivity. The Cr species in Cr-MSU-x are more efficient in activating and converting ethane molecules than are conventional catalysts.

Journal Article↗

Effect of cadmium and chromium toxicity on the demography and population growth of Brachionus calyciflonrs and Brachionus patulus (Rotifera).

This paper reports on the assessment of the effect of Cd+2 and Cr+6 to the rotifers Brachionus calyciflorus and B. patulus using life table demography and population growth. Based on acute toxicity tests, cadmium was nearly 100 times more toxic than chromium for both the rotifer species. Age-specific fecundity curves of both the brachionids showed increased offspring beyond the age of 4 days and after that the production nearly stabilized for about 10 days and later declined. At any given treatment, B. calyciflorus had the higher rate of offspring production than B. patulus. For any given rotifer, increased metal concentration (Cd or Cr) resulted in decreased offspring production. While chromium at a concentration of 8.0 mg L(-1), permitted reproduction in B. calyciflorus, the egg production of B. patulus was inhibited at half that level (4.0 mg L(-1)). Cd at concentrations as low as 0.056 mg L(-1) caused 10-30% reduction in survivorship and reproductive parameters of B. calyciflorus. The lowest chromium concentration chosen for B. calyciflorus (0.5 mg L(-1)) had, however, a lower impact (2-22%) on the life history variables. Corresponding values of life history variables for B. patulus at the lowest Cd (0.0028 mg L(-1)) and Cr (0.25 mg L(-1)) concentrations varied greatly (2-40% and < 1-24%, respectively). Compared to controls, both the rotifer species in Cd or Cr treatments had lower densities. In controls, B. calyciflorus reached a peak abundance of about 100 ind. mL(-1), while the corresponding value for B. patulus was slightly higher (120 ind. mL(-1)). The rate of population increase (r) derived from the population growth data varied from +0.42 to -0.40 depending on the concentration of the heavy metal in the medium.

Animals↗

Cytotoxic and neoplastic transforming effects of industrial hexavalent chromium pigments in Syrian hamster embryo cells.

Twenty eight moderately water-soluble to insoluble chromium (VI) compounds, such as zinc and lead chromate, industrial and laboratory synthesized pigments, and the analytical reagents strontium, barium and calcium chromate, were physicochemically characterized and studied for cytotoxicity and morphological transformation in cultured Syrian hamster embryo (SHE) cells. In vivo validation of malignancy of transformed SHE cells was performed. A high physicochemical diversity among the complex chromium pigments was revealed. The solubility of the compounds was greatly increased after incubation in a complete medium and even higher under cell culture conditions. The cytotoxic effects appeared to be due principally to extracellular solubilized chromium because the most solubilized compounds. Zn, Ca and Sr chromates, were equitoxic at about the same Cr concentration treatment and 8-fold more cytotoxic than less soluble compounds such as some Pb chromates and Ba chromate. However, certain physicochemical properties of lead chromate pigments could also influence their cytotoxic activity. All test compounds were, in a dose-dependent manner, efficient in inducing morphological transformation of SHE cells. Many of the Cr pigments, although physicochemically different, were similarly effective in transformation induction. Nevertheless, compounds among Zn and Pb chromates had various transforming potencies. Ba chromate was the least active in inducing transformation. Certain physicochemical properties could mediate the transforming activity but no particular relationship could be established between any one of the physicochemical parameters and the transforming potency. Cloned morphologically-transformed colonies of SHE cells were grown in soft agar medium and showed true neoplastic behaviour by tumour formation in syngeneic animals. These results show that various chromate pigments containing either Zn or Pb, of medium to very low aqueous solubility, induced neoplastic transformation of SHE cells.

Animals↗

Chromium picolinate effects on body composition and muscular performance in wrestlers.

PURPOSE: The purpose of this study was to assess the effects of 14 wk of chromium picolinate supplementation during the final 16 wk of a preseason resistance and conditioning program on body composition and neuromuscular performance in NCAA Division I wrestlers. During this phase of training, wrestlers are primarily interested in trying to improve physical performance and wrestling technique and are not engaged in severe, acute weight loss practices commonly employed before competition. METHODS: This double-blinded, randomized placebo-controlled study involved 20 wrestlers from the University of Oklahoma assigned to either a treatment group (Cr+3; N = 7; 20.4 yr +/- 0.1) receiving 200 micrograms chromium picolinate daily, a placebo group (P; N = 7; 19.9 yr +/- 0.2), or a control group (C; N = 6; 20.2 yr +/- 0.1) using a stratified random sampling technique based on weight classification. Body composition, neuromuscular performance, metabolic performance, and serum insulin and glucose were measured before and immediately following the supplementation and training period. RESULTS: Repeated measures ANOVA indicated no significant changes in body composition for any of the groups. Aerobic power increased significantly (P < 0.002) in all groups, independent of supplementation. There were significant trial and group x trial interactions for upper body endurance (P = 0.038) and relative bench press power (P = 0.050). Post-hoc analyses revealed that the C group increased upper body endurance (P = 0.006), but none of the pre- to post-test changes in bench press power were significant. CONCLUSIONS: These results suggest that chromium picolinate supplementation coupled with a typical preseason training program does not enhance body composition or performance variables beyond improvements seen with training alone.

Adolescent↗

Spin-3 chromium Bose-Einstein condensates.

We analyze the physics of spin-3 Bose-Einstein condensates, and, in particular, the new physics expected in ongoing experiments with condensates of chromium atoms. We first discuss the ground-state properties, which, depending on still unknown chromium parameters, and for low magnetic fields, can present various types of phases. We also discuss the spinor dynamics in chromium spinor condensates, which present significant qualitative differences when compared to other spinor condensates. In particular, dipole-induced spin relaxation may lead for low magnetic fields to transfer of spin into angular momentum similar to the well-known Einstein-de Haas effect. Additionally, a rapid large transference of population between distant magnetic states also becomes possible.

Journal Article↗

Chromium picolinate intake and risk of type 2 diabetes: an evidence-based review by the United States Food and Drug Administration.

The labeling of both health claims that meet significant scientific agreement (SSA) and qualified health claims on conventional foods and dietary supplements requires pre-market approval by the US Food and Drug Administration (FDA). Approval by the FDA involves, in part, a thorough review of the scientific evidence to support an SSA or a qualified health claim. This article discusses FDA's evidence-based review of the scientific evidence on the role of chromium picolinate supplements in reducing the risk of type 2 diabetes. Based on this evidence-based review, FDA issued a letter of enforcement discretion for one qualified health claim on chromium picolinate and risk of insulin resistance, a surrogate endpoint for type 2 diabetes. The agency concluded that the relationship between chromium picolinate intake and insulin resistance is highly uncertain.

Blood Glucose↗

Effects of resistive training and chromium picolinate on body composition and skeletal muscle size in older women.

This study assessed the effect of resistive training (RT), with or without highdose chromium picolinate (Cr-pic) supplementation, on body composition and skeletal muscle size of older women. Seventeen sedentary women, age range 54-71 years, BMI 28.8 +/- 2.4 kg/m2, were randomly assigned (double-blind) to groups (Cr-pic, n = 9; Placebo, n = 8) that consumed either 924 micrograms Cr/d as Cr-pic or a low-Cr placebo (< 0.2 microgram Cr/d) during a 12-week RT program (2 day/week, 3 sets.exercise-1.d-1, 80% of 1 repetition maximum). Urinary chromium excretion was 60-fold higher in the Cr-pic group, compared to the Placebo group (p < .001), during the intervention. Resistive training increased maximal strength of the muscle groups trained by 8 to 34% (p < .001), and these responses were not influenced by Cr-pic supplementation. Percent body fat and fat-free mass were unchanged with RT in these weight-stable women, independent of Cr-pic supplementation. Type I and type II muscle fiber areas of the m. vastus lateralis were not changed over time and were not influenced by Cr-pic supplementation. These data demonstrate that high-dose Cr-pic supplementation did not increase maximal strength above that of resistive training alone in older women. Further, these data show that, under these experimental conditions, whole body composition and skeletal muscle size were not significantly changed due to resistive training and were not influenced by supplemental chromium picolinate.

Aged↗