Chromium: increasing ATP production

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Willy
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Chromium: increasing ATP production

Bericht door Willy » zo aug 24, 2003 4:30 pm

<H4>Chromium in human nutrition: a review </H4><I>
J Nutr (UNITED STATES) Apr 1993, 123 (4 )</I><BR>
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.)
<H4>Nutritional ergogenic aids: chromium, exercise, and muscle mass </H4><I>
Int J Sport Nutr (UNITED STATES) Sep 1991, 1 (3) p289-93)</I><BR>
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.
<H4>Chromium Increases Insulin Internalization </H4><I>
Evans GW Bowman TD J Inorg Biochem (1992 Jun) 46(4):243-50)</I><BR>
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.
<H4>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 </H4><I>
Metabolism: Clinical and Experimental (USA), 1997, 46/5 (469-473) )</I><BR>
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.
<H4>Longevity Effect of Chromium Picolinate </H4><I>
McCarty MF Med Hypotheses (1994 Oct) 43(4):253-65)</I><BR>
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.
<H4>Efficacy of chromium supplementation in athletes: emphasis on anabolism </H4><I>
Int J Sport Nutr (UNITED STATES) Jun 1992, 2 (2) p111-22)</I><BR>
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.)
<H4>Chromium picolinate supplementation improves cardiac metabolism, but not myosin isoenzyme distribution in the diabetic heart </H4><I>
Journal of Nutritional Biochemistry (USA), 1996, 7/11 (617-622) )</I><BR>
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.
<H4>Insulin resistance in Mexican Americans--a precursor to obesity and diabetes? </H4><I>
Med Hypotheses (ENGLAND) Oct 1993, 41 (4) p308-15)</I><BR>
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.
Sources: http://www.lef.org/prod_hp/abstracts/php-ab233.html

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