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Chromium and exercise training: effect on obese women
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.
Author: Grant-KE; Chandler-RM; Castle-AL; Ivy-JL
Med-Sci-Sports-Exerc. 1997 Aug; 29(8): 992-8
Exploiting complementary therapeutic strategies for the treatment of type II diabetes and prevention of its complications
Impaired glycemic control in type II diabetes results from peripheral insulin resistance, hepatic insulin resistance, and a relative failure of beta cell function. Nutritional and pharmaceutical measures are now available for addressing each of these defects, presumably enabling a rational and highly effective clinical management of non insulin dependent diabetes mellitus. Peripheral insulin resistance, which usually responds to a very low fat diet, aerobic exercise training, and appropriate weight loss, can also treated with high dose chromium picolinate, high dose vitamin E, magnesium, soluble fiber, and possibly taurine; these measures appear likely to correct the diabetes associated metabolic derangements of vascular smooth muscle, and thus lessen risk for macrovascular disease. Metformin's clinical efficacy is primarily reflective of reduced hepatic glucose output; this action should complement the benefits of peripheral insulin sensitizers. When these measures are not sufficient for optimal control, beta cell function can be boosted with second generation sulfonylureas.
Author: McCarty MF
Med Hypotheses. 1997 Aug; 49(2): 143 52
Lack of toxicity of chromium chloride and chromium picolinate in rats
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.
Author: Anderson RA; Bryden NA; Polansky MM
J Am Coll Nutr. 1997 Jun; 16(3): 273 9
Chromium supplementation and resistance training: effects on body composition, strength, and trace element status of men
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.
Author: Lukaski HC; Bolonchuk WW; Siders WA; Milne DB
Am J Clin Nutr. 1996 Jun; 63(6): 954 65
Anabolic effects of insulin on bone suggest a role for chromium picolinate in preservation of bone density
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.
Author: McCarty MF
Med Hypotheses. 1995 Sep; 45(3): 241 6
A prediction of chromium(III) accumulation in humans from chromium dietary supplements
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 understood.
Author: Stearns DM; Belbruno JJ; Wetterhahn KE
FASEB J. 1995 Dec; 9(15): 1650 7
Beneficial effect of chromium supplementation on serum triglyceride levels in NIDDM
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 METHODS A 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.
Author: Lee NA; Reasner CA
Diabetes Care. 1994 Dec; 17(12): 1449 52
Longevity effect of chromium picolinate 'rejuvenation' of hypothalamic function?
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.
Author: McCarty MF
Med Hypotheses. 1994 Oct; 43(4): 253 65
Effects of chromium picolinate supplementation on body composition, strength, and urinary chromium loss in football players
The effects of 9 weeks of daily chromium supplementation (200 microgram Cr as picolinate) were investigated in a double blind design in football players during spring training. Testing was done pre , mid , and postsupplementation on the following criterion measures: urinary chromium excretion, girth and skinfold measures, percent body fat and lean body mass, and isometric and dynamic strength. With the exception of 2 variables (of 65 variables analyzed), no significant group by trials interactions were found (based on a repeated measures ANOVA). The two exceptions were unrelated and inconsequential. For 27 of the 38 subjects, average urinary chromium loss at pre was 0.36 microgram/24 hr, whereas it was undetectable (<0.1 microgram/24 hr) for 10 subjects and excessive in 1 subject (2.4 micrograms/24 hr). Subjects receiving chromium supplements demonstrated urinary chromium losses five times greater than those in the placebo group at mid and post. Chromium picolinate supplementation was ineffective in bringing about changes in body composition or strength during a program of intensive weight lifting training.
Author: Clancy SP; Clarkson PM; DeCheke ME; Nosaka K; Freedson PS; Cunningham JJ; Valentine B
Int J Sport Nutr. 1994 Jun; 4(2): 142 53
Chromium picolinate increases membrane fluidity and rate of insulin internalization
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.
Author: Evans GW; Bowman TD
J Inorg Biochem. 1992 Jun; 46(4): 243 50
The effect of chromium picolinate on serum cholesterol and apolipoprotein fractions in human subjects
Chromium has been implicated as a cofactor in the maintenance of normal lipid and carbohydrate metabolism. A deficiency of chromium results from diets low in biologically available chromium. Picolinic acid, a metabolite of tryptophan, forms stable complexes with transitional metal ions, which results in an improved bioavailability of the metal ion chromium. To determine whether or not chromium picolinate is effective in humans, 28 volunteer subjects were given either chromium tripicolinate (3.8 micromol [200 micrograms] chromium) or a placebo daily for 42 days in a double blind crossover study. A 14 day period off capsules was used between treatments. Levels of total cholesterol, low density lipoprotein (LDL) cholesterol, and apolipoprotein B, the principal protein of the LDL fraction, decreased significantly while the subjects were ingesting chromium picolinate. The concentration of apolipoprotein A I, the principal protein of the high density lipoprotein (HDL) fraction, increased substantially during treatment with chromium picolinate. The HDL cholesterol level was elevated slightly but not significantly during ingestion of chromium picolinate. Only apolipoprotein B, of the variables measured, was altered significantly during supplementation with the placebo. These observations show that chromium picolinate is efficacious in lowering blood lipids in humans.
Author: Press RI; Geller J; Evans GW
West J Med. 1990 Jan; 152(1): 41 5
Effects of chromium picolinate on body composition
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.
Author: Trent LK; Thieding Cancel D
J Sports Med Phys Fitness. 1995 Dec; 35(4): 273 80
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