Carb-Blocker by Yes You Can!

LIKELY EFFECTIVE

• Chromium deficiency. Oral or parenteral chromium is effective for the treatment and prevention of chromium deficiency. Details: Taking chromium orally is effective for preventing and treating symptoms of chromium deficiency, including hyperglycemia, glycosuria, sudden weight loss, peripheral neuropathy, and confusion (7135).

POSSIBLY EFFECTIVE

• Diabetes. Oral chromium seems to be modestly beneficial for improving glycemic control in diabetes, especially when used in doses greater than 200 mcg daily and in patients with poorly controlled diabetes. It is unclear if chromium helps to prevent the development of diabetes. Details: Epidemiological research has found that lower toenail chromium levels are associated with an increased risk of diabetes and cardiovascular disease (11908). In 2005, the US Food and Drug Administration (FDA) allowed a qualified health claim stating that chromium picolinate may reduce the risk of type 2 diabetes. However, the FDA has determined that any relationship between chromium picolinate and type 2 diabetes is highly uncertain and is based on limited scientific evidence (102362). Research on the use of chromium for the TREATMENT of type 2 diabetes is conflicting but seems to show modest benefit in some patients. Many small clinical studies show that taking chromium orally decreases fasting blood glucose, postprandial glucose, insulin, and glycated hemoglobin (HbA1C) levels, and increases insulin sensitivity (6867,7137,12390,15169,14440,42628,42638,95097,103745). However, other small clinical studies show that chromium is no better than placebo for improving glycemic indices in patients with diabetes (7060,14325,42679,42707,90059,103746,103749). Some of these studies may not have been adequately powered and some had a high risk of bias. Furthermore, these studies had high heterogeneity related to study population and size, chromium supplementation duration, formulation, and dose, and accepted standards of diabetes care. Multiple meta-analyses pooling results of these small clinical trials also show mixed results (90055,90063,95098,105026,110610). The most recent and comprehensive meta-analyses show that chromium picolinate lowers HbA1C by about 0.6%; while it is unclear if chromium yeast, chromium dinicocysteinate, or chromium with biotin or other natural ingredients are beneficial. Chromium seems to be most beneficial in doses of greater than 200 mcg taken for 12 weeks or longer, and in patients with poorly controlled diabetes with a baseline HbA1C of 8% or greater (90063,105026). There is also speculation that chromium might primarily benefit patients with low chromium levels; however, there has not been an analysis specifically evaluating this population (6867,7058,13725,14325,95098). Some research suggests that chromium might also modestly improve lipid levels in patients with type 2 diabetes (1934,6867,95098). A meta-analysis of randomized clinical trials including patients with type 2 diabetes shows that taking chromium 42-1000 mcg orally daily for 5-26 weeks decreases triglyceride levels by 7 mg/dL and increases high-density lipoprotein cholesterol levels by 2 mg/dL when compared with control. Taking chromium did not affect low-density lipoprotein cholesterol levels. However, the validity of these results is limited by high heterogeneity (110605). In addition, some meta-analyses have failed to demonstrate any effects of chromium on lipid levels (110610). A meta-analysis of randomized clinical trials including patients with type 2 diabetes shows that taking chromium 200-1000 mcg orally daily for 8-25 weeks lowers diastolic blood pressure by 2 mmHg, but not systolic blood pressure or body mass index, when compared with placebo (110607). Preliminary clinical research shows that chromium picolinate might improve metabolic parameters in patients with other forms of diabetes as well. This includes those with type 1 diabetes (1935), diabetes secondary to corticosteroid use (5039,42829), and gestational diabetes (42817).

POSSIBLY INEFFECTIVE

• Hypertension. Meta-analyses of small clinical trials suggest that oral chromium does not lower blood pressure by a clinically meaningful amount. Details: A meta-analysis of randomized clinical trials in adults with different metabolic disorders shows that taking chromium 42-1000 mcg orally daily for 12-24 weeks does not lower systolic or diastolic blood pressure when compared with placebo (110609). A meta-analysis of randomized clinical trials in adults with different chronic disorders shows that taking chromium 42-1000 mcg orally daily for 4-25 weeks lowers systolic and diastolic blood pressure by 3 mmHg and 1 mmHg, respectively, when compared with placebo. However, the validity of this meta-analysis is limited by high heterogeneity (110604). Another meta-analysis of randomized clinical trials including patients with type 2 diabetes shows that taking chromium 200-1000 mcg orally daily for 8-25 weeks lowers diastolic blood pressure by 2 mmHg, but not systolic blood pressure, when compared with placebo (110607). In addition, the validity of these results is limited by inclusion of patients with and without hypertension at baseline (110604,110607,110609).
• Impaired glucose tolerance (Prediabetes). Oral chromium does not seem to improve glycemic indices in patients with prediabetes. Details: Some clinical research shows that adults with impaired glucose tolerance do not have improved glycemic parameters or insulin sensitivity after taking chromium picolinate 500-1000 mcg daily for up to 6 months when compared with placebo (13053,42670). Likewise, a small clinical study in elderly patients with impaired glucose tolerance shows that chromium supplements do not improve glucose tolerance or triglyceride or cholesterol levels when compared with placebo (13722). Finally, a preliminary clinical study in overweight or obese adults with prediabetes shows that taking two capsules of a combination product containing chromium, cinnamon, and carnosine (Glycabiane, PiLeJe) daily for 4 months decreases fasting plasma glucose by approximately 4 mg/dL when compared with placebo, but does not improve fasting plasma insulin, measures of insulin sensitivity or resistance, or glycated hemoglobin (HbA1C) (94234). The small effect on fasting plasma glucose is clinically insignificant and may be due to the other ingredients in this product.
• Schizophrenia. Oral chromium does not seem to improve psychological measures in patients with schizophrenia. Details: Clinical research in patients with schizophrenia shows that taking chromium polynicotinate 400 mcg daily for 3 months does not affect weight or mental status when compared with placebo (42613).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Antiretroviral-induced insulin resistance. It is unclear if oral chromium is beneficial for preventing antiretroviral-induced insulin resistance. Details: Preliminary clinical research in HIV patients treated with highly active antiretroviral therapy (HAART) shows that taking chromium nicotinate 200 mcg or chromium picolinate 1000 mcg daily for 8-16 weeks may help decrease insulin resistance and increase glucose disposal when compared to baseline (42630,42662). The validity of this finding is limited by the lack of a control group.
• Athletic performance. It is unclear if chromium enhances athletic performance, although some research suggests that it may improve body composition when used in conjunction with exercise. Details: One large clinical study shows taking chromium 400 mcg daily, in conjunction with resistance training, can increase weight loss, body fat loss, and lean body mass when compared with placebo and resistance training (6868). However, other, very small clinical studies show that adding chromium picolinate or chromium chloride 177-400 mcg daily to a weight-training program does not improve body composition when compared with weight-training alone (6860,6861,6862,42747). These studies may not have been adequately powered to detect a difference in outcomes.
• Atypical depression. It is unclear if oral chromium is beneficial in patients with atypical depression. Details: Preliminary clinical research in patients with atypical depression shows that taking chromium picolinate 400 mcg daily for 2 weeks followed by 600 mcg daily for an additional 6 weeks improves response and remission rates when compared with placebo (10309). However, other clinical research shows that taking elemental chromium 400 mcg in the form of chromium picolinate daily for 2 weeks followed by 600 mcg daily for an additional 6 weeks does not improve most symptoms of atypical depression, although appetite and sexual drive may improve, when compared with placebo (42600).
• Beta blocker-induced dyslipidemia. It is unclear if oral chromium is beneficial in patients with dyslipidemia due to beta-blocker use. Details: One small clinical study in patients who take beta-blockers shows that taking glucose tolerance factor (GTF)-chromium 600 mcg daily for 2 months increases high-density lipoprotein (HDL) cholesterol levels by 16%, but does not affect other lipid parameters, when compared with placebo (5040).
• Binge eating disorder. It is unclear if oral chromium is beneficial in patients with binge eating disorder. Details: One small clinical study in overweight adults with binge eating disorder shows that taking chromium picolinate 600 or 1000 mcg by mouth daily for 6 months does not affect binge eating frequency, body weight, or depressive symptoms when compared with placebo (90057).
• Bipolar disorder. It is unclear if oral chromium is beneficial in patients with treatment-resistant bipolar disorder. Details: Preliminary clinical research in patients with treatment-resistant, rapid-cycling bipolar disorder shows that taking chromium chloride (Hypo-A Chrom, Hypo-A GmbH) 600-800 mcg daily for up to 2 years can decrease the frequency of affective episodes by approximately three episodes annually when compared to baseline (42618). The validity of this finding is limited by the lack of a control group.
• Cognitive impairment. It is unclear if oral chromium prevents cognitive impairment. Details: Some clinical research shows that taking chromium picolinate standardized to contain elemental chromium 1000 mcg daily for 12 weeks does not improve memory or depression in elderly patients with mild cognitive impairment when compared with placebo. However, results from neuroimaging scans suggest that chromium increases the activity of certain regions of the brain during memory tasks when compared with placebo (42666).
• Hyperlipidemia. Small clinical studies suggest that oral chromium may modestly reduce lipid levels in patients with hyperlipidemia. Details: One small clinical study in patients with atherosclerotic disease shows that taking chromium 250 mcg as chromium chloride daily for 7-16 months decreases triglycerides and increases high-density lipoprotein (HDL) cholesterol, but not other lipid parameters, when compared with placebo (7060). Other small clinical studies in adults with hyperlipidemia show that taking chromium picolinate 200 mcg daily for 6 weeks, chromium polynicotinate 200 mcg twice daily, or brewer's yeast containing 48 mcg elemental chromium daily for 6-8 weeks decrease total and low-density lipoprotein (LDL) cholesterol when compared to baseline (37178,42585,42710). The validity of this finding is limited by the lack of comparison with a control group. A meta-analysis of small heterogeneous clinical studies in patients mostly without hyperlipidemia shows that taking chromium orally does not affect lipid levels when compared with placebo (105029). A meta-analysis of randomized clinical trials including patients with type 2 diabetes shows that taking chromium 42-1000 mcg orally daily for 5-26 weeks modestly improves triglyceride and HDL cholesterol levels, but not LDL cholesterol levels, when compared with control. However, the validity of these results is limited by high heterogeneity and inclusion of patients with and without hyperlipidemia (110605). In addition, some meta-analyses have failed to demonstrate any effects of chromium on lipid levels in adults with diabetes (110610). Limited research has tested high-dose chromium in children. One small clinical study in children with hypercholesterolemia shows that taking chromium polynicotinate 400-600 mcg with glucomannan 1000-1500 mg twice daily for 8 weeks reduces total and LDL cholesterol when compared to baseline (90061). It is unclear if this effect is due to chromium, glucomannan, or the combination. Finally, chromium does not seem to reduce lipid levels in people without hyperlipidemia.
• Hypoglycemia. It is unclear if oral chromium helps to reverse or prevent hypoglycemia. Details: One very small clinical study in patients with reactive hypoglycemia shows that taking chromium chloride 200 mcg daily for 3 months increases blood glucose levels and improves insulin binding and hypoglycemic symptoms following an oral glucose load (6859). Another small clinical study in patients with symptomatic hypoglycemia shows that taking chromium yeast (Biochrome, Pharma-Nord) 125 mcg daily for 3 months improves symptoms, including chilliness, trembling, and disorientation, when compared with baseline (42711). The validity of this finding is limited by the lack of a control group.
• Metabolic syndrome. It is unclear if oral chromium is beneficial in patients with metabolic syndrome. Details: One small clinical study in patients with metabolic syndrome shows that taking a particular chromium picolinate product (Chromax, Nutrition 21) 500 mcg twice daily for 16 weeks does not affect weight, waist circumference, insulin sensitivity, glycated hemoglobin (HbA1C), or lipid levels when compared with placebo (42654).
• Myocardial infarction (MI). It is unclear if oral chromium helps to prevent MI. Details: Epidemiological research has found that low toenail chromium concentrations are associated with an increased risk of MI (13728). However, toenail chromium concentrations might not be a reliable predictor of body stores of chromium. There is also no reliable research showing that chromium supplements can prevent MI.
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral chromium slows NAFLD progression. Details: One small clinical study in patients with NAFLD shows that taking chromium picolinate 200 mcg two times daily after meals for 12 weeks does not affect liver enzyme levels or body weight when compared with placebo (105027).
• Obesity. Although some research suggests that oral chromium may increase weight loss, this increase in weight loss is not likely to be considered clinically relevant. Details: Meta-analyses of clinical studies in overweight or obese adults show that taking chromium picolinate 200-1000 mcg daily for 12-16 weeks might result in a cumulative weight loss of about 0.5-1 kg when compared with placebo (90062,90065). However, this small reduction in weight is unlikely to be considered clinically significant. Furthermore, certain small clinical studies in healthy, overweight or obese adults and children show that taking oral chromium 200-1000 mcg daily for 6-24 weeks does not reduce weight when compared with control (6860,13727,17224,42680). Some of these studies may not have been adequately powered to detect a smaller effect. A meta-analysis of randomized clinical trials including patients with type 2 diabetes shows that taking chromium 200-1000 mcg orally daily for 8-25 weeks does not lower body mass index when compared with placebo. However, the validity of these results is limited by inclusion of patients with and without obesity at baseline (110607).
• Polycystic ovary syndrome (PCOS). It is unclear if oral chromium improves symptoms of PCOS. Details: One small clinical study in patients with PCOS shows that taking chromium picolinate 1000 mcg daily for 6 months along with diet and exercise counseling decreases body mass index and improves rates of ovulation and regular menstruation when compared with placebo (95094). Also, some clinical research shows that taking chromium picolinate (21st Century HealthCare, Inc. or Nature Made) 200 mcg daily orally for 8 weeks increases insulin sensitivity when compared with placebo (95095,98687). However, other preliminary clinical research shows that taking chromium picolinate 200 mcg daily for 4 months does not affect insulin sensitivity or improve ovulation rates (42603). Although chromium picolinate at doses of less than 1000 mcg might have very small effects on fasting glucose, these doses do not seem to have clinically beneficial effects on fasting glucose, pregnancy rate, or testosterone levels (95094,95095,98687). A lower dose of chromium has also been studied in combination with carnitine. One small clinical study in overweight adults with PCOS shows that taking chromium picolinate 200 mcg daily with carnitine 1000 mg daily for 12 weeks modestly reduces fasting blood glucose, insulin resistance, and body weight, and slightly increases insulin sensitivity, when compared with placebo (103747). However, it is unclear if this benefit is clinically significant. Additionally, it is unclear if these effects are due to chromium, carnitine, or the combination. Carnitine has demonstrated clinical benefit when used alone in PCOS.
• Turner syndrome. It is unclear if oral chromium is beneficial in patients with this condition. Details: A small clinical study shows that taking brewer's yeast 30 grams containing chromium 50 mcg daily for 8 weeks might improve abnormalities in glucose and lipid metabolism when compared with baseline in patients with Turner syndrome, a genetic disorder that has a high incidence of diabetes (13729). The validity of this finding is limited by the lack of a comparator group. More evidence is needed to rate chromium for these uses.

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INSUFFICIENT RELIABLE EVIDENCE to RATE

• Diabetes. It is unclear if oral gymnema is beneficial for diabetes. Details: A meta-analysis of 10 small clinical studies in adults with type 2 diabetes shows that taking gymnema modestly reduces fasting and postprandial blood glucose levels, and also seems to reduce glycated hemoglobin (HbA1c), when compared to baseline. Gymnema may also modestly reduce total cholesterol and triglyceride levels. (110022). Another meta-analysis of 6 small clinical studies, that includes some of the same studies, also shows that taking gymnema modestly reduces fasting blood glucose, total cholesterol, and triglyceride levels when compared with diet or placebo. However, this analysis shows that gymnema does not improve HbA1c, oral glucose tolerance, or low-density lipoprotein cholesterol (112184). The validity of these analyses is limited by the inclusion of mostly low-quality studies that enrolled heterogeneous patient populations and employed varying gymnema dosing regimens of 0.4-10 grams daily, sometimes in conjunction with antidiabetes medications. In addition, many of the included studies were non-randomized and lacked a comparator group.
• Impaired glucose tolerance (prediabetes). It is unclear if oral gymnema is beneficial for impaired glucose tolerance. Details: One small clinical study in overweight or obese patients with impaired glucose tolerance shows that taking gymnema (Swanson Superior Herbs) 300 mg twice daily for 12 weeks does not improve glucose control, lipid profile, anthropometric indices, or blood pressure when compared with placebo (105346). However, this study may have been inadequately powered to detect a difference between groups.
• Metabolic syndrome. It is unclear if oral gymnema is beneficial for metabolic syndrome. Details: One small clinical study shows that taking gymnema leaf (Swanson Premium G. sylvestre leaf, Swanson Health Products) 300 mg twice daily for 12 weeks reduces body weight by 4% and body mass index (BMI) by 2% when compared to baseline in overweight adults with metabolic syndrome. However, it is unclear if these changes are significant when compared with placebo. In addition, gymnema does not appear to improve blood glucose levels, insulin sensitivity, or blood lipid levels when compared with placebo (96235).
• Obesity. It is unclear if oral gymnema improves weight loss in overweight or obese adults. Details: One small clinical study shows that taking gymnema leaf (Swanson Premium G. sylvestre leaf, Swanson Health Products) 300 mg twice daily for 12 weeks modestly reduces body weight and body mass index (BMI) when compared to baseline in overweight adults with metabolic syndrome. However, it is unclear if these changes are significant when compared with placebo (96235). Another small clinical study by the same authors evaluating overweight adults with impaired glucose tolerance shows that taking gymnema (Swanson Superior Herbs) 300 mg twice daily for 12 weeks does not reduce body weight or BMI when compared with placebo (105346). Gymnema has also been studied in combination with other ingredients. One small clinical study shows that taking a combination of gymnema extract 400 mg, hydroxycitric acid 2800 mg, and niacin-bound chromium 4 mg orally daily for 8 weeks decreases BMI and body weight when compared to baseline in overweight and obese adults. This product provided 400 mcg of elemental chromium and 100 mg of gymnemic acids (42604). It is unclear if these effects are due to gymnema, other ingredients, or the combination. More evidence is needed to rate gymnema for these uses.

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LIKELY SAFE ...when used orally and appropriately in medicinal amounts, short-term. Chromium has been safely used in doses up to 1000 mcg daily for up to 6 months (1934,5039,5040,6858,6859,6860,6861,6862,6867,6868)(7135,7137,10309,13053,14325,14440,17224,90057,90061)(90063,94234,95095,95096,95097,98687); however, most of these studies have used chromium doses in a range of 150-600 mcg. The Food and Drug Administration (FDA) and Institute of Medicine (IOM) evaluations of the safety of chromium suggest that it is safe when used in doses of 200 mcg daily for up to 6 months (13241,13242).

POSSIBLY SAFE ...when used orally and appropriately in medicinal amounts, long-term. Chromium has been safely used in a small number of studies at doses of 200-1000 mcg daily for up to 2 years (7060,7135,42618,42628,42666,110605,110607,110609). However, the Food and Drug Administration (FDA) and Institute of Medicine (IOM) evaluations of the safety of chromium suggest that it is safe when used in doses of 200 mcg daily for up to 6 months (13241,13242).

CHILDREN: LIKELY SAFE
when used orally and appropriately in amounts not exceeding the daily adequate intake (AI) levels by age: 0-6 months, 0. 2 mcg; 7-12 months, 5.5 mcg; 1-3 years, 11 mcg; 4-8 years, 15 mcg; males 9-13 years, 25 mcg; males 14-18 years, 35 mcg; females 9-13 years, 21 mcg; females 14-18 years, 24 mcg (7135). POSSIBLY SAFE...when used orally and appropriately in amounts exceeding AI levels. Chromium 400 mcg daily has been used safely for up to 6 weeks (42680).

PREGNANCY: LIKELY SAFE
when used orally and appropriately in amounts not exceeding adequate intake (AI) levels. The AI for pregnancy is 28 mcg daily for those 14-18 years of age and 30 mcg daily for those 19-50 years of age (7135).

PREGNANCY: POSSIBLY SAFE
when used orally in amounts exceeding the adequate intake (AI) levels. There is some evidence that patients with gestational diabetes can safely use chromium in doses of 4-8 mcg/kg (1953); however, patients should not take chromium supplements during pregnancy without medical supervision.

LACTATION: LIKELY SAFE
when used orally and appropriately in amounts not exceeding adequate intake (AI) levels. The AI for lactation is 44 mcg daily for those 14-18 years of age and 45 mcg daily for those 19-50 years of age (7135). Chromium supplements do not seem to increase normal chromium concentration in human breast milk (1937). There is insufficient reliable information available about the safety of chromium when used in higher amounts while breast-feeding.

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POSSIBLY SAFE ...when used orally and appropriately. Gymnema leaf extract has been used safely in doses of 200 mg twice daily for up to 20 months or 300 mg twice daily for 12 weeks (45,46,42604,105346).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

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ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = A Theoretically, chromium may have additive effects with antidiabetic agents and increase the risk of hypoglycemia.  Details Some research shows that taking chromium might lower blood glucose levels, especially in patients with poorly controlled type 2 diabetes (7137,14440,15169,94234,95097,95098,98687).

ASPIRIN Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Possible •  Level of Evidence = D Theoretically, aspirin might increase chromium absorption.  Details Animal research suggests that aspirin may increase chromium absorption and chromium levels in the blood (21055).

INSULIN Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, concomitant use of chromium and insulin might increase the risk of hypoglycemia.  Details In clinical research, chromium has been shown to increase insulin sensitivity (1952,14440,95095),

LEVOTHYROXINE (Synthroid, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Chromium might bind levothyroxine in the intestinal tract and decrease levothyroxine absorption.  Details Clinical research in healthy volunteers shows that taking chromium picolinate 1000 mcg with levothyroxine 1 mg decreases serum levels of levothyroxine by 17% when compared to taking levothyroxine alone (16012). Advise patients to take levothyroxine at least 30 minutes before or 3-4 hours after taking chromium.

NONSTEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDs) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D NSAIDs might increase chromium levels in the body.  Details Drugs that are prostaglandin inhibitors, such as NSAIDs, seem to increase chromium absorption and retention (7135).

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ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, taking gymnema with antidiabetes drugs might increase the risk of hypoglycemia.  Details Gymnema reduces blood glucose levels in some human and animal research. In human studies, it has been shown to enhance the blood glucose lowering effects of hypoglycemic drugs (45,46,92119,92121,92123). However, other research in adults with prediabetes or metabolic syndrome suggests that gymnema does not reduce fasting levels of blood glucose (96235,105346). Until more is known, monitor blood glucose levels closely.

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, gymnema might increase levels of drugs metabolized by CYP1A2.  Details Animal and in vitro research shows that gymnema can inhibit the CYP1A2 enzyme (96236,96237,96238). In one animal study, oral administration of gymnema for 7 days increased the plasma concentrations of phenacetin, a CYP1A2 substrate, by about 1.4-fold and reduced the clearance of phenacetin by about 29% (96237).

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, gymnema might increase or decrease levels of drugs metabolized by CYP2C9.  Details Animal research shows that gymnema can induce the CYP2C9 enzyme. In one animal study, gymnema caused a 2.4-fold increase in the clearance of tolbutamide, a CYP2C9 substrate, in rats (96237). In vitro research also shows that gymnema can inhibit CYP2C9 (96236,96238).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, gymnema might increase levels of drugs metabolized by CYP3A4.  Details One in vitro study using rat liver microsomes shows that gymnema can modestly inhibit the CYP3A4 enzyme (96238). However, other in vitro research using human liver microsomes shows that gymnema does not affect CYP3A4 activity (96236). Animal research also shows that gymnema does not alter the function of CYP3A4. In one study in rats, oral administration of gymnema for 7 days did not alter the clearance of amlodipine, a CYP3A4 substrate (96237).

PHENACETIN Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking gymnema with phenacetin might increase the levels of phenacetin.  Details Animal research shows that gymnema, administered orally for 7 days, decreases the clearance of phenacetin in a dose-dependent manner by about 21% to 29% and increases plasma levels about 1.3- to 1.4-fold when compared to control (96237,96238).

TOLBUTAMIDE (Orinase) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking gymnema with tolbutamide might the decrease levels of tolbutamide.  Details Animal research shows that gymnema, administered orally for 7 days, increases the clearance of tolbutamide by 2.4-fold when compared to control (96237).

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General ...Orally, chromium is generally well tolerated.
Most Common Adverse Effects:
Orally: Gastrointestinal irritation, headaches, insomnia, irritability, mood changes.
Serious Adverse Effects (Rare):
Orally: Rare cases of kidney and liver damage, rhabdomyolysis, and thrombocytopenia have been reported.

Dermatologic ...Orally, chromium-containing supplements may cause acute generalized exanthematous pustulosis (42561), skin rashes (42679), and urticaria (17224). Also, chromium picolinate or chromium chloride may cause systemic contact dermatitis when taken orally, especially in patients with contact allergy to chromium (6624,90058). In one clinical study, a patient taking chromium nicotinate 50 mcg daily reported itchy palms that improved after the intervention was discontinued. It is unclear of this effect was due to the chromium or another factor (95096).
Topically, hexavalent chromium, which can be present in some cement, leather products, or contaminated soil, may cause allergic contact dermatitis (42645,42789,90060,90064,110606).
A case of lichen planus has been reported for a patient following long-term occupational exposure to chromium (42688).

Endocrine ...Orally, cases of hypoglycemia have been reported for patients taking chromium picolinate 200-1000 mcg daily alone or 200-300 mcg two or three times weekly in combination with insulin (42672,42783). Chromium picolinate has also been associated with weight gain in young females who do not exercise and in those following a weight-lifting program (1938).

Gastrointestinal ...Orally, chromium in the form of chromium picolinate, chromium polynicotinate, chromium-containing brewer's yeast, or chromium-containing milk powder may cause nausea, vomiting, diarrhea, decreased appetite, constipation, flatulence, or gastrointestinal upset (14325,42594,42607,42622,42643,42679).
Long-term exposure to heavy metals, including chromium, has been associated with increased risk of gallbladder disease and cancer (42682,42704).

Genitourinary ...Orally, chromium polynicotinate has been associated with disrupted menstrual cycles in patients taking the supplement to prevent weight gain during smoking cessation (42643).

Hematologic ...Anemia, hemolysis, and thrombocytopenia were reported in a 33 year-old female taking chromium picolinate 1200-2400 mcg daily for 4-5 months (554). The patient received supportive care, blood product transfusions, and hemodialysis and was stabilized and discharged a few days later. Lab values were normal at a one-year follow-up.

Hepatic ...Liver damage has been reported for a 33-year-old female taking chromium picolinate 1200 mcg daily for 4-5 months (554). Also, acute hepatitis has been reported in a patient taking chromium polynicotinate 200 mcg daily for 5 months (9141). Symptoms resolved when the product was discontinued. Two cases of hepatotoxicity have been reported in patients who took a specific combination product (Hydroxycut), which also contained chromium polynicotinate in addition to several herbs (13037).

Musculoskeletal ...Acute rhabdomyolysis has been reported for a previously healthy 24-year-old female who ingested chromium picolinate 1200 mcg over a 48-hour time period (42786). Also, chromium polynicotinate has been associated with leg pain and paresthesia in patients taking the supplement to prevent weight gain during smoking cessation (42643).

Neurologic/CNS ...Orally, chromium picolinate may cause headache, paresthesia, insomnia, dizziness, and vertigo (6860,10309,14325,42594). Vague cognitive symptoms, slowed thought processes, and difficulty driving occurred on three separate occasions in a healthy 35-year-old male after oral intake of chromium picolinate 200-400 mcg (42751). Transient increases in dreaming have been reported in three patients with dysthymia treated with chromium picolinate in combination with sertraline (2659). A specific combination product (Hydroxycut) containing chromium, caffeine, and ephedra has been associated with seizures (10307). But the most likely causative agent in this case is ephedra.

Psychiatric ...Orally, chromium picolinate has been associated with irritability and mood changes in patients taking the supplement to lose weight, while chromium polynicotinate has been associated with agitation and mood changes in patients taking the supplement to prevent weight gain during smoking cessation (6860,42643).

Renal ...Orally, chromium picolinate has been associated with at least one report of chronic interstitial nephritis and two reports of acute tubular necrosis (554,1951,14312). Laboratory evidence suggests that chromium does not cause kidney tissue damage even after long-term, high-dose exposure (7135); however, patient- or product-specific factors could potentially increase the risk of chromium-related kidney damage. More evidence is needed to determine what role, if any, chromium has in potentially causing kidney damage.
Intravenously, chromium is associated with decreased glomerular filtration rate (GFR) in children who receive long-term chromium-containing total parenteral nutrition - TPN (11787). Topically, burns caused by chromic acid, a hexavalent form of chromium, have been associated with acute chromium poisoning with acute renal failure (42699). Early excision of affected skin and dialysis are performed to prevent systemic toxicity.

Other ...Another form of chromium, called hexavalent chromium, is unsafe. This type of chromium is a by-product of some manufacturing processes. Chronic exposure can cause liver, kidney, or cardiac failure, pulmonary complications, anemia, and hemolysis (9141,11786,42572,42573,42699). Occupational inhalation of hexavalent chromium can cause ulceration of the nasal mucosa and perforation of the nasal septum, and has been associated with pneumoconiosis, allergic asthma, cough, shortness of breath, wheezing, and increased susceptibility to respiratory tract cancer and even stomach and germ cell cancers (42572,42573,42601,42610,42636,42667,42648,42601,42788,90056,90066). Although rare, cases of interstitial pneumonia associated with chromium inhalation have been reported. Symptoms resolved with corticosteroid treatment (42614).

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General ...Orally, gymnema seems to be well tolerated.

Hepatic ...A case of drug-induced hepatitis characterized by weakness, fatigue, jaundice, and elevated liver enzymes, has been reported for a patient who consumed gymnema tea three times daily for 10 days. The patient was administered prednisone 60 mg once daily and was eventually tapered off prednisone and discharged. Laboratory values normalized after 6 months (95005). A case of hepatitis-associated aplastic anemia characterized by jaundice, elevated liver function tests, and pancytopenia has been reported for a patient who consumed gymnema 2 grams twice daily for at least a month. Treatment with ursodeoxycholic acid for 8 weeks led to resolution of cholestatic hepatitis; however, the pancytopenia was not responsive to treatment with immunosuppressive drugs and the patient died 5 months after presentation (110021). The exact reason for these adverse effects is not clear; they may have been idiosyncratic.

(Read more about GYMNEMA)