Bottom Line: Coenzyme Q10 has not been shown to treat or prevent cancer.
Coenzyme Q10 (CoQ10) is produced naturally by all cells in the body. It is necessary for production of adenosine triphosphate (ATP), the "fuel" of all living cells. During periods of ischemia (lack of oxygen), such as occurs during a heart attack, CoQ10 has been shown to reduce damage to heart tissue and its mitochondria (where ATP production takes place). It is known to be an antioxidant and to stabilize cell and organelle membranes. In animal studies, coenzyme Q10 is able to neutralize free radicals, which can damage DNA and cells. However, absorption of oral coenzyme Q10 through the intestine is low. Due to its antioxidant activity, CoQ10 may interfere with the actions of certain chemotherapy drugs and radiation therapy.
As an antioxidant Laboratory studies show CoQ10 has antioxidant effect.
To treat breast cancer A few case reports describe remission of breast cancer when treated with high doses of CoQ10, but this is insufficient evidence to support this use. There is no other proof from clinical trials that CoQ10 can treat breast cancer.
To manage cardiovascular disease Several studies show CoQ10 improves left ventricular function and reduce hypertension. Other studies yield negative results.
To reduce high cholesterol Clinical trials have inconsistent results: two show an increase in HDL, one shows a decrease in LDL, while two show that coenzyme Q10 has no effect on LDL oxidation (which contributes to the development of atheroclerotic plaques in the blood vessels).
To prevent cardiac toxicity from anthracyclines One clinical trials supports this use, but additional clinical trials are needed.
To improve athletic performance Clinical trials generally do not support this use.
To prevent the progression of Parkinson's disease One clinical trial showed that high doses of coenzyme Q10 slowed the progression of Parkinson's disease, but larger clinical trials are needed to support this use.
To treat Huntington's disease One clinical trial does not support this use.
To treat periodontal disease (disease of the gum, teeth, and underlying bone) One clinical trials supports this use, but additional clinical trials are needed.
Heart disease: A randomized, controlled trial studied the use of coenzyme Q10 (CoQ10) in patients with NYHA Class III or IV heart failure. Twenty-three patients received 200 mg/day of CoQ10 by mouth and 23 received a placebo pill for six months. There was no significant improvement found in oxygen consumption, left ventricular ejection fraction, or duration of exercise in the group receiving CoQ10 compared to the placebo group. However, recent studies suggest that 200 mg/day may not be an adequate dosage.
A randomized, crossover design study evaluated 99 mg/day of CoQ10 in 30 patients with chronic heart failure and left ventricular dysfunction. Patients received either a placebo pill or 33 mg of CoQ10 three times daily for three weeks. After a one-week "washout" period in which no treatments were given, the groups crossed over to the other treatment for 12 weeks. Patients taking CoQ10 for 12 weeks showed no improvements in echocardiogram (ECG), Swan-Ganz catheterization, or quality of life compared to the placebo group. No adverse events were reported during the study. However, recent studies suggest that 99 mg/day may not be an adequate dosage.
Parkinson's disease: A recent randomized, controlled trial studied the safety and effectiveness of various doses of coenzyme Q10 in preventing progression of early Parkinson's disease. Eighty patients with early Parkinson's disease were randomly assigned to eat wafers containing 300 mg, 600 mg, or 1200 mg of coenzyme Q10, or a placebo wafer, every day. They followed this treatment for 16 months or until their doctor felt they should start therapy with levodopa. At the end of the study, patients eating the placebo wafer had an average decline in symptoms and functional ability that was almost twice that of the group taking 1200 mg of coenzyme Q10 daily. The lower doses (300 and 600 mg) did not have significant effects. Because all reported side effects were mild and were similar to those patients taking the placebo, this study concluded that taking doses as high as 1200 mg is safe. Larger clinical trials are needed to support the idea that coenzyme Q10 can slow the progression of Parkinson's disease.
Breast cancer: A physician supplemented 32 breast cancer patients with 90 mg of coenzyme Q10, linolenic acid, fatty acids, beta-carotene, vitamin C, vitamin E, and selenium. Six patients had complete remissions. However, long-term success of these treatments was not reported. Because this study was so small, it is difficult to say whether these effects would occur in the general population, or if they occurred by chance. Therefore, these case reports need to be substantiated by controlled clinical trials.
In an additional case report series, the same physician described the complete remission of breast cancer (metastatic intraductal carcinoma) in three patients who were treated with 390 mg/day of CoQ10. More research is needed before CoQ10 is used to treat breast cancer.
A study in mice showed that high intake of CoQ10 reduced the effectiveness of radiation therapy against non-small cell lung cancer. Patients thinking of taking CoQ10 through radiation therapy should consult with their radiation oncologist.
This product is regulated by the F.D.A as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
You are taking warfarin (CoQ10 may lessen its effects).
You are undergoing chemotherapy (Theoretically, because it is an antioxidant, CoQ10 may decrease the effectiveness of chemotherapy; patients should consult with their oncologist).
Coenzyme Q10 (CoQ10) is a naturally occurring substance used in cellular respiration and energy production in mammals. It is consumed as a dietary supplement for its antioxidant property and is often promoted as a preventive agent for cardiovascular diseases, Parkinson's disease, infertility, and cancer. Although data of CoQ10's effects on congestive heart failure do not concur, its benefits have been reported in patients with coronary artery disease (2). Putative neuroprotective effects of CoQ10 have also been reported in patients with progressive supranuclear palsy (5) as well as those with early Parkinson's disease (6), but not with midstage Parkinson's disease (7). CoQ10 supplementation may increase sperm motility in asthenozoospermic men (8) and reduce fatigue induced by physical exertion (9). Case reports describing efficacy for breast cancer exist (3)(4), but no controlled clinical trials have been performed. Use of CoQ10 to prevent anthracycline-induced cardiomyopathy requires additional research. CoQ10 is structurally similar to vitamin K and therefore may antagonize the effects of warfarin (11)(12). It may also antagonize the effects of chemotherapy via antioxidant activity and may reduce the effect of radiation therapy (13).
CoQ10 is known to have antioxidant and membrane stabilizing properties and is the only endogenously produced lipid with a redox function in mammals. All cells are capable of synthesizing CoQ10 and no redistribution between organs occurs through the blood. CoQ10 is necessary for adenosine triphosphate (ATP) production. Its role as a mobile electron carrier in the mitochondrial electron-transfer processes of respiration and coupled phosphorylation is well established. It has a direct regulatory role on succinyl and NADH dehydrogenases (1). CoQ10 has been demonstrated to scavenge free radicals produced by lipid peroxidation and prevent mitochondrial deformity during episodes of ischemia, and it may have some ability to maintain the integrity of myocardial calcium ion channels during ischemic insults (2). CoQ10 appears capable of stabilizing cellular membranes and preventing depletion of metabolites required for ATP resynthesis (10).
Absorption: Uptake of dietary CoQ in the liver does not affect the synthesis of endogenous CoQ, which supports the notion that CoQ does not exert any feedback inhibition on its own biosynthesis. Animal studies demonstrate a bioavailability of 2-3%. With high doses of dietary CoQ, the blood concentration in both rats and humans can be increased about 2- to 4-fold (2). Following ingestion of 100 mg of CoQ, peak plasma levels occur between 5 and 10 hours. Tmax is approximately 6.5 hours, which indicates slow absorption from the GI tract possibly due to the high molecular weight and low water solubility of CoQ (1). Distribution: The mean plasma levels after a single 100 mg oral dose of CoQ in human subjects is 1.004+/- .37 mg/mL. In humans, CoQ is found in relatively high concentrations in the heart, liver, kidney, and pancreas. The plasma half-life of CoQ in different tissues varies between 49-125 hours. Following absorption from the GI tract, CoQ is taken up by chylomicrons. The major portion of an exogenous dose of CoQ is deposited in the liver and packaged into VLDL lipoprotein (1). Metabolism/Excretion: It is assumed that metabolism and excretion of exogenous CoQ is analogous to endogenously produced CoQ. The excretion of CoQ is predominantly via the biliary tract (1).
HMG-CoA reductase inhibitors: Endogenous levels of CoQ may be reduced by lovastatin, atorvastatin and simvastatin. The HMG-CoA reductase enzyme is responsible for catalyzing the conversion of acetyl CoA to cholesterol and synthesis of CoQ10 (14). Warfarin: CoQ may antagonize the effects of warfarin. CoQ is structurally similar to vitamin K (11). Chemotherapy: Theoretically, CoQ may decrease the efficacy of chemotherapy due to antioxidant activity.
Shults CW, et al. Effects of coenzyme Q10 in early Parkinson disease. Arch Neurol 2002;59:1541-50. A multicenter, randomized, placebo-controlled, double-blind, dose-ranging trial in 80 otherwise healthy patients with early Parkinson disease. Patients received placebo or coenzyme Q10 at dosages of 300, 600, or 1200 mg daily, split into 4 doses. Recent or concurrent use of antioxidants was not permitted. Patients were followed for up to 16 months or until treatment with levodopa was required. Primary outcome measured was Unified Parkinson Disease Rating Scale (UPDRS); the study was projected to have 73% power to detect a difference of 6 points in total UPDRS score. Mean total change was +11.99 in the placebo group and +6.69 in the 1200-mg/d group (p=0.4). Time until treatment with levodopa was not effected by treatment. Side effect profile for all doses of coenzyme Q10 was mild and similar to that for placebo. These results must be confirmed with larger studies.
Khatta M. The effect of coenzyme Q10 in patients with congestive heart failure. Ann Intern Med 2000;132:636-40. A prospective, randomized, double-blind, placebo-controlled trial evaluating coenzyme Q10 (CoQ) supplementation in patients with NYHA Class III or IV heart failure. Patients were randomized to receive 200 mg/day CoQ (n=23) or placebo (n=23) for 6 months. The study was designed to detect a 2.8 mL/kg/min difference in peak oxygen consumption. Other outcomes measured were changes in left ventricular ejection fraction and exercise duration. No adverse events were reported. No significant improvement was noted in patients supplemented with 200 mg/day CoQ. Balercia G, Buldreghini E, Vignini A, et al. Coenzyme Q(10) treatment in infertile men with idiopathic asthenozoospermia: a placebo-controlled, double-blind randomized trial Fertil Steril. Apr 5 2008. Because semen concentrations of coenzyme Q10 and ubiquinol are reduced in infertile men, this randomized, placebo-controlled, double-blind study of 60 infertile participants sought to determine if coenzyme Q10 supplementation (200 mg/day) for 6 months could influence fertility. As compared to placebo, coenzyme Q10 increased sperm motility, an effect that was reversed after a 3 month washout period. Those participants with the lowest baseline coenzyme Q10 and ubiquinol concentrations as well as sperm motility were most likely to receive benefits of coenzyme Q10 supplementation. The authors propose that coenzyme Q10's antioxidant properties may responsible for the increase in sperm motility; however, whether coenzyme Q10 enhances overall fertility, leading to pregnancy has yet to be determined.
