Friday, January 25, 2013

Coenzyme Q10: The Antioxidant Powerhouse!

Coenzyme Q10 is a vitamin-like substance used in the treatment of a variety of disorders primarily related to suboptimal cellular energy metabolism and oxidative injury. Studies supporting the efficacy of coenzyme Q10 appear most promising for neurodegenerative disorders such as Parkinson’s disease (PD) and certain encephalomyopathies for which coenzyme Q10 has gained orphan drug status. Results in other areas of research, including treatment of congestive heart failure and diabetes, appear to be contradictory or need further clarification before proceeding with recommendations. Coenzyme Q10 appears to be a safe supplement with minimal side effects and low drug interaction potential. Source: American Family Physician

Coenzyme Q10 (also known as CoQ10, Q10, vitamin Q10, ubiquinone, and ubidecarenone) is a benzoquinone compound synthesized naturally by the human body. The “Q” and the “10” in the name refer to the quinone chemical group and the 10 isoprenyl chemical subunits, respectively, that are part of this compound’s structure. The term “coenzyme” denotes it as an organic (contains carbon atoms), nonprotein molecule necessary for the proper functioning of its protein partner (an enzyme or an enzyme complex).

Chemical structure of Ubiquinone (Coenzyme Q10)

Coenzyme Q10 is used by cells of the body in a process known variously as aerobic respiration, aerobic metabolism, oxidative metabolism, or cell respiration. Through this process, energy for cell growth and maintenance is created inside cells in compartments called mitochondria.[1-4] Coenzyme Q10 is also used by the body as an endogenous antioxidant.[1,2,4-8] An antioxidant is a substance that protects cells from free radicals, which are highly reactive chemicals, often containing oxygen atoms, capable of damaging important cellular components such as DNA and lipids. In addition, the plasma level of coenzyme Q10 has been used in studies as a measure of oxidative stress (a situation in which normal antioxidant levels are reduced).[9,10]

  • Coenzyme Q10 is made naturally by the human body.
  • Coenzyme Q10 helps cells to produce energy, and it acts as an antioxidant.
  • Coenzyme Q10 has shown an ability to stimulate the immune system and to protect the heart from damage caused by certain chemotherapy drugs.
  • Low blood levels of coenzyme Q10 have been detected in patients with some types of cancer.
  • No report of a randomized clinical trial of coenzyme Q10 as a treatment for cancer has been published in a peer-reviewed scientific journal.
  • Coenzyme Q10 is marketed in the U.S. as a dietary supplement.

Coenzyme Q10 is present in most tissues, but the highest concentrations are found in the heart, the liver, the kidneys, and the pancreas.[11] The lowest concentration is found in the lungs.[11] Tissue levels of this compound decrease as people age, due to increased requirements, decreased production,[11] or insufficient intake of the chemical precursors needed for synthesis.[12] In humans, normal blood levels of coenzyme Q10 have been defined variably, with reported normal values ranging from 0.30 to 3.84 µg /mL.[2,4,13,14]

Given the importance of coenzyme Q10 in optimizing cellular energy production, use of this compound as a treatment for diseases other than cancer has been explored. Most of these investigations have focused on coenzyme Q10 as a treatment for cardiovascular disease.[2,4,15] In patients with cancer, coenzyme Q10 has been shown to protect the heart from anthracycline -induced cardiotoxicity (anthracyclines are a family of chemotherapy drugs, including doxorubicin, that have the potential to damage the heart)[3,16-18] and to stimulate the immune system.[19,20] Stimulation of the immune system by this compound has also been observed in animal studies and in humans without cancer.[21-27] In part because of its immunostimulatory potential, coenzyme Q10 has been used as an adjuvant therapy in patients with various types of cancer.[17,20,28-31,33]

While coenzyme Q10 may show indirect anticancer activity through its effect(s) on the immune system, there is evidence to suggest that analogs of this compound can suppress cancer growth directly. Analogs of coenzyme Q10 have been shown to inhibit the proliferation of cancer cells in vitro and the growth of cancer cells transplanted into rats and mice.[12,34] In view of these findings, it has been proposed that analogs of coenzyme Q10 may function as antimetabolites to disrupt normal biochemical reactions that are required for cell growth and/or survival and, thus, that they may be useful for short periods of time as chemotherapeutic agents.[12,34]

Several companies distribute coenzyme Q10 as a dietary supplement. In the U.S., dietary supplements are regulated as foods, not drugs. Therefore, premarket evaluation and approval by the U.S. Food and Drug Administration (FDA) are not required unless specific disease prevention or treatment claims are made. The FDA can, however, remove from the market dietary supplements that it deems unsafe. Because dietary supplements are not formally reviewed for manufacturing consistency, there may be considerable variation from lot to lot. The FDA has not approved coenzyme Q10 for the treatment of cancer or any other medical condition.

To conduct clinical drug research in the U.S., researchers must file an Investigational New Drug (IND) application with the FDA. The IND application process is highly confidential, and IND information can be disclosed only by the applicants. To date, no investigators have announced that they have applied for an IND to study coenzyme Q10 as a treatment for cancer.

In animal studies, coenzyme Q10 has been administered by injection (intravenous, intraperitoneal, intramuscular, or subcutaneous). In humans, it is usually taken orally as a pill (tablet or capsule), but intravenous infusions have been given.[4] Coenzyme Q10 is absorbed best with fat; therefore, lipid preparations are better absorbed than the purified compound.[2,4] In human studies, supplementation doses and administration schedules have varied, but usually have been in the range of 90 to 390 mg/day.

Adverse Effects

No serious toxicity associated with the use of coenzyme Q10 has been reported.[1-4] Doses of 100 mg /day or higher have caused mild insomnia in some individuals.[1] Liver enzyme elevation has been detected in patients taking doses of 300 mg/day for extended periods of time, but no liver toxicity has been reported.[1] Researchers in one cardiovascular study reported that coenzyme Q10 caused rashes, nausea, and epigastric (upper abdominal) pain that required withdrawal of a small number of patients from the study.[5] Other reported side effects have included dizziness, photophobia (abnormal visual sensitivity to light), irritability,[5] headache, heartburn, and fatigue.[6]

Certain lipid -lowering drugs, such as the statins (lovastatin, pravastatin, and simvastatin) and gemfibrozil, as well as oral agents that lower blood sugar, such as glyburide and tolazamide, cause a decrease in serum levels of coenzyme Q10 and reduce the effects of coenzyme Q10 supplementation.[1,7,8,9] Beta-blockers (drugs that slow the heart rate and lower blood pressure) can inhibit coenzyme Q10-dependent enzyme reactions.[1] The contractile force of the heart in patients with high blood pressure can be increased by coenzyme Q10 administration.[1] Coenzyme Q10 can reduce the body’s response to the anticoagulant (blood thinner) drug warfarin.[9] Finally, coenzyme Q10 can decrease insulin requirements in individuals with diabetes.[9] 

Safety Concerns

Coenzyme Q10 is "likely safe" for most adults when taken by mouth or when applied directly to the gums. While most people tolerate coenzyme Q10 well, it can cause some mild side effects including stomach upset, loss of appetite, nausea, vomiting, and diarrhea. It can cause allergic skin rashes in some people. It also might lower blood pressure, so check your blood pressure carefully if you have very low blood pressure. Dividing the total daily dose by taking smaller amounts two or three times a day instead of a large amount all at once can help reduce side effects.

Coenzyme Q10 is "possibly safe" for children. But coenzyme Q10 should not be used in children without medical supervision.

Special Precautions and Warnings
  • Pregnancy and breast-feeding: Not enough is known about the use of coenzyme Q10 during pregnancy and breast-feeding. Stay on the safe side and avoid use.
  • High blood pressure or low blood pressure: Coenzyme Q10 might lower blood pressure. It can increase the effects of medications used to lower blood pressure. Discuss your use of coenzyme Q10 with your healthcare provider if you have blood pressure problems.
  • Surgery: Coenzyme Q10 might interfere with blood pressure control during and after surgery. Stop using coenzyme Q10 at least two weeks before a scheduled surgery.

Potential Interactions with Medications

Be cautious with these combinations:
  • Medications for cancer (Chemotherapy): Coenzyme Q10 is an antioxidant. There is some concern that antioxidants might decrease the effectiveness of some medications used for cancers. But it is too soon to know if the interaction occurs.
  • Medications for high blood pressure (Antihypertensive drugs): Coenzyme Q10 seems to decrease blood pressure. Taking coenzyme Q10 along with medications for high blood pressure might cause your blood pressure to go too low. Some medications for high blood pressure include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), Amlodipine (Norvasc), hydrochlorothiazide (HydroDIURIL), furosemide (Lasix), and many others.
  • Warfarin (Coumadin): Warfarin (Coumadin) is used to slow blood clotting while coenzyme Q10 might increase blood clotting. By helping the blood clot, coenzyme Q10 might decrease the effectiveness of warfarin (Coumadin) and increase the risk of dangerous clots. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.

Potential Interactions with Herbs and Supplements
  • Red yeast: Red yeast might reduce coenzyme Q-10 levels.

Potential Interactions with Foods
  • There are no known interactions with foods.

Coenzyme Q10:
1.Crane FL, Sun IL, Sun EE: The essential functions of coenzyme Q. Clin Investig 71 (8 Suppl): S55-9, 1993.
2.Pepping J: Coenzyme Q10. Am J Health Syst Pharm 56 (6): 519-21, 1999.
3.Folkers K, Wolaniuk A: Research on coenzyme Q10 in clinical medicine and in immunomodulation. Drugs Exp Clin Res 11 (8): 539-45, 1985.
4.Overvad K, Diamant B, Holm L, et al.: Coenzyme Q10 in health and disease. Eur J Clin Nutr 53 (10): 764-70, 1999.
5.Beyer RE, Nordenbrand K, Ernster L: The role of coenzyme Q as a mitochondrial antioxidant: a short review. In: Folkers K, Yamamura Y, eds.: Biomedical and Clinical Aspects of Coenzyme Q. Vol 5. Amsterdam, The Netherlands: Elsevier Science Publishers B V (Biomedical Division), 1986, pp 17-24.
6.Gordon M: Dietary antioxidants in disease prevention. Nat Prod Rep 13 (4): 265-73, 1996.
7.Palazzoni G, Pucello D, Littarru GP, et al.: Coenzyme Q10 and colorectal neoplasms in aged patients. Rays 22 (1 Suppl): 73-6, 1997 Jan-Mar.
8.Ernster L, Dallner G: Biochemical, physiological and medical aspects of ubiquinone function. Biochim Biophys Acta 1271 (1): 195-204, 1995.
9.Yamamoto Y, Yamashita S, Fujisawa A, et al.: Oxidative stress in patients with hepatitis, cirrhosis, and hepatoma evaluated by plasma antioxidants. Biochem Biophys Res Commun 247 (1): 166-70, 1998.
10.Yamamoto Y, Yamashita S: Plasma ratio of ubiquinol and ubiquinone as a marker of oxidative stress. Mol Aspects Med 18 (Suppl): S79-84, 1997.
11.Ernster L, Forsmark-Andrée P: Ubiquinol: an endogenous antioxidant in aerobic organisms. Clin Investig 71 (8 Suppl): S60-5, 1993.
12.Folkers K: The potential of coenzyme Q 10 (NSC-140865) in cancer treatment. Cancer Chemother Rep 2 4 (4): 19-22, 1974.
13.Folkers K, Osterborg A, Nylander M, et al.: Activities of vitamin Q10 in animal models and a serious deficiency in patients with cancer. Biochem Biophys Res Commun 234 (2): 296-9, 1997.
14.Jolliet P, Simon N, Barré J, et al.: Plasma coenzyme Q10 concentrations in breast cancer: prognosis and therapeutic consequences. Int J Clin Pharmacol Ther 36 (9): 506-9, 1998.
15.Baggio E, Gandini R, Plancher AC, et al.: Italian multicenter study on the safety and efficacy of coenzyme Q10 as adjunctive therapy in heart failure. CoQ10 Drug Surveillance Investigators. Mol Aspects Med 15 (Suppl): s287-94, 1994.
16.Cortes EP, Gupta M, Chou C, et al.: Adriamycin cardiotoxicity: early detection by systolic time interval and possible prevention by coenzyme Q10. Cancer Treat Rep 62 (6): 887-91, 1978.
17.Folkers K, Brown R, Judy WV, et al.: Survival of cancer patients on therapy with coenzyme Q10. Biochem Biophys Res Commun 192 (1): 241-5, 1993.
18.Iarussi D, Auricchio U, Agretto A, et al.: Protective effect of coenzyme Q10 on anthracyclines cardiotoxicity: control study in children with acute lymphoblastic leukemia and non-Hodgkin lymphoma. Mol Aspects Med 15 (Suppl): s207-12, 1994.
19.Folkers K, Shizukuishi S, Takemura K, et al.: Increase in levels of IgG in serum of patients treated with coenzyme Q10. Res Commun Chem Pathol Pharmacol 38 (2): 335-8, 1982.
20.Complementary treatments highlighted at recent meeting. Oncology (Huntingt) 13 (2): 166, 1999.
21.Bliznakov E, Casey A, Premuzic E: Coenzymes Q: stimulants of the phagocytic activity in rats and immune response in mice. Experientia 26 (9): 953-4, 1970.
22.Folkers K, Hanioka T, Xia LJ, et al.: Coenzyme Q10 increases T4/T8 ratios of lymphocytes in ordinary subjects and relevance to patients having the AIDS related complex. Biochem Biophys Res Commun 176 (2): 786-91, 1991.
23.Kawase I, Niitani H, Saijo N, et al.: Enhancing effect of coenzyme, Q10 on immunorestoration with Mycobacterium bovis BCG in tumor-bearing mice. Gann 69 (4): 493-7, 1978.
24.Bliznakov EG: Effect of stimulation of the host defense system by coenzyme Q 10 on dibenzpyrene-induced tumors and infection with Friend leukemia virus in mice. Proc Natl Acad Sci U S A 70 (2): 390-4, 1973.
25.Bliznakov EG, Adler AD: Nonlinear response of the reticuloendothelial system upon stimulation. Pathol Microbiol (Basel) 38 (6): 393-410, 1972.
26.Bliznakov EG: Coenzyme Q in experimental infections and neoplasia. In: Folkers K, Yamamura Y, eds.: Biomedical and Clinical Aspects of Coenzyme Q. Vol 1. Amsterdam, The Netherlands: Elsevier/North-Holland Biomedical Press, 1977, pp 73-83.
27.Barbieri B, Lund B, Lundström B, et al.: Coenzyme Q10 administration increases antibody titer in hepatitis B vaccinated volunteers--a single blind placebo-controlled and randomized clinical study. Biofactors 9 (2-4): 351-7, 1999.
28.Lockwood K, Moesgaard S, Hanioka T, et al.: Apparent partial remission of breast cancer in 'high risk' patients supplemented with nutritional antioxidants, essential fatty acids and coenzyme Q10. Mol Aspects Med 15 (Suppl): s231-40, 1994.
29.Lockwood K, Moesgaard S, Folkers K: Partial and complete regression of breast cancer in patients in relation to dosage of coenzyme Q10. Biochem Biophys Res Commun 199 (3): 1504-8, 1994.
30.Lockwood K, Moesgaard S, Yamamoto T, et al.: Progress on therapy of breast cancer with vitamin Q10 and the regression of metastases. Biochem Biophys Res Commun 212 (1): 172-7, 1995.
31.Folkers K: Relevance of the biosynthesis of coenzyme Q10 and of the four bases of DNA as a rationale for the molecular causes of cancer and a therapy. Biochem Biophys Res Commun 224 (2): 358-61, 1996.
32.Ren S, Lien EJ: Natural products and their derivatives as cancer chemopreventive agents. Prog Drug Res 48: 147-71, 1997.
33.Hodges S, Hertz N, Lockwood K, et al.: CoQ10: could it have a role in cancer management? Biofactors 9 (2-4): 365-70, 1999.
34.Folkers K, Porter TH, Bertino JR, et al.: Inhibition of two human tumor cell lines by antimetabolites of coenzyme Q10. Res Commun Chem Pathol Pharmacol 19 (3): 485-90, 1978.

Adverse Effects:
1. Pepping J: Coenzyme Q10. Am J Health Syst Pharm 56 (6): 519-21, 1999.
2. Overvad K, Diamant B, Holm L, et al.: Coenzyme Q10 in health and disease. Eur J Clin Nutr 53 (10): 764-70, 1999.
3. Hodges S, Hertz N, Lockwood K, et al.: CoQ10: could it have a role in cancer management? Biofactors 9 (2-4): 365-70, 1999.
4. Heller JH: Disease, the host defense, and Q-10. Perspect Biol Med 16 (2): 181-7, 1973 Winter.
5. Baggio E, Gandini R, Plancher AC, et al.: Italian multicenter study on the safety and efficacy of coenzyme Q10 as adjunctive therapy in heart failure. CoQ10 Drug Surveillance Investigators. Mol Aspects Med 15 (Suppl): s287-94, 1994.
6. Feigin A, Kieburtz K, Como P, et al.: Assessment of coenzyme Q10 tolerability in Huntington's disease. Mov Disord 11 (3): 321-3, 1996.
7. Kaikkonen J, Nyyssönen K, Tuomainen TP, et al.: Determinants of plasma coenzyme Q10 in humans. FEBS Lett 443 (2): 163-6, 1999.
8. Thibault A, Samid D, Tompkins AC, et al.: Phase I study of lovastatin, an inhibitor of the mevalonate pathway, in patients with cancer. Clin Cancer Res 2 (3): 483-91, 1996.
9. Coenzyme Q10. In: Jellin JM, Hitchens K, eds.: Natural Medicines Comprehensive Database. Stockton, Calif: Therapeutic Research Faculty, 1999, pp 241-42.

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These statements have not been approved by the U.S. Food and Drug Administration (FDA). This information is not intended to diagnose, treat, cure or prevent any disease.

Information conveyed herein is based on pharmacological and other records - both ancient and modern. No claims whatsoever can be made as to the specific benefits accruing from the use of any herb, essential oil, dietary and/or nutritional supplement, home remedy, or therapeutic regimen. Holistic Lifestyle Community Blog has provided this material for general information and education purposes only. It is not intended as a substitute for or to take the place of professional medical advice. If you have a medical emergency call 9-1-1. Before beginning any type of alternative, integrative, or conventional treatment regimen, it is advisable to seek the advice of a licensed physician or qualified health care professional. The mention of any product, service, or therapy is not an endorsement by Holistic Lifestyle Community Blog. Any mention in the Holistic Lifestyle Community Blog of a specific brand name is not an endorsement of the product.

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