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Other common
name(s): CoQ10, Co-Q10, CoQ-10, vitamin Q10
Scientific/medical
name(s): ubiquinone, ubidecarenone
Description
Coenzyme Q10 (CoQ10) is part of an enzyme complex that affects
certain chemical reactions in the body. It occurs naturally in the body
and can also be found in a number of foods, such as mackerel, salmon,
sardines, beef, soybeans, peanuts, and spinach, as well as in dietary
supplements.
Overview
CoQ10 may promote health and fight some diseases, but more
research is needed to find out the role of this substance. Some small
studies have suggested that CoQ10 may help treat cancer or reduce
chemotherapy-related heart damage, but these results need to be
confirmed by larger randomized clinical trials. CoQ10 may reduce the
effectiveness of chemotherapy, so most oncologists would recommend
avoiding it during chemotherapy.
How is it promoted for use?
Scientists believe CoQ10 is an antioxidant, a compound that
blocks the actions of free radicals, activated oxygen molecules that
can damage cells. Scientists also believe that CoQ10 may have an effect
on the immune system. Some studies have suggested that deficiencies of
CoQ10 may contribute to certain diseases such as cancer.
CoQ10 is sometimes promoted as a treatment for cancer (most
commonly breast cancer), often in combination with other vitamins.
Supporters also claim CoQ10 supplements may protect the heart from the
damaging effects of certain chemotherapy drugs, such as doxorubicin
(Adriamycin).
CoQ10 supplements have also been promoted for heart disease,
stroke, gum disease, and immune deficiencies. Some claim that CoQ10 can
reduce pain and weight loss in people with cancer.
What does it involve?
Coenzyme Q10 occurs naturally in the body and can also be
obtained from a number of foods or as a supplement. The usual
supplement dose used in clinical studies is 90 to 400 milligrams per
day. Supplements are available as tablets, capsules, and gelcaps.
What is the history behind it?
Coenzyme Q10 was first identified in 1957. Particularly high
amounts were found in heart tissue, which is why researchers became
interested in the connection between CoQ10 and heart disease. Studies
in the 1960s found a possible connection between cancer (especially
breast cancer) and low levels of CoQ10 in the blood. Some laboratory
studies have suggested that CoQ10 may have a role as an immune system
booster. Since then, researchers have been testing CoQ10 supplements
for treating heart disease, cancer, and other conditions. However, no
firm conclusions have been reached about its usefulness in treating any
disease.
What is the evidence?
Some laboratory and animal studies indicate that CoQ10 could
theoretically have an effect on cancer. In addition to its ability to
act as an antioxidant, CoQ10 has effects on cellular energy and on the
immune system. Some laboratory and animal studies have supported this
idea. However, evidence from human studies is still minimal. Early
studies involving small numbers of patients have suggested certain
CoQ10 supplements may have some anticancer benefits. The studies of
CoQ10 for cancer done thus far have been fairly small and did not have
scientifically strong designs. More studies are needed with larger
groups of patients to determine what effect, if any, it has on cancer.
In a Danish study, 32 women with breast cancer that had spread
to the lymph nodes were treated with a nutritional supplement program
of vitamins, minerals, essential fatty acids, and CoQ10, in addition to
standard therapy. Six patients were reported to have some tumor
shrinkage, and all survived at least 2 years. However, there was no
comparison group in this study, and it was not clear whether the
effects were due to the CoQ10 or to the standard treatments. The study
was published in 1994 and has not been duplicated since.
In a Canadian study, 90 women with breast cancer that had not
spread to distant organs were given high doses of different
combinations of vitamins, minerals, and CoQ10 along with standard
treatment. They were compared to women not taking the supplements on
the basis of type of conventional therapy received and by several
breast cancer predictive factors such as patient age, how far the
cancer had spread, and whether cancer cells contained estrogen
receptors. Patients receiving only mainstream therapy tended to remain
disease-free longer and live longer, although the difference was not
quite statistically significant. One weak point of the study was that
since the women received a combination of supplements, it was not
possible to know how they might have responded to CoQ10 alone.
One clinical trial looked at 142 male smokers randomly chosen
to receive anti-oxidants including CoQ10 or a placebo for 2 months. The
study found no difference in a chemical indicator of DNA damage,
suggesting that CoQ10 is not likely to be useful in preventing cancer.
However, no long-term clinical studies of CoQ10 and cancer occurrence
have been published.
Low levels of CoQ10 have been linked to heart damage from
chemotherapy treatment for cancer, especially from drugs called
anthracyclines. A recent review looked at 6 clinical trials that tested
the use of CoQ10 to protect the heart against damage from chemotherapy.
The overall results suggested that CoQ10 may provide some protection
for the heart, but the study designs were weak in several areas. The
review concluded that further studies were needed to confirm the
results.
No scientific research has been published in available medical
journals concerning the possible effects of CoQ10 on pain, weight loss,
or increased appetite.
Are there any possible problems or
complications?
This product is sold as a
dietary supplement in the United States. Unlike companies that produce
drugs (which must provide the FDA with results of detailed testing
showing their product is safe and effective before the drug is approved
for sale), the companies that make supplements do not have to show
evidence of safety or health benefits to the FDA before selling their
products. Supplement products without any reliable scientific evidence
of health benefits may still be sold as long as the companies selling
them do not claim the supplements can prevent, treat, or cure any
specific disease. Some such products may not contain the amount of the
herb or substance that is written on the label, and some may include
other substances (contaminants).
Though the FDA has written
new rules to improve the quality of manufacturing processes for dietary
supplements and the accurate listing of supplement ingredients, these
rules do not take full effect until 2010. And, the new rules do not
address the safety of supplement ingredients or their effects on health
when proper manufacturing techniques are used.
Most such
supplements have not been tested to find out if they interact with
medicines, foods, or other herbs and supplements. Even though some
reports of interactions and harmful effects may be published, full
studies of interactions and effects are not often available. Because of
these limitations, any information on ill effects and interactions
below should be considered incomplete.
Few serious reactions to CoQ10 have been reported. Side
effects may include headache, heartburn, trouble sleeping, and fatigue.
Very high doses may cause involuntary muscle movements. Some users
report mild diarrhea and skin reactions. Little is known about dosage
or consequences of long-term use of CoQ10 supplements. There have been
reports that CoQ10 may interact with blood-thinning medications and
could pose a risk for prolonged bleeding.
Because CoQ10 is a strong antioxidant, there are theoretical
reasons to suspect that it might interfere with the effectiveness of
chemotherapy and radiation therapy. This question has not been
adequately studied in clinical trials. Many oncologists would recommend
avoiding CoQ10 and other antioxidant supplements during chemotherapy
and radiation therapy, as well as for a few weeks before and after
these treatments.
Relying on this type of treatment alone and avoiding or
delaying conventional medical care for cancer may have serious health
consequences.
Additional Resources
More information from your American Cancer
Society
The following information on complementary and alternative
therapies may also be helpful to you. These materials may be found on
our Web site (www.cancer.org)
or ordered from our toll-free number (1-800-ACS-2345).
References
Fetrow CW, Avila JR. Professional's
Handbook of Complementary and Alternative Medicines.
Springhouse, Pa: Springhouse Corp; 1999.
Folkers K, Brown R, Judy WV, Morita M. Survival of cancer
patients on therapy with coenzyme Q10. Biochem Biophys Res Commun.
1993;192:241-245.
Hodges S, Hertz N, Lockwood K, Lister R. CoQ10: could it have
a role in cancer management? Biofactors.
1999;9:365-370.
Lesperance ML, Olivotto IA, Forde N, Zhao Y, Speers C, Foster
H, Tsao M, MacPherson N, Hoffer A. Mega-dose vitamins and minerals in
the treatment of non-metastatic breast cancer: an historical cohort
study. Breast Cancer
Res Treat. 2002 Nov;76(2):137-143.
Lockwood K, Moesgaard S, Hanioka T, Folkers K. Apparent
partial remission of breast cancer in 'high risk' patients supplemented
with nutritional antioxidants, essential fatty acids and coenzyme Q10. Mol Aspects Med.
1994;15:S231-240.
Memorial Sloan Kettering Cancer Center. Coenzyme Q10. Accessed
at: http://www.mskcc.org/mskcc/html/69186.cfm on June 11, 2008.
.
National Cancer Institute Physician Data Query (PDQ). Coenzyme
Q10. 2006. Accessed at:
www.cancer.gov/cancertopics/pdq/cam/coenzymeQ10/healthprofessional on
June 11, 2008.
Prieme H. Loft S. Nyyssönen K. Salonen JT. Poulsen
HE. No effect of supplementation with vitamin E, ascorbic acid, or
coenzyme Q10 on oxidative DNA damage estimated by
8-oxo-7,8-dihydro-2'-deoxyguanosine excretion in smokers. Amer J Clin Nutr.
65(2):503-7, 1997
Roffe L, Schmidt K, Ernst E. Efficacy of coenzyme Q10 for
improved tolerability of cancer treatments: a systematic review. J Clin Oncol.
2004;22(21):4418-4424.
Spigset O. Reduced effect of warfarin caused by
ubide-carenone. Lancet.
1994;344:1372-1373.
Note: This information may not cover
all possible claims, uses, actions, precautions, side effects or
interactions. It is not intended as medical advice, and should not be
relied upon as a substitute for consultation with your doctor, who is
familiar with your medical situation.
Last Medical Review: 11/01/2008
Last Revised: 11/01/2008
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