Overview of Coenzyme Q10.
Coenzyme Q10, also referred to as CoQ10 or ubiquinone,
is a vitamin-like compound which is present in all cells. It occurs naturally in the body and is found
in highest amounts in the mitochondria, where cellular energy is created. CoQ10 levels are highest in the
hardest-working tissues of the body, especially the heart.
Coenzyme Q10 is an antioxidant, that is, it helps to
protect cells from damage caused by the body's own free radicals. The body produces free radicals in the normal
course of energy production. However as
we get older our bodies generate an excess of free radicals. This can be deleterious for individuals whose
bodies are not producing enough Coenzyme Q10 and other antioxidants to control
these free radicals.
Coenzyme Q10 has several different actions in the
body. Its most notable effects/help are:
•
it scavenges free radicals as an Antioxidant
•
Improves the efficacy of cellular energy production in the
mitochondria (energy factories) of the cell
•
Regulates genes concerned with energy production
•
Stabilizes membranes
As we age there is a decline in the amount of CoQ10
our body produces. It is not possible to
get large amounts of CoQ10 from diet alone.
Therefore taking a daily
supplement, especially as we age, can increase cell energy levels and
strengthen the body's antioxidant defence network.
Basic Cardiovascular Function
In a variety of laboratory and animal experiments,
coenzyme Q10 has been shown to be effective in reducing the adverse effects of
ischaemia-reperfusion injury. It can
enhance energy production in mitochondria and cells and improve clinical
outcomes.
Coenzyme
Q10 in Hypertension
There have been twelve clinical trials of coenzyme Q10
in the treatment of hypertension. Four
were prospective randomized trials and eights were before and after
studies. Overall, the twelve studies
showed a fall in blood pressure of 17 mmHg systolic and 10 mmHg diastolic. coenzyme Q10 has shown to be particularly
effective with hypertension in diabetics were it not only lowers blood pressure
but also improves diabetic control. The
mechanism of action of coenzyme Q10 in hypertension is almost certainly as an
antioxidant, were it scavenges free oxygen radicals, protects the endothelium
from oxygen free radical attack and thus improves vascular dilatation by nitric
oxide.
Coenzyme Q10
in Heart Failure
A review of all the published trials of coenzyme Q10
in heart failure was first published in 1997.
This showed a beneficial effect of coenzyme Q10. We updated the findings for this analysis by analyzing
nine randomized trials of coenzyme Q10 in heart failure published up to 2003
(2). Only prospective randomized,
double-blind and placebo-controlled trials were included in that analysis. The three parameters with adequate numbers of
patients for meaningful analysis were coenzyme Q10 levels (5 trials), ejection
fraction at rest (7 trials) and mortality (5 trials). Other parameters were measured in only two
trials each. For CoQ10 levels (279
patients), the weighted mean differences was 1.4 µg/µl representing an increase
of 161%. For ejection fraction at rest
(384 patients) the weighted mean difference showed a trend in favor of CoQ10 of
1.9% (95% confidence limits - 0.13% to 3.9%).
An updated meta-analysis has been published recently
(12). This meta-analysis included eleven
randomized trials of coenzyme Q10 in heart failure including cross-over and
parallel trial designs. The main
end-point of resting ejection fraction showed an absolute 3.7% net improvement
(P < 0.0006). Stroke index also
increased by 5.8 ml (P = 0.02).
Sub-group analyses showed that the ejection fraction improvement was
more pronounced when only idiopathic cardiomyopathy was evaluated and among
patients not receiving angiotensin converting enzyme (ACE) inhibitors. When the results were re-analyzed using a less
conservative statistical test (fixed effects modeling) than was used in the
initial analysis (random effects modeling), increases in cardiac output,
cardiac index and stroke volume all became significant.
In light of the encouraging findings of the abovementioned
meta-analyses it is not unreasonable to recommend to patients with symptomatic
heart failure despite conventional therapy or those who are experiencing side
effects from conventional therapy (especially ACE inhibitors) to take 150-300
mg of coenzyme Q10 daily and to monitor CoQ10 blood levels and clinical
response.
Coenzyme
Q10 in Cardiac Surgery
Coenzyme Q10 has been used in the cardiothoracic
surgical setting in order to offset reperfusion-related increases in free
radical formation and oxidative stress.
From 1982 to 2004 at least eight controlled trials of coenzyme Q10 in
cardiac surgery have been published.14-22 All but one of these have shown a
beneficial effect of some kind. The one
trial showing an absence of effect20 used oral CoQ10 for only 12 hours before
surgery, an inadequate time frame for sufficient dosing to increase myocardial
levels. A prospective randomized,
placebo-controlled trial from our unit of 300 mg per day of oral CoQ10 for two
weeks preoperatively in 121 coronary bypass or valve replacement procedures
showed increased mitochondrial CoQ10 content, increased effiency of mitochondrial
energy production and improved contractile function in myocardial trabeculae.
Cardiac
Arrhythmias
There is some anecdotal experimental and clinical
evidence of a beneficial effect of coenzyme Q10 in cardiac arrhythmias. This would make sense in light of the effect
of coenzyme Q10 in improving cellular membrane function and energy production,
thus reducing the myocardial ischaemia that can generate arrhythmias.
Side Effects and Drug Interactions
Coenzyme Q10 is essentially devoid of side effects. There are occasional reports of
gastrointestinal upset but no other major side effects.
Does coenzyme Q10 Interfere with Warfarin?
The literature contains a case report describing a
reduction in the efficacy of warfarin caused by coenzyme Q10. However, a subsequent prospective randomised
trial of coenzyme Q10 showed no effect of coenzyme Q10 on coagulation status in
patients receiving Warfarin therapy. In
summary, anticoagulation should be closely monitored during the initiation or
withdrawal of coenzyme Q10therapy.
Dosage
Doses between 150 and 300 mg per day are used for
heart failure or hypertension. Ideally,
dosage is adjusted according to serum coenzyme Q10 levels. Therapeutic effects
are most likely when serum levels are increased to twice normal. CoQuinone 30 dietary supplement was developed to deliver high-quality, highly bioavailable CoQ10 to the cells to support the production of adenosine-5-triphosphate (ATP).
Conclusions
There is accumulating laboratory and clinical evidence
of the efficacy of coenzyme Q10 in a variety of cardiovascular disorders. Not all of these have been conclusively
proven, but in the absence of side effects, it is reasonable to administer
coenzyme Q10 to selected patients with various types of cardiovascular disease
and gauge the response.
Major Reference: Coenzyme Q10 Research
