COENZYME Q10, also called CoQ10 or ubiquinone, is an antioxidant found in small amounts in many foods, especially meat and seafood.
It is chemically similar to the fat-soluble vitamins E and K, though it is not classified as a vitamin. Vitamins must be ingested in the diet because the human body does not make enough for its needs. However, the body normally produces sufficient CoQ10.
CoQ10 plays an important role in the production of energy by the body's cells and in preventing damage to cells via oxidation. It is found throughout the body, but in especially large concentrations in the heart, liver, kidney and pancreas.
A very small number of people produce insufficient CoQ10, and suffer from extreme fatigue and muscle weakness. CoQ10 has been approved in Japan for many years as a treatment for heart failure, after if was noted that people with heart disease have reduced levels of CoQ10.
The body normally produces less CoQ10 as we age and this led to claims in the 1990s that CoQ10 was the "fountain of youth" and a miracle treatment for many diseases.
Recent research has shown that CoQ10 might be useful for some people with heart disease, but it's not going to cure everything.
Evidence from studies
Research on CoQ10 gives a confusing array of contradictory results.
Part of the problem is that heart failure can develop for a number of different reasons. One treatment is, therefore, unlikely to help everyone.
However, a number of patterns are visible in the results of the studies. One is that when CoQ10 is used as the only treatment for heart failure, the results are much less encouraging.
Another pattern is seen when CoQ10 is used along with conventional drugs for heart disease (such as beta-blockers, ACE inhibitors or aspirin), the results are much more encouraging. Most of these studies found that CoQ10 along with prescription medications led to a better quality of life and improvements in objective measures of heart failure.
Similarly, taking CoQ10 along with medications for high blood pressure led to larger reductions in blood pressure than occurred with the drugs alone.
Conventional treatment for high cholesterol levels often includes statin drugs. These drugs hinder the body's production of cholesterol, but at the same time they interfere with the production of CoQ10.
Researchers are examining whether CoQ10 supplements given with statins might reduce the side-effects that some people experience with these drugs.
However, the results of these studies are preliminary at this point.
Problematic aspects
CoQ10 does not usually lead to adverse effects. Fewer than 1 per cent of people get gastro-intestinal problems such as nausea, heartburn or diarrhoea. However, given that the supplements appear to be most beneficial along with conventional heart medications, anyone taking such medications should talk to the doctor before taking CoQ10. If benefits arise, it may require adjustments to the dose of any prescription medications.
Recommendations
The early hype about CoQ10 as a fountain of youth has been shown to be just that: hype. As a single treatment, only those with a rare deficiency in CoQ10 production are likely to have clear benefits.
CoQ10 is a powerful antioxidant and has an important general role in the body. Heart disease is associated with damage from oxidation. An antioxidant like CoQ10 would, therefore, be expected to provide some benefits to heart disease patients.
However, an antioxidant will not correct any underlying heart disease, hence the importance of taking conventional treatments along with CoQ10 supplements.
Studies show only that CoQ10 is beneficial for heart failure when taken along with conventional medications. Taken on its own, there is very little evidence that it helps with heart failure, or any of the other conditions for which it is sometimes recommended.
Dónal O'Mathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing at DCU