Question

My nutritionist has advised me to start taking a supplement called coenzyme Q10 (CoQ10) which, she says, will boost my energy levels and improve my memory problems. What is CoQ10 and is this claim justified? Are there any side-effects? Can I take it with prescription-only medicines?

Answer

Coenzyme Q10 (CoQ10), which is also known as ubiquinone, is often referred to as a vitamin. However, this isn’t strictly true as it is made in the liver from an amino acid called tyrosine. Deficiency can occur as a result of reduced dietary intake, decreased production, or increased usage – or a combination of all three. CoQ10 is also present in a wide variety of foods. Good food sources of CoQ10 include:

• Cold water fish, like tuna, salmon, mackerel, and sardines
• Vegetable oils
• Meats

CoQ10 is known as a coenzyme because it helps other enzymes in the body to carry out their normal functions. It acts as an antioxidant, which protects cells from damage and plays an important part in the metabolism. In relation to muscle fatigue, it is involved in energy producing chemical pathways inside the mitochondria – parts of the cell where energy in the form of a chemical called ATP is produced. There are clearly some theoretical reasons why CoQ10 might be helpful in ME/CFS, but despite all the claims being made for it, there is very little scientific evidence linking deficiency with disease in relation to ME/CFS.

There has been one small clinical trial carried out in Spain (1) to assess the use of CoQ10 in ME/CFS. This was an 8-week randomised, double-blind, placebo-controlled trial involving 73 people with ME/CFS who were given either a placebo or oral CoQ10 (200mg per day) and another supplement called NADH (20mg per day). Those receiving the combination of supplements reported a decrease in fatigue levels and beneficial changes in biochemical markers in the blood were seen. However, these results need to be viewed with caution because the trial involved two supplements (it wasn't just about CoQ10) and the follow-up period was very short.

Results from a research study on mice (2) suggested that prolonged intake of CoQ10 in low amounts had no discernable impact on cognitive and motor functions whereas intake at higher amounts exacerbated cognitive and sensory impairments in older mice. The researchers concluded that these findings do not support the notion that CoQ10 is a fitness-enhancing or an “antiaging” substance under normal physiological conditions. Neither is there much evidence of benefit in diseases where CoQ10 is sometimes recommended, such as heart failure, mitochondrial muscle diseases, and Parkinson’s disease (where decreased levels of CoQ10 have been found in spinal fluid).

As far as side-effects are concerned, CoQ10 is normally well tolerated with no serious side effects being reported. But it has not been properly assessed in pregnancy. One important note of caution relates to its use with statins which are prescription-only drugs used for lowering blood cholesterol. Statins can also lower the levels of CoQ10, and it has been suggested that this could make people more liable to develop statin-induced myopathy (muscle damage). This is a well recognised side-effect of statins, and is something that is occasionally reported by people with ME/CFS. So there may be a case for taking CoQ10 if you have ME/CFS and are also taking a statin (3). It has also been reported that CoQ10 can interfere with anticoagulants (blood-thinning drugs such as warfarin) at high doses.

Overall, CoQ10 is a supplement that may be worth a try if you have ME/CFS but please bear in mind that reports of benefit are highly speculative rather than scientifically proven.

In summary:

• Side effects from CoQ10 seem to be rare and mild. They include diarrhea, nausea, and heartburn.
• People with chronic diseases such as heart failure, kidney or liver problems, or diabetes should be wary of using this supplement. CoQ10 may lower blood sugar levels and blood pressure.
• People taking statins, blood thinners and thyroid medications as well as chemotherapy should check with their doctors before using CoQ10 supplements.
• Given the lack of evidence about its safety, CoQ10 supplements are not recommended for children or for women who are pregnant or breastfeeding.

References:

1. Castro-Marrero J et al. Does Oral Coenzyme Q10 Plus NADH Supplementation Improve Fatigue and Biochemical Parameters in Chronic Fatigue Syndrome? Antioxidants and Redox Signaling | March 2015
2. Sumien N et al. Prolonged Intake of Coenzyme Q₁₀ Impairs Cognitive Functions in Mice. The Journal of Nutrition | August 2009

3. Sandwell Area Formulary NHS: Should patients on statins take Coenzyme Q10 supplementation to reduce the risk of statin-induced myopathy?