Barely a week goes by without a doctor or scientist extolling the virtues of the cholesterol-quelling drugs known as statins.

So great is the enthusiasm for these drugs that the Department of Health recently decreed that one particular statin (simvastatin) should be available over the counter (OTC). This might seem like a smart move by a government concerned for our health and longevity. But, as was pointed out in the Lancet recently, statin use in individuals without known cardiovascular disease has not been proven to reduce overall risk of death. With the NHS spend on statins expected to rise to £2bn per annum by 2010, it seems the move to make statins available to buy OTC may be motivated by a desire not to save lives, but to save money.

Another reason we should be cautious about rushing out to buy statins from pharmacies is that this class of drug is known to have the potential for side effects including liver damage, digestive symptoms, muscle pain and fatigue. Some of the side effects are a direct product of their primary mode of action in the body. Statins work by inhibiting enzymes in the body's cells that are responsible for the internal manufacturing of cholesterol. Unfortunately, the same enzyme is responsible for manufacturing a substance known as Coenzyme Q10 (CoQ10), which plays a critical part in the reactions that generate energy within the body's cells.

Several studies show that dosing up on statins can deplete the body of CoQ10. Bearing in mind CoQ10's starring role in the generation of energy in the body, it is no surprise that people taking statins can find themselves suffering from fatigue and exhaustion.

CoQ10 also seems to be particularly important for maintaining a healthy heart. This is why, as I mentioned in my column three weeks ago, CoQ10 is a useful agent in the treatment of cardiac failure. Logic dictates that statins, through their CoQ10 depleting effects, might weaken the primary organ they are designed to protect.

Because it can take a long time after starting statin therapy for CoQ10 levels to be lowered enough to provoke symptoms, it is easy for the drug's role in fatigue to go unrecognised. Those taking statins, particularly in the long term, should ensure a good intake of CoQ10. The richest dietary sources are organ meats such as liver and kidney. Other foods offering useful amounts of CoQ10 include nuts, sesame seeds, oily fish and broccoli.

I recommend 50-100mg of CoQ10 per day if you are on statins. For those who have symptoms of CoQ10 depletion, I suggest 100-150mg of CoQ10 be taken daily, though it may take some months for symptoms to abate.