Coenzyme Q10 for Heart Failure: the Controversy.

As a component of the electron transport chain, CoQ10 plays a key role in energy production, and is therefore essential for all energy-dependent process, including myocardial contraction. Myocardial concentrations of CoQ10 are significantly lower in patients with congestive heart failure (CHF) than in healthy people, but these levels can be increased by oral administration of CoQ10. Numerous clinical trials have shown that CoQ10 supplementation improves symptoms, increases left ventricular ejection fraction, and decreases the number of hospitalizations in patients with CHF. In other studies, however, CoQ10 was of no benefit.

The conflicting results in the different studies might be explained in part by differences in patient populations. One of the negative studies was conducted at an inner-city hospital and a Veterans Affairs hospital. The participants in that study may have had a relatively high prevalence of alcoholism (alcoholic heart disease) and dietary inadequacies. Those factors, combined with the use of diuretics, could have led to clinically significant deficiencies of magnesium, thiamine, or other nutrients that are needed for normal cardiac function. The effectiveness of CoQ10 may be diminished when deficiencies of other cardioprotective nutrients are present.

Based on the available evidence, the nutritional treatment of CHF should include not only CoQ10, but all nutrients known to play a role in heart function.

Baggio E et al. Italian multicenter study on the safety and efficacy of coenzyme Q10 as adjunctive therapy in heart failure. Mol Aspects Med. 1994;15(Suppl):S287-S294.

Langsjoen PH et al. Long-term efficacy and safety of coenzyme Q10 therapy for idiopathic dilated cardiomyopathy. Am J Cardiol. 1990;65:521-523.

Morisco C et al. Effect of coenzyme Q10 in patients with congestive heart failure: a long-term multicenter randomized study. Clin Investing. 1993;71:S134-S136.

by Alan R. Gaby, MD

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