Herbal medicinal products for the treatment of hypercholesterolemia: a systematic review

Background: Hypercholesterolemia is a major risk factor for heart disease, the leading cause of death in the US. A large number of herbal medicinal products are promoted for hypercholesterolemia. It is therefore important to establish the efficacy and safety of herbal supplements in reducing serum cholesterol levels. Methods and results: Systematic searches were performed in six electronic databases and the reference fists of all papers located were checked for further relevant publications. No language restrictions were imposed. Experts in the field and manufacturers of identified herbal extracts were also contacted. All clinical trials of mono-preparations of herbal treatments administered as supplements to human subjects were included. Seventeen herbal extracts with evidence from clinical trials for use in lowering elevated serum cholesterol levels were identified, including six for which only non-randomised clinical trials have been performed. Artichoke, guggul and fenugreek have been most extensively studied and have demonstrated reductions in total serum cholesterol levels ranging from 10 to 33%. The methodological quality as assessed by the Jadad score was less than three (maximum = 5) for 13 of the 24 randomised clinical trials. The mechanism of any hypocholesterolemic activity has yet to be fully defined. However, several herbal extracts have similar postulated mechanisms involving the effects of soluble fibres and saponins. Conclusions: There are a large number of herbal medicinal products with potential hypocholesterolentic activity, and encouraging safety profiles. However, only a limited amount of clinical research exists to support their efficacy. Further research is warranted to establish the value of these extracts in the treatment of hypercholesterolemia.