Hypercholesterolaemia is directly associated with an increased risk for coronary heart disease and other sequelae of atherosclerosis. Artichoke leaf extract (ALE) has been implicated in lowering cholesterol levels. Whether ALE is truly effective for this indication, however, is still a matter of debate.
To assess the evidence of ALE versus placebo or reference medication for treating hypercholesterolaemia defined as mean total cholesterol levels of at least 5.17 mmol/L (200 mg/dL).
We searched the Cochrane Central Register of Controlled Trials 2008 Issue 2, MEDLINE, EMBASE, AMED and CINAHL from their respective inception until June 2008; CISCOM until June 2001. Reference lists of articles were checked. Manufacturers of preparations containing artichoke extract and experts on the subject were contacted.
Randomised controlled trials (RCTs) of ALE mono-preparations compared with placebo or reference medication for patients with hypercholesterolaemia were included. Trials assessing ALE as one of several active components in a combination preparation or as a part of a combination treatment were excluded.
Data collection and analysis
Data were extracted systematically and methodological quality was evaluated using a standard scoring system and the Cochrane risk of bias assessment. The screening of studies, selection, data extraction and assessment of methodological quality were performed independently by two reviewers. Disagreements in the evaluation of individual trials were resolved through discussion.
Three RCTs (262 participants) met all inclusion criteria. In one trial the total cholesterol level in participants receiving ALE decreased by 4.2% from 7.16 (0.62) mmol/L to 6.86 (0.68) mmol/L after 12 weeks and increased from 6.90 (0.49) mmol/L to 7.04 (0.61) mmol/L in patients receiving placebo, the total difference being statistically significant (P = 0.025). In a further trial ALE reduced total cholesterol levels by 18.5% from 7.74 mmol/L to 6.31 mmol/L after 42 ± 3 days of treatment whereas the placebo reduced cholesterol by 8.6% from 7.69 mmol/L to 7.03 mmol/L (P = 0.00001). Another trial did state that ALE significantly reduced blood cholesterol compared with placebo in a sub-group of patients with baseline total cholesterol levels of more than 230 mg/dL (P < 0.05). Trial reports indicate mild, transient and infrequent adverse events.
Some data from clinical trials assessing ALE for treating hypercholesterolaemia exist. There is an indication that ALE has potential in lowering cholesterol levels, the evidence is, however, as yet not convincing. The limited data on safety suggest only mild, transient and infrequent adverse events with the short term use of ALE.
Plain language summary
Artichoke leaf extract for treating high cholesterol levels
Too much cholesterol in the blood can lead to cholesterol depositing on the walls of the arteries (major blood vessels). This blocks the arteries and can cause heart attacks and strokes. High cholesterol can be lowered by quitting smoking, dietary changes and exercise. Some drugs such as statins are used, but these can have adverse events. Artichoke (Cynara scolymus) leaf extract is a herbal remedy marketed as an aid to lowering cholesterol. The review found that few studies have researched this topic in people with high cholesterol. Artichoke leaf extract might be effective and relatively safe, but further research is needed. —Cochrane Review