ScopeCruciferous‐rich diets have been associated with reduction in plasma LDL‐cholesterol (LDL‐C), which may be due to the action of isothiocyanates derived from glucosinolates that accumulate in these vegetables. This study tests the hypothesis that a diet rich in high glucoraphanin (HG) broccoli will reduce plasma LDL‐C.Methods and resultsOne hundred and thirty volunteers were recruited to two independent double‐blind, randomly allocated parallel dietary intervention studies, and were assigned to consume either 400 g standard broccoli or 400 g HG broccoli per week for 12 weeks. Plasma lipids were quantified before and after the intervention. In study 1 (37 volunteers), the HG broccoli diet reduced plasma LDL‐C by 7.1% (95% CI: –1.8%, –12.3%, p = 0.011), whereas standard broccoli reduced LDL‐C by 1.8% (95% CI +3.9%, –7.5%, ns). In study 2 (93 volunteers), the HG broccoli diet resulted in a reduction of 5.1% (95% CI: –2.1%, –8.1%, p = 0.001), whereas standard broccoli reduced LDL‐C by 2.5% (95% CI: +0.8%, –5.7%, ns). When data from the two studies were combined the reduction in LDL‐C by the HG broccoli was significantly greater than standard broccoli (p = 0.031).ConclusionEvidence from two independent human studies indicates that consumption of high glucoraphanin broccoli significantly reduces plasma LDL‐C.