There is evidence that caffeine can reduce the risk of cardiovascular disease. However, its mechanism is unknown. Recently, Canadian scholars published research results that caffeine may prevent cardiovascular disease because it can reduce the level of "bad cholesterol". The researchers analyzed the effects of caffeine on the expression of two regulators of blood "bad cholesterol" - low density lipoprotein cholesterol (LDL-C): PCSK9 (pre protein invertase subtilisin / kexin9) and low density lipoprotein receptor (LDLR). Cell experiments observed that caffeine decreased circulating PCSK9 levels and increased liver LDL receptor expression. And the higher the concentration of caffeine, the more obvious the effect. The researchers confirmed the results of the cell experiment in the mouse experiment. After taking caffeine, the level of PCSK9 in the blood circulation of the mice decreased, the hepatocytes showed that the low-density lipoprotein receptor increased, and the contents of triglycerides and cholesterol in the blood decreased significantly. Subsequently, the researchers conducted human experiments and confirmed the effect of caffeine on reducing PCSK9 in 12 healthy volunteers. Plasma PCSK9 levels decreased by 25% and 21% at 2 and 4 hours of caffeine intake, respectively. (outlook new era)