What is the fine-grained topic of the following text: The review encompasses 14 clinical trials from seven countries, including Canada and is the first to investigate the effects of barley on LDL, non-HDL and apolipoprotein B (apoB); a lipoprotein carrying total bad cholesterol in the blood. Only return the topic.
Investigation of barley's effects on LDL, non-HDL, and apolipoprotein B in clinical trials.