The analysis combined the results of 29 studies with a total of more than 1,500 participants. The researchers included only randomized controlled trials that compared garlic with a placebo, which is the gold standard for any study design and means the meta-analysis is of high quality, says Alyssa Kwan, a registered dietitian who works with patients in the cardiovascular ICU and surgical units at Stanford Health Care in California.
A large body of evidence supports garlic's effectiveness
Overall, the results are consistent with previous studies, which found that garlic may lower A1C levels somewhat and slightly reduce LDL (or “bad”) cholesterol. Matthew Badgett, MDThe integrative medicine physician at the Cleveland Clinic in Ohio was not involved in the study.
According to Badget, every study that looked at A1C levels saw a reduction in levels in those taking garlic, with the average reduction in LDL cholesterol across studies being 8.2 points.
This is a modest effect in terms of lowering “bad” cholesterol, but most studies are likely too short in duration to show garlic's full effect, he says.