Effect of proanthocyanidins on blood lipids: A systematic review and meta-analysis

Proanthocyanidins (PCs) are natural antioxidant polyphenols and their effect on the regulation of blood lipids is still controversial. This study was conducted to evaluate the effect of PCs on lipid metabolism. We searched PubMed, Embase, Web of Science, Chinese biomedical literature service system, China National Knowledge Internet, and Wanfang Data with no time restriction until March 18, 2022, using various forms of "proanthocyanidins" and "blood lipid" search terms. Randomized controlled trials investigating the relationship between PCs and lipid metabolism were included. The standard system of Cochrane Collaboration was used to assess the quality of studies. We standardized mean differences (SMDs) with 95% confidence interval (CI) using the random-effects model, Cohen approach. Seventeen studies (17 trials, N = 1138) fulfilled the eligibility criteria. PCs significantly reduced triglyceride, and increased recombinant apolipoprotein A1. Subgroup analysis showed a significant reduction in triglycerides in older adults (≥60 years) and total cholesterol for participants who were not overweight or obese (body mass index <24). An intervention duration of greater than 8 weeks reduced triglyceride and low-density lipoprotein cholesterol levels but increased high-density lipoprotein cholesterol. Different doses of PCs could regulate triglycerides, high-density lipoprotein cholesterol and total cholesterol. PCs have beneficial effects on circulating lipids and may represent a new approach for treating or preventing lipid metabolism disorders. However, more high-quality studies are needed to confirm these results.