Effects of consumption of coconut oil or coconut on glycemic control and insulin sensitivity: A systematic review and meta-analysis of interventional trials

Background and aims: The often purported claim that coconut fat is beneficial for cardiovascular health and was disputed in several recent meta-analyses. However, the evidence on the effects of coconut fat intake on glycemic control remains equivocal. We conducted a systematic review and meta-analysis in accordance with the PRISMA guidelines to determine the effects of dietary coconut fats on markers of acute and long-term glycemic control.

Methods and results: PubMed, Scopus, ProQuest, and Web-of-Science databases were searched and the records were screened by three independent reviewers to identify interventional studies examining acute and long-term (i.e., >10 days) effects of coconut fat on glycemic control. DerSimonian-Laird random-effects meta-analyses were performed using the meta-package in R (4.0.2). Seven interventional studies on acute effects and 11 interventional studies on long-term effects of coconut fat were included. Meals with coconut fat acutely increased the incremental area under the curve (AUC) of glucose (p = 0.046) and decreased the incremental AUC of insulin (p = 0.037) vs. control meals. Long-term coconut fat intake increased HOMA-IR (p = 0.049), but did not significantly affect fasting glucose, insulin, or HOMA-β vs. control meals.

Conclusions: Coconut fat in meals seems to be associated with a diminished postprandial insulin response, resulting in a subtle increase in the postprandial glycemic response. Long-term intake of coconut fat seems to increase insulin resistance, yet does not seem to be beneficial for long-term glycemic control. Thus, our results disprove the popular claim that coconut fat improves glycemic control.

Registration: PROSPERO registry (CRD42020183450).