Saturated Fatty Acid Intake and Risk of Type 2 Diabetes: An Updated Systematic Review and Dose–Response Meta-Analysis of Cohort Studies

This systematic review and meta-analysis was conducted to pool findings of cohort studies that investigated hazards of type 2 diabetes mellitus (T2DM) in relation to intakes of SFAs. A systematic search was conducted in the PubMed, Scopus, and Embase databases up to June 2021 to find eligible studies. Review articles or commentaries, clinical trials, cross-sectional studies, studies on gestational or type 1 diabetes patients, animal studies, articles with no access to full-texts, articles published in non-English languages, and articles with missing critical data needed for the systematic review were excluded from the meta-analysis. A random-effects model was used to combine study-specific results. Thirteen cohort studies with 361,686 participants and 11,865 T2DM events were included. Dietary total SFA intake, as well as dietary palmitic acid (PA) or stearic acid (SA) were not associated with risk of T2DM when the highest was compared with the lowest intake category (HR = 0.99; 95% CI: 0.91, 1.09; n = 13 for total SFAs; HR = 0.96; 95% CI: 0.79, 1.15; n = 4 for PA; and HR = 1.08; 95% CI: 0.79, 1.49; n = 4 for SA). However, the risk of T2DM decreased by 11% in the highest compared with the lowest category of dietary lauric acid (HR = 0.89; 95% CI: 0.82, 0.97; n = 2), and by 17% in the highest compared with lowest category of dietary myristic acid (MA) (HR = 0.83; 95% CI: 0.74, 0.92; n = 3). There was evidence of publication bias among studies on dietary total SFAs and T2DM. Our results indicated no significant association between dietary total SFA and risk of T2DM. However, dietary intake of MA was negatively associated with developing T2DM.