Differential effects of medium- and long-chain saturated fatty acids on blood lipid profile: a systematic review and meta-analysis

Saturated fatty acids of different chain lengths may have variable effects on blood lipids and lipoproteins, likely due to their differing routes of digestion, absorption and metabolism. This review investigated whether ingestion of medium- (MCFA) and long (LCSFA)-chain saturated fatty acids have differential impact on blood lipids. Five databases were searched (EMBASE, MEDLINE, CINAHL, Cochrane and Scopus) and clinical trials investigating the effect of MCFA and LCSFA on blood lipid profile were included. Studies were pooled for meta-analysis. The principle summary measure was the mean difference between groups calculated using the random effects model. Eleven cross-over studies
and one parallel study were identified with a total of n = 299 participants (weighted means  ± SDs age: 38  ± 3 y; body mass index (BMI): 24  ± 2 kg/m2).  MCFA were associated with significantly higher high-density lipoprotein cholesterol (HDL-C) (mean difference: 0.11 mmol/L; 95% CI: 0.07,
0.15) and apolipoprotein A-I (Apo A-I) level (mean difference: 0.08 g/L; 95% CI: 0.02, 0.14) compared to LCSFA, with no change in total cholesterol. The findings demonstrate a differential effect of MCFA and LCSFA on HDL-C levels. Therefore, dietary recommendations to reduce saturated fatty acids for reducing CVD risk should be limited to foods rich in LCSFA.