Background/Aim: Triglycerides (TGs) are measured in studies evaluating changes in non-fasting lipid profiles after a fat tolerance test (FTT); however, the optimal timing for TG measurements after the oral fat load is unclear. The aim of this study was to evaluate how non-fasting TG levels vary after an oral FTT in healthy subjects. Methods: This meta-analysis included 113 studies with > 5 participants of Caucasian race that were indexed in PubMed from its inception through March 2010, using the search term “postprandial lipemia”. We only included studies that provided mean values and standard deviation (SD) (or standard error of the mean) for TG measurements at baseline (=fasting) and for at least one other time-point. Exclusion criteria included uncommon sampling time-points after the FTT, baseline TGs≥2.0 mmol/L (≥177mg/dl), and a body mass index ≥30kg/m2. Results: All studies combined, weighted mean±SD TG values in mmol/L were 1.25±0.32 fasting, 1.82±0.40 at 2 h, 2.31±0.62 at 4 h, 1.87±0.63 at 6 h, and 1.69±0.80 at 8 h. After stratifying studies based on fat quantity in the test meal ( < 40,≥40- < 50, ≥50- < 60, ≥60- < 70, ≥70- < 80, ≥80- < 90, ≥90- < 100, ≥100- < 110, ≥110-120, ≥120 g), the highest standardized mean difference in TG levels from fasting levels was found in those having an oral fat load of ≥70 g and < 80 g, and at 4 h (difference=1.74 mmol/L; p < 0.001). Conclusion: The 4 h time-point after an oral fat load during a FTT was the most representative measurement of TGs. The highest standardized mean difference of TGs was found after a meal containing 70-79g of fat. The relevance of these two key parameters determined in healthy subjects should be considered for further developments of an oral FFT for clinical purposes.
Keywords: Fat tolerance test, meta-analysis, postprandial lipaemia, standardized mean difference, triglycerides, very low density lipoproteins, chylomicrons, fat load, coronary artery disease, gene polymorphisms