In a double-blind parallel-group study, serum lipids and visceral fat/total fat ratio in young women (n = 49) with variants of lipid transporters, i.e., fatty acid binding protein 2 (FABP2) and microsomal triglyceride transfer protein (NITP), were analyzed by substituting dietary triacylglycerol (TAG) with sn-1,3-diacylglycerol (DAG). All subjects, including some with the hyperlipidemia-prone genotypes Ala54Thr of FABP2 and c-493g of MTP, received DAG or TAG (20 g/day) for 8 weeks. Reductions of serum lipids from weeks 4 to 8 in FABP2-Ala54Thr heterozygotes and MTP -493g homozygotes were significantly different between the DAG and TAG groups (p < 0.05, p < 0.01). Visceral fat/total fat (%), as determined by computed tomography (CT), was lower in FABP2-Ala54Thr heterozygotes (p < 0.05) of the DAG group. The apoCII/CIII ratio was higher in the DAG group than in the TAG group (p < 0.01). Other variants of lipid metabolism, including peroxisome proliferator activated receptors (PPARs) alpha and y and SREBP cleavage-activating protein (SCAP), were only slightly affected by dietary DAG. Conclusion: improvement of serum lipid profiles and visceral fat/total fat ratio (CT) was potentiated by DAG intake in subjects with hyperlipidemia-prone genotypes (Ala54Thr heterozygotes of FABP2 and -493g homozygotes of MTP). (C) 2003 Elsevier Science (USA). All rights reserved.