Randomized structured triglycerides increase lymphatic absorption of tocopherol and retinol compared with the equivalent physical mixture in a rat model of fat malabsorption

Previously we demonstrated that the digestion, absorption and lymphatic tra nsport of lipid and key essential fatty acids (EFA) from randomly intereste rified fish oil/medium-chain structured triglycerides (STG) were significan tly higher than an equivalent physical mixture (PM) in a normal lymph fistu la rat model and in a rat model of lipid malabsorption caused by ischemia/r eperfusion (I/R) injury. The goals of this study were to further explore th e potential absorptive benefits of STG by comparing the intestinal absorpti on and lymphatic transport of tocopherol and retinol when delivered gastric ally with either STG or PM under normal conditions and after I/R injury to the small bowel. Food-deprived male Sprague-Dawley rats were randomly assig ned to two treatments (sham controls or I/R). Under halothane anesthesia, t he superior mesenteric artery (SMA) was occluded for 20 min and then reperf used in I/R rats. The SMA was isolated but not occluded in control rats. In both groups, the mesenteric lymph duct was cannulated and a gastric tube w as inserted. Each treatment group received 1 mL of the fish oil/MCT STG or PM (7 rats/group) along with C-14-alpha -tocopherol and H-3-retinol through the gastric tube followed by an infusion of PBS at 3 mL/h for 8 h. Lymph w as collected hourly for 8 h. Under steady-state conditions, the amount of C -14-alpha -tocopherol and 3 H-retinol transported into lymph was significan tly higher in the STG-fed rats compared with those fed PM in both control a nd I/R groups. In addition, control and I/R rats given STG had earlier stea dy-state outputs of C-14-alpha -tocopherol and H-3-retinol and maintained s imilar to 30% higher outputs in lymph throughout the 8-h lymph collection p eriod compared with rats given the PM. We conclude that STG provides the op portunity to potentiate improved absorption of fat-soluble vitamins under n ormal and malabsorptive states.