Benefits of Structured and Free Monoacylglycerols to Deliver Eicosapentaenoic (EPA) in a Model of Lipid Malabsorption

Abstract: In the present study, we used a preclinical model of induced lipolytic enzyme insufficiency, and hypothesized that the use of monoacylglycerols (MAG) will enhance their bioavailability and delivery to the tissues. Experimental diets containing 20% lipids were fed to rats for 21 days with or without Orlistat. The control diet of fish oil (FO), a source of EPA and DHA, was tested against: structured (A) vanillin acetal of sn-2 MAG (Vanil + O) and (B) diacetyl derivative of sn-2 MAG (Acetyl + O) and (C) free MAG (MAG + O). FA profiles with an emphasis on EPA and DHA levels were determined in plasma, red blood cells (RBC), liver, spleen, brain and retina. We observed significant reduction of lipid absorption when rats co-consumed Orlistat. As expected, the FO groups with and without Orlistat showed the biggest difference. The Vanil + O, Acetyl + O and MAG + O groups, demonstrated higher levels of EPA (5.5 ± 1.9, 4.6 ± 1.6 and 5.6 ± 0.6, respectively) in RBC compared with FO + O diets (3.3 ± 0.2, 2.6 ± 0.2). Levels of EPA incorporation, in plasma, were similar to those obtained for RBC, and similar trends were observed for the collected tissues and even with DHA levels. These observations with two MAG derivatives providing the fatty acid esterified in the sn-2 position, show that these molecules are efficient vehicles of EPA in malabsorption conditions which is in line with our hypothesis. Free MAG, characterized as having exclusively sn-1(3) isomers of EPA, demonstrated better absorption efficiencies and accretion to tissues when compared to structured MAG. The study demonstrated that structured and free MAG can be used efficiently as an enteral vehicle to supply bioactive fatty acids such as EPA and DHA in lipid malabsorption where diminished lipolytic activity is the underlying cause.