title: Lymphatic absorption of α-linolenic acid in rats fed flaxseed oil-based emulsion.
abstract: The bioavailability of α-linolenic acid (ALA) from flaxseed oil in an emulsified form v. a non-emulsified form was investigated by using two complementary approaches: the first one dealt with the characterisation of the flaxseed oil emulsion in in vitro gastrointestinal-like conditions; the second one compared the intestinal absorption of ALA in rats fed the two forms of the oil. The in vitro study on emulsified flaxseed oil showed that decreasing the pH from 7·3 to 1·5 at the physiological temperature (37°C) induced instantaneous oil globule coalescence. Some phase separation was observed under acidic conditions that vanished after further neutralisation. The lecithin used to stabilise the emulsions inhibited TAG hydrolysis by pancreatic lipase. In contrast, lipid solubilisation by bile salts (after lipase and phospholipase hydrolysis) was favoured by preliminary oil emulsification. The in vivo absorption of ALA in thoracic lymph duct-cannulated rats fed flaxseed oil, emulsified or non-emulsified, was quantified. Oil emulsification significantly favoured the rate and extent of ALA recovery as measured by the maximum ALA concentration in the lymph (Cmax = 14 mg/ml at 3 h in the emulsion group v. 9 mg/ml at 5 h in the oil group; P < 0·05). Likewise, the area under the curve of the kinetics was significantly higher in the emulsion group (48 mg × h/ml for rats fed emulsion v. 26 mg × h/ml for rats fed oil; P < 0·05). On the whole, ALA bioavailability was improved with flaxseed oil ingested in an emulsified state. Data obtained from the in vitro studies helped to partly interpret the physiological results.
authors.affiliation: Université Bordeaux 1, Laboratoire CBMN UMR 5248, Talence Cedex, France.
authors.forename: Leslie
authors.initials: L
authors.lastname: Couëdelo
authors.forename: Carole
authors.initials: C
authors.lastname: Boué-Vaysse
authors.forename: Laurence
authors.initials: L
authors.lastname: Fonseca
authors.forename: Emeline
authors.initials: E
authors.lastname: Montesinos
authors.forename: Sandrine
authors.initials: S
authors.lastname: Djoukitch
authors.forename: Nicole
authors.initials: N
authors.lastname: Combe
authors.forename: Maud
authors.initials: M
authors.lastname: Cansell
mesh_terms: D000818:Animals; D019540:Area Under Curve; D001647:Bile Acids and Salts / Q000378:metabolism; D001682:Biological Availability; D004041:Dietary Fats / Q000493:pharmacokinetics*; D004655:Emulsions / Q000737:chemistry*; D019597:Flax / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008043:Linseed Oil / Q000737:chemistry*; D008208:Lymphatic System / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012995:Solubility; D013696:Temperature; D014280:Triglycerides / Q000378:metabolism; D017962:alpha-Linolenic Acid / Q000493:pharmacokinetics*
chemical_list: D001647:Bile Acids and Salts; D004041:Dietary Fats; D004655:Emulsions; D014280:Triglycerides; D017962:alpha-Linolenic Acid; D008043:Linseed Oil