Possible Interaction: Vitamin A and Conjugated Linoleic Acid

“ CLA has been shown to increase tissue levels of retinol (vitamin A alcohol) and its sole specific circulating carrier protein retinol-binding protein (RBP or RBP4).”

“Here, we provide a summary of the current knowledge in this specific area of research and speculate that retinol and CLA may compete for catabolic pathways modulated by the activity of PPAR-α and RXR heterodimer.”

“Milk of cows supplemented with CLA had higher concentrations of retinol (+34%), α-tocopherol (+44%) and γ-tocopherol (+21%) than milk of control cows (p < 0.05).”

“This study was performed to investigate the hypothesis that supplementation of conjugated linoleic acid CLA ) changes the concentrations of retinol and tocopherols in the milk of cows.”

“By gavaging wild-type and retinol-binding protein knockout mice with an … radiolabeled retinol containing 1 of these 2 isomers, we showed that both CLA t10,c12 and CLA c9,… hepatic uptake of dietary vitamin A and its resecretion from the liver in … retinol bound to retinol-binding protein.”

“Here we hypothesized that an acute administration of either CLA isomer may also influence vitamin A metabolism.”

“Previous studies in rodents demonstrated that chronic intake of CLA t10,c12 or CLA c9,t11 isomers perturbs the metabolism of retinoids ( vitamin A and its derivatives).”

“However, only CLA t10,c12 enhances hepatic retinol secretion, resulting in increased serum levels of retinol and its specific carrier, retinol-binding protein (RBP).”

“2) Is the increase in vitamin A associated with the anticarcinogenic effect of CLA?”