Dose effect of alpha-linolenic acid on PUFA conversion, bioavailability, and storage in the hamster.
If an increased consumption of alpha-linolenic acid (ALA) is to be promoted in parallel with that of n-3 long-chain-rich food, it is necessary to consider to what extent dietary ALA can be absorbed, transported, stored, and converted into long-chain derivatives. We investigated these processes in male hamsters, over a broad range of supply as linseed oil (0.37, 3.5, 6.9, and 14.6% energy). Linoleic acid (LA) was kept constant (8.5% energy), and the LA/ALA ratio was varied from 22.5 to 0.6. The apparent absorption of individual FA was very high (>96%), and that of ALA remained almost maximum even at the largest supply (99.5%). The capacity for ALA transport and storage had no limitation over the chosen range of dietary intake. Indeed, ALA intake was significantly correlated with ALA level not only in cholesteryl esters (from 0.3 to 9.7% of total FA) but also in plasma phospholipids and red blood cells (RBC), which makes blood components extremely reliable as biomarkers of ALA consumption. Similarly, ALA storage in adipose tissue increased from 0.85 to 14% of total FA and was highly correlated with ALA intake. As for bioconversion, dietary ALA failed to increase 22:6n-3, decreased 20:4n-6, and efficiently increased 20:5n-3 (EPA) in RBC and cardiomyocytes. EPA accumulation did not tend to plateau, in accordance with identical activities of delta5- and delta6-desaturases in all groups. Dietary supply of ALA was therefore a very efficient means of improving the 20:4n-6 to 20:5n-3 balance.
Morise
Anne
A
Laboratoire de Physiologie de la Nutrition, Université Paris Sud, 91405 Orsay cedex. anne.morise@ibaic.u-psud.fr
Combe
Nicole
N
Boué
Carole
C
Legrand
Philippe
P
Catheline
Daniel
D
Delplanque
Bernadette
B
Fénart
Evelyne
E
Weill
Pierre
P
Hermier
Dominique
D
D000273:Adipose Tissue / Q000737:chemistry; D000818:Animals; D001835:Body Weight; D006224:Cricetinae; D004042:Dietary Fats, Unsaturated / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000378:metabolism*; D006801:Humans; D050356:Lipid Metabolism; D008297:Male; D008647:Mesocricetus / Q000378:metabolism*; D009206:Myocardium / Q000737:chemistry; D017962:alpha-Linolenic Acid / Q000008:administration & dosage* / Q000378:metabolism
D004042:Dietary Fats, Unsaturated; D005231:Fatty Acids, Unsaturated; D017962:alpha-Linolenic Acid