Rumenic acid significantly reduces plasma levels of LDL and small dense LDL cholesterol in hamsters fed a cholesterol- and lipid-enriched semi-purified diet.

Conjugated linoleic acids (CLAs) consist of a series of positional and geometrical isomers of linoleic acid. CLA have been reported to beneficially affect cardiovascular risk factors in animal models. In order to assess the role of individual CLA isomers on lipoprotein cholesterol concentration, 30 hamsters were fed for 12 weeks an hyperlipidic diet containing pure cis-9,trans-11 CLA (c9,t11) or pure trans-10, cis-12 CLA (t10,c12) isomers given alone or as a mixture. Plasma total cholesterol, LDL and HDL cholesterol concentrations were significantly lower in the c9,t11 CLA isomer fed hamsters relative to the Control group, with the most substantially effect on LDL cholesterol (-56%; P < 0.05). Plasma triacylglycerol concentrations did not differ significantly regarding those two groups. Plasma cholesterol parameters showed a tendency to decrease in the t10,c12 CLA isomer and CLA mixture fed hamsters compared with the Control group, but differences were not significant. For the first time, the atherogenic fraction of small dense LDL was investigated. Plasma small dense LDL cholesterol concentration was lower in the c9,t11 CLA relative to Control, while the t10,c12 and CLA mixture groups showed only a non significant tendency to decrease. Taken together, these data indicate that feeding rumenic acid (c9,t11 CLA) may beneficially affect lipoprotein profile in hamster fed a cholesterol- and lipid-enriched semi-purified diet, when t10,c12 CLA isomer or CLA mixture would be less active.

[Dietary fat consumption of the French population and quality of the data on the composition of the major food groups]. / Consommation lipidique de la population française et qualité des données de composition des principaux groupes d'aliments vecteurs.

The validity of estimated association between dietary fat intake and cancer depends both on the methodology of dietary assessment used and on the quality of food composition data. The food composition database of Afssa/Ciqual shows that there is a deficiency in data on fatty acids. In order to identify the priorities for improving the quality of the database, we analysed the data quality of major dietary contributors of fatty acids in the French population. These food contributors, listed according to their contribution to fat intake, have been identified by French national consumption survey Inca. Consumption studies in France show a high dietary fat contribution (37-38% even 40% of total energy) with over-consumption of saturated fatty acids, under-consumption of monounsaturated fat and, to a lesser extent of polyunsaturated fatty acids. Major food contributors of total fat and saturated fatty acids are butter, cheese, meat products, meats, dishes, dressing, cakes and pastry and, only in children, biscuits. Among contributors of monounsaturated fatty acids, vegetable oils and sauces are listed after processed meats before meats, butter, cheese and dishes. Vegetable oils and sauces are the major contributors of polyunsaturated fatty acids before "fatty" potatoes (such as chips...) in adults whereas the opposite was observed in children. Composition tables do not presently allow the identification of contributors of specific fatty acids (omega 3, omega 6, conjugated linoleic acid). If nutritional data of milk products, fats, and oils are reliable because of existing specific tables for these products, there is a need for improving quality of composition data for other major contributors such as: meats, processed meats, fish and dishes such as pizzas, pasteries...