¹Laboratoire de Biologie et Biochimie des Lipides, EA 2033, Biochimie A, Institut de Biologie, Bd Henri IV, 34060 Montpellier

²INSERM U500, Ho�pital La Colombiére, 39 av. Ch. Flahault, 34093 Montpellier Cedex 5, France

Correspondence to: Pr Descomps, Laboratoire de Biologie et Biochimie des Lipides, Biochimie A, Institut de Biologie, Université de Montpellier I, Bd Henri IV, 34060 Montpellier, France. lbbl@sc.univ-montp1.fr

Objective: To evaluate the polyunsaturated fatty acid (PUFA) status in non-institutionalised elderly women and to detect a possible essential fatty acid bioconversion defect.

Design and subjects: The fatty acid composition of total plasma lipids, plasma triglycerides (TG), cholesterol esters (CE), phospholipids (PL), and erythrocytes was determined by capillary column gas-liquid chromatography in a sample of 200 non-institutionalised healthy elderly women over 75 years of age. The data were compared with those of a control group of 50 young female volunteers aged 20-48 y.

Results: In elderly women, the n-6 series precursor, linoleic acid (18:2 n-6), was lower in TG and CE (P=0.029 and 0.014, respectively). In CE, this fatty acid was highly correlated with vegetable and vegetal fat intakes (P<0.0001), suggesting a lower dietary supply than in controls. Higher percentages of 16:1 n-7 were found in all the plasma lipid fractions in elderly women, especially in CE (P<0.0001). The ratios 20:4 n-6/20:3 n-6 and 22:6 n-3/20:5 n-3 were significantly lower in PL from elderly women (P<0.005 and P<0.002, respectively), raising the question of the efficiency of the terminal steps of 20:4 n-6 and 22:6 n-3 biosynthesis. Dietary investigations in elderly women indicated that a high dietary protein intake via meat probably contributed to the supply of 20:4 n-6 and thus maintained the status of this fatty acid, despite the suspected altered biosynthesis.

Conclusion: The PUFA status in the elderly women group could be more fragile and dependent on exogenous supply of long-chain PUFAs than previously suspected.

non-institutionalised elderly women; polyunsaturated fatty acid; 5 desaturase; peroxisomal oxidation; deficiency; plasma lipid fractions; erythrocyte; capillary gas-chromatography