A DIET RICH IN WALNUTS FAVORABLY INFLUENCES PLASMA FATTY-ACID PROFILEIN MODERATELY HYPERLIPIDEMIC SUBJECTS

Objective: To compare two low fat diets one rich in walnuts on paramet ers of Iipid metabolism in a group of hyperlipidaemic subjects. Design : A randomised cross over study. Setting: Department of Human Nutritio n, University of Otago, Dunedin, New ZeaIand Subjects: Twenty one men with mean (s.d) levels of total and LDL cholesteroI of 6.58 (0.60) and 4.63 (0.58) respectively. Interventions: For two periods of four week s subjects were asked to consume two low fat diets (fat 30% total ener gy), one containing, on average, 78 g/d walnuts. Walnuts obtained thro ugh Lincoln University and the Walnut Growers Group (South Canterbury) . Results: Participants reported a higher total fat intake on the waln ut diet (38% compared with 30% on the low fat diet P < 0.01) The most consistent change in fatty acid profile of triacylglycerol, phospholip id and cholesterol eater on the walnut diet was a significant (P < 0.0 1) increase in linoleic acid. Triacylglycerol linolenate also increase d significantly (P < 0.01). Total and LDL cholesterol were lower on bo th experimental diets than at baseline, 0.25 mmol/l and 0.36 mmol/l re spectively on the walnut diet and 0.13 mmol/l and 0.20 mmol/1 respecti vely on the low fat diet, High density lipoprotein cholesterol was hig her on both the walnut and low fat diets when compared to baseline (0. 15 mmol/l and 0.12 mmol/l, respectively). When comparing the walnut an d low fat diets only apo B was significantly lower (P < 0.05) on the w alnut diet. Conclusions: Despite an unintended increase in the total f at intake on the walnut diet, fatty acid profile of the major lipid fr actions showed changes which might be expected to reduce risk of cardi ovascular disease. The reduction of apolipoprotein B suggests a reduct ion in lipoprotein mediated risk, the relatively low myristic acid con tent of both diets perhaps explaining the absence of more extensive di fferences in Lipoprotein levels on the two diets.