Overall , high-walnut-enriched diets significantly decreased total and LDL cholesterol for the duration of the short-term trials .
BACKGROUND Consumption of nuts has been associated with a decreased risk of  cardiovascular disease events  and death .
Walnuts in particular have a unique profile : they are rich in polyunsaturated fatty acids , which may improve blood lipids and other cardiovascular disease risk factors .
OBJECTIVES We aim ed to conduct a literature review and a meta- analysis to combine the results from several trials and to estimate the effect of walnuts on blood lipids .
Effect of a traditional Mediterranean diet on lipoprotein oxidation: a randomized controlled trial.
BACKGROUND Despite the richness in antioxidants of the Mediterranean diet , to our knowledge , no r and omized controlled trials have assessed its effect on in vivo lipoprotein oxidation . METHODS A total of 372 subjects at high cardiovascular risk ( 210 women and 162 men ; age range , 55 - 80 years ) , who were recruited into a large , multicenter , r and omized , controlled , parallel-group clinical trial ( the Prevención con Dieta Mediterránea [ PREDIMED ] Study ) directed at testing the efficacy of the traditional Mediterranean diet ( TMD ) on the primary prevention of coronary heart disease , were assigned to a low-fat diet ( n = 121 ) or one of 2 TMDs ( TMD + virgin olive oil or TMD + nuts ) . The TMD participants received nutritional education and either free virgin olive oil for all the family ( 1 L/wk ) or free nuts ( 30 g/d ) . Diets were ad libitum . Changes in oxidative stress markers were evaluated at 3 months . RESULTS After the 3-month interventions , mean ( 95 % confidence intervals ) oxidized low-density lipoprotein ( LDL ) levels decreased in the TMD + virgin olive oil ( -10.6 U/L [ -14.2 to -6.1 ] ) and TMD + nuts ( -7.3 U/L [ -11.2 to -3.3 ] ) groups , without changes in the low-fat diet group ( -2.9 U/L [ -7.3 to 1.5 ] ) . Change in oxidized LDL levels in the TMD + virgin olive oil group reached significance vs that of the low-fat group ( P = .02 ) . Malondialdehyde changes in mononuclear cells paralleled those of oxidized LDL . No changes in serum glutathione peroxidase activity were observed . CONCLUSIONS Individuals at high cardiovascular risk who improved their diet toward a TMD pattern showed significant reductions in cellular lipid levels and LDL oxidation . Results provide further evidence to recommend the TMD as a useful tool against risk factors for CHD . Trial Registration is rct n.org Identifier : IS RCT N35739639
Overall , high-walnut-enriched diets significantly decreased total and LDL cholesterol for the duration of the short-term trials .
BACKGROUND Consumption of nuts has been associated with a decreased risk of  cardiovascular disease events  and death .
Walnuts in particular have a unique profile : they are rich in polyunsaturated fatty acids , which may improve blood lipids and other cardiovascular disease risk factors .
OBJECTIVES We aim ed to conduct a literature review and a meta- analysis to combine the results from several trials and to estimate the effect of walnuts on blood lipids .