***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: OBJECTIVE To test the effects of two Mediterranean diet ( MedDiet ) interventions versus a low-fat diet on incidence of diabetes . RESEARCH DESIGN AND METHODS This was a three-arm r and omized trial in 418 nondiabetic subjects aged 55–80 years recruited in one center ( PREDIMED-Reus , northeastern Spain ) of the Prevención con Dieta Mediterránea [ PREDIMED ] study , a large nutrition intervention trial for primary cardiovascular prevention in individuals at high cardiovascular risk . Participants were r and omly assigned to education on a low-fat diet ( control group ) or to one of two MedDiets , supplemented with either free virgin olive oil ( 1 liter/week ) or nuts ( 30 g/day ) . Diets were ad libitum , and no advice on physical activity was given . The main outcome was diabetes incidence diagnosed by the 2009 American Diabetes Association criteria . RESULTS After a median follow-up of 4.0 years , diabetes incidence was 10.1 % ( 95 % CI 5.1–15.1 ) , 11.0 % ( 5.9–16.1 ) , and 17.9 % ( 11.4–24.4 ) in the MedDiet with olive oil group , the MedDiet with nuts group , and the control group , respectively . Multivariable adjusted hazard ratios of diabetes were 0.49 ( 0.25–0.97 ) and 0.48 ( 0.24–0.96 ) in the MedDiet supplemented with olive oil and nuts groups , respectively , compared with the control group . When the two MedDiet groups were pooled and compared with the control group , diabetes incidence was reduced by 52 % ( 27–86 ) . In all study arms , increased adherence to the MedDiet was inversely associated with diabetes incidence . Diabetes risk reduction occurred in the absence of significant changes in body weight or physical activity . CONCLUSIONS MedDiets without calorie restriction seem to be effective in the prevention of diabetes in subjects at high cardiovascular risk Aims /hypothesisThe role of diet in the prevention of diabetes remains uncertain . The aim of this study was to investigate two different dietary aspects , i.e. adherence to the Mediterranean diet and glycaemic load ( GL ) , in relation to diabetes occurrence . Methods We analysed data from the Greek cohort of the population -based European Prospect i ve Investigation into Cancer and Nutrition ( EPIC ) . From a total of 22,295 participants , actively followed for a median of 11.34 years , 2,330 cases of incident type 2 diabetes were recorded . All participants completed a vali date d , interviewer-administered semi-quantitative food frequency question naire at enrolment . From this information , we calculated a ten point Mediterranean diet score ( MDS ) , reflecting adherence to the traditional Mediterranean diet , as well as the dietary GL . We estimated HRs and the corresponding 95 % CIs of diabetes using Cox proportional hazards regression models adjusted for potential confounders . Results A higher MDS was inversely associated with diabetes risk ( HR 0.88 [ 95 % CI 0.78 , 0.99 ] for MDS ≥6 vs MDS ≤3 ) . GL was positively associated with diabetes ( HR 1.21 [ 95 % CI 1.05 , 1.40 ] for the highest vs the lowest GL quartile ) . A significant protection of about 20 % was found for a diet with a high MDS and a low GL . Conclusions /interpretationA low GL diet that also adequately adheres to the principles of the traditional Mediterranean diet may reduce the incidence of type 2 diabetes Background Hypertension can be prevented by adopting healthy dietary patterns . Our aim was to assess the 4-year effect on blood pressure ( BP ) control of a r and omized feeding trial promoting the traditional Mediterranean dietary pattern . Methods The PREDIMED primary prevention trial is a r and omized , single-blinded , controlled trial conducted in Spanish primary healthcare centers . We recruited 7,447 men ( aged 55 to 80 years ) and women ( aged 60 to 80 years ) who had high risk for cardiovascular disease . Participants were assigned to a control group or to one of two Mediterranean diets . The control group received education on following a low-fat diet , while the groups on Mediterranean diets received nutritional education and also free foods ; either extra virgin olive oil , or nuts . Trained personnel measured participants ’ BP at baseline and once yearly during a 4-year follow-up . We used generalized estimating equations to assess the differences between groups during the follow-up . Results The percentage of participants with controlled BP increased in all three intervention groups ( P-value for within-group changes : P<0.001 ) . Participants allocated to either of the two Mediterranean diet groups had significantly lower diastolic BP than the participants in the control group ( −1.53 mmHg ( 95 % confidence interval ( CI ) −2.01 to −1.04 ) for the Mediterranean diet supplemented with extra virgin olive oil , and −0.65 mmHg ( 95 % CI -1.15 to −0.15 ) mmHg for the Mediterranean diet supplemented with nuts ) . No between-group differences in changes of systolic BP were seen . Conclusions Both the traditional Mediterranean diet and a low-fat diet exerted beneficial effects on BP and could be part of advice to patients for controlling BP . However , we found lower values of diastolic BP in the two groups promoting the Mediterranean diet with extra virgin olive oil or with nuts than in the control group . Trial registration Current Controlled Trials IS RCT BACKGROUND Adherence to the Mediterranean diet ( Med-Diet ) is associated with a reduced risk of cardiovascular disease ( CVD ) . However , the molecular mechanisms involved are not fully understood . OBJECTIVE The objective was to compare the effects of 2 Med-Diets with those of a low-fat diet on immune cell activation and soluble inflammatory biomarkers related to atherogenesis in subjects at high risk of CVD . DESIGN In a controlled study , we r and omly assigned 112 older subjects with diabetes or > or =3 CVD risk factors to 3 dietary intervention groups : Med-Diet with supplemental virgin olive oil ( VOO ) , Med-Diet with supplemental nuts , and low-fat diet . Changes from baseline in cellular and serum inflammatory biomarkers were assessed at 3 mo . RESULTS One hundred six participants ( 43 % women ; average age : 68 y ) completed the study . At 3 mo , monocyte expression of CD49d , an adhesion molecule crucial for leukocyte homing , and of CD40 , a proinflammatory lig and , decreased ( P < 0.05 ) after both Med-Diets but not after the low-fat diet . Serum interleukin-6 and soluble intercellular adhesion molecule-1 , inflammatory mediators crucial in firm adhesion of leukocytes to endothelial surfaces , decreased ( P < 0.05 ) in both Med-Diet groups . Soluble vascular cellular adhesion molecule-1 and C-reactive protein decreased only after the Med-Diet with VOO ( P < 0.05 ) , whereas interleukin-6 , soluble vascular cellular adhesion molecule-1 , and soluble intercellular adhesion molecule-1 increased ( P < 0.05 ) after the low-fat diet . CONCLUSIONS Med-Diets supplemented with VOO or nuts down-regulate cellular and circulating inflammatory biomarkers related to atherogenesis in subjects at high risk of CVD . The results support the recommendation of the Med-Diet as a useful tool against CVD & NA;The PREvención con DIeta MEDiterránea ( PREDIMED ) trial showed that Mediterranean diets ( MedDiets ) supplemented with either extravirgin olive oil or nuts reduced cardiovascular events , particularly stroke , compared with a control , lower fat diet . The mechanisms of cardiovascular protection remain unclear . We evaluated the 1-year effects of supplemented MedDiets on 24-hour ambulatory blood pressure ( BP ) , blood glucose , and lipids . R and omized , parallel- design , controlled trial was conducted in 2 PREDIMED sites .  Diets were ad libitum , and no advice on increasing physical activity or reducing sodium intake was given . Participants were 235 subjects ( 56.5 % women ; mean age , 66.5 years ) at high cardiovascular risk ( 85.4 % with hypertension ) . Adjusted changes from baseline in mean systolic BP were −2.3 ( 95 % confidence interval [ CI ] , −4.0 to −0.5 ) mm Hg and −2.6 ( 95 % CI , −4.3 to −0.9 ) mm Hg in the MedDiets with olive oil and the MedDiets with nuts , respectively , and 1.7 ( 95 % CI , −0.1 to 3.5 ) mm Hg in the control group ( P<0.001 ) . Respective changes in mean diastolic BP were −1.2 ( 95 % CI , −2.2 to −0.2 ) , −1.2 ( 95 % CI , −2.2 to −0.2 ) , and 0.7 ( 95 % CI , −0.4 to 1.7 ) mm Hg ( P=0.017 ) . Daytime and nighttime BP followed similar patterns . Mean changes from baseline in fasting blood glucose were −6.1 , −4.6 , and 3.5 mg/dL ( P=0.016 ) in the MedDiets with olive oil , MedDiets with nuts , and control diet , respectively ; those of total cholesterol were −11.3 , −13.6 , and −4.4 mg/dL ( P=0.043 ) , respectively . In high-risk individuals , most with treated hypertension , MedDiets supplemented with extravirgin olive oil or nuts  reduced 24-hour ambulatory BP , total cholesterol , and fasting glucose . Clinical Trial Registration —URL : http://www . clinical trials.gov . Unique identifier : IS RCT N35739639 Context Some experts attribute a low incidence of heart disease in Mediterranean countries to dietary habits . Contribution In this multicenter , 3-group trial , investigators r and omly assigned 772 adults at high risk for cardiovascular disease to a low-fat diet or to a Mediterranean diet supplemented with either virgin olive oil ( 1 L per week ) or nuts ( 30 g per day ) . After 3 months , the Mediterranean diet groups had lower mean plasma glucose level , systolic blood pressure , and total cholesterolhigh-density lipoprotein cholesterol ratio than the low-fat diet group . Caution s The Mediterranean diet groups received more nutritional education than the low-fat diet group . Implication s Mediterranean diets supplemented with olive oil or nuts may improve cardiovascular risk factors . The Editors Cardiovascular disease is the main cause of death in industrialized countries , but incidence rates have marked geographic differences . The low incidence of coronary heart disease ( CHD ) in Mediterranean countries has been partly ascribed to dietary habits ( 1 - 3 ) . Recent findings from large European cohort studies ( 4 - 6 ) suggest that a high degree of adherence to the Mediterranean diet is associated with a reduction in mortality . In small clinical studies , the Mediterranean diet or some of its components have reduced blood pressure ( 7 ) and have improved lipid profiles ( 8 , 9 ) and endothelial function ( 10 ) . Moreover , a recent cross-sectional study ( 11 ) and a 2-year feeding trial ( 12 ) have shown that adherence to the Mediterranean diet is associated with reduced markers of vascular inflammation . These beneficial effects on surrogate markers of cardiovascular risk add biological plausibility to the epidemiologic evidence that supports a protective effect of the Mediterranean diet . Olive oil , a rich source of monounsaturated fatty acids , is a main component of the Mediterranean diet . Virgin olive oil retains all the lipophilic components of the fruit , -tocopherol , and phenolic compounds with strong antioxidant and anti-inflammatory properties ( 13 , 14 ) . Tree nuts , which are also typical in the Mediterranean diet , have a favorable fatty acid profile and are a rich source of nutrients and other bioactive compounds that may beneficially influence the risk for CHD , such as fiber , phytosterols , folic acid , and antioxidants ( 15 ) . Frequent nut intake has been associated with decreased CHD rates in prospect i ve studies ( 15 ) . Walnuts differ from all other nuts through their high content of polyunsaturated fatty acids , particularly -linolenic acid , a plant n-3 fatty acid ( 16 ) , which may confer additional antiatherogenic properties ( 17 ) . Therefore , we design ed a large-scale feeding trial in high-risk participants to assess the effects of 2 Mediterranean diets , one supplemented with virgin olive oil and the other supplemented with mixed nuts , compared with a low 
    Output:
    
The results of the PREDIMED study , a r and omized trial providing a higher level of scientific evidence than cohort studies , confirmed that the Mediterranean diet reduces the incidence of cardiovascular events .
This effect may be exerted by reducing blood pressure ; improving glucose metabolism , lipid profile , and lipoprotein particle characteristics ; and decreasing inflammation and oxidative stress .
It may also stem from a favorable interaction between diet and gene polymorphisms related to cardiovascular risk factors and events .