***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: CONTEXT Laboratory findings have suggested that oxidative stress may contribute to the pathogenesis of Alzheimer disease . Therefore , the risk of Alzheimer disease might be reduced by intake of antioxidants that counteract the detrimental effects of oxidative stress . OBJECTIVE To determine whether dietary intake of antioxidants is related to risk of Alzheimer disease . DESIGN AND SETTING The Rotterdam Study , a population -based , prospect i ve cohort study conducted in the Netherl and s. PARTICIPANTS A total of 5395 participants who , at baseline ( 1990 - 1993 ) , were aged at least 55 years , free of dementia , and noninstitutionalized and had reliable dietary assessment . Participants were reexamined in 1993 - 1994 and 1997 - 1999 and were continuously monitored for incident dementia . MAIN OUTCOME MEASURES Incidence of Alzheimer disease , based on Diagnostic and Statistical Manual of Mental Disorders , Revised Third Edition ( DSM-III-R ) criteria and National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer Disease and Related Disorders Association ( NINCDS-ADRDA ) criteria , associated with dietary intake of beta carotene , flavonoids , vitamin C , and vitamin E. RESULTS After a mean follow-up of 6 years , 197 participants developed dementia , of whom 146 had Alzheimer disease . When adjustments were made for age , sex , baseline Mini-Mental State Examination score , alcohol intake , education , smoking habits , pack-years of smoking , body mass index , total energy intake , presence of carotid plaques , and use of antioxidative supplements , high intake of vitamin C and vitamin E was associated with lower risk of Alzheimer disease ( rate ratios [ RRs ] per 1-SD increase in intake were 0.82 [ 95 % confidence interval [ CI ] , 0.68 - 0.99 ] and 0.82 [ 95 % CI , 0.66 - 1.00 ] , respectively ) . Among current smokers , this relationship was most pronounced ( RRs , 0.65 [ 95 % CI , 0.37 - 1.14 ] and 0.58 [ 95 % CI , 0.30 - 1.12 ] , respectively ) and also was present for intake of beta carotene ( RR , 0.49 [ 95 % CI , 0.27 - 0.92 ] ) and flavonoids ( RR , 0.54 [ 95 % CI , 0.31 - 0.96 ] ) . The associations did not vary by education or apolipoprotein E genotype . CONCLUSION High dietary intake of vitamin C and vitamin E may lower the risk of Alzheimer disease Abstract The traditional Mediterranean diet ( MedDiet ) has shown beneficial effects on cognitive decline . Nevertheless , diet – gene interactions have been poorly evaluated . We aim ed to investigate diet – gene interaction in the PREDIMED-NAVARRA r and omized trial . A total of 522 participants ( 67 ± 6 years at baseline ) enrolled in the PREDIMED-NAVARRA trial were r and omly allocated to one of three diets : two MedDiets ( supplemented with either extra-virgin olive oil or nuts ) or a low-fat diet . They were evaluated with the  Mini-Mental State Examination ( MMSE ) and the Clock Drawing Test ( CDT ) after 6.5 years of intervention . Subjects were genotyped for CR1-rs3818361 , CLU-rs11136000 , PICALM-rs3851179 and Apolipoprotein E ( ApoE ) genes . We studied MedDiet – gene interactions for cognition and assessed the effect of the MedDiet on cognition across different genetic profiles . A significant interaction ( p = 0.041 ) between CLU-rs11136000 and the MedDiet intervention on the MMSE was found with a beneficial effect of MedDiet among carriers of the T minor allele ( B = 0.97 , 95 % CI 0.45–1.49 ) . Similar effect was observed for CR1-rs3818361 , but no significant interaction was observed ( p = 0.335 ) . For PICALM-rs3851179 , the MedDiet intervention showed a beneficial effect in both genotype groups . No apparent interaction was found for the CDT between intervention and gene variants . Similarly , participants r and omly allocated to MedDiet groups , with favorable profiles of CR1 , CLU and PICALM genes , significantly improved CDT scores compared to controls with the same genetic profile . Cognitive performance was better for non-ApoE4 and for ApoE4 carriers of MedDiet groups compared to controls , but for CDT performance , we only found statistical significant differences for non-ApoE4 carriers . A MedDiet intervention modulates the effect of genetic factors on cognition . The effect of MedDiet might be greater for subjects with a more favorable genetic profile BACKGROUND Adherence to a Mediterranean diet may improve longevity , but relevant data are limited . METHODS We conducted a population -based , prospect i ve investigation involving 22,043 adults in Greece who completed an extensive , vali date d , food-frequency question naire at base line .  Adherence to the traditional Mediterranean diet was assessed by a 10-point Mediterranean-diet scale that incorporated the salient characteristics of this diet ( range of scores , 0 to 9 , with higher scores indicating greater adherence ) . We used proportional-hazards regression to assess the relation between adherence to the Mediterranean diet and total mortality , as well as mortality due to coronary heart disease and mortality due to cancer , with adjustment for age , sex , body-mass index , physical-activity level , and other potential confounders . RESULTS During a median of 44 months of follow-up , there were 275 deaths . A higher degree of adherence to the Mediterranean diet was associated with a reduction in total mortality ( adjusted hazard ratio for death associated with a two-point increment in the Mediterranean-diet score , 0.75 [ 95 percent confidence interval , 0.64 to 0.87 ] ) . An inverse association with greater adherence to this diet was evident for both death due to coronary heart disease ( adjusted hazard ratio , 0.67 [ 95 percent confidence interval , 0.47 to 0.94 ] ) and death due to cancer ( adjusted hazard ratio , 0.76 [ 95 percent confidence interval , 0.59 to 0.98 ] ) . Associations between individual food groups contributing to the Mediterranean-diet score and total mortality were generally not significant . CONCLUSIONS Greater adherence to the traditional Mediterranean diet is associated with a significant reduction in total mortality CONTEXT Higher adherence to a Mediterranean-type diet is linked to lower risk for mortality and chronic diseases , but its association with cognitive decline is unclear . OBJECTIVE To investigate the association of a Mediterranean diet with change in cognitive performance and risk for dementia in elderly French persons . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve cohort study of 1410 adults ( > or = 65 years ) from Bordeaux , France , included in the Three-City cohort in 2001 - 2002 and reexamined at least once over 5 years .  Adherence to a Mediterranean diet ( scored as 0 to 9 ) was computed from a food frequency question naire and 24-hour recall . MAIN OUTCOME MEASURES Cognitive performance was assessed on 4 neuropsychological tests : the Mini-Mental State Examination ( MMSE ) , Isaacs Set Test ( IST ) , Benton Visual Retention Test ( BVRT ) , and Free and Cued Selective Reminding Test ( FCSRT ) . Incident cases of dementia ( n = 99 ) were vali date d by an independent expert committee of neurologists . RESULTS Adjusting for age , sex , education , marital status , energy intake , physical activity , depressive symptomatology , taking 5 medications/d or more , apolipoprotein E genotype , cardiovascular risk factors , and stroke , higher Mediterranean diet score was associated with fewer MMSE errors ( beta = -0.006 ; 95 % confidence interval [ CI ] , -0.01 to -0.0003 ; P = .04 for 1 point of the Mediterranean diet score ) . Performance on the IST , BVRT , or FCSRT over time was not significantly associated with Mediterranean diet adherence . Greater adherence as a categorical variable ( score 6 - 9 ) was not significantly associated with fewer MMSE errors and better FCSRT scores in the entire cohort , but among individuals who remained free from dementia over 5 years , the association for the highest compared with the lowest group was significant ( adjusted for all factors , for MMSE : beta = -0.03 ; 95 % CI , -0.05 to -0.001 ; P = .04 ; for FCSRT : beta = 0.21 ; 95 % CI , 0.008 to 0.41 ; P = .04 ) . Mediterranean diet adherence was not associated with the risk for incident dementia ( fully adjusted model : hazard ratio , 1.12 ; 95 % CI , 0.60 to 2.10 ; P = .72 ) , although power to detect a difference was limited . CONCLUSIONS Higher adherence to a Mediterranean diet was associated with slower MMSE cognitive decline but not consistently with other cognitive tests . Higher adherence was not associated with risk for incident dementia IMPORTANCE Oxidative stress and vascular impairment are believed to partly mediate age-related cognitive decline , a strong risk factor for development of dementia . Epidemiologic studies suggest that a Mediterranean diet , an antioxidant-rich cardioprotective dietary pattern , delays cognitive decline , but clinical trial evidence is lacking . OBJECTIVE To investigate whether a Mediterranean diet supplemented with antioxidant-rich foods influences cognitive function compared with a control diet . DESIGN , SETTING , AND PARTICIPANTS Parallel-group r and omized clinical trial of 447 cognitively healthy volunteers from Barcelona , Spain ( 233 women [ 52.1 % ] ; mean age , 66.9 years ) , at high cardiovascular risk were enrolled into the Prevención con Dieta Mediterránea nutrition intervention trial from October 1 , 2003 , through December 31 , 2009 . All patients underwent neuropsychological assessment at inclusion and were offered retesting at the end of the study . INTERVENTIONS Participants were r and omly assigned to a Mediterranean diet supplemented with extravirgin olive oil ( 1 L/wk ) , a Mediterranean diet supplemented with mixed nuts ( 30 g/d ) , or a control diet ( advice to reduce dietary fat ) . MAIN OUTCOMES AND MEASURES Rates of cognitive change over time based on a neuropsychological test battery : Mini-Mental State Examination , Rey Auditory Verbal Learning Test ( RAVLT ) , Animals Semantic Fluency , Digit Span subtest from the Wechsler Adult Intelligence Scale , Verbal Paired Associates from the Wechsler Memory Scale , and the Color Trail Test . We used mean z scores of change in each test to construct 3 cognitive composites : memory , frontal ( attention and executive function ) , and global . RESULTS Follow-up cognitive tests were available in 334 participants after intervention ( median , 4.1 years ) . In multivariate analyses adjusted for confounders , participants allocated to a Mediterranean diet plus olive oil scored better on the RAVLT ( P = .049 ) and Color Trail Test part 2 ( P = .04 ) compared with controls ; no between-group differences were observed for the other cognitive tests . Similarly adjusted cognitive composites ( mean z scores with 95 % CIs ) for changes above baseline of the memory composite were 0.04 ( -0.09 to 0.18 ) for the Mediterranean diet plus olive oil , 0.09 ( -0.05 to 0.23 ; P = .04 vs controls ) for the Mediterranean diet plus nuts , and -0.17 ( -0.32 to -0.01 ) for the control diet . Respective changes from baseline of the frontal cognition composite were 0.23 ( 0.03 to 0.43 ; P = .003 vs controls ) , 0.03 ( -0.25 to 0.31 ) , and -0.33 ( -0.57 to -0.09 ) . Changes from baseline of the global cognition composite were 0.05 ( -0.11 to 0.21 ; P = .005 vs controls ) for the Mediterranean diet plus olive oil , -0.05 ( -0.27 to 0.18 ) for the Mediterranean diet plus nuts , and -0.38 ( -0.57 to -0.18 ) for the control diet .  All cognitive composites significantly ( P < .05 ) decreased from baseline in controls . CONCLUSIONS AND RELEVANCE In an older population , a Mediterranean diet supplemented with olive oil or nuts is associated with improved cognitive function . TRIAL REGISTRATION is rct n.org Identifier : IS RCT N35739639 CONTEXT Both higher adherence to a Mediterranean-type 
    Output:
    
Based on the findings and the limitations in study design , we conclude that adherence to the MD is associated with better cognitive performance .
However , it should be noted that the majority of findings come from epidemiologic studies that provide evidence for a correlation between the MD and cognition but not for a cause- and -effect relation .