***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: Walnuts are rich in polyunsaturated fatty acids and have been shown to improve various cardiometabolic risk factors . We aim ed to investigate the association between walnut intake and incident type 2 diabetes  in 2 large cohort studies : the Nurses ’ Health Study ( NHS ) and NHS II . We prospect ively followed 58,063 women aged 52–77 y in NHS ( 1998–2008 ) and 79,893 women aged 35–52 y in NHS II ( 1999–2009 ) without diabetes , cardiovascular disease , or cancer at baseline .  Consumption of walnuts and other nuts was assessed every 4 y using vali date d food frequency question naires .  Self-reported type 2 diabetes was confirmed by a vali date d supplemental question naire . We documented a total of 5930 incident type 2 diabetes cases during 10 y of follow-up . In the multivariable-adjusted Cox proportional hazards model without body mass index ( BMI ) , walnut consumption was associated with a lower risk of type 2 diabetes , and the HRs ( 95 % CIs ) for participants consuming 1–3 servings/mo ( 1 serving = 28 g ) , 1 serving/wk , and ≥2 servings/wk of walnuts were 0.93 ( 0.88–0.99 ) , 0.81 ( 0.70–0.94 ) , and 0.67 ( 0.54–0.82 ) compared with women who never/rarely consumed walnuts ( P-trend < 0.001 ) . Further adjustment for up date d BMI slightly attenuated the association and the HRs ( 95 % CIs ) were 0.96 ( 0.90–1.02 ) , 0.87 ( 0.75–1.01 ) , and 0.76 ( 0.62–0.94 ) , respectively ( P-trend = 0.002 ) . The consumption of total nuts ( P-trend < 0.001 ) and other tree nuts ( P-trend = 0.03 ) was also inversely associated with risk of type 2 diabetes , and the associations were largely explained by BMI . Our results suggest that higher walnut consumption is associated with a significantly lower risk of type 2 diabetes in women 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 CONTEXT Reduced intake of saturated fat is widely recommended for prevention of cardiovascular disease . The type of macronutrient that should replace saturated fat remains uncertain . OBJECTIVE To compare the effects of 3 healthful diets , each with reduced saturated fat intake , on blood pressure and serum lipids . DESIGN , SETTING , AND PARTICIPANTS R and omized , 3-period , crossover feeding study ( April 2003 to June 2005 ) conducted in Baltimore , Md , and Boston , Mass. Participants were 164 adults with prehypertension or stage 1 hypertension . Each feeding period lasted 6 weeks and body weight was kept constant . INTERVENTIONS A diet rich in carbohydrates ; a diet rich in protein , about half from plant sources ; and a diet rich in unsaturated fat , predominantly monounsaturated fat . MAIN OUTCOME MEASURES Systolic blood pressure and low-density lipoprotein cholesterol . RESULTS Blood pressure , low-density lipoprotein cholesterol , and estimated coronary heart disease risk were lower on each diet compared with baseline . Compared with the carbohydrate diet , the protein diet further decreased mean systolic blood pressure by 1.4 mm Hg ( P = .002 ) and by 3.5 mm Hg ( P = .006 ) among those with hypertension and decreased low-density lipoprotein cholesterol by 3.3 mg/dL ( 0.09 mmol/L ; P = .01 ) , high-density lipoprotein cholesterol by 1.3 mg/dL ( 0.03 mmol/L ; P = .02 ) , and triglycerides by 15.7 mg/dL ( 0.18 mmol/L ; P<.001 ) . Compared with the carbohydrate diet , the unsaturated fat diet decreased systolic blood pressure by 1.3 mm Hg ( P = .005 ) and by 2.9 mm Hg among those with hypertension ( P = .02 ) , had no significant effect on low-density lipoprotein cholesterol , increased high-density lipoprotein cholesterol by 1.1 mg/dL ( 0.03 mmol/L ; P = .03 ) , and lowered triglycerides by 9.6 mg/dL ( 0.11 mmol/L ; P = .02 ) . Compared with the carbohydrate diet , estimated 10-year coronary heart disease risk was lower and similar on the protein and unsaturated fat diets . CONCLUSION In the setting of a healthful diet , partial substitution of carbohydrate with either protein or monounsaturated fat can further lower blood pressure , improve lipid levels , and reduce estimated cardiovascular risk . Clinical Trials Registration Clinical Trials.gov Identifier : NCT00051350 BACKGROUND Antioxidant vitamins may play a role in the prevention of stroke because they scavenge free radicals and prevent LDL oxidation . Epidemiologic studies that have examined this relation produced conflicting results . OBJECTIVE We examined the association between antioxidant vitamin intakes and death from stroke .  DESIGN This was a prospect i ve cohort study of 34492 postmenopausal women . RESULTS During follow-up , 215 deaths from stroke were documented . Total vitamin A , carotenoid , and vitamin E intakes were not associated with death from stroke after multivariate adjustment . Relative risks ( RRs ) and 95 % CIs of the highest compared with the lowest category were 0.79 ( 0.45 , 1.38 ; P for trend = 0.33 ) for vitamin A , 0.80 ( 0.45 , 1.40 ; P for trend = 0.40 ) for carotenoids , and 0.91 ( 0.55 , 1.52 ; P for trend = 0.86 ) for vitamin E. The test for trend for total vitamin C intake was significant , although the association appeared somewhat U-shaped , not monotonic . An inverse association was seen between death from stroke and vitamin E intake from food . RRs ( and 95 % CIs ) of death from stroke from the lowest to highest intake categories were 1.0 , 0.80 ( 0.51 , 1.26 ) , 0.93 ( 0.58 , 1 . 49 ) , 0.67 ( 0.39 , 1.14 ) , 0.40 ( 0.20 , 0.80 ) ; P for trend = 0.008 . The results suggest inverse associations between death from stroke and intakes of the most concentrated vitamin E food sources consumed by this cohort : mayonnaise , nuts , and margarine . CONCLUSIONS Our results suggest a protective effect of vitamin E from foods on death from stroke but do not support a protective role for supplemental vitamin E or other antioxidant vitamins . However , given the number of deaths from stroke in the present cohort , a small-to-moderate association could not be ruled out Adherence to the Mediterranean diet ( MD ) has been reported to improve CHD prognosis and to be inversely associated with CHD mortality . The aim of the present study was to investigate the association of adherence to the MD with CHD incidence and mortality in the Greek European Prospect i ve Investigation into Cancer and Nutrition cohort , a population with traditional Mediterranean roots . In a general population sample of 23,929 adult men and women with no CVD or cancer at enrolment , a vali date d FFQ was interviewer-administered , sociodemographic , physical activity and other characteristics were recorded , and arterial blood pressure and anthropometric characteristics were measured . In a median period of 10 years , 636 incident CHD cases and 240 CHD deaths were recorded . Associations of adherence to the MD , operationalised through a nine-component score ( 0 , poor ; 9 , excellent ) , with CHD incidence and mortality were evaluated through Cox regression controlling for potentially confounding variables . A two-point increase in the MD score was associated with lower CHD mortality by 25 % ( 95 % CI 0.57 , 0.98 ) among women and 19 % ( 95 % CI 0.67 , 0.99 ) among men . The association of adherence to the MD with CHD incidence was again inverse , but weaker ( hazard ratios 0.85 ( 95 % CI 0.71 , 1.02 ) among women and 0.98 ( 95 % CI 0.87 , 1.10 ) among men ) . With respect to score components , only meat among men ( positively ) and fruits and nuts among women ( inversely ) were associated with both the incidence of and mortality from CHD . The MD , as an integral entity , is inversely associated with CHD incidence and , particularly , mortality Background and Purpose — Few dietary protein sources have been studied prospect ively in relation to stroke . We examined the relation between foods that are major protein sources and risk of stroke . Methods — We prospect ively followed 84 010 women aged 30 to 55 years at baseline and 43 150 men aged 40 to 75 years at baseline without diagnosed cancer , diabetes , or cardiovascular disease .  Diet was assessed repeatedly by a st and ardized and vali date d question naire . We examined the association between protein sources and incidence of stroke using a proportional hazard model adjusted for stroke risk factors . Results — During 26 and 22 years of follow-up in women and men , respectively , we documented 2633 and 1397 strokes , respectively . In multivariable analyses , higher intake of red meat was associated with an elevated risk of stroke , whereas a higher intake of poultry was associated with a lower risk . In models estimating the effects of exchanging different protein sources , compared with 1 serving/day of red meat , 1 serving/day of poultry was associated with a 27 % ( 95 % CI , 12%–39 % ) lower risk of stroke , nuts with a 17 % ( 95 % CI . 4%–27 % ) lower risk , fish with a 17 % ( 95 % CI , 0%–30 % ) lower risk , low-fat dairy with an 11 % ( 95 % CI , 5%–17 % ) lower risk , and whole-fat dairy with a 10 % ( 95 % CI , 4%–16 % ) lower risk . We did not see significant associations with exchanging legumes or eggs for red meat . Conclusions — These data suggest that stroke risk may be reduced by replacing red meat with other dietary sources of protein BACKGROUND Although dietary factors are suspected to be important determinants of coronary heart disease ( CHD ) risk , the direct evidence is relatively sparse . METHODS The Adventist Health Study is a prospect i ve cohort investigation of 31,208 non-Hispanic white California Seventh-Day Adventists . Extensive dietary information was obtained at baseline , along with the values of traditional coronary 
    Output:
    
A higher consumption of nuts was associated with reduced risk of CAD and hypertension but not stroke or T2D .