***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: Background Managing cardiovascular risk factors is important for reducing vascular complications in type 2 diabetes , even in individuals who have achieved glycemic control . Nut consumption is associated with reduced cardiovascular risk ; however , there is mixed evidence about the effect of nuts on blood pressure ( BP ) , and limited research on the underlying hemodynamics . This study assessed the effect of pistachio consumption on BP , systemic hemodynamics , and heart rate variability in adults with well‐controlled type 2 diabetes . Methods and Results We enrolled 30 adults ( 40 to 74 years ) with type 2 diabetes in a r and omized , crossover , controlled feeding study . After a 2‐week run‐in period , participants consumed a low‐fat control diet ( 27 % fat ) containing low‐fat/high‐carbohydrate snacks and a moderate‐fat diet ( 33 % fat ) containing pistachios ( 20 % of total energy ) for 4 weeks each , separated by a 2‐week washout . Following each diet period , we assessed BP , systemic hemodynamics , and heart rate variability at rest and during acute mental stress , and , in a subset of participants ( n=21 ) , 24‐hour ambulatory BP . BP at rest and during stress did not differ between treatments . The pistachio diet significantly reduced total peripheral resistance ( −3.7±2.9 % , P=0.004 ) , increased cardiac output ( 3.1±2.3 % , P=0.002 ) , and improved some measures of heart rate variability ( all P<0.05 ) . Systolic ambulatory BP was significantly reduced by 3.5±2.2 mm Hg ( P=0.046 ) following the pistachio diet , with the greatest reduction observed during sleep ( −5.7±2.6 mm Hg , P=0.052 ) . Conclusions A moderate‐fat diet containing pistachios modestly improves some cardiovascular risk factors  in adults with well‐controlled type 2 diabetes . Clinical Trial Registration URL : www . clinical trials.gov . Unique identifier : NCT00956735 Definitive solutions wo n’t come from another million observational papers or small r and omized trials Substitution analysis has been increasingly used in nutritional epidemiologic research . It was originally used to compare the health effects of different macronutrients in an isocaloric setting [ 1 ] . This application is easy to underst and , since calories are considered relatively constrained for an individual . In essence , substitution analysis provides a statistical technique to mimic feeding studies that aim to identify the optimal diet by altering macronutrient composition while holding total caloric intake constant [ 2 ] . Using this approach , for instance , it has been established that replacing saturated fats and trans fats with monounsaturated and polyunsaturated fats ismore effective in preventing coronary heart disease than reducing overall fat intake by replacing it with the commonly consumed carbohydrate sources [ 3 ] . Beyond the health effects of macronutrient composition , an increasing number of studies have started using substitution analysis to compare the relative health associations of different food sources of certain macronutrients . For example , as a major source of carbohydrate in the US , potatoes and potato products have been compared with whole grains and refined grains for the influence on type 2 diabetes ( T2D ) [ 4 ] . Reciprocal substitution of major dietary protein sources , such as red meat , fish , poultry , dairy , and plants , have been studied in cardiovascular disease and mortality [ 5 , 6 ] . Exemplified as further expansion of the application , two studies in this issue of the Journal used substitution analysis to assess intake of different foods within a certain category in relation to disease risk . van den Br and t [ 7 ] compared the associations of two commonly consumed beverages , tea and coffee , with  mortality  in the Netherl and s Cohort Study and observed a sex-specific association pattern : while replacing coffee with tea was associated with lower mortality in men , a higher percentage of tea consumption of total coffee and tea was associated with increased mortality in women [ 7 ] . Laursen et al. [ 8 ] evaluated the associations for substitutions between subgroups of dairy products with the risk of stroke in the Danish Diet , Cancer and Health cohort , and found a beneficial association with ischemic stroke for substitution of whole-fat fermented milk for semi-skimmed fermented milk , cheese , buttermilk or milk of any fat content . Applying similar principles , Schwingshackl et al. [ 9 ] performed a network meta- analysis of 56 r and omized trials to assess the comparative efficacy of nine different dietary approaches on glycemic control in T2D patients . The findings suggest that , while all dietary approaches significantly reduce HbA1c and fasting glucose compared to a control diet , the Mediterranean diet seems most efficacious for improving glycemic control in T2D patients . These studies represent exp and ed applications of the substitution modeling approach from nutrient-based analysis to comparison of food groups or dietary patterns . These applications are particularly useful to inform dietary guidelines by either prioritizing foods within a certain group ( e.g. , beverage , dairy ) or identifying the optimal diet for better disease control and prevention . However , these applications pose new challenges , because compared to macronutrients , foods are far more complicated in several aspects . First , most food groups encompass more than three types of foods . For example , besides tea and coffee , there are other beverages such as water , juice and soda that may & Edward Giovannucci Beneficial effects of n-3 fatty acids on a variety of physiological functions have been reported , but information related to the effects of oily fish consumed within a varied diet on glucose metabolism and diabetes risk is scarce . The objective of the study was to compare the effects of a diet rich in oily fish to those of a diet rich in red meat on lipid profile , oxidative status , glucose metabolism and insulin sensitivity in young , iron-deficient women . The study was design ed attending the CONSORT statement guidelines . It was a r and omised crossover dietary intervention study with two 8-week periods . Two diets were design ed differing only in their oily fish or red meat content ( four portions per week ) . Twenty-five young iron-deficient women with normal lipid , glucose and insulin levels participated in the assay . Lipid profile ( total , LDL- and HDL-cholesterol , TAG ) , fasting glucose , fasting insulin , and oxidation ( lipoperoxides ) and inflammation ( soluble intercellular adhesion molecule-1 and soluble vascular cell adhesion molecule-1 ) biomarkers were analysed . Insulin sensitivity was assessed by the Homeostasis Model Assessment ( HOMA ) and Quantitative Insulin Sensitivity Check Index ( QUICKI ) . Insulin levels significantly decreased and insulin sensitivity significantly increased with the oily fish diet .  HDL-cholesterol significantly increased with the oily fish diet . Other parameters did not significantly differ between diets . An increase in oily fish consumption increases insulin sensitivity in young iron-deficient women . This outcome should be considered when giving dietary advice to this population Background : The effect of whole grains on the regulation of energy balance remains controversial . Objective : We aim ed to determine the effects of substituting whole grains for refined grains , independent of body weight changes , on energy-metabolism metrics and glycemic control . Design : The study was a r and omized , controlled , parallel-arm controlled-feeding trial that was conducted in 81 men and postmenopausal women [ 49 men and 32 women ; age range : 40 - 65 y ; body mass index ( in kg/m2 ) : < 35.0 ] . After a 2-wk run-in period , participants were r and omly assigned to consume 1 of 2 weight-maintenance diets for 6 wk . Diets differed in whole-grain and fiber contents [ mean ± SDs : whole grain-rich diet : 207 ± 39 g whole grains plus 40 ± 5 g dietary fiber/d ; refined grain-based diet : 0 g whole grains plus 21 ± 3 g dietary fiber/d ] but were otherwise similar . Energy metabolism and body-composition metrics , appetite , markers of glycemic control , and gut microbiota were measured at 2 and 8 wk . Results : By design , body weight was maintained in both groups . Plasma alkylresorcinols , which are biomarkers of whole-grain intake , increased in the whole grain-rich diet group ( WG ) but not in the refined grain-based diet group ( RG ) ( P-diet-by-time interaction < 0.0001 ) . Beta ± SE changes ( ΔWG compared with ΔRG ) in the resting metabolic rate ( RMR ) ( 43 ± 25 kcal/d ; P = 0.04 ) , stool weight ( 76 ± 12 g/d ; P < 0.0001 ) , and stool energy content ( 57 ± 17 kcal/d ; P = 0.003 ) , but not in stool energy density , were higher in the WG . When combined , the favorable energetic effects in the WG translated into a 92-kcal/d ( 95 % CI : 28 , 156-kcal/d ) higher net daily energy loss compared with that of the RG ( P = 0.005 ) . Prospect i ve consumption ( P = 0.07 ) and glycemia after an oral-glucose-tolerance test ( P = 0.10 ) trended toward being lower in the WG than in the RG . When nonadherent participants were excluded , between-group differences in stool energy content and glucose tolerance increased , and between-group differences in the RMR and prospect i ve consumption were not statistically significant . Conclusion : These findings suggest positive effects of whole grains on the RMR and stool energy excretion that favorably influence energy balance and may help explain epidemiologic associations between whole-grain consumption and reduced body weight and adiposity . This trial was registered at clinical trials.gov as NCT01902394 Background / objectives Milk contributes with saturated fat , but r and omized controlled trials ( RCT ) on the effects of dairy on the risk of type 2 diabetes ( T2D ) where dairy is given as whole foods are scarce . The objective of our study was to investigate the long-term effects of semi-skimmed milk on insulin sensitivity and further to compare milk with sugar-sweetened soft drinks (SSSD).Subjects/ methods A secondary analysis of a 6-month RCT with 60 overweight and obese subjects r and omly assigned to 1 L/d of either milk ( 1.5 g fat/100 mL ) , SSSD , non-calorie soft drink ( NCSD ) , or water was conducted . Insulin sensitivity was evaluated by oral glucose tolerance test ( OGTT ) and plasma free fatty acids . Second , fasting blood lipids , blood pressure , and concentration of plasminogen activator inhibitor-1 were assessed . Results There were no differences between milk , SSSD , NCSD , and water on insulin sensitivity assessed by OGTT ( Matsuda Index , fasting , and area under the curve glucose , insulin and homeostasis model assessment values ) . SSSD increased total cholesterol compared to NCSD ( P = 0.007 ) , and triacylglycerol compared to NCSD and water ( P = 0.045 and 0.045 , respectively ) . None of the other parameters differed significantly between the groups . Conclusions In conclusion , there were no differences in effect between intake of milk , SSSD , NCSD , and water ( 1 L/d ) for 6-month on risk markers of T2D in overweight and obese adults . As a secondary analysis , these results need confirmation in future studies Intestinal microbiota is related to obesity and serum lipid levels , both risk factors for chronic diseases constituting a challenge for public health . We investigated how a diet rich in whole grain ( WG ) products and red meat ( RM ) influences microbiota . During a 10-week crossover intervention study , 20 healthy adults consumed two isocaloric diets , one rich in WG products and one high in RM . Repeatedly data on microbiota were assessed by 16S rRNA based denaturing gradient gel electrophoresis ( DGGE ) . A blood sample and anthropometric data were collected . Mixed models and logistic regression were used to investigate effects . Microbiota showed interindividual variability . However , dietary interventions modified microbiota appearance : 8 b and s changed in at least 4 participants during the interventions . One of the b and s appearing after WG and one increasing after RM remained significant in regression models and were identified as Collinsella aerofaciens and Clostridium sp. The WG intervention lowered obesity parameters , while the RM diet increased serum levels of uric acid and creatinine . The study showed that diet is a component of major relevance regarding its influence on intestinal microbiota and that WG has an important role for health . The results could guide investigations of diet and microbiota in observational prospect i ve cohort studies . Trial registration Clinical Trials.gov BACKGROUND Epidemiologic studies have found whole-grain intake to be inversely associated with the risk of  type 2 diabetes and heart disease . OBJECTIVE We tested the hypothesis that whole-grain consumption improves insulin sensitivity in overweight and obese adults . DESIGN This controlled experiment compared insulin sensitivity between diets ( 55 % carbohydrate , 30 % fat ) including 6 - 10 
    Output:
    
Conclusion The present NMA provides evidence that increased intake of nuts , legumes , and whole grains is more effective at improving metabolic health than other food groups .