***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 Few prospect i ve studies have examined the mortality of vegetarians . OBJECTIVE We present results on mortality among  vegetarians and nonvegetarians  in the European Prospect i ve Investigation into Cancer and Nutrition ( EPIC-Oxford ) . DESIGN We used a prospect i ve study of men and women recruited throughout the United Kingdom in the 1990s . RESULTS Among 64,234 participants aged 20 - 89 y for whom diet group was known , 2965 had died before age 90 by 30 June 2007 . The death rates of participants are much lower than average for the United Kingdom . The st and ardized mortality ratio for all causes of death was 52 % ( 95 % CI : 50 % , 54 % ) and was identical in vegetarians and in nonvegetarians . Comparing vegetarians with meat eaters among the 47,254 participants who had no prevalent cardiovascular disease or malignant cancer at recruitment , the death rate ratios adjusted for age , sex , smoking , and alcohol consumption were 0.81 ( 95 % CI : 0.57 , 1.16 ) for ischemic heart disease and 1.03 ( 95 % CI : 0.90 , 1.16 ) for all causes of death . CONCLUSIONS The mortality of both the vegetarians and the nonvegetarians in this study is low compared with national rates . Within the study , mortality from circulatory diseases and all causes is not significantly different between vegetarians and meat eaters , but the study is not large enough to exclude small or moderate differences for specific causes of death , and more research on this topic is required OBJECTIVE The aim of this study was to determine the effect of plant-based diets on weight loss . METHODS Participants were enrolled in a 6-mo , five-arm , r and omized controlled trial in 2013 in South Carolina . Participants attended weekly group meetings , with the exception of the omnivorous group , which served as the control and attended monthly meetings augmented with weekly e-mail lessons . All groups attended monthly meetings for the last 4 mo of the study . Diets did not emphasize caloric restriction . RESULTS Overweight adults ( body mass index 25 - 49.9 kg/m(2 ) ; age 18 - 65 y , 19 % non-white , and 27 % men ) were r and omized to a low-fat , low-glycemic index diet : vegan ( n = 12 ) , vegetarian ( n = 13 )  , pesco-vegetarian ( n =  13  ) , semi-vegetarian  ( n = 13 ) , or omnivorous  ( n = 12 ) . Fifty ( 79 % ) participants completed the study . In intention-to-treat analysis , the linear trend for weight loss across the five groups was significant at both 2 ( P < 0.01 ) and 6 mo ( P < 0.01 ) . At 6 mo , the weight loss in the vegan group ( -7.5 % ± 4.5 % ) was significantly different from the omnivorous ( -3.1 % ± 3.6 % ; P = 0.03 ) , semi-vegetarian ( -3.2 % ± 3.8 % ; P = 0.03 ) , and pesco-vegetarian ( -3.2 % ± 3.4 % ; P = 0.03 ) groups . Vegan participants decreased their fat and saturated fat more than the pesco-vegetarian , semi-vegetarian , and omnivorous groups at both 2 and 6 mo ( P < 0.05 ) . CONCLUSIONS Vegan diets may result in greater weight loss than more modest recommendations Importance Defining what represents a macronutritionally balanced diet remains an open question and a high priority in nutrition research . Although the amount of protein may have specific effects , from a broader dietary perspective , the choice of protein sources will inevitably influence other components of diet and may be a critical determinant for the health outcome . Objective To examine the associations of animal and plant protein intake with the risk for mortality . Design , Setting , and Participants This prospect i ve cohort study of US health care professionals included 131 342 participants from the Nurses ' Health Study ( 1980 to end of follow-up on June 1 , 2012 ) and Health Professionals Follow-up Study ( 1986 to end of follow-up on January 31 , 2012 ) .  Animal and plant protein intake was assessed by regularly up date d vali date d food frequency question naires . Data were analyzed from June 20 , 2014 , to January 18 , 2016 . Main Outcomes and Measures Hazard ratios ( HRs ) for all-cause and cause-specific mortality . Results Of the 131 342 participants , 85 013 were women ( 64.7 % ) and 46 329 were men ( 35.3 % ) ( mean [ SD ] age , 49 [ 9 ] years ) .  The median protein intake , as assessed by percentage of energy , was 14 % for animal protein ( 5th-95th percentile , 9%-22 % ) and 4 % for plant protein ( 5th-95th percentile , 2%-6 % ) . After adjusting for major lifestyle and dietary risk factors , animal protein intake was not associated with all-cause mortality ( HR , 1.02 per 10 % energy increment ; 95 % CI , 0.98 - 1.05 ; P for trend = .33 ) but was associated with higher cardiovascular mortality ( HR , 1.08 per 10 % energy increment ; 95 % CI , 1.01 - 1.16 ; P for trend = .04 ) . Plant protein was associated with lower all-cause mortality ( HR , 0.90 per 3 % energy increment ; 95 % CI , 0.86 - 0.95 ; P for trend < .001 ) and cardiovascular mortality ( HR , 0.88 per 3 % energy increment ; 95 % CI , 0.80 - 0.97 ; P for trend = .007 ) . These associations were confined to participants with at least 1 unhealthy lifestyle factor based on smoking , heavy alcohol intake , overweight or obesity , and physical inactivity , but not evident among those without any of these risk factors . Replacing animal protein of various origins with plant protein was associated with lower mortality . In particular , the HRs for all-cause mortality were 0.66 ( 95 % CI , 0.59 - 0.75 ) when 3 % of energy from plant protein was substituted for an equivalent amount of protein from processed red meat , 0.88 ( 95 % CI , 0.84 - 0.92 ) from unprocessed red meat , and 0.81 ( 95 % CI , 0.75 - 0.88 ) from egg . Conclusions and Relevance High animal protein intake was positively associated with cardiovascular mortality and high plant protein intake was inversely associated with all-cause and cardiovascular mortality  , especially among individuals with at least 1 lifestyle risk factor . Substitution of plant protein for animal protein , especially that from processed red meat , was associated with lower mortality , suggesting the importance of protein source OBJECTIVE To describe the lifestyle characteristics and nutrient  intakes of the Oxford cohort of the European Prospect i ve Investigation into Cancer and Nutrition ( EPIC ) . DESIGN Cohort of men and women recruited through general practice s or by post to include a high proportion of non meat-eaters .  Dietary , anthropometric and lifestyle data were collected at baseline and four diet groups were defined . SETTING United Kingdom . PARTICIPANTS In total , 65 429 men and women aged 20 to 97 years , comprising 33 883 meat-eaters , 10 110 fish-eaters , 18 840 lacto-ovo vegetarians and 2596 vegans .  RESULTS Nutrient intakes and lifestyle factors differed across the diet groups , with striking differences between meat-eaters and vegans , and fish-eaters and vegetarians usually having intermediate values . Mean fat intake in each diet group was below the UK dietary reference value of 33 % of total energy intake . The mean intake of saturated fatty acids in vegans was approximately 5 % of energy , less than half the mean intake among meat-eaters ( 10 - 11 % ) . Vegans had the highest intakes of fibre , vitamin B1 , folate , vitamin C , vitamin E , magnesium and iron , and the lowest intakes of retinol , vitamin B12 , vitamin D , calcium and zinc . CONCLUSIONS The EPIC-Oxford cohort includes 31 546 non meat-eaters and is one of the largest studies of vegetarians in the world . The average nutrient intakes in the whole cohort are close to those currently recommended for good health . Comparisons of the diet groups show wide ranges in the intakes of major nutrients such as saturated fat and dietary fibre . Such variation should increase the ability of the study to detect associations of diet with major cancers and causes of death OBJECTIVE To explore the potential role of the endogenous peptide YY ( PYY ) in the long-term regulation of body weight and energy homeostasis . RESEARCH METHODS AND PROCEDURES Fasting and postpr and ial plasma PYY concentrations were measured after an overnight fast and 30 to 180 minutes after a st and ardized meal in 29 ( 21 men/8 women ) non-diabetic subjects , 16 of whom had a follow-up visit 10.8 + /- 1.4 months later .  Ratings of hunger and satiety were collected using visual analog scales . Resting metabolic rate ( RMR ) ( 15-hour RMR ) and respiratory quotient ( RQ ) were assessed using a respiratory chamber . RESULTS Fasting PYY concentrations were negatively correlated with various markers of adiposity and negatively associated with 15-hour RMR ( r = -0.46 , p = 0.01 ) . Postpr and ial changes in PYY ( area under the curve ) were positively associated with postpr and ial changes in ratings of satiety ( r = 0.47 , p = 0.01 ) . The maximal PYY concentrations achieved after the meal ( peak PYY ) were negatively associated with 24-hour RQ ( r = -0.41 , p = 0.03 ) . Prospect ively , the peak PYY concentrations were negatively associated with changes in body weight ( r = -0.58 , p = 0.01 ) . DISCUSSION Our data indicate that the endogenous PYY may be involved in the long-term regulation of body weight . It seems that this long-term effect was not exclusively driven by the modulation of food intake but also by the control of energy expenditure and lipid metabolism Long-term dietary intake influences the structure and activity of the trillions of microorganisms residing in the human gut , but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change . Here we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression . The animal-based diet increased the abundance of bile-tolerant microorganisms ( Alistipes , Bilophila and Bacteroides ) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides ( Roseburia , Eubacterium rectale and Ruminococcus bromii ) . Microbial activity mirrored differences between herbivorous and carnivorous mammals , reflecting trade-offs between carbohydrate and protein fermentation . Foodborne microbes from both diets transiently colonized the gut , including bacteria , fungi and even viruses . Finally , increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat , bile acids and the outgrowth of microorganisms capable of triggering inflammatory bowel disease . In concert , these results demonstrate that the gut microbiome can rapidly respond to altered diet , potentially facilitating the diversity of human dietary lifestyles Regular walnut consumption is associated with  better health . We have previously shown that eight weeks of walnut consumption ( 43 g/day ) significantly improves  lipids in healthy subjects . In the same study , gut microbiome was evaluated . We included 194 healthy subjects ( 134 females , 63 ± 7 years , BMI 25.1 ± 4.0 kg/m2 ) in a r and omized , controlled , prospect i ve , cross-over study . Following a nut-free run-in period , subjects were r and omized to two diet phases ( eight weeks each ) ; 96 subjects first followed a walnut-enriched diet ( 43 g/day ) and then switched to a nut-free diet , while 98 subjects followed the diets in reverse order . While consuming the walnut-enriched diet , subjects were advised to either reduce fat or carbohydrates or both to account for the additional calories . Fecal sample s were collected from 135 subjects at the end of the walnut-diet and the control-diet period for microbiome analyses . The 16S rRNA gene sequencing data was clustered with a 97 % similarity into Operational Taxonomic Units ( OTUs ) . UniFrac distances were used to determine diversity between groups . Differential abundance was evaluated using the Kruskal – Wallis rank sum test . All 
    Output:
    
We found robust evidence for short- to moderate-term beneficial effects of plant-based diets versus conventional diets ( duration ≤ 24 months ) on weight status , energy metabolism and systemic inflammation in healthy participants , obese and type-2 diabetes patients .
Initial experimental studies proposed novel microbiome-related pathways , by which plant-based diets modulate the gut microbiome towards a favorable diversity of bacteria species , yet a functional “ bottom up ” signaling of plant-based diet-induced microbial changes remains highly speculative .