***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 Probiotics purportedly reduce symptoms of gastrointestinal and upper respiratory-tract illness by modulating commensal microflora . Preventing and reducing symptoms of respiratory and gastrointestinal illness are the primary reason that dietary supplementation with probiotics are becoming increasingly popular with healthy active individuals . There is a paucity of data regarding the effectiveness of probiotics in this cohort . The aim of this study was to evaluate the effectiveness of a probiotic on faecal microbiology , self-reported illness symptoms and immunity in healthy well trained individuals . Methods Competitive cyclists ( 64 males and 35 females ; age 35 ± 9 and 36 ± 9 y , VO2max 56 ± 6 and 52 ± 6 ml.kg-1.min-1 , mean ± SD ) were r and omised to either probiotic ( minimum 1 × 109Lactobacillus fermentum ( PCC ® ) per day ) or placebo treatment for 11 weeks in a double-blind , r and omised , controlled trial . The outcome measures were faecal L. fermentum counts , self-reported symptoms of illness and serum cytokines . Results Lactobacillus numbers increased 7.7-fold ( 90 % confidence limits 2.1- to 28-fold ) more in males on the probiotic , while there was an unclear 2.2-fold ( 0.2- to 18-fold ) increase in females taking the probiotic . The number and duration of mild gastrointestinal symptoms were ~2-fold greater in the probiotic group . However , there was a substantial 0.7 ( 0.2 to 1.2 ) of a scale step reduction in the severity of gastrointestinal illness at the mean training load in males , which became more pronounced as training load increased . The load ( duration ×severity ) of lower respiratory illness symptoms was less by a factor of 0.31 ( 99%CI ; 0.07 to 0.96 ) in males taking the probiotic compared with placebo but increased by a factor of 2.2 ( 0.41 to 27 ) in females . Differences in use of cold and flu medication mirrored these symptoms . The observed effects on URTI had too much uncertainty for a decisive outcome . There were clear reductions in the magnitude of acute exercise-induced changes in some cytokines . Conclusion L. fermentum may be a useful nutritional adjunct for healthy exercising males . However , uncertainty in the effects of supplementation on URTI and on symptoms in females needs to be resolved . Trial registration The trial was registered in the Australia and New Zeal and Clinical Trials Registry ( ACTRN12611000006943 ) Background : To evaluate whether a fermented dairy drink containing the probiotic strain Lactobacillus casei DN-114 001 could reduce the incidence of common infectious diseases ( CIDs ) and the change of behavior because of illness in children . Subjects/ Methods : We conducted a double-blinded , r and omized , placebo-controlled allocation concealment clinical trial in the Washington , DC metropolitan area . Participants were 638 children 3–6 years old in daycare/schools . The intervention was a fermented dairy drink containing a specific probiotic strain or matching placebo with no live cultures for 90 consecutive days . Two primary outcomes were assessed : incidence of CIDs and change of behavior because of illness ( both assessed by parental report ) . Results : The rate of change of behavior because of illness was similar among active and control groups . However , the incidence rate for CIDs in the active group ( 0.0782 ) is 19 % lower than that of the control group ( 0.0986 ) ( incidence rate ratio=0.81 , 95 % CI : 0.65 , 099 ) P=0.046 . Conclusions : Daily intake of a fermented dairy drink containing the probiotic strain L. casei DN-114 001 showed some promise in reducing overall incidence of illness , but was primarily driven by gastrointestinal infections and there were no differences in change of behavior College students are susceptible to upper respiratory infections ( URI ) due to inadequate sleep , stress and close living quarters . Certain probiotic strains modulate immune function and may improve health-related quality of life ( HRQL ) during URI . The present study recruited apparently healthy college students and assessed the effect of probiotics on HRQL outcomes ( i.e. self-reported duration , symptom severity and functional impairment of URI ) in those who developed URI .  Missed school and work days due to URI were also considered . Subjects ( n 231 ) were apparently healthy college students living on campus in residence halls at the Framingham State University ( Framingham , MA , USA ) , and were r and omised to receive placebo ( n 117 ) or probiotic-containing powder ( daily dose of minimum 1 billion colony-forming units of each Lactobacillus rhamnosus LGG ® ( LGG ® ) and Bifidobacterium animalis ssp . lactis BB-12 ® ( BB-12 ® ) ; n 114 ) for 12 weeks . Subjects completed The Wisconsin Upper Respiratory Symptom Survey-21 to assess HRQL during URI . The final analyses included 198 subjects ( placebo , n 97 and probiotics , n 101 ) . The median duration of URI was significantly shorter by 2 d and median severity score was significantly lower by 34 % with probiotics v. placebo ( P,0·001 ) , indicating a higher HRQL during URI . Number of missed work days was not different between groups ( P=0·429 ) ; however , the probiotics group missed significantly fewer school days ( mean difference = 0·2 d ) compared to the placebo group ( P=0·002 ) . LGG ® and BB-12 ® may be beneficial among college students with URI for mitigating decrements in HRQL . More research is warranted regarding mechanisms of action associated with these findings and the cost-benefit of prophylactic supplementation A mixture of neutral short-chain galactooligosaccharides ( scGOS ) and long-chain fructooligosaccharides ( lcFOS ) has been shown to reduce the incidence of atopic dermatitis ( AD ) and infectious episodes during the first 6 mo of life . This dual protection occurred through the intervention period . The present study evaluated if these protective effects were lasting beyond the intervention period . In a prospect i ve , r and omized , double-blind , placebo-controlled design , healthy term infants with a parental history of atopy were fed either a prebiotic-supplemented ( 8 g/L scGOS/lcFOS ) or placebo-supplemented ( 8 g/L maltodextrin ) hypoallergenic formula during the first 6 mo of life . Following this intervention period , blind follow-up continued until 2 y of life . Primary endpoints were cumulative incidence of allergic manifestations . Secondary endpoints were number of infectious episodes and growth .  Of 152 participants , 134 infants ( 68 in placebo , 66 in intervention group ) completed the follow-up . During this period , infants in the scGOS/lcFOS group had significantly lower incidence of allergic manifestations . Cumulative incidences for AD , recurrent wheezing , and allergic urticaria were higher in the placebo group , ( 27.9 , 20.6 , and 10.3 % , respectively ) than in the intervention group ( 13.6 , 7.6 , and 1.5 % ) ( P < 0.05 ) . Infants in the scGOS/lcFOS group had fewer episodes of physician-diagnosed overall and upper respiratory tract infections ( P < 0.01 ) , fever episodes ( P < 0.00001 ) , and fewer antibiotic prescriptions ( P < 0.05 ) . Growth was normal and similar in both groups . Early dietary intervention with oligosaccharide prebiotics has a protective effect against both allergic manifestations and infections . The observed dual protection lasting beyond the intervention period suggests that an immune modulating effect through the intestinal flora modification may be the principal mechanism of action Background The efficacy of probiotics is currently well documented with regard to the improvement of gastrointestinal functions , whereas their potential role in the prevention of infectious respiratory diseases has not been sufficiently analyzed . Purpose of the Study and Methods A 3-stage prospect i ve , r and omized , double blind , placebo-controlled study was carried out with several synbiotic preparations containing 3 to 5 strains of Lactobacillus plantarum , Lactobacillus rhamnosus , and Bifidobacterium lactis , lactoferrin and prebiotics such as either FOS ( short-chain fructooligosaccharides ) or GOS ( galactooligosaccharides ) . The study was performed over 3 different winter seasons between 2003 and 2007 , and was aim ed at assessing the ability of the different preparations to improve intestinal functions and to increase the body 's defences against respiratory infections . In 2003/04 ( stage 1 ; 237 healthy volunteers ) an active formulation ( A ) containing 3 probiotic strains and FOS was used versus placebo ; in 2005/06 ( stage 2 ; 234 healthy volunteers ) the same formulation versus a similar preparation enriched with lactoferrin ( B ) , and versus placebo ; in 2006/07 ( stage 3 ; 250 healthy volunteers ) , 2 new synbiotic formulations each containing 5 probiotics and FOS ( C ) or GOS ( D ) , respectively , versus placebo . Results In stage 1 , bowel functions improved ( P=0.004 ) in terms of reduced bloating and more regular intestinal motility . The length of acute respiratory infection episodes considered as a whole ( −0.97 d ; P=0.007 ) and upper respiratory tract infections ( URTIs , −1.96 d ; P=0.044 ) were significantly decreased in the synbiotic group . The severity of episodes recorded a statistically significant drop in both episodes considered as a whole ( 3.21 average score vs. 3.98 in the placebo group , P<0.001 ) and in URTI ( 2.56 vs. 3.82 ; P=0.004 ) and flu classes ( 3.80 vs. 4.67 , P=0.001 ) . In stage 2 , improvement of bowel functions was statistically significant ( P=0.005 ) in synbiotic preparation A. A statistically significant reduction in the number of respiratory tract infections episodes was noted with both the two active formulations ( P=0.002 in group A and P=0.003 in group B ) . The duration of episodes considered as a whole ( −1.12 d in one of the 2 active formulation groups ; P=0.005 ) , URTIs ( −2.08 d in group A ; P=0.036 ) and influenza-like illness episodes ( −1.40 d in group A ; P=0.049 ) was significantly decreased in the synbiotic group . A reduction trend in cold episodes was also recorded . The severity of episodes recorded a statistically significant drop in episodes considered as a whole ( −0.73 in group A , P=0.003 ; −0.65 in group B , P=0.004 ) and in the case of flu ( −1.25 in group A , P<0.001 ; −1.18 in group B , P<0.001 ) . In stage 3 , the improvement of bowel functions was confirmed for both active formulations ( P<0.001 ) . A significant decrease in the total length of respiratory episodes ( −1.51 d ; P<0.001 in the group C and −1.39 d ; P<0.001 in the group D ) and in the length of cough ( −3.08 d ; P<0.001 in group C ; −2.83 d ; P<0.001 in group D ) , cold ( −1.02 d ; P=0.019 in group C ; −1.32 d ; P=0.001 in group D ) and flu episodes was reported . The severity of episodes recorded a statistically significant drop in regard to episodes considered as a whole , the cold and flu classes in both groups and for cough too in group C. The number of episodes also dropped considerably in terms of overall episodes , cold ( group C ) and flu . Conclusions These results demonstrate that a regular , long-term intake of various synbiotics may improve health by reducing the incidence and severity of respiratory diseases during the cold season The purpose of this study was to examine the effects of a probiotic supplement during 4 mo of spring training in men and women engaged in endurance-based physical activities on incidence of  upper respiratory tract infections ( URTI ) and mucosal immune markers . Sixty-six highly active individuals were r and omized to probiotic ( n = 33 ) or placebo ( n = 33 ) groups and , under double-blind procedures , received probiotic ( PRO : Lactobacillus salivarius , 2 × 1010 bacterium colony-forming units ) or placebo ( PLA ) daily for 16 wk . Resting blood and saliva sample s were collected at baseline and after 8 and 16 wk . Weekly training and illness logs were kept . Fifty-four subjects completed the study ( n = 27 PRO , n = 27 PLA ) . The proportion of subjects on PRO who experienced 1 or more wk with URTI symptoms was not different from that of those on 
    Output:
    
Side effects of probiotics were minor and gastrointestinal symptoms were the most common .
Probiotics were better than placebo in reducing the number of participants experiencing episodes of acute URTI , the mean duration of an episode of acute URTI , antibiotic use and cold-related school absence .
This indicates that probiotics may be more beneficial than placebo for preventing acute URTIs .