Why publish science in peer-reviewed journals? Left unanswered, however, is a more fundamental question: What value does the existence of these journals add? Google Scholar in ?
Positive modulation of colonic microbiota 2. Oligosaccharides, including fructo-oligosaccharides and galacto-oligosaccharides, inulin, and possibly other soluble fibers, are therefore regarded as prebiotics that may stimulate the preferential growth of lactobacilli, bifidobacteria, and other health-promoting bacteria in the colon [ 314 — 16 ].
The gut microbiota are thought to play a crucial role in human health and prevention of disease through a variety of mechanisms, including production of short-chain fatty acids SCFAwhich are important for maintaining gut homeostasis and optimal immune function [ 314 — 16 ].
Changes in the gut microenvironment have been associated with many common conditions, including irritable bowel syndrome, obesity, cardiovascular disease, and asthma [ 1516 ]. The relationship between the gut microbiota, dietary fiber, and health outcomes is an area of rapidly growing interest, but well-controlled human trials are required in order to confirm the emerging links noted in animal and epidemiological studies [ 1516 ].
Increasing fluid in the diet has long been considered a first-line treatment for constipation [ 31718 ]; the evidence to support this is mixed. Fiber should be introduced gradually into the diet over weeks rather than days, to allow the body to adjust [ 1819 ].
Stool frequency is thought to be improved by soluble fiber through an increase in stool bulk and weight, and by insoluble fiber through the acceleration of intestinal transit time; for both, however, and especially for insoluble fibers, high-quality evidence is lacking [ 14 ].
The best evidence for fiber supplementation is for psyllium in the management of chronic constipation [ 18 ]. Evidence for the efficacy of fiber is particularly lacking for individual constipation subtypes: In patients with obstructive diseases of the intestine, a high-fiber diet should be avoided.
Delayed colon transit or dyssynergic defecation may be present when patients experience marked worsening of their constipation-related symptoms with fiber [ 172021 ]. A high-fiber diet may be protective against, and therapeutically useful in the treatment of, constipation. Additionally, psyllium supplementation may be appropriate in the management of chronic constipation.
The role of fiber in other forms of constipation is limited, and a high-fiber diet may exacerbate symptoms in some individuals. Soluble fiber supplements—including linseed, methylcellulose, partially hydrolyzed guar gum, and psyllium—have demonstrated therapeutic benefit in a number of clinical trials, particularly for patients with constipation-predominant IBS IBS-C [ 3142223 ].
Highly fermentable fibers, such as oligosaccharides, inulin, and wheat bran fiber by virtue of its oligosaccharide content may contribute to increased gas production, thus exacerbating symptoms of bloating, flatus, and gastrointestinal discomfort in IBS [ 142223 ]. Highly fermentable fibers, including oligosaccharides and inulin, and also wheat bran may exacerbate symptoms of IBS.
Conversely, soluble fiber supplements including psyllium, linseed, and methylcellulose may be of therapeutic benefit, particularly in IBS-C. However, due to the potential anti-inflammatory and immune-modulating effects of fiber, this warrants further investigation [ 24 ].
Restriction of dietary fiber in IBD is unnecessary except in the case of significant intestinal stenosis [ 24 ]. There is currently a paucity of evidence supporting a therapeutic role of dietary fiber in IBD.
Further high-quality studies are therefore required. The intake of dietary fiber should not be restricted in IBD patients, except in the case of intestinal obstruction. It is not clear whether a high-fiber diet is beneficial in patients with diverticulosis, as its pathogenesis is probably multifactorial and complex.
More studies are needed in order to evaluate the role of fiber in the pathogenesis and treatment of diverticular disease [ 2728 ]. A few poor-quality studies have suggested that fiber may improve symptoms associated with uncomplicated diverticulosis and decrease the risk of diverticulitis.
However, high-quality evidence is lacking [ 2728 ]. During an episode of acute diverticulitis, a low-fiber diet is often recommended in order to minimize bowel irritation [ 2728 ].
However, there is limited evidence to support this strategy. Consumption of a high-fiber diet may be protective against the development of diverticular disease, and the risk of complications diverticulitis may be higher in those on a low-fiber diet.
Short-term use of a low-fiber diet may be indicated in the case of diverticulitis. However, all of these recommendations are supported by limited evidence and expert opinion only. A analysis from the European Prospective Investigation into Cancer and Nutrition EPIC study showed that total dietary fiber was inversely associated with colorectal cancer risk, with similar results for colon and rectal cancers.
Dietary fiber sources from cereals, fruits, and vegetables were similarly associated with a reduced risk of colon cancer [ 30 ]. Only cereal fiber was associated with a decreased risk of rectal cancer [ 30 ].
There is no evidence from randomized controlled trials RCTs to suggest that increased dietary fiber intake will reduce the incidence or recurrence of adenomatous polyps within a 2—8-year period [ 31 ].How to write an introduction and methods of a systematic review of literature Table: Review of background/introduction part of systematic reviews published by Cochrane review from the list of top 50 most-accessed abstracts .
How to write an introduction and methods of a systematic review of literature Article (PDF Available) in Journal of the Pakistan Medical Association 64(10) · October with Reads.
Rule 3: Take Notes While Reading. If you read the papers first, and only afterwards start writing the review, you will need a very good memory to remember who wrote what, and what your impressions and associations were while reading each single paper.
COPE Best Practice Guidelines for Journal Editors • adopt peer-review methods best suited for their journal and the research community it serves.
This model comprises prescriptions for writing the systematic review's review question and eligibility criteria, the identification of the relevant literature, the type of data to extract on reasons and publications, and the derivation and presentation of results.
The publishing process as it stands currently. As most readers here are aware, the path to publishing a scientific paper has two major obstacles: first, the editor of a journal has to decide that a paper is potentially “interesting” enough for publication in their journal; if it passes that threshold, it is then sent out for “peer review” by two to four people chosen by the editor.