Review for 10.1186/1471-230X-12-61 (2012)

Reviewer's report
Title:Diet in subjects with irritable bowel syndrome: a cross-sectional study in
the general population
Version: 1Date:2 April 2012
Reviewer: Jacqueline Barrett
Reviewer's report:
Major Compulsory Revisions
1. There is no mention of the validity of the FFQ used in this study? Has it been
validated against weighed food records in this or other patient groups? An FFQ
cannot be deemed reliable without validation and conclusions cannot be drawn
from the data without considerable apprehension – I am especially concerned
about the reliability of this tool, if not validated, given the food questions are so
broad
2. Paragraph 2, page 9 – the final couple of sentences need to be rephrased.
When considering the possibility of milk protein intolerance, you need to be
mindful that there are multiple components of milk that may be involved in IBS
symptoms in some people and reference each of these – milk protein, lactose,
amines in cheeses etc. Concluding milk protein intolerance based on an
individual’s assumption that milk is a trigger is dangerous as it can have
significant nutritional implications
3. Paragraph 1, page 10 – the references here are muddled. Ref 22 is
inappropriate and as such the wording around this ref needs to be rephrased as
you will no longer be referencing other studies. Ref 24 is also not the best to
support this information. Suggest the authors read Ong et al (2010).
"Manipulation of dietary short chain carbohydrates alters the pattern of gas
production and genesis of symptoms in irritable bowel syndrome." Journal of
Gastroenterology and Hepatology 25: 1366-1373. I would also add after the
“handle gas poorly” sentence, the following “Some fruits can exert a laxative
effect dye to their carbohydrate composition which may suggest a cause of
symptoms in D-IBS.” (Barrett, J. S., R. B. Gearry, et al. (2010). "Dietary poorly
absorbed, short-chain carbohydrates increase delivery of water and fermentable
substrates to the proximal colon." Aliment Pharmacol Ther 31(8): 874-82. The
final sentence of this paragraph should read “Thus, the higher intake of fruits,
berries and vegetables are likely to be a combination of consequence and cause
of symptoms”.
4. Paragraph 2, page 10 – You need to consider the natural salicylate content of
tea which has been implicated in GI disturbance
5. Paragraph 3, page 11 – needs to be expanded. There needs to be more of a
discussion on how this should be handled by a dietitian considering what has
been learnt from this paper. Dietetic consultation should be encouraged
6. Page 12, strengths and limitations – this needs to discuss limitations of a FFQ
in general
Minor Essential Revisions
1. Please clarify if the survey was completed alone or with assistance of the
researchers
2. There is mention of BMI, BP and pulse in the survey, but how were these
measured? If these were measured on interview, then this information should not
be listed under the survey, rather later in the medical assessment when bloods
were also taken
3. Paragraph 1 of the discussion needs to catch the reader and entice the reader
to hear more about your findings. I found this paragraph somewhat pointless.
Suggest this is rephrased to be more exciting
4. Fig 1 – The numbers do not add up on the flow chart
5. Table 3- there is a bracket missing on the 95% CI of Dairy products
6. Table 4 – ensure BMI is in capitals throughout text here
Discretionary Revisions
1. I prefer the presentation of symptom results with 95% CI rather than SD. It
think it provides more detail for the reader when symptoms are such a subjective
measure
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests