Review for 10.1186/s12876-020-01435-4 (2020)

Reviewer ’s report  
 
Title: The association between inflammatory potential of diet and d isease activity: results from a 
cross -sectional study in patients with inflammatory bowel disease  
 
Version: 0 Date: 03 Jun 2020  
 
Reviewer's report:  
 
The study by Lamers et al aimed to fin d an association between the inflammatory potential of 
diet and disease activity in inflammatory bowel diseases patients. All data was collected with a 
questionnaire sent to IBD patients and the inflammatory potential of diet was calculated using 
the Dieta ry Inflammatory Index (DII).  
The authors conclude that disease activity (only clinically measured) is higher in IBD patients 
consuming more pro -inflammatory diet.  
 
The introduction is well written and gives an overview of the available literature. Howeve r, some 
references should be changed to more recent and relevant one.  
- Page 1, line 7/8; Dietary Inflammatory Potential and Risk of Crohn's Disease and Ulcerative 
Colitis, Lo, Chun -Han et al., Gastroenterology, In press  
- Page 4 , line 28: Llewellyn SR, B ritton GJ, Contijoch EJ, et al. Interactions Between Diet and 
the Intestinal Microbiota Alter Intestinal Permeability and Colitis Severity in Mice. 
Gastroenterology. 2018;154(4):1037 ‐1046.e2. doi:10.1053/j.gastro.2017.11.030  
 
 
The methodology is clear to u nderstand. However, can the authors explain in 1 -2 sentences the 
Nijmegen Exercise Study, from which participants were recruited. Do I understand it correctly 
that all the characteristics (current medication, age at diagnosis,...) came only from the self -
reported questionnaire?  
 
Discussion: I would include following studies into the discussion: Dietary Inflammatory 
Potential and Risk of Crohn's Disease and Ulcerative Colitis, Lo, Chun -Han et al., 
Gastroenterology, In press.  
The limitations are well explain ed. The patients who have participated are probably more 
interested in nutrition and have a high education level. It is all the more surprising that the 
patients tend to follow a pro -inflammatory diet. Is there a study on a healthy population 
regarding DII  (in other words, do we all eat in Western countries a pro -inflammatory diet?).  
Another important limitation to mention is the fact, that disease activity was only measured with 
the self -reported questionnaire.  
 
Although no causality can be established, the study is very interesting and shows that there is an 
association between higher clinical CD activity and pro -inflammatory diet.  
 
 
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supporte d by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any statistics in the manus cript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please spe cify what aspects require further 
assessment in your comments to the editors.  
 
I recommend additional statistical review  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, f ees, funding, or salary from an 
organisation that may in any way gain or lose financially from the publicati on of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation t hat may in any way gain or lose 
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currentl y applying for any patents  relating to the content of the 
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have  no competing interests' 
below. If your reply is y es to any, please give details below.  
 
Consultant fee from Janssen, Pfizer and Takeda. Travel support from Falk Pharma.  
 
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