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The challenges of control groups, placebos and blinding in clinical trials of dietary interventions
journal contribution
posted on 2017-08-01, 00:00 authored by Heidi StaudacherHeidi Staudacher, P M Irving, M C E Lomer, K WhelanHigh-quality placebo-controlled evidence for food, nutrient or dietary advice interventions is vital for verifying the role of diet in optimising health or for the management of disease. This could be argued to be especially important where the benefits of dietary intervention are coupled with potential risks such as compromising nutrient intake, particularly in the case of exclusion diets. The objective of the present paper is to explore the challenges associated with clinical trials in dietary research, review the types of controls used and present the advantages and disadvantages of each, including issues regarding placebos and blinding. Placebo-controlled trials in nutrient interventions are relatively straightforward, as in general placebos can be easily produced. However, the challenges associated with conducting placebo-controlled food interventions and dietary advice interventions are protean, and this has led to a paucity of placebo-controlled food and dietary advice trials compared with drug trials. This review appraises the types of controls used in dietary intervention trials and provides recommendations and nine essential criteria for the design and development of sham diets for use in studies evaluating the effect of dietary advice, along with practical guidance regarding their evaluation. The rationale for these criteria predominantly relate to avoiding altering the outcome of interest in those delivered the sham intervention in these types of studies, while not compromising blinding.
History
Journal
Proceedings of the Nutrition SocietyEvent
Nutrition-Society Summer Meeting / Conference on New Technology in Nutrition Research and PracticeVolume
76Issue
3Pagination
203 - 212Publisher
Cambridge University PressLocation
Cambridge, Eng.Publisher DOI
Start date
2016-07-11End date
2016-07-14ISSN
0029-6651eISSN
1475-2719Language
EnglishPublication classification
C1 Refereed article in a scholarly journalUsage metrics
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Categories
Keywords
ACTIVE CROHNS-DISEASECARDIOVASCULAR RISKClinical trialControlsCROSSOVER TRIALDietary interventionGASTROINTESTINAL DISORDERSIRRITABLE-BOWEL-SYNDROMELife Sciences & BiomedicineMEDITERRANEAN DIETMICROPARTICLE DIETNutrition & DieteticsPlaceboPOSTMENOPAUSAL WOMENRANDOMIZED CONTROLLED-TRIALREDUCES SYMPTOMSResearch designScience & TechnologyIBS irritable bowel syndrome