Looking Beyond Nutrients, How to Assess Diet Quality in an Inflammatory Bowel Disease Population-A Narrative Review

Background: Dietary assessment in inflammatory bowel disease (IBD) is moving away from individual food and nutrient analyses and towards dietary patterns (e.g., Mediterranean diet, Western diet) and diet quality assessment that are increasingly implicated in IBD onset and course. However, an IBD-specific diet quality index (DQI) does not exist. This review aimed to identify current DQIs and assess their suitability for an IBD population. Methods: MEDLINE and EmCare databases were systematically searched for a-priori, food-based DQI reflecting current dietary guidelines and/or nutrition science. Data extracted were adapted from optimal DQI criteria, including quality measures of adequacy, moderation, variety and balance and DQI evaluation. Results: Twenty-four DQI were identified. No DQI included all optimal DQI criteria. The Dietary Guideline Index 2013 (DGI-2013) most closely met the criteria, followed by the Dutch Healthy Diet Index-2015 (DHD-Index 2015), Planetary Health Diet Index (PHDI) and Healthy Eating Index for Australian Adults-2013 (HEIFA-2013). Most DQI assessed adequacy (22/24, 92%) and moderation (21/24, 88%), half assessed balance (12/24) while few assessed variety (8/24, 33%). Application of other optimal DQI criteria varied. Food frequency questionnaire (13/24) and 24 h diet recall (12/24) were the most common dietary assessment methods used. Most DQI (17/24, 71%) were validated; however, not for an IBD population. Few were evaluated for reliability (6/24) or reproducibility (1/24). Conclusions: No DQI meets all optimal criteria for an IBD-specific DQI. The DGI-2013 met the most criteria, followed by the DHD Index-2015, PHDI and HEIFA-2013 and may be most appropriate for an IBD population. An IBD-specific DQI is lacking and needed.