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Development and validation of a food frequency questionnaire to assess fermented food consumption in adults
This research article discusses the health benefits of fermented foods and their role in modulating the microbiota–gut–brain axis. The growing popularity of these foods in Western cultures has led to calls for their inclusion in dietary guidelines. The primary objective of this study was to create and validate a Fermented Food Intake Questionnaire (FFIQ) for assessing habitual intake among adults aged 18–60 in the United States, Canada, the United Kingdom, Ireland, Australia, and New Zealand.
A 32-item self-administered FFIQ was developed based on existing international food consumption data. The validation involved an online sample of 167 adults, using six online 24-hour automated dietary recalls (intake24.com) as a reference. Correlation and Bland–Altman analyses were employed to evaluate the agreement and bias between the FFIQ and the dietary recalls.
The findings revealed that the most commonly consumed fermented foods included cheeses, yoghurt, kefir, and kombucha. The median intake of total fermented foods was 85.4 g/day (IQR: 42.3, 143.0) for the FFIQ and 54.9 g/day (IQR: 20.8, 112.1) for the 24-hour dietary recalls, demonstrating a significant correlation (r = 0.56, p < 0.001). Furthermore, the FFIQ accurately classified 93.4% of participants in the same or adjacent tertile of total fermented food intake. Bland–Altman plots indicated good concordance between the FFIQ and the dietary recalls, while the FFIQ exhibited good to excellent reliability upon re-administration, as indicated by intraclass correlation coefficients.
In conclusion, the FFIQ is a reliable tool for estimating fermented food consumption among adults in English-speaking countries, with implications for clinical and epidemiological research investigating the relationship between fermented foods and health outcomes. [NPID: Fermented foods, microbiota-gut-brain axis, kefir, kombucha, food frequency questionnaire]
Year: 2026
