High prevalence of food intolerances among US internet users

Abstract

Objective: Food intolerances are commonly reported and are predicted to have gastrointestinal health implications. We aimed to quantify the prevalence of food intolerances among US adults and identify culprit foods through a brief web-based survey. Design: We invited participation in an online cross-sectional survey involving a single questionnaire. Data were summarised using percentages or medians and interquartile range. Participant characteristics by self-reported food intolerance were compared using the Wilcoxon rank sum test and Pearson’s χ 2 test. Adjusted analyses were performed using multivariable logistic regression. Setting: The survey was internet-based via Amazon’s mechanical Turk, a crowdsourcing website for the completion of requester directed tasks. Participants: Adults who were US-based internet users were invited at ages 18–80. Results: We collected 2133 survey responses (ages 18–79 years). The rate of food intolerance was 24·8 % (95 % CI 23·0, 26·6) in US adults. Younger (P < 0·01), female (P = 0·05) and Asian, African American or multiple race individuals (P < 0·01) predominated. Lactose intolerance was most common. Frequency of a non-lactose food intolerance was 18·1 % (95 % CI 16·5, 19·8). When categorised broadly, grains, fruit, lactose, fish, vegetables, alcohol and nuts were most troublesome for individuals in that order. Conclusions: Self-reported food intolerance is common in US internet users. The effect of food on gastrointestinal symptoms and avoidant behaviours deserves further attention.