Objectives Functional foods have demonstrated potential in preventing gastrointestinal and musculoskeletal (osteo-related) disorders; however, evidence from cross-sectional studies in adults remains limited. This study aimed to examine the relationship between the frequency of functional food consumption and the prevalence of gastrointestinal and osteo-related conditions among adults in Bangladesh.

Design Cross-sectional study.

Setting A face-to-face interview was conducted in Southern Bangladesh.

Participants A total of 959 adults participated. Socio-demographic characteristics, lifestyle factors, health status and patterns of functional food consumption were collected using a structured questionnaire.

Main outcome measures The prevalence of gastrointestinal and musculoskeletal (osteo-related) diseases, as well as their associations with the frequency of functional food consumption, were assessed using binary logistic regression.

Results Gastrointestinal and musculoskeletal (osteo-related) diseases were reported by 55.4% and 44.1% of participants, respectively. Multivariate logistic regression showed that several functional foods were associated with lower odds of gastrointestinal conditions, including regular seed intake (OR=0.35, p=0.034), weekly fibre-rich foods (OR=0.48, p=0.021), weekly probiotics (OR=0.26, p=0.012), monthly probiotics (OR=0.33, p<0.001), monthly nuts (OR=0.58, p=0.031), daily tea/coffee (OR=0.58, p=0.008), weekly tea/coffee (OR=0.54, p=0.008) and occasional tea/coffee intake (OR=0.51, p=0.006), as well as monthly (OR=0.34, p=0.003) and occasional natural products (OR=0.54, p=0.030). For osteo-related diseases, lower odds were associated with daily seed intake (OR=0.29, p=0.028), weekly probiotics (OR=0.28, p=0.025), monthly probiotics (OR=0.56, p=0.024), weekly nuts (OR=0.59, p=0.037), weekly fortified foods (OR=0.39, p<0.001), weekly tea/coffee intake (OR=0.64, p=0.046), occasional tea/coffee intake (OR=0.60, p=0.038), and monthly natural products (OR=0.48, p=0.041).

Conclusions The consumption of functional foods, particularly seeds, probiotics, fibre-rich foods, nuts, tea/coffee and natural products were associated with a lower risk of gastrointestinal and musculoskeletal diseases in adults. These findings provide robust evidence to inform future prospective studies and support public health strategies in Bangladesh aimed at promoting the consumption of functional foods to prevent diet-related health conditions.