Associations of functional foods consumption with gastrointestinal and musculoskeletal conditions: a cross-sectional study among Bangladeshi adults

Abstract

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.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• The large sample size increased statistical power and enhanced external validity.

• Comprehensive data collection enabled detailed analysis of dietary patterns and health outcomes.

• The use of robust statistical methods (eg, logistic regression) minimised bias and improved reliability.

• The duration of disease was not considered in the current study survey.

• Specific amounts of functional food intake were not measured in this study.

Introduction

Diet plays a fundamental role in human health, influencing both the prevention and management of disease.¹ Beyond providing essential nutrients, food is increasingly recognised as a determinant of well-being and longevity.² Rising life expectancy, the pursuit of better quality of life and escalating healthcare costs have heightened consumer awareness of dietary choices.² Within this context, functional foods (FFs) have emerged as a major focus of research and industry, with the global market projected to exceed US$500 billion by 2028.³ Functional foods are defined as those containing bioactive components that provide health benefits beyond basic nutrition.² These include vitamins, minerals, probiotics and other bioactive compounds that enhance physiological functions and reduce the risk of chronic diseases.^{4 5} For example, probiotics in fermented foods support gastrointestinal health, omega-3 fatty acids in nuts and seeds promote cardiovascular protection and calcium with vitamin D fortification contributes to bone health while reducing the incidence of osteoporosis and osteoarthritis.15,7 Despite the therapeutic potential of functional foods in mitigating gastrointestinal disorders, millions of people worldwide, including those in Bangladesh, continue to be affected by these conditions, leading to reduced quality of life and increased healthcare expenditures.6,9 The prevalence and incidence of gastrointestinal (GI) illnesses in Bangladesh highlight significant public health challenges. Multiple studies have reported a high burden of disorders such as gastro-oesophageal reflux disease (GERD), irritable bowel syndrome (IBS) and functional dyspepsia.^{9 10} For instance, one study reported a prevalence of 55.7% for GERD and 24.4% for IBS among Bangladeshi adults.^{9 10} In addition to GI disorders, musculoskeletal (osteo-related) diseases represent another major health concern in Bangladesh. Approximately 37.3% of the population is at risk of osteoporosis,¹¹ while musculoskeletal conditions such as osteoarthritis and low back pain affect nearly one-quarter of adults.¹² These findings underscore the urgent need for dietary strategies, including functional foods that can address both gastrointestinal and musculoskeletal health challenges. Given the high morbidity and mortality associated with gastrointestinal and musculoskeletal diseases, numerous clinical trials have explored the health-promoting effects of functional foods and their underlying cellular mechanisms.13,16 However, evidence from population-based studies examining the association between functional food consumption and these diseases in adults remains limited. While some research has demonstrated links between dietary patterns—such as adherence to the Mediterranean diet—and gastrointestinal health,¹ there is still insufficient evidence regarding the role of specific functional foods in the prevention and management of osteo-related diseases, both globally and in Bangladesh.

Therefore, the present study aimed to investigate the relationship between functional food consumption and the prevalence of gastrointestinal and musculoskeletal diseases. By addressing this gap, the study seeks to advance understanding of the role of diet in disease prevention and management among populations at risk. The findings are expected to provide a foundation for future prospective studies and inform evidence-based dietary strategies.

Methods

Study setting and design

This cross-sectional study was conducted among adults in the southern districts of Bangladesh, which together have a population of 5.46 million (2022 census).¹⁷ These districts were selected due to their heightened vulnerability to chronic health conditions, providing valuable insights into local health and lifestyle patterns. Data collection was conducted from May to June 2024, using a multistage sampling strategy. One upazila (a subdistrict administrative division in Bangladesh) per district was selected, comprising one urban and two rural areas, to ensure a diverse and representative study population. This design captured variations in socioeconomic status and lifestyle factors relevant to dietary habits and health outcomes. The overall methodological framework of the study is illustrated in figure 1.

Figure 1. Flow chart of methodological framework.

Study participants and sampling

The inclusion criteria for the study were Bangladeshi adults aged 18–40 years who were physically fit and able to participate in the survey. The exclusion criteria for the study included individuals maintaining special diets for the management or recovery from long-term chronic diseases (such as diabetes) or conditions (stroke, organ transplantation, etc), as well as those undergoing lactation or pregnancy, and bodybuilders who generally maintain a special diet with functional or nutritious foods. The sample size for this cross-sectional study was determined using a standard formula for large populations. Initially, a minimum of 384 participants was estimated through an online calculator,¹⁷ assuming a 95% confidence level and a 5% margin of error. The application of finite population correction (FPC) had minimal effect due to the large population size. To enhance data reliability and account for potential non-responses or incomplete questionnaires, the study aimed to exceed this minimum. Consequently, 1010 respondents were surveyed through face-to-face interviews. After excluding incomplete or invalid responses, the final sample comprised 959 participants. This rigorous sampling approach ensured high-quality and representative data for subsequent analyses.

Survey questionnaire

The survey questionnaire was developed based on previous studies and adapted to the Bangladeshi context, with a focus on food consumption and its association with gastrointestinal and osteo-related health outcomes. The questionnaire comprised two sections: (1) socio-demographic information, lifestyle factors and health status, capturing the general characteristics of participants and (2) functional food consumption patterns, including knowledge of functional foods, sources of information, monthly expenditure and frequency of intake over the past year (online supplemental file 2). The questionnaire design was informed by a thorough literature review,12 5 18,22 and functional foods were tailored to locally available items throughout the year. Foods that are traditionally or habitually consumed were excluded.

The reliability and content validity of the questionnaire were assessed using the content validity ratio (CVR) and Cronbach’s alpha. For content validation, 12 experts evaluated the essentiality of items related to functional food consumption using a 3-point Likert-type scale (‘not essential’, ‘useful but not essential’ and ‘essential’). The CVR was calculated using the formula:

$${\displaystyle {\displaystyle CVR=\frac{N_e­N/2}{N/2}}}$$

where Ne is the number of experts rating an item as ‘essential’ and N is the total number of experts.²³ According to Lawshe, the minimum acceptable CVR for a panel of 12 experts is 0.56.²⁴ In this study, all items exceeded this threshold, with CVR values ranging from 0.67 to 1, and an overall CVR of 0.71, indicating strong content validity.

Reliability analysis using Cronbach’s alpha showed values between 0.64 and 0.69 for individual items related to functional food consumption patterns, with an overall alpha of 0.68, demonstrating acceptable internal consistency. The questionnaire, including the functional food items, was reviewed by a public health nutrition expert and a clinical nutritionist. Modifications were made based on their feedback to ensure content accuracy and relevance. The questionnaire was initially drafted in English, translated into Bengali, and then back-translated into English to verify linguistic and contextual consistency. To further ensure clarity and applicability, the final version was piloted and pretested on 50 individuals. This process confirmed the questionnaire’s relevance, comprehensibility and accuracy for the target population.

Data collection procedure

Prior to data collection, participants were fully briefed on the study objectives, ensuring transparency and emphasising the anonymity of their responses. Trained enumerators conducted face-to-face household interviews, and each participant provided written informed consent after being informed about the study’s purpose, confidentiality measures and their right to withdraw at any time. Functional food consumption over the past year was assessed by asking participants whether they consumed specific foods daily, weekly, monthly, occasionally or never. Participants were also asked about the presence of gastrointestinal or osteoarticular diseases. Self-reported disease status was verified through participants’ medical diagnosis reports, which were reviewed by qualified health professionals to ensure accuracy. Body mass index (BMI) was calculated using data on weight and height, which were obtained either through self-report or direct measurement. Participants who were unable to self-report their weight and/or height were measured by trained staff using a calibrated stadiometer for height and a digital weighing scale for weight. Among the total 959 participants, 42.33% (n=406) provided self-reported measurements, whereas 57.66% (n=553) had their anthropometric data collected directly by trained personnel. To protect privacy, no personally identifiable information, such as phone numbers or identification numbers, was collected. The average time to complete the questionnaire was approximately 20 min.

Independent variables

The explanatory variables in this study included socio-demographic characteristics: sex, education, family size, profession, residence, monthly household income, monthly cost for functional food consumption, lifestyle factors, BMI categories, self-reported health status, regular exercise, duration of exercise, smoking status, sleeping late at night, consuming fried foods regularly and consuming sugary foods regularly; functional food consumption frequency in the last 1 year: never, daily (5/6 days weekly), weekly (3/4 days weekly), monthly (1/2 days weekly) and occasionally (3/4 times monthly)¹; most available functional foods throughout the year in Bangladesh (probiotics, prebiotics, nuts, seed, fibre-rich foods, tea and coffee, natural products (natural products from plants, animals and microbes are increasingly valued for preventing diseases by offering antioxidant, anti-inflammatory and anticancer effects through specific biological mechanisms; for instance—mushrooms, spirulina, fenugreek, etc),²⁵ honey, black cumin, spices, citrus fruit, dry fruits, eggs, fortified foods)^{1 5 20 22}; knowledge of functional foods and their sources.¹⁸

Outcome variables

The outcome variables in this study were the participants’ disease status, specifically focusing on gastrointestinal and musculoskeletal conditions. Gastrointestinal diseases included ulcerative colitis, irritable bowel syndrome and GERD, while musculoskeletal (osteo-related) encompassed osteoporosis and osteoarthritis. These outcomes were used to assess potential associations between functional food consumption and these health conditions.

Statistical analysis

Data analysis was conducted using SPSS (V.26.0) and R (V.4.3.0). Descriptive statistics were used to summarise the data distribution with the R package gt-summary, while multicollinearity was assessed using model fit tests in SPSS. Visualisations for functional food consumption frequency, knowledge sources of functional foods and multivariate binary logistic regression results were prepared using GraphPad Prism and Excel 365. BMI was calculated in kg/m² and categorised based on Asian standards: underweight (<18.5), normal (18.5–22.9), overweight (23–24.9) and obese (25–29.9).²⁶ Associations between the frequency of functional food consumption and the prevalence of gastrointestinal and osteo-related diseases were initially assessed using χ² tests. Binary logistic regression analyses, implemented with the gtsummary R package, were then performed to examine the associations between functional food consumption and disease prevalence. Two adjusted models were constructed to explore the associations between 14 functional food consumption variables and the prevalence of gastrointestinal and osteo-related diseases, with statistical significance defined as p<0.05 and 95% CIs.

Results

The socio-demographic, lifestyle and health characteristics of the participants are summarised in table 1. A total of 959 adults were surveyed, and several notable findings emerged. More than half of the participants (54.6%) were female, 19.1% had no formal education and 20.3% were unemployed. Over one-third (35.6%) of respondents reported a monthly family income exceeding US$164.81, while nearly two-thirds (63.4%) resided in rural areas. In terms of health and lifestyle factors, 41.3% of participants had a normal weight and approximately 61% engaged in moderate physical activity; however, only 26.4% reported exercising regularly. Among those who exercised, 66.4% spent 30 min or more per session. With respect to health conditions, 55.4% reported gastrointestinal problems and 44.1% reported osteo-related conditions. Online supplemental table S1 presents the distribution of gastrointestinal and osteo-related diseases according to functional food consumption patterns. The prevalence of gastrointestinal disease was significantly associated with the consumption of probiotics (p<0.001), tea and coffee (p=0.001), natural products (p<0.001) and honey (p=0.028). Consumption of probiotics (64.1%) and tea and coffee (67.0%) was more common among participants with gastrointestinal disease. Similarly, osteo-related diseases were significantly associated with the consumption of probiotics (p=0.009), tea and coffee (p=0.005), natural products (p=0.023) and fortified foods (p<0.001). Notably, the weekly consumption of fortified foods was lower among participants with osteo-related disease (25.3%).

Table 1. Socio-demographic, life-style and health status characteristics of the participants (n=959).

Variables	Characteristic	n (%)
Gender	Male	435 (45.4)
	Female	524 (54.6)
Age	18–29 years	541 (56.4)
	30–40 years	418 (43.6)
Religious	Muslim	906 (94.5)
	Hindu	49 (5.1)
	Others	4 (0.4)
Education	Primary level	210 (21.9)
	No formal education	183 (19.1)
	Secondary level	249 (26.0)
	Higher secondary level and above	317 (33.1)
Family Size	Nuclear family (<4)	434 (45.3)
	Extended family (≥4)	525 (54.7)
Profession	Business holder	76 (7.9)
	Housewife	398 (41.5)
	Informal worker	167 (17.4)
	Formal worker	123 (12.8)
	Unemployment	195 (20.3)
Monthly household income	<US$164.81	618 (64.4)
	≥US$164.81	341 (35.6)
Residence	Rural	608 (63.4)
	Urban	351 (36.6)
BMI categories	Normal	396 (41.3)
	Underweight	70 (7.3)
	Overweight	212 (22.1)
	Obese	280 (29.3)
Self-reported physical activity	Moderate	585 (61.0)
	Poor	166 (17.3)
	Good	208 (21.7)
Exercise	No	706 (73.6)
	Yes	253 (26.4)
If Yes, duration exercise	<30 min	85 (33.64)
	≥30 min	168 (66.4)
Smoking status	No	784 (81.8)
	Yes	132 (13.8)
	People who have quit smoking	43 (4.5)
Consuming fried foods regularly	No	489 (51.0)
	Yes	470 (49.0)
Consuming sugary foods regularly	No	456 (47.5)
	Yes	503 (52.5)
Sleeping late at night	No	543 (56.6)
	Yes	416 (43.4)
Gastrointestinal disease	No	428 (44.6)
	Yes	531 (55.4)
Osteo disease	No	536 (55.9)
	Yes	423 (44.1)
Knowledge of health benefits of functional foods	No	475 (49.5)
	Yes	484 (50.5)
The monthly cost of functional foods consumption	<US$4.12	331 (34.5)
	US$4.12–8.23	401 (41.8)
	>US$8.23	227 (23.7)

US$1=121.37 BDT (Bangadeshi Taka).

As shown in figure 2, friends and relatives (40.08%) were the primary source of knowledge regarding functional foods, followed by books/newspapers/magazines (35.33%), online media (27.47%), healthcare professionals (25.41%) and traditionally known sources (13.63%).

Figure 2. Sources of knowledge of functional foods among those who know about functional foods (N=484).

Figure 3 illustrates the frequency of consumption of selected functional foods. Tea and coffee were the most frequently consumed items, reported by 35.2% of participants. Eggs (43.2%) and prebiotics (41.6%) were consumed weekly by the majority of respondents. Only a small proportion reported never consuming eggs (3.2%) or prebiotics (4.1%), while 6.7% and 13.2% consumed eggs and prebiotics occasionally, respectively.

Figure 3. Consumption frequency of functional foods among the participants (N=959). Note: probiotics: sour yoghurt/cheese/apple cider vinegar; prebiotics: banana/apple/garlic/onion; nuts: peanuts/walnuts/almonds; seeds: pumpkin/sesame/flaxseed; fibre-rich foods: psyllium herbs/oat bran/chia seed; whole grain: rice/flour; tea and coffee: green or black tea/black coffee; natural products: fenugreek/mushroom/spirulina; honey, black cumin; spices: garlic/ ginger/ turmeric/ clove; citrus fruit: lemon/orange/grapefruit; dry fruits: dates/raisins; egg; fortified foods: noodles/cake/biscuits.

The multivariate logistic regression analysis (figure 4) was conducted to explore the association between functional food consumption and gastrointestinal-related and osteo-related diseases. Regular consumption of seeds (OR=0.35, 95% 0.13 to 0.92, p=0.034) and weekly consumption of dietary fibre-rich foods, including psyllium herbs, oat bran and chia seeds (OR=0.48, 95% CI 0.26 to 0.90, p=0.021) were associated with lower likelihood of having gastrointestinal diseases. Moreover, consumption of probiotics such as sour yoghurt, cheese and apple cider vinegar on a weekly (OR=0.26, 95% CI 0.09 to 0.72, p=0.012) and monthly basis (OR=0.33, 95% CI 0.20 to 0.54, p<0.001) was associated with lower odds of gastrointestinal diseases. Monthly nuts consumption was associated with lower odds of gastrointestinal diseases (OR=0.58, 95% CI 0.35 to 0.95, p=0.031) as compared with non-consumers. Additionally, daily (OR=0.58, 95% CI 0.39 to 0.87, p=0.008), weekly (OR=0.54, 95% CI 0.34 to 0.85, p=0.008) and occasional (OR=0.51, 95% CI 0.31 to 0.82, p=0.006) intake of tea and coffee, including green tea, black tea and black coffee, was associated with a lower odd of gastrointestinal disease. Monthly (OR=0.34, 95% CI 0.16 to 0.68, p=0.003) and occasional (OR=0.54, 95% CI 0.34 to 0.85, p=0.030) intake of natural products, such as fenugreek, mushrooms and spirulina, were associated with less likelihood of having gastrointestinal diseases.

Figure 4. Multivariate binary logistic regression analysis of functional food consumption associated with gastrointestinal and musculoskeletal (osteo-related) diseases among participants (N=959). *p<0.05; **p<0.01; ***p<0.001.

For osteo-related diseases, including osteoarthritis, significant associations were found between functional food intake and lower odds of these conditions. Consumption of seeds daily (OR=0.29, 95% CI 0.09 to 0.82, p=0.028) was associated with lower odds of having osteo-related diseases, including osteoarthritis and osteoporosis. Weekly (OR=0.28, 95% CI 0.08 to 0.81, p=0.025) and monthly (OR=0.56, 95% CI 0.34 to 0.92, p=0.024) consumption of probiotic foods was associated with lower odds of having osteo diseases, compared with non-consumers. Furthermore, weekly (OR=0.59, 95% CI 0.36 to 0.97, p=0.037) consumption of nuts and fortified foods (OR=0.39, 95% CI 0.23 to 0.66, p<0.001) was associated with lower odds of osteo diseases. Individuals who consume tea on a weekly (OR=0.64, 95% CI 0.41 to 0.99, p=0.046) and occasional (OR=0.60, 95% CI 0.37 to 0.97, p=0.038) basis have lower odds of having osteo diseases than those who never consume tea. Finally, monthly consumption of natural products, including fenugreek, mushrooms and spirulina, was associated with lower odds of osteo-related diseases (OR=0.48, 95% CI 0.23 to 0.96, p=0.041).

Discussion

This study examined the relationship between functional food consumption and the prevalence of gastrointestinal and musculoskeletal (osteo-related) diseases among Bangladeshi adults. The findings indicated that participants who consumed probiotics, including sour yoghurt, cheese and apple cider vinegar, on a weekly, monthly or occasional basis had lower odds of developing gastrointestinal diseases compared with those who never consumed these foods. This aligns with evidence that probiotic metabolites can modulate gut function, including motility and sensation. Certain probiotics enhance the production of short-chain fatty acids and lactates, which lower gut pH, improve colonic peristalsis, reduce overall gut transit time and help prevent gastrointestinal disorders.^{1 7} Consistent with these mechanisms, an Indian survey involving over 10 000 participants reported that regular consumption of homemade sour yoghurt led to 91% of participants experiencing IBS remission within 180 days and 96.4% achieving full recovery by 300 days.⁶ Similarly, a 60-day randomised controlled trial in India with 77 participants found that apple cider vinegar effervescent tablets improved appetite, alleviated constipation and reduced gas-related symptoms.¹⁶ Additionally, the present study found that participants who consumed nuts monthly had lower odds of gastrointestinal disease than those who never consumed them. This observation is consistent with previous research indicating that consuming nuts at least two times per week is associated with reduced risk of gastrointestinal disorders, particularly Crohn’s disease.²⁷ In the present study, participants who regularly consumed green tea, black tea or black coffee exhibited a lower likelihood of gastrointestinal diseases compared with those who consumed these beverages less frequently or not at all. Previous research has linked regular tea consumption, rich in polyphenols such as flavanols and catechins, with reduced odds of irritable bowel disease, potentially through protection of the intestinal barrier, modulation of gut microbiota and enhanced short-chain fatty acid production.²⁸ A Mendelian randomisation study in China further corroborated these findings, demonstrating a significant association between increased green tea consumption and a reduced incidence of gastrointestinal disorders.²⁹ The study also found that regular consumption of pumpkin, sesame and flaxseed was associated with lower odds of gastrointestinal diseases, likely due to their bioactive compounds and nutritional profiles. Flaxseeds, in particular, are rich in lignans and omega-3 fatty acids, which can reduce inflammation, lower gastric acidity and promote a healthy gastrointestinal environment.³⁰ Similarly, the present study found that participants consuming a high-fibre diet, including foods such as oat bran, chia seeds and psyllium, exhibited lower odds of gastrointestinal disorders, particularly inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis. Consistent with prior studies, higher dietary fibre intake is associated with a 13% reduction in Crohn’s disease risk per 10 g/day increase in fibre consumption.^{31 32} Soluble and moderately fermentable fibres such as psyllium were also linked to a lower likelihood of irritable bowel syndrome, likely by alleviating symptoms without excessive gas production.³³ Furthermore, participants who consumed fenugreek, mushrooms or spirulina monthly had lower odds of gastrointestinal diseases compared with non-consumers. Spirulina extract has been shown to reduce oxidative stress and inflammation, protect colonic mucosa and modulate gut microbiota in ulcerative colitis, thereby alleviating gastrointestinal disorders.¹⁵ Fenugreek seeds, due to their gluten-free nature and high mucilaginous fibre content, have been used to support gastrointestinal health, including the management of coeliac disease.³⁴ This study found that participants who consumed probiotic foods, including sour yoghurt, cheese and apple cider vinegar, on a weekly or monthly basis had lower odds of osteo-related diseases compared with non-consumers. Probiotic foods such as cheese and sour yoghurt are rich in bioactive peptides, proteins and live cultures, which have been associated with improved bone health.⁸ These findings are consistent with previous research indicating that individuals consuming more than four servings of yoghurt per week had higher trochanteric bone mineral density than those who did not (p=0.03).³⁵ The current study also demonstrated that weekly consumption of nuts, including peanuts, walnuts and almonds, was associated with lower odds of osteo-related diseases compared with non-consumers. Nuts are rich in resveratrol and other bioactive compounds, which have been linked to higher bone mineral density and reduced risk of osteoporosis.³⁶ These findings are consistent with a previous study showing that individuals who consumed five or more servings of nuts per week had approximately a 20% lower risk of developing frailty compared with those who consumed fewer nuts.³⁷ This evidence suggests that habitual nut consumption may contribute to improved musculoskeletal health and reduced risk of osteo-related conditions. In terms of tea consumption, participants who consumed tea (black or green) weekly, monthly or occasionally exhibited lower odds of osteo-related diseases compared with non-consumers. Tea is rich in flavonoids, which possess osteoprotective properties.^{18 38} Supporting this, a meta-analysis of 40 studies reported that tea consumption was negatively associated with the incidence of osteoporosis and fractures, while positively correlated with bone mineral density.³⁸ The present study also found that participants who consumed fenugreek, mushrooms or spirulina monthly or occasionally had lower odds of osteo-related diseases compared with non-consumers. Mushrooms contain β-glucans, polysaccharides that promote bone development and mineralisation, providing potential protective effects against osteo-related conditions.³⁹ Similarly, trigonelline, a bioactive compound in fenugreek seeds, has been shown to prevent and improve osteoporosis.⁴⁰ The study further showed that regular consumption of pumpkin, sesame and flaxseeds was associated with lower odds of osteoarthritis and osteoporosis. Sesame seeds, which are rich in copper and other bioactive compounds, may help alleviate joint stiffness and soreness and potentially reduce cartilage deterioration associated with osteoarthritis.⁴¹ Additionally, weekly consumption of fortified foods was linked to lower odds of osteo-related diseases compared with non-consumers. This aligns with research from Japan indicating that vitamin K2, present in fermented soybean products such as natto, promotes bone development and may help prevent osteoporosis in older women.⁴²

Overall, these findings underscore the potential role of functional foods in supporting gastrointestinal and musculoskeletal health. Future studies employing longitudinal or interventional designs are warranted to establish causal relationships and strengthen the evidence base for dietary guidelines and disease-prevention strategies.

Limitations of the study

The study has certain limitations. The duration of disease was not accounted for, and specific quantities of functional food intake were not measured, which may limit the precision of dietary outcomes. Additionally, as the study was conducted within a specific population in Bangladesh, the findings may not be fully generalisable to populations with different cultural, dietary or lifestyle practices. At the same time, reliance on self-reported data may introduce bias, as participants may have inaccurately reported their dietary habits and health conditions. Despite these limitations, the study provides valuable insights into the potential role of functional foods in health outcomes and offers a strong foundation for future research in this area.

Future research

Further longitudinal studies are recommended to establish the causal relationships between functional food consumption, consideration of the exact amount of specific functional food intake and health outcomes, while also considering lifestyle factors. Therefore, exploring the mechanisms underlying the health benefits of functional foods is essential. Research focusing on specific demographic groups, such as older adults or those with specific chronic conditions, could offer more targeted insight. Additionally, investigating the barriers to functional food consumption in different socioeconomic groups may help to develop interventions that increase their uptake.

Conclusion

This study highlights the potential role of functional foods in the association with lower odds of gastrointestinal and osteo-related diseases among Bangladeshi adults. Regular consumption of probiotics, nuts, tea, seeds, mushrooms, fenugreek, spirulina and fortified foods was associated with lower odds of gastrointestinal disorders and improved musculoskeletal health. These findings underscore the importance of dietary patterns that include bioactive-rich foods in promoting overall health and preventing chronic diseases. The results provide evidence to inform dietary guidelines and public health strategies in Bangladesh, emphasising the integration of functional foods into daily diets. Future research should employ longitudinal or interventional designs to establish causal relationships, explore underlying biological mechanisms and consider lifestyle and demographic factors. Investigating barriers to functional food consumption across diverse socioeconomic groups could further support the development of targeted interventions to enhance their uptake and maximise health benefits.

Data availability statement

Data are available upon reasonable request.