Type 2 diabetes is a serious global health concern. The global prevalence of type 2 diabetes is >400 million individuals (Braunwald, 2019). In 2019, the global prevalence of diabetes was estimated to be 9.3%, affecting approximately 463 million people. This projected prevalence is expected to increase to 10.2% (578 million people) by 2030 and to 10.9% (700 million people) by 2045 (Saeedi et al., 2019). Type 2 diabetes is the most common metabolic disorder related to aging, affecting approximately 25% of individuals aged ≥65 years worldwide (12. Older adults: standards of Medical care in diabetes-2019, 2019). Notably, individuals with type 2 diabetes typically present with other manifestations of metabolic syndrome. Metabolic abnormalities, including overweight, obesity, hypertension, and dyslipidemia in patients with type 2 diabetes, increase the risk of developing chronic kidney disease, cardiovascular disease, and heart failure. This leads to higher mortality rates and increased healthcare expenditure (Birkeland et al., 2020; Zerga and Bezabih, 2020). It is characterized by impaired insulin secretion from beta cells in pancreatic islets, resulting in persistent hyperglycemia. Type 2 diabetes typically manifests in older adults and is a progressive ailment that initiates with compromised glucose tolerance and progresses to diabetes mellitus as the beta cells progressively decline. Upon diagnosis, approximately 50% of beta cell functionality may already be depleted (Haythorne et al., 2022; “U.K. prospective diabetes study 16. Overview of 6 years' therapy of type II diabetes: a progressive disease. U.K. Prospective Diabetes Study Group,” U.K. Prospective Diabetes Study Group, 1995). Evidence suggests that the deterioration of beta cells is primarily caused by increasing hyperglycemia, leading to a significant reduction in insulin content and beta cell metabolism (Brereton et al., 2014; Haythorne et al., 2019). Certain dietary factors can influence the risk of type 2 diabetes both positively and negatively. For instance, certain compounds in specific foods can affect the risk of type 2 diabetes and alter the composition and distribution of the gut microbiota, thereby influencing type 2 diabetes outcomes (Chen et al., 2021).

The Areca nut, derived from the seed of the Areca catechu palm tree, is considered the fourth most commonly used psychoactive substance globally after caffeine, nicotine, and alcohol (Gupta and Ray, 2004; Tseng, 2010). Chewing of areca nut, often accompanied by Piper beetle leaves, is commonly referred to as “betel nut chewing” in the English literature (Gupta and Warnakulasuriya, 2002). Betel nut chewing is a prevalent habit and means of social interaction (Chu, 2001; Nelson and Heischober, 1999; Tseng, 2010). Globally, approximately 600 million people are estimated to engage in betel nut chewing (Nelson and Heischober, 1999). Betel nut chewing is associated with various health complications including proteinuria in individuals with diabetes (Tseng, 2006), onset of diabetes (Dowse, 1994; Tung et al., 2004a), and the occurrence of metabolic syndrome (Chen et al., 2006; Yen et al., 2006). Previous studies have demonstrated an increased risk of type 2 diabetes among betel nut chewers (Tung et al., 2004a).

Despite the initial refreshing effects, long-term betel nut chewing may contribute to the onset of various diseases. In addition to its transient effects, the sustained practice of betel nut chewing is believed to contribute significantly to the development of debilitating conditions. Further research is needed to thoroughly investigate the long-term and significant effects of betel nut chewing on type 2 diabetes given its addictive properties. In large-scale psychiatric studies, individuals with a chronic betel quid chewing habit displayed signs of dependence (Huang et al., 2020; Lee et al., 2014; Lee et al., 2018; Lee et al., 2012a). Epidemiological investigations have further revealed that betel quid users have a higher risk of developing systemic diseases that affect multiple organs, including the brain, heart, lungs, gastrointestinal tract, and reproductive organs (Garg et al., 2014; Tai et al., 2013; Yang et al., 1999). Moreover, chewing betel quid has been found to increase reactive oxygen species and arecoline N-oxide within the oral cavity, which may increase the risk of developing carcinomas in the upper aerodigestive tracts (Ko et al., 2020; Lee et al., 2005; Lee et al., 2012b). These effects can exert both direct and indirect influences on metabolic functioning, potentially contributing to the onset and progression of type 2 diabetes.

Therefore, given the increasing global prevalence of type 2 diabetes and broader systemic implications extending beyond oral health, a comprehensive exploration of the effects of betel nut chewing on type 2 diabetes is imperative.