Table 3. Intake of simple sugars of the total participants among PGCS population. |
|
Intake (g/day) |
Q1 |
Q2 |
Q3 |
Fructose |
16.31 |
22.92 |
31.62 |
Glucose |
13.08 |
17.96 |
24.46 |
Fructose + Glucose |
29.45 |
40.93 |
56.16 |
Sucrose |
17.59 |
28.68 |
46.02 |
Lactose |
0.94 |
1.88 |
3.94 |
Q1: First quartile; Q2: Second quartile; Q3: Third quartile. |
To better determine the impact of sugar intake on the incidence of diabetes, the risk of DM in the total population was assessed using PAR formula. In the study by Montonen et al., the relative risk of type 2 DM incidence for individuals with fructose and glucose intake exceeding 56.2 g/day was 1.87. According to Table 3, Q3 of fructose and glucose intake was 56.16 g/day, which is close to the cut-off point reported in Montonen et al.'s study. Therefore, the authors conducted two scenarios to calculate PART2DM in the population.
First scenario: The analysis revealed that 25% of the population had more than 56.16 g/day fructose and glucose intake. Accordingly, 17.86% of the total population is at risk of type 2 DM incidence.
Second scenario: Evaluation of the data revealed that 24.92% of the total population consumed more than 56.2 g/day of fructose and glucose (the cut-off point of Montonen et al. (Montonen et al., 2007). Therefore, 17.82% of the total population is at risk of type 2 DM incidence.
Discussion
Socio-demographic and food intake information of the diabetic patients showed a high correlation between food habits and the development of DM. Food intake evaluation revealed a relatively high intake of carbohydrates and a low intake of fiber in this study (Table 2). This is likely attributed to the low proportion of patients with high socio-economic status and the low number of academically educated patients, especially among women. Inadequate knowledge is a significant factor affecting body health. According to Table 1, most patients had no academic degree, and likely, were not educated enough to follow a balanced diet. The role of socio-economic status in dietary patterns was confirmed in a study by Casari et al., where the rural population of Burkina Faso with lower socio-economic status consumed more carbohydrates than urban inhabitants (Casari et al., 2022). Additionally, rural Polish adolescents with low socio-economic status followed a low-fiber diet in a study by Krusinska et al. (Krusinska et al., 2017). Similarly, Egyptian mothers with low socio-economic status believed that a healthy diet is expensive and preferred to spend less to simply keep their children full. In comparison, those with high socio-economic status spent more money on their food (Ismail et al., 2022). Therefore, it would be expected that people with low to moderate socio-economic status tend to choose low-cost foods, such as carbohydrate-based rather than protein-based meals.
Fruits and vegetables are the main sources of dietary fiber in daily diet. The World Health Organization recommends at least 400 g/day of fruits and vegetables combined to maintain health (World Health Organization, 2022) . Moreover, a consumption of 200 g/day of fruits is recommended to prevent type 2 DM (Park, 2021). However, fruit consumption is controversial, and its effect on diabetes prevention is dose-dependent. It is reported that fruit intake exceeding the recommendation does not show a positive effect and might lead to an increased prevalence of type 2 DM (Park, 2021). According to Table 2, the consumption of fruits by patients exceeded the recommended amount, supplying high levels of simple sugars to the body. It was reported that the type of fruit is a deterministic factor in the development of DM, with some fruits potentially increasing the risk of type 2 DM (e.g., cantaloupe), while others have a protective effect (e.g., pear and apple). The authors suggested that phytochemicals such as flavonoids and chlorogenic acid present in fruits play different roles concerning DM development (Park, 2021, Seino et al., 2021). Flavonoids are associated with β-cell proliferation and insulin secretion. Furthermore, the consumption of lower glycemic index fruits is of interest in the control of DM. Importantly, the concentration of fructose and fiber in fruits is a deterministic factor in this regard. After ingestion, fibers are consumed by the intestinal microflora, leading to the production of short-chain fatty acids and the satiety hormone GLP-1. Moreover, both fructose and sucrose stimulate the secretion of GLP-1 and FGF-21 satiety hormones (Seino et al., 2021). As mentioned above, the effect of fructose (the main sugar in fruits) is dose-dependent. Chronic high intake of fructose may lead to insulin resistance, hyperglycemia, and fatty liver by depleting ATP stores and causing uric acid accumulation in the body, which increases the risk of oxidative stress. However, moderate fruit intake results in lower food consumption and a low glycemic index, which supports diabetes prevention and control (Ang and Yu, 2018, Mai and Yan, 2019). In addition, the consumption of sweetened foods appears to be high among diabetic patients, with the intake of simple sugars (Table 3) exceeding the maximum recommended range by health agencies (Cozma and Sievenpiper, 2014).
The average of two PART2DM predictions based on the Q3 and the cut-off point reported by Montonen et al. was 17.84% (Montonen et al., 2007). This predicted average differed slightly from the proportion of diabetic patients in the total population (24.01%). However, 17.46% of the total population were prediabetic individuals (fasting blood sugar 100-125 mg/dl), who may develop DM if they do not modify their dietary patterns toward lower intake of simple sugars and carbohydrates and increase their intake of dietary fibers. Accordingly, Tabak et al. reported that up to 70% of prediabetic individuals might eventually develop DM (Tabák et al., 2012). Nonetheless, a comparison of predictive data and observed results confirmed the association of an imbalanced diet with the incidence of type 2 DM in the population. The findings of this study are a breakthrough for the development of educational programs for both virtual and in-person education.
This study benefits from its large, population-based design within the PGCS, which enhances generalizability and leverages standardized protocols to ensure methodological rigor. The use of a validated, culturally adapted FFQ and the exclusion of implausible energy intakes strengthened the reliability of dietary assessments, while the integration of USDA and Iranian food composition databases improved nutrient estimation accuracy. Furthermore, calculating population attributable risk provided actionable insights into the preventable diabetes burden linked to simple sugars. However, the cross-sectional design precludes causal inference, and reliance on self-reported dietary data introduces potential recall bias, particularly as processed/ready-to-eat food sugars were excluded, possibly underestimating total intake. The use of external relative risk values for PAR calculations, though methodologically sound, may not fully reflect regional biological or behavioral contexts. Future longitudinal studies with repeated dietary measures and biomarkers (e.g., HbA1c) are warranted to establish causality, and expanding the Iranian Food Composition Table could refine nutrient assessments. Replication in diverse geographic and ethnic populations would improve generalizability, and inclusion of processed food sugar data would provide a more comprehensive risk profile.
Conclusion
This study revealed that an imbalanced diet was significantly associated with the development of DM in individuals. The calculation of PART2DM, as a predictive tool, confirmed that a high intake of simple sugars (especially fructose and glucose) affected DM incidence. It is expected that fruits play a major role, as they are considered the main source of dietary fiber and fructose (one of the dominant simple sugars in the diet) simultaneously. Fruits have a preventive role in DM development up to the recommended level (200 g/day), while they could be deleterious if consumed at higher levels. The type of fruit, considering its glycemic index and inclusion of phytochemicals, is a determining factor. Moreover, it is established that dietary patterns are affected by socio-economic status. In this study, a high proportion of the patients were those with low to moderate socio-economic status, low daily fiber, and high carbohydrate intake. It is assumed that changing food intake habits is difficult for individuals with low socio-economic status because they have limited options in selecting food items for their food basket. However, promoting their knowledge about the outcomes of an imbalanced and unhealthy diet may help them follow a cost-effective healthy dietary pattern. For example, using inexpensive and valuable proteinaceous meals such as herbal proteins instead of high carbohydrate-based foods to overcome hunger would be greatly important. On the other hand, changing preferences towards low-sugar foods and/or using alternative sweeteners with a low glycemic index will significantly affect the control of diabetes in the general population and diabetic patients.
Acknowledgments
This article is derived from a research project approved at Guilan University of Medical Sciences, Rasht, Iran. We would like to thank the staff of Guilan University of Medical Sciences for their efforts in data collection.
Authors’ contributions
Mansour-Ghanaei F, Moslemi M, Joukar F, and Mahdavi-Roshan M participated in the research design. Moslemi M, Joukar F, and Mahdavi-Roshan participated in writing the first draft. Mansour-Ghanaei F, Moslem M, Joukar F, and Mahdavi-Roshan M participated in the performance of the research and analytic tools. Moslem M, and Joukar F participated in data analysis. All authors reviewed and confirmed the final manuscript.
Conflict of interest
The authors declared no conflict of interest.
Funding
No funding.
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