Gastric cancer represents a public health challenge worldwide despite a decrease in its incidence over the last 50 years. According to GLOBOCAN 2023, nearly a million new cases of gastric cancer occur annually, with two-thirds resulting in death (1, 2).

Gastric cancer incidence rates were highest in Eastern Asia for both males and females; specifically, males in Japan (48.1%), Mongolia (47.2%), and Korea (39.7%) exhibited the highest rates globally. Furthermore, Eastern Asia had the highest mortality rates for both males (21.1%) and females (8.8%). Although the incidence of gastric cancer is decreasing in Korea, it remains among the most common malignant tumors worldwide (1, 2).

Previous epidemiological studies have suggested that Helicobacter pylori infection and family history play important roles in the etiology of gastric cancer (3–6). Additionally, smoking, occupational exposure, previous gastric surgery, and low socioeconomic status increase the risk of gastric cancer.

Dietary factors linked to a heightened risk of gastric cancer include obesity, alcohol consumption (7), and salt-preserved food consumption (8). In contrast, the consumption of fresh fruits, vegetables, and antioxidant vitamins may decrease the risk of gastric cancer.

Previous studies have shown an elevated risk of gastric cancer associated with high consumption of staple foods, noodles, dumplings, and bread (9, 10). Overeating can be harmful to the stomach and increases the risk of gastric cancer by causing physical damage to the gastric mucosa through repeated stretching of the stomach lining. Moreover, the traditional Korean diet has been linked to gastric cancer. This association could be attributed to the continuous irritation of the stomach wall from the consumption of salty and spicy foods, which potentially contribute to gastric cancer development. Although various other dietary factors have been associated with gastric cancer, the evidence varies and remains inconclusive.

This study aimed to investigate the association between gastric cancer and nutrient intake, socioeconomic factors, and eating habits using data from the Korea National Health and Nutritional Examination Survey (KNHANES).

This study was conducted in Korea and was based on the KNHANES dataset (2012–2016), aiming to explore the nutritional risk factors for gastric cancer.

KNHANES is a yearly cross-sectional health and nutritional survey conducted by the Division of Chronic Disease Surveillance of the Korea Centers for Disease Control and Prevention and the Korean Ministry of Health and Welfare. Utilizing a multistage, complex sampling methodology ensures that the survey is representative of the country’s non-institutionalized population. The KNHANES dataset is publicly available on the Korea Centers for Disease Control and Prevention website and is often used for research purposes.

The initial sample comprised 39,157 participants who completed health interviews, health behavior surveys, and health examination surveys. The exclusion criteria for the study included individuals aged under 19 years (N = 8,447), missing values for baseline characteristics and cancer history (N = 9,299), and missing nutritional survey data (N = 2,517). Ultimately, this study included 18,894 participants (Figure 1).

In this study, we identified the associations between gastric cancer and various nutritional and lifestyle factors in a nationally representative sample of Korean adults. Our findings underscore the role of factors such as advanced age, male sex, BMI, socioeconomic status, and eating outside fasting periods in the association with gastric cancer. Moreover, reduced protein and fat intake, thiamine deficiency, and increased consumption of rice cake and soju have been identified as factors associated with gastric cancer risk.

Previous studies have suggested that the incidence of gastric cancer is associated with environmental factors, including socioeconomic status, occupational exposure, alcohol consumption, smoking, dietary habits, and consumption of salt-preserved foods (12–15). Among these factors, dietary intake showed the strongest association with gastric cancer. In previous studies, a high-salt diet has been linked to the risk of gastric cancer (16), whereas a high consumption of fresh fruits and vegetables has shown protective effects (17), consistent with the findings of our study. However, we found no association between sodium or potassium intake and the risk of gastric cancer.

A previous meta-analysis reported a 17% increase in gastric cancer risk when salted fish were consumed and a 15% increased risk per 40 g of pickled vegetables consumed (18). Bouras et al. (19) suggested that a high intake of salted fish was associated with an increased risk of gastric cancer, whereas the consumption of salt itself and that of several other high-salt products showed nominal associations. This study revealed no effect of either sodium or potassium intake on gastric cancer risk; however, multivariate analysis results showed that soy and kimchi stew intake were associated with the disease. However, accurately measuring the total amount of salt consumed in an individual’s diet is difficult and frequently subject to error when conducted within a standard epidemiological study setting (20). The higher consumption of sodium by Koreans compared to other groups may be attributed to soup-based diets (21, 22). The mechanisms responsible for the observed associations are complex and involve more than just sodium chloride. High consumption of salt-preserved foods may be an indicator of poor diet quality and low socioeconomic status, which might increase susceptibility to H. pylori infection and hence increase the risk of gastric cancer (23).

Smoking and alcohol consumption are recognized as carcinogenic factors (24–26). Smokers or alcohol drinkers prefer salty food (22), whereas smokers have a low intake of fruit and dairy products and a high intake of fast food (27). Previous studies have shown a dose–response relationship between the number of cigarettes smoked and the risk of gastric cancer (28, 29). Moreover, former male (but not female) smokers tend to have an increased risk of gastric cancer. Furthermore, the shorter the interval since quitting smoking, the higher the risk of gastric cancer, even after accounting for cigarette smoking years. In our study, we observed an association between smoking and gastric cancer. The mechanisms underlying this relationship remain unclear, although several mechanisms have been proposed. Nitrosamines and other nitroso compounds found in cigarette smoke may play a role in the development of gastric cancer (30, 31). Cigarette smoking has also been associated with an increased risk of transitioning to dysplasia and intestinal metaplasia, which are key steps in gastric carcinogenesis (32). In addition, a randomized crossover study demonstrated that smoking could delay stomach emptying and gastroesophageal reflux disease, which are closely associated with the development of cardiac cancer (33, 34).

The impact of alcohol on gastric cancer involves the generation of inflammatory markers and oxidative stress compounds induced by inflammation, such as oxygen radical species (24). Alternatively, ethanol, being soluble in fat, could have potentially detrimental effects on the gastric mucosa (35). A previous study reported that the most popular type of alcoholic beverage in Korea is soju (58.2%), followed by beer (35.6%) (36). Kim et al. found that individuals who consumed soju exhibited a heightened risk of gastric cancer, although the association did not reach statistical significance (36). Contrary to previous findings, we have shown a statistically significant correlation between both beer and soju consumption and gastric cancer risk in Korean patients.

Our results also suggest an association between tteok (rice cake) consumption and gastric cancer. Traditional Korean rice cakes, known as “tteok,” are generally perceived as healthy foods because they are made from rice and often include various nutritious ingredients such as nuts, beans, and pumpkin. They are typically steamed until the texture becomes light and chewy. However, the health benefits of rice cakes remain controversial. While predominantly composed of carbohydrates and not previously reported to be directly associated with gastric cancer, rice cakes have been linked to gastrointestinal conditions such as peptic ulcer disease and intestinal obstruction, which may be attributed to their glutinous texture and tendency to delay gastric emptying (37, 38). Although rice cakes are widely regarded as a healthy food, their glutinous nature and potential to delay gastric emptying may contribute to mucosal irritation. This repeated irritation could promote gastric carcinogenesis, particularly in individuals with underlying risk factors. Given that rice is the primary ingredient, our findings align with previous reports that frequent meals or dietary patterns centered around rice may be associated with gastric cancer (39). Nevertheless, due to the cross-sectional design of this study, we cannot infer a causal relationship, and further longitudinal studies are warranted to clarify these associations and underlying mechanisms.

This is the first study to compare the consumption patterns of micronutrients and dietary components, including food types, between individuals with gastric cancer and healthy controls. Our results specifically emphasize that primary dish groups are potential contributors to gastric cancer in the Korean population, suggesting a previously unreported association between disease onset and the consumption of soju and tteok. Furthermore, we found that the risk of gastric cancer was correlated with factors such as older age, male sex, lower BMI, smoking, and frequent food consumption outside the home.

Our study had several limitations. First, we were unable to account for the H. pylori status of the study participants. Second, the study design was cross-sectional rather than longitudinal, limiting our ability to discuss the associations between risk factors and exposure over time. Third, the number of participants with gastric cancer included in the study was lower than expected based on the national prevalence estimates. This could be attributed to the characteristics of the KNHANES dataset, which primarily consists of individuals undergoing regular health screenings and may have a bias toward those with better health outcomes. Volunteers for research studies and individuals undergoing routine health checkups often have a higher socioeconomic status, potentially introducing selection bias and influencing the study findings.

In summary, we found an association between gastric cancer, various nutrients, and lifestyle parameters in a nationally representative sample of Korean adults. This study highlights the importance of considering individual factors, such as advanced age, male sex, low body mass index, and lower intake of protein and fat, alongside higher intake of niacin and increased consumption frequency of soju and tteok, in assessing the risk of gastric cancer. Nutrient intake and lifestyle-related factors play pivotal roles in the prevalence of gastric cancer, suggesting that tailored interventions could potentially mitigate gastric cancer risk in specific populations.