This study concluded that the principal dietary patterns of Koreans (Korean, Western, and New diets) substantially influenced HTN prevalence. Based on the moderation effect analysis, we highlighted that the Korean diet had no discernible impact on the HTN risk in the HTN high-risk population. In contrast, the Western diet significantly increased the likelihood of developing HTN in high-risk populations, whereas the New diet reduced the risk (p = 0.059, with the statistical significance borderline). It is crucial as the score determining the HTN risk group considered a variety of risk factors for high blood pressure, including heredity, obesity, alcohol consumption, and smoking status. If the results are supported through longitudinal research, they can be the foundation for establishing dietary guidelines tailored to Koreans to prevent and manage HTN.

The calculated HTN risk score, composed of almost all known risk factors (genetic predisposition, BMI, alcohol consumption, and smoking status), reliably reflects HTN risk. Mapped genes with significant SNPs in the current study (WNT2B, DNAJC5B, ATXN2, ALDH2, and OAS1) are previously reported regarding association with HTN risk. WNT2B is critical in cardiovascular development and homeostasis involving the Wnt signaling pathway. Variants in this gene may influence blood pressure regulation by affecting vascular remodeling and endothelial function [24,25,26]. DNAJC5B is responsible for cellular stress responses and may contribute to HTN by regulating the survival and function of cardiac myocytes [27, 28]. ATXN2 has also been suggested to modulate HTN through multifaceted ways, with its involvement in inflammation, stress responses, and neuronal blood pressure regulation potentially affecting how signals relate to blood pressure regulation [29, 30]. ALDH2 is essential for aldehyde metabolism, and its variants are associated with alcohol-related HTN; Individuals with deficient ALDH2 activity may experience elevated blood pressure due to the accumulation of toxic aldehydes [31,32,33]. OAS1 is part of the immune response system and has been shown to influence inflammation, a known risk factor for HTN [34, 35]. Also, polymorphism of OAS1 was reported as a predisposing risk factor for Korean type 2 diabetes patients [36].

In general, individuals who smoke, consume alcohol, or are obese become more susceptible to HTN [7]. However, the current study found that smokers had a decreased risk of HTN than non-smokers. The explanation might be that smoking status data was gathered from self-reported data. Respondents may not properly evaluate their health state or habits, and there is a possibility of social desirability bias, which occurs when people underreport or overreport their behaviors, such as smoking status or alcohol consumption [37]. Another thing to consider is that this study is a cross-sectional design. Given that the data were collected at the same time, the participants may quit smoking after becoming aware of the onset of the disease. Therefore, in this study, two HTN risk scores, including and without smoking status, were calculated and used for the analysis. Further, longitudinal research is needed to consider the association between smoking and HTN accurately.

Results related to the Korean diet are interesting, as they provide different insights from previously known facts. A positive association between the Korean diet and HTN in the age- and gender-adjusted logistic model means that higher Korean diet pattern adherence is associated with higher HTN risk. However, the significance disappeared when other risk factors were added as an adjustment. Besides, the Korean diet did not significantly influence the HTN risk in the high HTN risk score group in the moderation effect analysis; the nonsignificant increase in R² due to the interaction between the HTN risk score and the Korean diet score indicated that the interaction effect did not meaningfully improve the explanatory power of the model for HTN (R² increases due to interaction of p > 0.05).

As the Korean diet represented by soup, Kimchi, and fermented food (ex., Gochujang) contains higher salt levels, it is considered a risk factor for HTN; our logistic model adjusting for age and gender also consistently supports this. Meanwhile, a recent animal study revealed that fermented food exerts antihypertensive effects, regardless of its high salt content, by regulating the renin-angiotensin-aldosterone system [38]. Beyond that, the Korean diet allows for consuming diverse food categories. Indeed, the Korean diet was classified with grain, mixed protein sources, vegetables, and Kimchi in the factor analysis of the present study. Pigmented and multigrain rice are rich in dietary fiber, magnesium, and antioxidants, which help decrease blood pressure [39]. Furthermore, whole grains have a more substantial favorable effect on blood pressure than refined grains [40]. This evidence suggests that multigrain rice, with higher nutrient density, can contribute to healthier blood pressure management, especially when consumed as part of a balanced diet. Also, since Kimchi, frequently consumed by Koreans, contains not only salt but also various vegetables as its main ingredient, we cannot state for certain that it has an unconditionally detrimental influence on HTN. From this perspective, further studies are needed to clarify the association between the Korean diet and HTN risk. Besides, in the principal component analysis, the rotated factor for mixed protein sources was highest in the Korean diet; the rotated factor for the Korean diet in our study was 0.526, and the Western diet was 0.409. This could reflect increased protein consumption among Koreans compared to the past [41]. However, it could also be a limitation arising from merging different protein sources into a single question, as the Western diet generally has higher animal protein intake [42]. Therefore, further research on the relationship between HTN and dietary patterns, including protein intake, is needed through more detailed data collection that specifies protein sources.

Western diet, including oil, sugar, and egg, appeared to worsen HTN risk. Especially in moderation effects analysis, R² increases due to the interaction between the Western diet and HTN risk score (F = 24.741, p < 0.001) in total subjects was significant. Previously reported results regarding the components of the Western diet are diverse. First, dietary oils have a complex relationship with blood pressure, presenting both risks and benefits. It was found that the degradation of frying oils can lead to increased HTN, inducing the harmful effects of oxidized fats on cardiovascular health [43]. Similarly, He et al. [44] employed latent class analysis to categorize participants based on their dietary intake patterns; they found that excessive oil and salt intake significantly contribute to high blood pressure, highlighting the need for moderation. In contrast, Massaro et al. [45] demonstrated that olive oil, particularly extra virgin, can lower blood pressure due to its polyphenol content. Interestingly, several studies contend that sugar is a more critical dietary factor than salt in contributing to HTN, as it can lead to insulin resistance and obesity [46, 47]. A clear link between sugar intake and increased risk of HTN based on a systematic review and dose-response meta-analysis supported this view [47]. The last one is an egg. Vu et al. [48]. analyzed nutritional data obtained through 24-hour dietary recalls and food frequency questionnaires in the U.S. population aged 40 to 59 years, suggesting that individual nutritional patterns and lifestyle factors may influence the effects of eggs, and Mesas et al. [49] indicated that the association varies based on BMI. However, a meta-analysis using mixed populations across various randomized control trials concluded that egg intake does not significantly affect blood pressure [50]. In conclusion, the negative effect of the Western diet on the risk of HTN, considering genetic traits, BMI, alcohol consumption, and smoking status shown in this study, could be valuable evidence.

The adherence to a New diet consisting of fruit, vegetables, milk, and low sugar was inversely associated with HTN risk in our study (p of all logistic models < 0.001). However, there was no significance in the moderation effect analysis (p-value with a statistical significance borderline). Recent studies underscore the link between fruit and vegetable consumption and reduced HTN risk. Kong et al. [51] reported that higher intakes of fruits, vegetables, and legumes are associated with reduced HTN risk among middle-aged and older Koreans. In that study [51], most subgroups exhibited inverse relationships, particularly among males with higher BMI. Various studies have reported consistent results [52, 53]. Notably, the New diet of our research seems to be similar to the DASH diet. The DASH eating plan recommends the consumption of fruits, vegetables, nuts/legumes/vegan protein, whole grains, low-fat dairy, and limiting the intake of sodium, red or processed meats, and sugar-sweetened drinks [15]. However, as protein sources are mixed in our dietary survey, it is difficult to estimate legumes, vegan protein intake, and the restriction of red or processed meats suggested by the DASH diet. Indeed, a rotated factor of mixed protein sources was 0.526 for the Korean diet, 0.409 for the Western diet, and < 0.300 for the New diet in our research, making it challenging to comprehend clearly. Hence, more detailed data collection is needed to establish dietary guidelines for preventing and managing HTN tailored to Koreans.

There are some limitations to the dietary questionnaire when applying it to HTN research. One major limitation is that three protein sources—meat, fish, and beans—were grouped in a single question, making it difficult to distinguish their individual effects on HTN. Animal and plant proteins have different effects on blood pressure; a diet high in animal and low in plant protein may raise blood pressure through increased BMI, whereas a plant-based diet is associated with lower blood pressure [54, 55]. A longitudinal study in China found that consuming less of both animal and plant protein, as well as total protein, was associated with a reduced risk of HTN [56]. Another important limitation is the absence of sodium intake data, which directly affects HTN risk. The study questionnaire did not allow for an accurate calculation of sodium intake, making it difficult to assess its contribution to HTN. The last one is that our brief questionnaire consisted of only 17 items. It could have lower reliability or accuracy than a more comprehensive FFQ or dietary record. However, this brief questionnaire was validated against 3-day food records in a prior study [21]. Furthermore, in the present study population, significant positive correlations were observed between total energy intake and both BMI (r = 0.259, p < 0.001) and waist circumference (r = 0.329, p < 0.001), suggesting that the dietary data retains reasonable reliability despite its limitations. Established validity from previous research and significant correlation with anthropometric measures (BMI and waist circumference) support its reliability, even though evaluating total caloric intake based only on the frequency and portion size of 17 items may overlook a significant portion of the diet and potentially compromise the accuracy of the dietary data. Although simplified, this questionnaire could efficiently capture key dietary information in large-scale population studies. To mitigate potential inaccuracies and provide a broader understanding of dietary influences on HTN, we focused on major dietary patterns rather than individual food items. This approach captures the interactions between food groups, offering a more comprehensive view of dietary habits and their impact on health [57].

Despite several limitations, it is noteworthy that we made a high-risk group in which risk variables were weighed in a large Korean population and evaluated the moderation impact of diet patterns on high-risk groups. Consequently, the nutritional moderation effect was evident in the HTN high-risk group, where the Western diet increased risk, while the New diet showed a borderline protective effect. To our knowledge, there are no comparable research designs on HTN among the Korean population. Collectively, this study pointed out that diet has a considerable impact on HTN risk. However, uncovering evidence by collecting dietary data through more detailed nutritional questionnaires on longitudinal study designs is necessary to develop evidence-based dietary guidelines such as the DASH eating plan.