Hypertension has been a significant global health challenge for human, affecting approximately 1.39 billion individuals worldwide, it is also the leading modifiable risk factor for cardiovascular disease and early mortality (1). Furthermore, hypertension is the primary factor of death among all cardiovascular disease risk factors. Meanwhile, it is a major contributor to the exacerbation of kidney failure (2, 3). Additionally, hypertension increases the risk of heart disease and stroke, which ranked as the first and fifth leading causes of death in the United States for 2017 (4). Therefore, the adverse consequences of hypertension are notably multifaceted.

Previous research provides substantial evidence on the serious impacts of hypertension. As shown in Table 1, the prevalence of hypertension in the United States varies by age group and gender, with elderly women (aged 65 and above) having a higher prevalence of hypertension, highlighting the importance of early prevention (5). Furthermore, a cohort study found that hypertension and changes in blood pressure during early adulthood were linked to differences in brain volume and white matter in later life, which are associated with neurodegeneration and dementia (6). These results highlight the importance of preventing and managing hypertension in early adulthood.

Beyond the significant health implications, hypertension also imposes substantial economic burdens. Compared to normotensive individuals, those with hypertension had approximately 2.5 times the inpatient cost, nearly twice the outpatient cost, and almost triple the prescription medication expenditure (7). Additionally, women may face mounting disease and economic burdens due to hypertension, emphasizing the significance of research in the prevention of this disease.

Studies have shown that certain nutrients can promote the management of hypertension. A re-analysis of National Health and Nutrition Examination Survey (NHANES) data revealed that higher Vitamin E intake was significantly associated with a lower prevalence of hypertension, and another systematic review found that Vitamin D concentration was inversely associated with systolic blood pressure (8, 9). Also, some studies emphasize the importance of Selenium and Vitamin C in preventing hypertension individually. Vitamin C, also known as L-ascorbic acid, is a water-soluble vitamin, which can be obtained either through diet or dietary supplements (10). A meta-analysis has shown that Vitamin C supplementation has significantly reduced blood pressure in subjects with essential hypertension (11). As for Selenium, it is a nutrient, which is essential for the normal functioning of the immune system (12). Furthermore, as a component of glutathione peroxidase, Selenium is a key enzyme in the body’s antioxidant defense system (13). For example, glutathione peroxidase helps maintain nitric oxide in its reduced form and protects against oxidative stress, which suggests that Selenium deficiency could increase the risk of cardiovascular disease (14). On the other hand, dietary Selenium intake has a linear negative correlation with hypertension prevalence in adults (15).

Despite studies exploring the individual effects of these micronutrients, there is a dearth of the interaction of diverse nutrients. This study aims to address the existing research gap by analyzing the interactive effects of Vitamin C and Selenium intake on hypertension and exploring the potential mechanisms among women aged 20 and above. The purpose of our study is twofold. We seek to validate the independent effects of these micronutrients and analyze their interactions, eventually providing new insights to guide nutritional strategies for hypertension prevention.

While previous studies have examined the independent effects of Vitamin C and Selenium on cardiovascular health, there has been limited research on investigating their combined interaction effect on hypertension. This study aims to bridge this research gap by analyzing how the interaction of Vitamin C and Selenium intake affects hypertension among women in the United States using NHANES data from 2011 to 2020.

This research demonstrates that women with Vitamin C and Selenium intake individually showed significantly lower risk of developing hypertension compared to those with deficient intake of the nutrients. The result notably supports previous studies on the correlation between the intake of Vitamin C and Selenium on hypertension separately. Furthermore, it articulates that the interaction of Vitamin C and Selenium is associated with lower blood pressure among women in the United States, although no synergistic effect was observed and its causation cannot be definitively established.

Our findings both support and extend previous research on the role of Selenium in human health, which received less attention compared to Vitamin C. In the early 1990s, research showed that there is an association between serum Selenium levels and cardiovascular disease in populations that exhibit low Selenium concentrations (17). A study in 2007 found that consuming more foods rich in Selenium could have positive effects on human health, especially cancer prevention (18). In 2012, a study on Selenium and human health found that when Selenium is integrated into selenoproteins, it exerts a variety of pleiotropic effects, including antioxidant and anti-inflammatory actions, as well as the production of active thyroid hormones (19).

Nevertheless, most of the studies reviewed the relationship between Selenium consumption and human health. The interaction of other nutrients and their mechanisms still needs to be further explored. For example, a previous study concluded that the elevated blood pressure and higher prevalence of hypertension at high Selenium levels observed in the NHANES 2003–2004 study align with earlier research (20). It is important to note that high Selenium levels can have toxic effects, potentially leading to adverse health outcomes including selenosis, gastrointestinal disorders, and neurological complications which highlights the complexity of its role in human health (21). The interaction between diverse nutrients and Selenium on specific diseases still lacks enough attention from scholars, which remains an area that requires further accelerated expedition in the future.

Several limitations should be considered when interpreting these results. From the perspective of data transparency, this study obtained data from NHANES between 2011 and 2020, which consists of unilateral state samples, with certain demographic groups or geographic regions are underrepresented or excluded from the survey, potentially causing a dearth of validation and pervasiveness worldwide. In addition, the accuracy and reliability of some self-reported data like health behaviors, dietary intake, and blood pressure in NHANES may be affected by recall bias or social desirability bias, which could lead to misclassification or underestimation of the true associations between nutrients and hypertension. Moreover, the use of cross-sectional data from NHANES restricts the ability to establish causal relationships between the intake of Vitamin C and Selenium and hypertension among the life course population in the United States, making infants, children, and adolescents neglected. Furthermore, while the large sample size provides statistical power, it may also detect very small effects that, although statistically significant, might not be clinically meaningful or could be due to chance rather than true associations.

In conclusion, our findings provide evidence that the combination of adequate Vitamin C and Selenium intake is associated with lower hypertension risk among U.S. women, suggesting that considering nutrient interactions, may be crucial for understanding and managing hypertension. This highlights the need for a more comprehensive approach to studying nutrient interactions in disease prevention, including their potential synergistic or antagonistic effects.

Future research should focus on longitudinal studies to validate these results and explore the underlying mechanisms of interacted effect between these nutrients and hypertension. Such studies would also benefit from including diverse populations to enhance the generalizability of the findings and provide clearer guidelines for hypertension prevention through nutrition.