Association between dietary calcium and magnesium intake and Helicobacter pylori seropositivity: a cross-sectional study of US adults

Helicobacter pylori (H. pylori) infection stands as a notable contributor to gastroduodenal diseases. While crucial nutrients play a role in microbial pathogenesis and host immune responses, epidemiological evidence remains scarce on the association between specific nutrients, including calcium and magnesium, and H. pylori seropositivity. We conducted a cross-sectional analysis of data from 3670 adults enrolled in the National Health and Nutrition Examination Survey (NHANES). The determination of H. pylori infection status was based on serum H. pylori immunoglobulin G (IgG) levels, while dietary intake was evaluated through 24-h recalls. Associations were examined using multivariable logistic regression, adjusting for sociodemographic factors, comorbidities, lifestyle factors, and dietary covariates. We further employed restricted cubic splines to evaluate potential dose–response patterns. Of the 3670 participants (mean age: 51.1 years), 45.5% (n = 1669) tested positive for H. pylori. Compared to uninfected individuals, infected individuals had significantly lower intakes of calcium (565.1 vs. 708.6 mg/day, p < 0.001) and magnesium (257.3 vs. 291.5 mg/day, p < 0.001). After full adjustment (Model 3), each 100 mg increment in dietary calcium was associated with a 2% reduction in the odds of infection (odds ratio (OR): 0.98, 95% confidence intervals (CI) 0.96–1.00, p = 0.021), whereas each 100 mg increment in magnesium was associated with a 9% reduction in the odds of infection (OR 0.91, 95% CI 0.84–0.99, p = 0.029). Dose-dependent protective effects were observed, with the highest calcium quartile (≥ 1005 mg/day) showing the significant inverse association versus the lowest quartile (OR 0.75, 95% CI 0.58–0.99; p = 0.039). The highest magnesium quartile (≥ 344 mg/day) also showed a significant inverse association versus the lowest quartile (OR 0.72, 95% CI 0.53–0.98; p = 0.039). Spline analyses confirmed linear inverse relationships (P-nonlinear > 0.05). Subgroup analyses revealed significant magnesium-associated protection in individuals with a body mass index (BMI) below 25 kg/m2 (P-interaction = 0.022). This study suggests that a higher intake of dietary calcium and magnesium may be associated with a lower prevalence of H. pylori seropositivity. The findings highlight the potential impact of sufficient calcium and magnesium intake on susceptibility to H. pylori. Additional prospective investigations are warranted to validate this observed association.