A ferritin-related dietary pattern is positively associated with iron status but negatively associated with vitamin D status in pregnant women: a cross-sectional study

Purpose: Vitamin D supplementation positively impacts anemia, but the relationship between a ferritin-related dietary pattern, iron parameters, and vitamin D in anemia is unclear. Methods: This cross-sectional study analyzed data from the 2017–2019 National Nutrition and Health Survey, including 1423 pregnant women over 15 years old. Dietary intake was assessed using a semi-quantitative food frequency questionnaire and a 24-hour dietary recall. The FrDP was identified using reduced rank regression with blood parameters as response variables and 32 food groups as predictors. Linear and binomial logistic regression analyses evaluated the associations between the FrDP and serum biomarkers, adjusting for demographic and dietary variables. Risk associations between the FrDP and vitamin D concentrations were also assessed. Results: The FrDP explained 18.5% of the variation in 6 response variables and was characterized by high consumption of fish, soy, gluten pasta, nuts, organ meat, pickled vegetables, and marine plants. The FrDP correlated positively with serum hemoglobin (r = 0.76), iron (r = 0.52), ferritin (r = 0.79), folate (r = 0.86), and vitamin B₁₂ (r = 0.86). Linear regression revealed a positive association between the FrDP and serum iron. Women in the highest FrDP tertile were less likely to have low serum iron (OR = 0.65, 95% CI 0.50–0.85) but more likely to have low 25(OH) vitamin D concentrations (OR = 1.79, 95% CI 1.32–2.43). Conclusions: The FrDP was positively associated with serum iron but negatively associated with serum 25(OH) vitamin D in pregnant women. Graphical Abstract: (Figure presented.)