Dietary inadequacy, inflammation, and micronutrient status in pregnant women in South Africa: evidence of a triple burden

Abstract

BACKGROUND: Maternal malnutrition remains a major contributor to adverse pregnancy outcomes in low- and middle-income countries, yet limited data exist on how dietary inadequacy, food insecurity, and inflammation co-occur to influence micronutrient status in semiurban South African settings. OBJECTIVE: We characterized the co-occurrence of dietary inadequacy, food insecurity, gestational body mass index (GBMI), and inflammation-adjusted micronutrient biomarkers among pregnant women in Kroonstad and quantified the overlap between these nutritional vulnerabilities. METHODS: In this baseline cross-sectional analysis of 205 pregnant women (≤21 wk' gestation, median age 26 y, interquartile ranges: 22.2-30.5), we assessed socio-demographic characteristics, food security (Household Food Insecurity Access Scale), dietary intake (quantified food frequency questionnaire and 24-h recall), GBMI, and haematological biomarkers. Biomarkers (n = 142) included hemoglobin, ferritin, soluble transferrin receptor (sTfR), retinol-binding protein, C-reactive protein, α1-acid glycoprotein, and thyroglobulin (Tg), adjusted for inflammation using established correction factors. A triple burden of malnutrition was evident, with 25.4% underweight (GBMI <19.8 kg/m²) and 25.8% overweight/obese (GBMI ≥26.1 kg/m²). RESULTS: Severe food insecurity affected 10.2% of households, and 40% consumed insufficient energy. More than 95% of participants had inadequate dietary iron and calcium intake, while vitamin C, E, and folate intakes were also frequently insufficient. Inflammation was highly prevalent (C-reactive protein elevated in 71.8%; α1-acid glycoprotein in 61.3%). Iron-deficient erythropoiesis (sTfR >8.3 mg/L) was more prevalent (52.1%) than iron deficiency (adjusted ferritin <15 µg/L) (23.2%), despite routine iron supplementation, consistent with impaired iron utilization in the presence of inflammation. Elevated Tg (≥13 µg/L), suggestive of possible iodine insufficiency, was observed in 49% of participants, although this finding should be interpreted with caution given the limitations of Tg as a standalone biomarker during pregnancy. An exploratory association was observed between high fat intake (>35% TE) and elevated sTfR and Tg concentrations. CONCLUSIONS: This study demonstrates substantial clustering of dietary inadequacy, food insecurity, inflammation, and micronutrient deficiencies in pregnant women in a semiurban South African community. These findings highlight the need for integrated antenatal strategies addressing dietary quality, inflammation, and socio-economic constraints, while recognizing that observed associations require confirmation in longitudinal follow-up analyses.