Anti-inflammatory diets reduce the risk of excessive gestational weight gain in urban South Africans from the Soweto First 1000-Day Study (S1000)

PURPOSE: To (i): examine whether maternal dietary inflammation assessed using the dietary inflammatory index (DII) is associated with gestational weight gain (GWG) and delivery outcomes in urban South African women from the Soweto First 1000-Day Study (S1000); and (ii): explore whether serum high-sensitivity c-reactive protein (hs-CRP) levels mediate these associations. METHODS: Energy-adjusted-DII (E-DII™) scores were calculated for 478 pregnant women using a quantitative food frequency questionnaire. GWG (kg/week) was assessed via anthropometry and hs-CRP concentrations were assessed in a sub-sample at < 14 (n = 263) and at 24–28 (n = 270) weeks gestational age. Multivariable linear and logistic regression models were used to examine associations between maternal E-DII scores, GWG, hs-CRP concentrations, and delivery outcomes. RESULTS: Positive vs. negative E-DII scores were associated with an increased odds of excessive weight gain (OR (95% CI): 2.23 (1.20; 4.14); P = 0.01) during pregnancy. Higher hs-CRP concentrations in the first trimester were associated with lower weight-for-length z-score (β (95% CI): −0.06 (−0.11; −0.01) per 1 mg/l hs-CRP; P = 0.02) and a reduction in odds of a large-for-gestational age delivery (OR (95% CI): 0.66 (0.47; 0.94); P = 0.02). Higher hs-CRP concentrations in the second trimester were associated with an increased odds of delivering preterm (OR (95% CI): 1.16 (1.01; 1.32); P = 0.03). CONCLUSIONS: Consumption of an anti-inflammatory diet during pregnancy reduced the risk of excessive GWG in a rapidly urbanising setting (Soweto, South Africa), where obesity prevalence rates are high. Further research is needed to better understand how maternal diet may ameliorate the effects of maternal adiposity on inflammatory milieu and fetal programming. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00394-022-02931-x.