Vitamin C status of pregnant and lactating women: Negative associations with body weight and current smoking

Pregnancy and lactation are believed to elevate requirements for vitamin C. Body weight and smoking status are also known significantly impact vitamin C status. The hypothesis of the current study premised that pregnant and lactating women would have lower vitamin C status than nonpregnant/nonlactating women and higher body weight and current smoking would further impact this. Relevant data was extracted from NHANES 2017-18 and NHANES 2003-6 datasets; this included demographic, reproductive and anthropometric variables, vitamin C intake (dietary and supplemental) and serum vitamin C concentrations. The final combined dataset comprised 3730 women aged 18-44 years; 601 (16%) were confirmed pregnant and 476 (13%) had infants, of whom 129 (27%) were breastfeeding. The vitamin C intake and serum status of the pregnant group was higher than the nonpregnant group (P < .001). Despite this, approximately 40% were not consuming the recommended vitamin C intake of 85 mg/d and 27% did not achieve adequate vitamin C status of 50 µmol/L. Vitamin C status was 9 µmol/L lower at nine months relative to two months of pregnancy (P < .001), despite a 56 mg/d higher vitamin C intake (P = .007). Vitamin C status was negatively associated with body weight and smoking status (P < .001). Breastfeeding woman had comparable vitamin C status to nonbreastfeeding women with infants (P = .3), despite a 36 mg/d higher vitamin C intake (P < .001). The results indicate that pregnant and lactating women, particularly smokers, have higher requirements for vitamin C and are recommended to increase their vitamin C intakes to meet current dietary intake guidelines.