Nutrition and pregnancy: evaluation of correlation between Mediterranean diet and iron status in pregnant women at first trimester

BACKGROUND Pregnancy is associated with maternal physiological changes in metabolism. The evaluation of dietary patterns in pregnant women and their correlation with maternal nutritional status and obstetric outcomes has scientific and clinical relevance. Mediterranean diet (MD) is a dietary pattern well studied in general population. Regarding pregnancy, epidemiological studies have reported positive outcomes associated with MD, such as prevention of gestational diabetes and premature delivery. There are no studies in Italy that investigate the adherence to MD during pregnancy, whereas only few studies investigate the correlation between adherence to MD and maternal nutritional biomarker status. On the other hand, iron requirements are greater in pregnancy and iron deficiency anemia (IDA) is still prevalent among pregnant women throughout the world. IDA occurring early in pregnancy is associated with low birth weight, prematurity and increased risk for maternal and fetal perinatal mortality. Serum ferritin is considered the best measure of total body iron, with low levels diagnostic of iron deficiency. AIM The aim of the present study was to evaluate the impact of MD adherence during first trimester on iron status, since there are no data in scientific literature, up to the present. METHODS Fifty pregnant women were enlisted at gestational age of 12 weeks at Sacco Hospital, based in Milan. At the enrollment, personal and anamnestic data were registered, anthropometric measures were assessed, the adherence to MD (score ≥8) was evaluated through a validated 14-item Food Frequency Questionnaire (FFQ), blood samples were collected for the assessment of iron status. RESULTS Among the sample, score ≥8 in MD results in 16%; 26% of women have ferritin deficiency (<30 µg/L) and 32% have hemoglobin levels <12,5 mg/dl (no cases of hemoglobin <10,5 mg/dl). A direct correlation was found between MD score and serum ferritin levels (β=0.35, p=0.026), adjusted for supplements intake. Among the 14 items investigated, fish and legumes consumption (according to the frequency criteria for 1-point assessment in FFQ) were found to be directly correlated with serum ferritin levels (β =0.41, p= 0.005 and β =0.33, p= 0.02), but the contribution of the single item was lost when analysed in a multivariate model, confirming the effect of Mediterranean pattern rather than single foods. CONCLUSIONS The present pilot study showed a direct correlation between MD score and serum ferritin levels. If confirmed in a larger sample size, these results could suggest the promotion of MD also to control iron status during pregnancy.