Listeria monocytogenes and diet during pregnancy; balancing nutrient intake adequacy v. adverse pregnancy outcomes

Objective: To evaluate the impact of adherence to public health recommendations on Listeria monocytogenes food safety to limit exposure to potential food sources on micronutrient intakes of pregnant women and whether more frequent consumption of ‘high-risk’ foods increases risk for adverse pregnancy outcomes. Design: A cohort study in women assessing Listeria exposure from an FFQ based on consumption of potential Listeria-containing food sources, the Listeria Food Exposure Score (LFES). Pregnancy status was defined as pregnant, trying to conceive, had a baby within the previous 12 months, or other. Nutrient intakes were compared with Nutrient Reference Values and self-reported pregnancy outcome history three years later. Setting: Australia. Subjects: Women aged 25–30 years (n 7486) participating in the Australian Longitudinal Study on Women’s Health. Results: There were weak positive correlations (r=0.13–0.37, P<0.001) between LFES and all nutrients, with fibre, folate, Fe and vitamin E intakes consistently below the Nutrient Reference Values in every quintile of LFES. Women in the highest quintile of LFES reported 19% more miscarriages (rate ratio =1.19; 95% CI 1.02, 1.38) than those in the lowest quintile, after adjusting for important confounding factors. Conclusions: More frequent consumption of foods potentially containing L. monocytogenes is associated with higher nutrient intakes, but an increased risk of miscarriage. L. monocytogenes pregnancy recommendations require review and should include the list of ‘risky’ food items in addition to low-risk alternatives that would adequately replace nutrient intakes which may be reduced through avoidance strategies.