Location: Children's Nutrition Research Center2022 Annual Report
Objective 1: To define the effect of pregnancy and lactation on carotenoid and vitamin A status and markers of bioactivity in diverse healthy weight and obese women. Subobjective 1A: We will define the changes in plasma, skin, and macular (a marker of brain lutein and zeaxanthin) carotenoid status changes over the course of pregnancy and lactation in healthy and obese women. This will allow us to define the dietary, anthropometric, and genetic determinants of carotenoid status. Subobjective 1B: We will determine if carotenoid status is associated with markers of inflammation and cognitive function in pregnant and lactating women. Subobjective 1C: We will define the relationship between maternal and infant carotenoid status at birth and 8 wk in lean and obese mothers. Objective 2: To determine the pharmacokinetic basis for why adiposity affects breast milk carotenoid composition. Subobjective 2A: We will define the plasma and breast milk pharmacokinetics of 2H-labeled lutein and beta-carotene in normal and obese lactating mothers. Subobjective 2B: We will determine the bioavailability of 2H-labeled lutein and beta-carotene from intrinsically-labeled spinach in lactating mothers.
Women with either a pre-pregnancy normal or obese BMI will be recruited in the first trimester of pregnancy. Subjects will undergo a dietary, carotenoid status, body mass and composition, physical activity and sleep, and cognitive function assessments at 24 and 34 weeks of gestation and at 8 weeks post-partum. At the post-natal visit, mothers will participate in the same tests, will be asked to provide a breast milk sample and infant anthropometrics and carotenoid status will be assessed by blood sampling and dermal carotenoid intensity measures. Maternal and cord blood will be collected upon delivery for carotenoid analysis. Through these studies we will determine if maternal carotenoid status changes over the course of pregnancy and if that change can be explained by changes in maternal carotenoid intake and body composition.
While the COVID-19 pandemic and critical staff shortages precluded our ability to recruit and meet with pregnant women, new mothers, and their infants for the proposed studies, we pursued and completed the following supportive research efforts by analyzing data from the literature or previously collected data and samples from our lab. First, related to Objectives 1 and 2, which focuses on the study of carotenoids and lactation, we conducted a systematic review and analysis to describe the average concentrations of carotenoids found in human milk, both worldwide and in the United States, by lactation stage (colostrum, transitional, and mature milk). We found that all major dietary carotenoids are present in human milk with the greatest overall concentrations being found in colostrum (early milk), followed by transitional, then mature milk. We found that the relative abundance of particular carotenoids differs by lactation stage. This is the first systematic review of human milk carotenoid concentrations and provides a foundation of information to inform future studies of human milk carotenoids and infant formula carotenoid supplementation. Second, related to Objectives 1 and 2, we conducted a systematic review and analysis of infant blood carotenoid concentrations at birth, 0-6 months of age, and 6-12 months of age. We found that infants have all the major dietary carotenoids in their blood from birth onward, and that these concentrations are lower than those found in older children and adults, and that the abundance of specific carotenoids varies by age or feeding stage (newborn, exclusive milk feeding, solids and milk feeding). This review provides the first systematic analysis of infant blood carotenoid concentrations, creating a set of reference data by which to evaluate the blood carotenoid concentrations of infants. In addition, we have worked to implement and test sensitive laboratory methods developed by the USDA, ARS Grand Forks Human Nutrition Center to measure carotenoid concentrations in very small volumes of blood using mass spectrometry technology. This analytical approach will allow us to minimize the amount of blood needed from infant research participants for measuring blood carotenoid concentrations. Next, we collaborated to test methods for measuring inflammatory biomarkers in human milk and infant blood samples and conducted a pilot test to determine whether markers of inflammation are associated with blood carotenoid concentrations in infants and in human milk. This testing helped us prepare for the proposed study of carotenoid intake and markers of inflammation. Using previously collected data, we analyzed the feasibility and reliability of non-invasive skin carotenoid measurement as a biomarker of infant carotenoid intake and blood carotenoid concentrations. We found that skin carotenoids can be feasibly and reliably measured in 4, 6, and 8 month old infants, and may provide a long-term biomarker of infant carotenoid intake. Finally, we used previously collected data to evaluate the accuracy of different types of dietary assessment methods (surveys, food diaries), and nutrient analysis approaches for estimating infant intakes of carotenoids, calories, and fruits and vegetables. We found that for exclusively milk-fed infants, different assessment methods tend to perform well, when compared to a 7-day food diary analyzed by a comprehensive nutrient analysis method, and that assessment methods vary in their accuracy as infants' diets become more complex. These findings will help researchers define the most efficient and accurate methods to define infant carotenoid, energy, and fruit and vegetable intakes at different ages/feeding stages. In short, while we were not able to recruit participants for the proposed studies, we worked to expand knowledge on the maternal and infant carotenoid status, biological activities, and intake assessment methods.