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Research Project: The Effect of Pregnancy and Lactation on Carotenoid Status and Bioactivity

Location: Children's Nutrition Research Center

2021 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.

Progress Report
Carotenoids are a class of red, orange, and yellow pigments in fruits and vegetables that contribute to meeting our vitamin A requirements. Research has shown that consuming carotenoids are associated with reduced risks of chronic diseases like cancer and cardiovascular disease, improved vision and thinking ability, and reduced inflammation and oxidative stress. Despite being an impactful class of dietary compounds, we know very little about the nutritional role of carotenoids in pregnancy and early life. The goal of this project is to learn how pregnancy and lactation affect carotenoid status in mothers and infants and if carotenoid status in mothers and infants is associated with reduced inflammation and improved thinking ability. Objective 1 of the study was to determine how mothers' carotenoid status changes across the course of pregnancy, if their changes in carotenoid status are associated with their thinking ability and markers of inflammation during pregnancy, and how a mothers' carotenoid status in pregnancy correlates with her infant's carotenoid status after birth. Objective 2 was to determine if a mother's body composition affects her and her infant's carotenoid status during breast feeding. This year our team continued to make progress on both objectives of the project. While the COVID-19 pandemic prevented us from recruiting and enrolling participants into the studies, we were able to redirect our efforts to a number of synergistic activities that ultimately supported the completion of the objectives. For both Objectives 1 and 2, we completed the preparation of the standard operating procedures needed to support both research studies. For Objectives 1, we worked with the Children's Nutrition Research Center Stable Isotope Mass Spectrometry Lab to test the conditions for carotenoid analysis from volumes of blood. This will permit researchers to detect carotenoids from very small blood samples collected by heel pricks from infants, as well as stable isotope abundance in mothers' blood samples for Objective 2. Similarly, we used infant plasma and maternal breast milk samples collected from a pilot study to establish our laboratory methods for carotenoid concentrations in these specimens necessary for Objective 1 and 2. Furthermore, in a pilot study in infants, we analyzed data on the use of a specialized tool called the Veggie Meter for optical measurement of skin carotenoids and found the measurement to be feasible and valid on the basis that infant skin carotenoids are correlated with plasma carotenoid concentrations during exclusive milk-feeding, supporting the methods needed for Objectives 1 and 2. In preparation for participant recruitment and retention efforts for Objectives 1 and 2, we developed social media advertising and "news" content to improve the visibility of the study to potential participants. In support of Objective 2, we conducted a meta-analysis of human milk carotenoid concentrations across lactation stages and of infant blood carotenoid concentrations. While there have been numerous reports from around the world on human milk and infant blood carotenoid concentrations, there are no summaries of these reports to give an overall description of a typical infant blood carotenoid concentration and mother's milk carotenoid concentration. This information is needed to establish a basis for interpreting the infant population's dietary exposures to carotenoids, designing experiments of human-relevant carotenoid exposures in model systems, and designing experiments in human mothers and infants to test the effect of changing carotenoid exposures on health outcomes.

1. Non-invasive measurement of infant carotenoid intake offers new tool for studying early life nutrition. Early life nutrition may be important to an infant's short- and long-term health, however determining what infants consume is challenging since they cannot report on their diet and they often have many caregivers involved in their daily feeding. Carotenoids are an antioxidant and pro-vitamin A, seen in the orange, red, and yellow pigments in some fruits and vegetables. Blood and skin levels of carotenoids can be used as a way to estimate a person's intake of fruits and vegetables. Researchers in Houston, Texas, determined that optical measurement of the skin, called reflection spectroscopy, could be used to measure skin carotenoids in infants. They found that the skin measurements agreed with both blood carotenoid measurements and diet reports of carotenoid intake for the infants, indicating that this measurement could be a useful tool to monitor infant carotenoid and fruit and vegetable intake. Development of precise and accurate non-invasive tools to measure infants' diet will make it easier to study infant nutrition and health and aid in developing evidence-based guidance for infant nutrition.