Kimberly O'Brien
Kimberly O'Brien
Division of Nutritional Sciences

230 Savage Hall


Kimberly O’Brien is a Professor of Human Nutrition in the Division of Nutritional Sciences at Cornell University. She received her B.S. in Biology from the University of New Hampshire and her PhD in Nutrition from the University of Connecticut, Storrs. Her professional training included fellowships with the National Institute of Child Health and Human Development, Laboratory of Theoretical and Physical Biology/Section for Metabolic Analysis and Mass Spectrometry and the Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine. Professor O'Brien joined the faculty in the Division of Nutritional Sciences after working for 10 years as a faculty member in the Center of Human Nutrition at Johns Hopkins Bloomberg School of Public Health.

Professor O’Brien’s research has centered on studies designed to better understand mineral metabolism and bone health in infants, children, and pregnant and lactating women in both developed and developing countries. To address issues of calcium metabolism, she has undertaken metabolic studies in groups including children from osteoporotic families, pregnant and lactating adolescents, and children with chronic diseases such as cystic fibrosis and HIV infection. Her current research focuses on the impact of adolescent pregnancy, particularly among minority populations, on maternal and fetal bone health, risk of anemia, and maternal and neonatal vitamin D and iron physiology.  Partitioning of nutrients between the mother and fetus is addressed at the cellular level by assessing placental mineral transporters in relation to maternal and neonatal status.

To allow for kinetic studies of human mineral metabolism, a mass spectrometry laboratory has been added to the existing resources in the Human Metabolic Research Unit. This laboratory includes instrumentation for high-sensitivity mineral stable isotope analysis using a  Triton TI magnetic sector thermal ionization mass spectrometer. This laboratory also provides analytical services through collaboration with other academic institutions in the country.

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Graduate students

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2024 - 2025 Available

Calcium Metabolism and Bone Health; Maternal and Neonatal Anemia, Control of Maternal/Fetal Nutrient; Partitioning and Placental Mineral Transport;  Vitamin D Kinetics during Pregnancy, Erythroferrone concentrations in maternal-neonatal dyads, Genetic control of iron absorption

I teach a one-semester undergraduate Human Anatomy and Physiology course and co-teach a graduate course on micronutrient metabolism. I am committed to promoting hands-on, investigative, opportunities for undergraduate and graduate students interested in clinical research. Our laboratory group actively involves undergraduates; many of whom are authors on the research generated. Scientific writing is emphasized and facilitated with weekly undergraduate and graduate writing groups and with weekly meetings for all on-site and off-site study personnel.  Graduate and post-doctoral students gain mentoring experience by providing guidance in methods development and data analysis to undergraduate laboratory students.

NS3410: Human Anatomy and Physiology

NS6310: Micronutrients

NS6190: Field of Nutrition Seminar

NS4010: Independent Study BIOG

BIOG 4990: Independent Study

NS7940: Presidential Life Scholars Fellowship Seminar

Delaney KM, Cao Chang, Guillet R, Pressman EK, O’Brien KO. Fetal Iron Uptake from Recent Maternal Diet and Red Blood Cell Catabolism. Am J Clin Nutr 2022; 1;115(4):1069-79. Published along with an accompanying editorial; Fairweather-Tait. How much iron does a healthy pregnant woman require? AJCN 2022; 00:1-2.

O’Brien KO. Maternal, Fetal and Placental Regulation of Placental Iron Trafficking. Placenta 2022; 125:47-53.

Best CM, Sherwood R, Novotny JA, Zhang S, Pressman EK, O’Brien KO. Vitamin D3 kinetics in nonpregnant and pregnant women after a single oral dose of trideuterated vitamin D3. J Steroid Biochemistry and Molecular Biology, 2022; Feb 216:106034.  

Barad A, Guillet R, Pressman EK, Katzman PJ, Miller RK, Darrah TH. Placental Iron Content is Lower than Previously Estimated and is Associated with Maternal Iron Status in Women at Greater Risk for Gestational Iron Deficiency and Anemia. J Nutr 2022; Mar 3: 152(3):737-746.

Delaney KM, Guillet R, Pressman EK, Ganz T, Nemeth E, O’Brien KO. Umbilical cord erythroferrone is inversely associated with hepcidin but does not capture the most variability in iron status of neonates born to teens carrying singletons and women carrying multiples. J Nutr 2021; 4:151(9):2590-2600.  Published along with an editorial: Kling PJ. Ironing out the details of maternal-fetal iron trafficking: New Tools in the Toolbox. J Nutr 2021; 151(9):2509-2510.

Kang W, Barad, A, Clark AG, Wang Y, Gu Z, O’Brien KO. Ethnic differences in iron status: A systematic review and meta-analysis. Adv Nutr Res 2021; Oct 1:12(5):1838-53.

Delaney KM, Guillet R, Pressman EK, Ganz T, Nemeth E, O’Brien KO. Serum erythroferrone during pregnancy is related to erythropoietin but does not predict the risk of anemia. J Nutr 2021; Jul 1; 151(7):1824-33.

Kang W, Baer N, Ramsan M, Vermeylen, F, Stoltzfus RJ, O’Brien, KO. Iron Supplementation in anemic Zanzibari toddlers is associated with greater loss in erythrocyte iron isotope enrichment. Am J Clin Nutr 2021; Jul 1;114(1):330-7.

Delaney KM, Guillet R, Pressman EK, Caulfield LE, Zavaleta N, O’Brien KO. Iron absorption during pregnancy is underestimated when iron utilization by the placenta and fetus are ignored. Am J Clin Nutr 2020; 112:576-585.

Complete List of Published Work in MyBibliography:'brien.1/bibliography/47582544/public/?sort=date&direction=ascending


Adjunct Professor, University of Rochester School of Medicine and Dentistry, Department of Obstetrics and Gynecology, Rochester, NY

1995, NRSA Fellowship, Baylor College of Medicine, Children's Nutrition Research Center

1993, IRTA Fellowship , Section on Metabolic Analysis and Mass Spectrometry, National Institutes of Health

1991, PhD, Nutrition, University of Connecticut

1985, BS, Biology, University of New Hampshire

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