School of Agriculture, Food and Rural Development

Staff Profile

Dr Georg Lietz

Senior Lecturer



My expertise lies in the area of human nutrition, with specific focus on fat soluble vitamins, fatty acids and related micronutrients. My group is known both nationally and internationally for our research on diet-gene interactions as an important factor in the determination of high inter-individual variations, as well as in determining total body stores of vitamin A by using the isotope dilution technique. Earlier on in my carreer, I was involved in the four centre FINGEN trial, the first UK based prospective genotyping study for the ApoE gene to investigate how n-3 fatty acids could influence cardiovascular disease risk depending on ApoE genotype.  Following on from this, I was leading a research project within the European Nutrigenomics Organisation NUGO involving seven different European laboratories, which revealed through the application of genome-wide expression analysis, that β-carotene supplementation down-regulated genes affecting lipid and glucose metabolism related pathways. A milestone discovery in my research group was the discovery of novel single nucleotide polymorphisms in the beta-carotene monoxygenase (BCO1) gene. Recently, I initiated collaborations with colleagues in international nutrition (i.e. Prof. Keith West from John Hopkins University, Baltimore (US) and Dr. Marjorie Haskell from UC Davis, California (US)) to determine if a range of single nucleotide polymorphisms can influence the effectiveness of plant-based provitamin A carotenoids to increase vitamin A status in at-risk population groups.  

My research group has established the most sensitive and cost-effective method to analyse vitamin A status in humans. In collaboration with Prof. Mike Green from PennState University,  we applied compartmental modelling to stable isotope derived data, which for the first time allowed to determine vitamin A status in individuals.  Through our efforts to define the best practise of vitamin A total body store (TBS) determination, we were invited to lead an international study group which is evaluating the potential risk of vitamin A toxicity, currently funded by both the IAEA and the Gates Foundation. Our drive to develop a simpler and accurate method to measure vitamin A status in humans has informed on-going research to define new and simple approaches to determine vitamin A status in communities that suffer from both vitamin A deficiency and inflammation.  We are in the process of developing new strategies for the assessment of vitamin A status in collaboration with the IAEA and the Gates Foundation. The overall outcome of this work will be the determination of safe upper levels of vitamin A intake to aid in the monitoring of vitamin A intervention regimens and thereby optimisation of the efficacy of vitamin A intervention programmes.  

Roles and Responsibilities

Teaching undergraduate Nutrition students
Supervision of PhD students
Project lead PI for the Gates Foundation funded GlovitAs project



Member of the American Nutrition Society
Member of the Deutsche Gesellschaft für Ernährung
Member of the International Carotenoid Society
Member of the European Nutrition Leadership Programme Alumni Association 



My group has gained an increasing international reputation with the development of collaborations with research partners in the US (John Hopkins University, UC Davis, PennState University, Case Western, Berkeley University), and Europe (INSERM; Wageningen University; University of the Balearic Islands; Kiel University; Freiburg University). We were the first to identify key genetic variants in the pro-vitamin A metabolism [Leung et al., 2009] in a BBSRC funded project. Securing funds to lead the European Carotenoid focus team within NUGO (The European Nutrigenomics Organisation), we were able to establish for the first time a link between beta-carotene and fat metabolism [Amengual et al., 2011]. We also developed the gold standard for the determination of vitamin A status in individuals in collaboration with Prof. Green [Green et al., 2016], resulting from a BBSRC project. More recently, I secured a $2M grant from the Bill and Melinda Gates Foundation, to lead a project involving international institutions from the Philippines, Bangladesh, Guatemala and the US. This project will enable our consortium to evaluate new strategies to detect novel biomarkers of vitamin A toxicity and to refine and verify the usefulness of the isotope dilution technique in children in community settings with high rates of inflammation. Thanks to the development of the isotope dilution technique, my research group is now working with the International Atomic Energy Agency (IAEA) in Vienna (Austria). We have also trained scientists from Wageningen University (The Netherlands) and the BATAN Institute in Jakarta (Indonesia) to use this technique.  



Our funding comes from a range of funding bodies, including the Bill and Melinda Gates Foundation, the International Atomic Energy Agency (IAEA), BBSRC,  and Industrial sponsorship from DSM.



Gene/nutrient interactions
Carotenoids/ Vitamin A

Stable isotopes

Tea polyphenols 


Undergraduate Teaching

I have published book chapters with relevance for undergraduate and postgraduate teaching and contributed to a range of nutrition relevant courses offered at Newcastle University.  I was the admissions tutor for the Food and Human Nutrition / Food Marketing and Nutrition Degree programme from 2013-15, during which time applications and registrations rose by 44% / 83% and 30% / 35%, respectively.