Qualifications

• PhD Nutritional Lipid Biochemistry (University of Bergen, Norway).
• MRes (Dist) Applied Fish Biology (University of Plymouth, UK).
• BSc (Hons) Biology (University of Leeds, UK).

Roles and Responsibilities

• HTA Person Designate for the Human Nutrition Research Centre (HNRC).
• Health and Safety Committee member for the Population Health Sciences Institute.
• Supervision of MSc students.
  

Previous Positions

• Post-doctoral researcher in Aquaculture Nutrition at the Institute of Marine Research, Bergen, Norway (2006-2008).

Google Scholar Profile

ORCID ID

Research Interests

• Retinol isotope dilution.
  
• Carotenoid bioavailability.
  
• Retinoid-lipid interactions.
• Vitamin A toxicity.
  

Current Research Projects

• BIOCRYPT: Determination of relative bioavailability, bioconversion and bioefficacy of beta-cryptoxanthin in comparison to beta-carotene from biofortified maize and external stable isotopes using compartmental modelling (HarvestPlus).
• NISPA: Capacity building program for state of the art technologies of nutritional intake, status and physical activity assessment (BBSRC/UKRI).
  

Previous Research Projects

• Detection of total body stores of vitamin A from finger prick samples in low income country settings (MRC CIC).
• Optimising nuclear techniques to assess vitamin A status and the risk of excess vitamin A intakes due to multiple vitamin A programmes (IAEA).
  
• GloVitAS: Assessing the risk of vitamin A toxicity due to large scale food fortification and other interventions (Bill & Melinda Gates Foundation).
• BETASNP2: Effects of SNPs in the beta-carotene monooxygenase (BCMO1) enzyme on retinol formation and beta-carotene plasma responses (DSM Nutritional Products).
• BETASNP: Do genetic polymorphisms in a beta-carotene metabolising key enzyme influence dietary vitamin A requirements? (BBSRC).
  

• Lietz G, Oxley A, Engle-Stone R, Miller J, Reario D, Stormer A, Capanzana M, Cabanilla C, Haskell M. Assessment of Vitamin a (VA) Total Body Stores (TBS) Using Dried Serum Spots (DSS). Current Developments in Nutrition 2020, 4(Suppl. 2), 861.
• Ford JL, Green JB, Haskell MJ, Ahmad SM, Mazariegos Cordero DI, Oxley A, Engle-Stone R, Lietz G, Green MH. Use of Model-Based Compartmental Analysis and a Super-Child Design to Study Whole-Body Retinol Kinetics and Vitamin A Total Body Stores in Children from 3 Lower-Income Countries. The Journal of Nutrition 2020, 150(2), 411–418.
• Lietz G, Oxley A, Finney K, Clark A, Giles T, Foster N, Southam A, Jankevics A, Lloyd G, Winder C, Dunn W. Effects of Chronic Hypervitaminosis a on Global Plasma Metabolome Changes and Liver Gene Expression (OR05-06-19). Current Developments in Nutrition 2019, 3(Suppl. 1), OR05-06-19.
• Finney K, Oxley A, Winder C, Southam A, Jankevics A, Lloyd G, Giles T, Foster N, Dunn W, Lietz G. The Effect of Chronic High Dose Vitamin a Supplementation on Lipid Metabolism in Adipose Tissue (P02-013-19). Current Developments in Nutrition 2019, 3(Suppl. 1), P02-013-19.
• Ford J, Lietz G, Oxley A, Green J, Green M. Updated Estimates of Vitamin a Total Body Stores in Healthy Young Adults Determined by Compartmental Modeling with Vitamin a Intake Added as Data (FS06-07-19). Current Developments in Nutrition 2019, 3(Suppl. 1), FS06-07-19.
• Sakkas P, Oikeh I, Blake DP, Nolan MJ, Bailey RA, Oxley A, Rychlik I, Lietz G, Kyriazakis I. Does selection for growth rate in broilers affect their resistance and tolerance to Eimeria maxima?. Veterinary Parasitology 2018, 258, 88-98.
• Ford JL, Green MH, Green JB, Oxley A, Lietz G. Intestinal β-carotene bioconversion in humans is determined by a new single-sample, plasma isotope ratio method and compared with traditional and modified area-under-the-curve methods. Archives of Biochemistry and Biophysics 2018, 653, 121-126.
• Ford JL, Green JB, Lietz G, Oxley A, Green MH. A Simple Plasma Retinol Isotope Ratio Method for Estimating β-Carotene Relative Bioefficacy in Humans: Validation with the Use of Model-Based Compartmental Analysis. The Journal of Nutrition 2017, 147(9), 1806-1814.
• Green MH, Ford JL, Green JB, Berry P, Boddy AV, Oxley A, Lietz G. A Retinol Isotope Dilution Equation Predicts Both Group and Individual Total Body Vitamin A Stores in Adults Based on Data from an Early Postdosing Blood Sample. Journal of Nutrition 2016, 146(10), 2137-2142.
• Green MH, Ford JL, Oxley A, Green JB, Park H, Berry P, Boddy AV, Lietz G. Plasma Retinol Kinetics and β-Carotene Bioefficacy Are Quantified by Model-Based Compartmental Analysis in Healthy Young Adults with Low Vitamin A Stores. Journal of Nutrition 2016, 146(10), 2129-2136.
• Lietz G, Oxley A, Ford J, Green M. A modified isotope dilution equation predicts Vitamin a total body stores in individuals. The FASEB Journal 2015, 29(Suppl. 1), 604.5.
• Oxley A, Warnke I, Wyss A, Schalch W, Lietz G. The BETASNP2 study: Effect of β-carotene formulation and rs6564851 on β-carotene plasma responses. The FASEB Journal 2015, 29(Supp 1), 605.7.
• Lietz G, Oxley A, Berry P, Hesketh J, Tourniaire F, Park H, Green M, Boddy A. β-carotene (BC) bioconversion is similar in men and women. The FASEB Journal 2015, 29(Suppl. 1).
• Oxley A, Berry P, Taylor GA, Cowell J, Hall MJ, Hesketh J, Lietz G, Boddy AV. An LC/MS/MS method for stable isotope dilution studies of β-carotene bioavailability, bioconversion and vitamin A status in humans. Journal of Lipid Research 2014, 55(2), 319-328.
• Park H, Lietz G, Oxley A, Boddy A, Berry P, Wyss A, Schalch W, Green M. Simplified approaches for estimating vitamin A stores and β-carotene bioconversion in humans. The FASEB Journal 2014, 28(Suppl. 1), 39.6.
• Lietz G, Oxley A, Bosch-Saadatmandi C. Consequences of common genetic variations on beta-carotene cleavage for vitamin A supply. In: Sommerburg, O; Siems, W; Kraemer, K, ed. Carotenoids and Vitamin A in Translational Medicine. CRC Press, 2013, pp.383-396.
• Oxley A, Berry P, Hesketh J, Boddy AV, Lietz G. Gender differences in retinol metabolism are independent of β-carotene bioconversion. In: Nutrition Society Annual Summer Meeting. 2013, Newcastle upon Tyne, UK: Cambridge University Press.
• Lietz G, Oxley A, Boesch-Saadatmandi C, Kobayashi D. Importance of b,b-carotene 15-15'-monooxygenase 1 (BCMO1) and b,b-carotene 9,10-dioxygenase 2 (BCDO2) in nutrition and health. Molecular Nutrition and Food Research 2012, 56(2), 241.
• Lietz G, Oxley A, Leung W, Hesketh J. Single Nucleotide Polymorphisms Upstream from the β-Carotene 15,15'-Monoxygenase Gene Influence Provitamin A Conversion Efficiency in Female Volunteers. Journal of Nutrition 2012, 142(1), 161S-165S.
• Oxley A, Jolly C, Jordal AEO, Svardal A, Olsen RE. The combined impact of plant-derived dietary ingredients and acute stress on the intestinal arachidonic acid cascade in Atlantic salmon (Salmo salar). British Journal of Nutrition 2010, 103(6), 851-861.
• Oxley A, Bogevik AS, Henderson RJ, Waagbo R, Tocher DR, Olsen RE. Digestibility of Calanus finmarchicus wax esters in Atlantic salmon (Salmo salar) freshwater presmolts and seawater postsmolts maintained at constant water temperature. Aquaculture Nutrition 2009, 15(5), 459-469.
• Bogevik AS, Oxley A, Olsen RE. Hydrolysis of acyl-homogeneous and fish oil triacylglycerols using desalted midgut extract from Atlantic salmon, Salmo salar. Lipids 2008, 43(7), 655-662.
• Oxley A, Jutfelt F, Sundell K, Olsen RE. Sn-2-monoacylglycerol, not glycerol, is preferentially utilised for triacylglycerol and phosphatidylcholine biosynthesis in Atlantic salmon (Salmo salar L.) intestine. Comparative Biochemistry and Physiology, Part B: Biochemistry & Molecular Biology 2007, 146(1), 115-123.
• Oxley A, Torstensen BE, Rustan AC, Olsen RE. Enzyme activities of intestinal triacylglycerol and phosphatidylcholine biosynthesis in Atlantic salmon (Salmo salar L.). Comparative Biochemistry and Physiology: Biochemistry & Molecular Biology 2005, 141B(1), 77-87.
• Oxley A, Tocher DR, Torstensen BE, Olsen RE. Fatty acid utilisation and metabolism in caecal enterocytes of rainbow trout (Oncorhynchus mykiss) fed dietary fish or copepod oil. Biochimica et Biophysica Acta: Molecular and Cell Biology of Lipids 2005, 1737(2-3), 119-129.