UC Davis Nutrition Department Faculty

Distinguished Professor, Department of Nutrition
Nutritionist in Agricultural Experiment Station
Office: 3147 Meyer Hall
Phone: (530) 752-3376
e-mail: ajclifford@ucdavis.edu

B.S., University College, Dublin, Ireland, 1962
M.S., University College, Dublin, Ireland, 1963
Ph.D., Oklahoma State University, Stillwater, OK, 1967

Dr. Clifford's research in vitamin A and ßeta-carotene seeks to determine the nutritional status of humans with respect to these nutrients. A variety of gas, liquid, and supercritical fluid chromatography procedures in tandem with mass spectroscopy and stable isotopes are employed to study human subjects. It appears that intermediate states of vitamin A nutritional status can be reliably determined in humans. Analytical protocols are now being modified (simplified) to be useful in large clinical trials and epidemiological studies.

Dr. Clifford's research on folates seeks to provide better information concerning the folate cofactor patterns of foods and the nutritional bioavailability of these compounds in human diets. Analytical approaches to determine folate patterns of foods include chromatographic and mass spectroscopic techniques. Bioavailability assays measure the potency of foods to replete growth, hematological values and body stores of folate in folate depleted animals and humans.

Overall, the research relies on experimental laboratory science approaches to solving nutrition science and clinical and community nutrition problems.

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Metabolites by HPLC:

Lin Y, Dueker SR, Jones AD, and Clifford AJ. A parallel processing SPE protocol for the determination of whole blood folate. Anal Biochem 2002, 301:14-20.

Hickenbottom SJ, Follett JR, Lin Y, Dueker SR, Burri BJ, Neidlinger TR, and Clifford AJ. Variability in conversion of ß-carotene to vitamin A in men measured using a double-tracer study design. Am J Clin Nutrition, 2002, 75:900-907.

Lunetta JM, Zulim RA, Dueker SR, Lin Y, Flaig V, Schneider PD, Wolfe BM, and Clifford AJ. Methods for the simultaneous determination of retinol and b-carotene concentrations in human tissues and plasma. Anal Biochem 2002, 304:100-109.

Hickenbottom SJ, Lemke SL, Dueker SR, Lin Y, Follett JR, Carkeet C, Buchholz BA, Vogel JA, and Clifford AJ. Dual isotope test for assessing b-carotene cleavage to vitamin A in humans. European J Clinical Nutrition 2002;41:141-147.

Ebeler SE, Brenneman CA, Kim GS, Jewell WT, Webb MR, Chacon-Rodriguez L, MacDonald E, Cramer AC, Levi A, Islas A, Kraus A, Hinrichs SH, and Clifford AJ. Dietary catechin and tumor onset in a transgenic mouse model. Am J Clin Nutrition 2002, 76:865-872.

Mueller HG, Su CL, Dueker SR, Follett JR, Lin Y, Clifford AJ, Buchholz BA, and Vogel JS. Semiparametric modeling of labeled cell kinetics, with application to isotope labeling erythrocytes. Biometrics 2002;58:937-945.

Lin Y, Dueker SR, Jones AD, and Clifford AJ. Human whole blood folate analysis using a SIM GCMS protocol. Anal Biochem 2003,312:255-257.

Yao F, Muller H-G, Clifford AJ, Dueker SR, Follett J, Lin Y, Buchholz BA, and Vogel JS. Shrinkage estimation for functional component scores with application to the population kinetics of plasma folate. Biometrics 2003, 59:676-685.

Koutsos EA, Clifford AJ, Calvert CC, and Klasing KC. Maternal carotenoid status modifies the incorporation of dietary carotenoids into immune tissues of growing chickens (Gallus gallus domesticus). J Nutrition 2003;133:1132-1138.

Lemke SL, Dueker SR, Follett JR, Lin Y, Carkeet C, Buchholz BA, Vogel JS, and Clifford AJ. Absorption and retinol equivalence of b-carotene in humans is influenced by dietary vitamin A intake. J Lipid Res 2003;44:1591-1600.

Dingley KH, Ubick EA, Chiarappa-Zucca ML, Nowell S, Abel S, Ebeler SE, Mitchell AE, Burns SA, Steinberg FM, and Clifford AJ. Effect of dietary constituents with chemoproventive potential on adduct formation of a low dose of the heterocyclic amines PhIP and IQ and phase II hepatic enzymes. Nutrition and Cancer 2003;46:212-221.

Vogel JS, Dueker SR, Lin Y, Clifford AJ, Ognibene T, Hillegonds, and Buchholz BA. Quantifying human vitamin kinetics with AMS. in Synthesis and Applications of Isotopically Lableled Compounds. 2003:171-4.

Ross SA, Srinivas PR, Clifford AJ, Lee SC, Philbert MA, Hettich RL. New technologies for nutrition research. J Nutr. 2004;134:681-685.

Lin Y, Dueker SR, Follett JR, Fadel JG, Arjomand A, Schneider PD, Miller JA, Green R, Buchholz BA, Vogel JS, Phair RD, and Clifford AJ. Quantitation of in vivo human folate metabolism. Am J Clin Nutrition 2004; 80:680-691

Burri BY and Clifford AJ. Carotenoid and retinoid metabolism: Insights from isotope studies. Arch Biochem Biophysics. 2004; 430:110-119
Clifford AJ, Lin Y, Noceti EM, Block-Joy A, Ho CC, Block T, and Block G. Erythrocyte folate and its response to folic acid supplementation is assay dependent in women. J Nutr 2005;135:137-143.

Ebeler SE, Dingley KH, Ubick E, Abel S, Mitchell AE, Burns SA, Steinberg FM, and Clifford AJ. Animal models and analytical approaches for understanding the relationships between wine and cancer. Drugs Exp Clin Res. 2005;31:19-27.

Burri BY and Clifford AJ. b-Carotene metabolism measured by accelerator mass spectrometry. Sight and Life. 2005;1:6-8.

Dueker SR, Lame M, Lin Y, Clifford AJ, Buchholz BA, and Vogel JS. Traditional mass spectrometry for quantitation of human folate pools. Trends in Food Sci and Technol. 2005;16:267-70.

Owens JE, Holstege DM, and Clifford AJ. Quantitation of folate in whole blood using LC/MS/MS. J Agricultural and Food Chemistry 2005;53:7390-7394.

Moura FF, Ho CC, Getachew G, Hickenbottom S, and Clifford AJ. Metabolism of a tracer dose of 14C-lutein in an adult woman. Lipids 2005;40:1069-1073.

de Moura FF, Burri BJ, and Clifford AJ. Accelerator mass spectrometry in the study of vitamins and mineral metabolism in humans. Handbook of Vitamins. Eds MCCormick DB, Rucker RB, Suttie JW, Zempleni J. 2006; Marcel Dekker, NY. pp 545-557.

Getachew G, Burri BJ, Kelly P, Haack KW, Ognebene TJ, Buchholz BA, Vogel JS, and Clifford AJ. How to convert biological and environmental carbon to graphite for AMS. Radiocarbon 2006;48:325-36.

Clifford AJ, Moura FF, Ho CC, Follett JR, Fadel JG, Vogel JS, and Novotny JA. A feasibility study to quantify in vivo human a-tocopherol metabolism. Am J Clin Nutrition 2006; 84:1430-41.

Owens JE, Holstege DM, Noceti EM, and Andrew J. Clifford. High-throughput method for the quantitation of total folate in whole blood using LC-MS/MS. J Agric Food Chem. 2007;55:3292-7.

Owens JE, Holstege DM, Noceti EM, and Andrew J. Clifford. Comparison of two dietary folate intake instruments and their validation by RBC folate. J Agric Food Chem. 2007;55:3737-40.

Ho CC, de Moura FF, Kim S-H, and Clifford AJ. Excentral cleavage of b-carotene in a healthy adult man. Am J Clin Nutr. 2007;85:770-7.

Clifford AJ, Owens JE, Liu B, Mueller HG, Medrano JFR, Moghaddam B, and Clifford AJ. Effect genetic polymorphisms on the kinetics of in vivo human folate metabolism. in Mathematical Modeling in Nutrition and the Health Sciences. eds Hannigan, M and Novotny N. CRC Press. 2007; 242-64.