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United States Department of Agriculture

Agricultural Research Service

Gerald F. Combs (Jerry)


Gerald Combs Jr


Center Director


Dr. Combs was named Center Director, Grand Forks Human Nutrition Research Center, in January, 2002. He came to Grand Forks from Ithaca, NY, where he was a Professor of Nutrition in the Division of Nutritional Sciences at Cornell University, having been on that faculty since 1975. At Cornell, Dr. Combs served as the Director of Graduate Studies for the Field of Nutrition of the Graduate School and as a coordinator of the Food Systems for Improved Health Program in the College of Agriculture and Life Sciences.

Dr. Combs was born in Ithaca, NY, but grew up in Silver Spring, MD, the son of a Professor of Nutrition at the University of Maryland. He also attended that university, completing a B.S. degree in Zoology in 1969 whereupon he matriculated in the Graduate School at Cornell, completing a M.S. degree (Entomology) in 1971 and a Ph.D. degree (Nutrition) in 1973. That year he accepted an appointment as Assistant Professor at Auburn University, Auburn, AL, which he held through1975 when he joined the Cornell faculty.

Dr. Combs' is internationally recognized for his research in the nutritional biochemistry of trace elements and vitamins. His special interests have concerned the metabolism and physiological actions of the antioxidant nutrients selenium, vitamin E, vitamin C and factors that can affect their metabolic functions and dietary needs (e.g., vitamin A, carotenoids, iron, copper, zinc), particularly as they relate to health maintenance in and reduction of chronic disease (e.g., cancer) risks in humans and animals. He has presented more than 275 invited lectures and has published widely in this area (some 350 articles, reviews, chapters and book), including two important text/reference books, The Role of Selenium in Nutrition (Academic Press, 1986) and The Vitamins: Fundamental Aspects in Nutrition and Health (Academic Press, 1992; revised edition 1997) . At Cornell, Dr. Combs taught two graduate-level courses (The Vitamins; Mineral Nutrition) and one undergraduate course (Integrating Food Systems and Human Nutrition Needs); in previously years, he taught courses in human and animal (poultry) nutrition.

Dr. Combs’ His original research has employed several animal models (e.g., intact chicks, rats, mice and rabbits; isolated perfused rat liver preparations; isolated rat or chick hepatocytes and erythrocytes) with appropriate biochemical techniques for the study of questions relevant to human health. This basic arm of his research program has served to produce understanding as well as specific methodologies that he has employed in clinical intervention studies with humans. Dr. Combs may be best known for the work of his team in demonstrating for the first time that nutritional supplements of selenium can substantially reduce cancer risks in humans.

Dr. Combs is keenly interested in nutrition and health issues relating to national development and in the linkage of those issues to agricultural production. To that end, he has maintained since 1980 collaborations in China aimed at developing effective and sustainable food-based approaches to combating endemic selenium deficiency much of that in that country. He has served on numerous national and international scientific bodies.

As Center Director, Dr. Combs maintains an adjunct appointment as Professor, Department of Biochemisty and Molecular Biology, School of Medicine and Health Sciences, University of North Dakota. He is also a Professor Emeritus, Cornell University. He is a member of the American Society for Nutritional Sciences, the British Nutrition Society, the New York Academy of Sciences, the Society for Experimental Biology and Medicine, the Poultry Science Association, the International Society for Trace Element Research in Humans. He is also a member of the International Nutrition Forum of the Institute of Medicine, National Academy of Sciences, the Board of Scientific Advisors of the American Council on Science and Health, the scientific research society Sigma Xi, and the honor society Phi Kappa Phi.

Dr. Combs has lived and worked in China, India, Nepal, Indonesia, Australia and Bangladesh, and has visited more some 30 countries. In addition to English, he speaks French and Mandarin.


Research Interests

Dr. Combs is a leader in the area of selenium nutrition, metabolism and anti-carcinogenesis.  His group conducted the first randomized, placebo-controlled clinical trial, finding that supplemental Se can reduce cancer risks in humans, particularly for cancers of the lung, prostate, and colon, as well as all cancers combined and total cancer mortality.

Selenium, an element with a chemistry similar to that of sulfur, was recognized as an essential nutrient only four decades ago, and for years the best characterized of its functions have been those involved in its nutritional "sparing" of vitamin E. It is now known to have essential functions in several enzymes in each of which it occurs as the amino acid selenocysteine.  While these selenoenzymes are thought to discharge the nutritional roles of selenium, the fact that supranutritional levels of selenium are cancer-preventive suggests metabolic functions of other selenium metabolites.

Dr. Combs's research addresses the metabolism of selenium and the effects of selenium supplementation, genotype and other dietary factors.  His group uses stable isotopes of selenium to study this metabolism in health adults.  This also involves the development of new biomarkers of selenium status, including the characterization of non-protein bound selenium in plasma, the validation of buccal cell selenium and urinary selenium-metabolites to assess selenium status.  Such parameters have relevance to both cancer risk reduction and safety assessment.

Dr. Combs also interested in the development of safe and effective foods that provide nutritionally relevant or cancer protective amounts of selenium, including those produced on high-selenium soils.  He recently conducted a 12-mo. study to characterize plasma selenium concentration as a function of baseline plasma selenium level and level of daily selenium supplementation.  This algorithm will be useful in determining the amount of food selenium necessary to reach a selenium status target based on minimization of cancer risk, and thus to provide empirical data for establishing cancer-protective food selenium levels.


Research Accomplishments

  • Demonstrated for the first time that supplemental selenium can substantially reduce the cancer risks of free-living Americans.
  • Identified a low molecular weight form of selenium in plasma which responds to dietary selenium level.
  • Demonstrated that non-absorbed selenium can affect the metabolism of the hind gut microbial community in ways that may be protective of tumor transformation of colonocytes.
  • Documented the prevalence of calcium-deficiency rickets in southeastern Bangladesh.
  • Demonstrated that rickets in Bangladesh can be prevented by food-based supplementation of calcium.


Last Modified: 12/3/2013
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