ABSTRACT

Title of Document:

EFFECTS OF GRAPE POMACE ON METABOLIC SYNDROME: DIABETES AND OBESITY

Haiwen Li, Doctor of Philosophy, 2015

Directed by:

Professor Thomas W. Castonguay

Department of Nutrition and Food Science

Diabetes and obesity are twin epidemics that are closely linked to each other. In the United States, diabetes currently affects approximately 29.1 million adults and children. The estimated economic cost of treating diabetic patients and their related complications reached $245 billion in the US in 2012. Additionally, the prevalence of obesity is increasing during the recent decades. The National Health and Nutrition Examination Survey 2011-2012 reported that more than two-thirds of US adults (68.5%) are overweight, and more than one-third (34.9%) were obese.

Both diabetes and obesity are currently considered diseases. Although they cannot be completely cured, diabetes and obesity can sometimes be prevented by increasing physical activity and eating healthy foods. Producing healthy foods or healthy agro-produced supplements would be the first line of defense against such diseases. In search of plant products that can be used for preventative medicine, we recently discovered that grape pomace, the by-product

from the waste of the wine and juice industries, has great potential to prevent diabetes and obesity. The fundamental goal of this research is to elucidate the molecular mechanism(s) of the grape pomace extract’s (GPE) preventive functions on diabetes and obesity, and to provide scientific evidence to guide its use in developing functional foods for diabetes and obesity prevention. We hypothesize that GPE may prevent diabetes and obesity through altering the expression of genes on the signaling or metabolic pathways that lead to diabetes and obesity manifestation. This research project targeted on 4 specific objectives: 1) to characterize the action of GPE in reducing postprandial hyperglycemia through inhibition of alpha-glucosidase; 2) to understand the mode of molecular action of GPE in control of diabetes; 3) to understand the mode of molecular action of GPE in control of obesity; 4) to examine the effects of GPE on diabetes and obesity at genome wide.

Throughout these research activities, we provided molecular evidence toward understanding the mode action of GPE in preventing diabetes and obesity. Such knowledge will provide guidance for future studies in developing GPE as an alternative therapeutic for the control of diabetes and obesity. Moreover this study may also lead to food industry applications in producing functional foods for diabetic and obese populations.