Doctor of Philosophy / Department of Human Nutrition / Valentina M. Remig / Preventing foodborne illness and promoting safe food practices among all age groups is a high priority, particularly for college students because little about their food safety awareness and food handling practices has been reported. The research aim was to evaluate food safety attitudes, beliefs, knowledge, and self-reported practices of current upper-division college students, and to determine whether a three-module interactive educational intervention, developed for this study, positively influenced these variables. Comparisons between health and non-health majors were made. Two methods of data collection were used with volunteer health and non-health majors: focused food safety discussion groups during academic year 2004-05, and a pre-experimental design. Prior to engaging in either method, students completed an on-line food safety questionnaire (FSQ), adapted from a telephone survey used at K-State with older adults. The FSQ was administered again to those in the pre-experimental design group one week after exposure to the food safety educational intervention. Five weeks later, the FSQ was administered to determine whether changes in attitudes, beliefs, knowledge, and self-reported practices persisted over time. Focused food safety discussion group responses were qualitatively evaluated. Pre-experimental statistical analyses included Wilcoxin Signed Rank, Friedman, Mann-Whitney U, Chi Square tests, and Spearman rho. Focused discussion group findings indicated that students perceived themselves at low risk for foodborne illness; few used food thermometers; students without health backgrounds mimicked undesirable home practices; and students stated being open to changing non-recommended behaviors. Pre-experimental findings showed the effects of intervention were improved food safety attitudes, beliefs, and knowledge, with the strongest effects seen in health majors. Students' FSQ attitude scores increased from 114 to 122 (P<0.001), FSQ belief scores increased from 86 to 98 (P<0.001), and FSQ knowledge scores increased from 11 to 13 (P<0.001). Intervention resulted in some improved food safety self-reported practices for health majors but not non-health majors. Intervention module post-test scores improved significantly for all students; health majors had greater increases. Conclusions. Focused food safety discussion groups were useful for obtaining food safety information from college students; educational intervention improved college students’ food safety attitudes, beliefs, and knowledge and for health majors, some self-reported practices improved.

Doctor of Philosophy / Department of Human Nutrition / Weiqun Wang / Wheat lignans are phenylpropane dimers linked by β-β bonds with a 1, 4-diarylbutane structure. They are biosynthesized in the cell cytoplasm through action of enzymes of the phenylpropanoid pathway. Pinoresinol lariciresinol reductase (PLR) catalyzes the final steps of biosynthesis of wheat lignans. In epidemiological and clinical investigations, studies show that high plasma lignan amounts correlate with reduced risks of breast, colon, and prostate cancers. However, in some of the studies, the results are not consistent. More consistent results are observed when animal and cell culture models are used. Our previous studies in the Wang lab demonstrated that treatment of human colon cancer cells, SW480 with lignans results in a dose and time dependent inhibition of cancer cell growth. In the first paper, we investigated direct experimental cancer preventative characteristics of a wheat lignan, secoisolariciresinol diglucoside (SDG) vs. its metabolite enterolactone in human colon cancer SW480 cells. Treatment of cancer cells with 0-40 µM SDG or enterolactone resulted into inhibition of cancer cell growth as observed by reduction of cell numbers. The reduction appeared related to induction of S-phase cell cycle arrest rather than cytotoxic effect. Further analysis revealed that SDG was more stable in cell culture medium than enterolactone. HPLC-MS/ESI showed that enterolactone is the principle metabolite in cancer cells but undetectable SDG or its metabolites were in the cells treated with SDG. In the second paper, we investigated over expression of the PLR gene and enhancement of lignan levels in transgenic wheat. We transformed wheat cultivars (‘Bobwhite’, ‘Madison’, and ‘Fielder’ respectively) with the Forsythia intermedia PLR gene under the regulatory control of the maize ubiquitin promoter. Of the total 217 transgenic wheat lines, we successfully obtained 7 transformants with the inserted ubiquitin PLR gene as screened by PCR. Real-time PCR further indicated 109-117% PLR over expression over the transgenic control in 3 transformants of the 7 at T0 generation. In addition, the levels of SDG, as determined by HPLC was found to be significantly elevated in one of the 3 positive transgenic plants. To the best of our knowledge, this is the first study reported that genetically engineered wheat with over expressed PLR enzyme enhancing phytochemical lignan has been successfully achieved.

Doctor of Philosophy / Department of Human Nutrition / David A. Dzewaltowski / The environment can be broadly defined as all things external to an individual. One of the most important environments for children is the home in which they live, particularly with regard to the role that parents play to provide opportunities for healthful development, including adequate physical activity and healthful eating habits. Parents are the gatekeepers of children's healthful opportunities, and are influential in numerous aspects related to obesity. The present paper consists of four chapters related to impacting the home environment for prevention of obesity in children. Although obesity is a complex issue, its cause is energy imbalance, wherein less energy is expended than is consumed. Consideration of both sides of the equation is essential for obesity prevention. In this dissertation, chapter 1 serves as a literature review for the home food environment. A conceptual model is presented as an attempt to place relevant literature in the greater context of environmental variables related to childhood obesity. Frequent family meals have been shown to be protective for child and adolescent obesity, and to promote fruit and vegetable consumption. However, time pressures and lack of cooking skills are potential barriers to this healthful practice. Decreases in television viewing and sugar-sweetened beverage consumption are other home environmental aspects showing promise in the obesity prevention literature. Chapters two and three address the influence of parents on children's obesity-preventive behaviors and relative weight status. These chapters help to inform the planning of interventions to prevent obesity in children. Parent-child shared physical activity may hold promise as a strategy to decrease the likelihood of children becoming obese, and bonding may be an important consideration in programs aimed at obesity treatment or prevention. Chapter four describes the evaluation of an intervention developed to impact the home environment of young girl scouts. This intervention was implemented by troop leaders altering troop-meeting environments toward more healthful opportunities for physical activity and nutrition, and through the delivery of a scouts-tailored curriculum. Results of the intervention showed marked changes to troop meeting environments, but apparently little impact on parents or the home environment.