Dissertation/Thesis Abstract

Relationships between plasma cytokines, leukocyte telomere length, serum lipid profile, and nutrient intake in healthy adults following a 4-week dietary intervention study
by Harbison, Gregory James, M.S., Colorado State University, 2016, 177; 10149868
Abstract (Summary)

Colorectal cancer is the third most commonly diagnosed cancer worldwide and the fourth leading cause of cancer-related death. The etiology of colorectal cancer is predominately attributed to modifiable lifestyle factors that promote chronic inflammation, and only 20% of colorectal cases are credited to hereditary syndromes. Specifically, recent nutritional studies have suggested that diet modification is a promising lifestyle intervention for reducing systemic inflammation and promoting colorectal cancer prevention and remission. In particular, rice and navy beans have been identified as two foods with anti-inflammatory and anti-neoplastic properties that warrant evaluation for chemoprevention through dietary supplementation in humans. In this study, plasma cytokines (IL-2, IL-4, IL-6, IL-8, IL-10, TNF, and VEGF) and leukocyte telomere length were measured at baseline, two weeks, and four weeks in individuals with and without a history of colorectal cancer who consumed a diet supplemented with rice bran, navy beans, or a placebo-control for 28 days. Serum lipid profile and nutrient intake were also measured. At baseline, the three diet intervention groups had no significant differences in cytokine concentration, telomere length, or lipid profile. At the end of the study, individuals with a history of colorectal cancer who consumed the navy bean supplemented diet had significantly higher plasma TNF and VEGF concentrations than individuals consuming the control diet. Otherwise, at the end of the study, no significant differences in cytokine concentration or telomere length between groups existed. Additionally, compared to males, females with a history of colorectal cancer had significantly longer telomeres at baseline but not at four weeks. Females with a history of colorectal cancer also had significantly lower IL-4, IL-6, and IL-10 at baseline, but no significant difference was found at four weeks. Linear correlation analysis on repeated measures that adjusted for sex, age, and total energy intake showed significant correlations between several study variables. Telomere length was inversely correlated with age, serum triglyceride level, carbohydrate intake, and saturated fat intake. IL-2 and IL-4 concentrations were inversely correlated with β-Tocopherol intake. IL-8 was inversely correlated with vitamin B3 intake. VEGF was positively correlated with vitamin B9 intake. Total serum cholesterol was positively correlated with saturated fat intake and inversely correlated with β-Carotene intake. Serum LDL was inversely correlated with β-Carotene intake, and serum HDL was positively correlated with intake of saturated fat and linolenic acid. Triglyceride level was inversely correlated with intake of β-Carotene and fiber and was positively correlated with selenium intake. Finally, comparison of two experimental methods for telomere length measurement showed positive but inconclusive correlations.

Indexing (document details)
Advisor: Ryan, Elizabeth P.
Commitee: Bailey, Susan M., Tjalkens, Ronald B., Weir, Tiffany L.
School: Colorado State University
Department: Environmental and Radiological Health Sciences
School Location: United States -- Colorado
Source: MAI 55/06M(E), Masters Abstracts International
Source Type: DISSERTATION
Subjects: Toxicology, Surgery, Nutrition, Immunology
Keywords: Colorectal cancer, Cytokine, Inflammation, Navy bean, Rice bran, Telomere
Publication Number: 10149868
ISBN: 9781369049640
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