THE EFFICACY OF FUNCTIONAL FOODS FOR THE MITIGATION OF OBESITY- RELATED PATHOLOGIES
Open Access
- Author:
- Chrisfield, Benjamin James
- Graduate Program:
- Food Science
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 19, 2017
- Committee Members:
- Joshua D Lambert, Thesis Advisor/Co-Advisor
Kathleen Loralee Keller, Committee Member
Connie Jo Rogers, Committee Member - Keywords:
- Obesity
Fatty Liver
NAFLD
Soy
High-oleic Soybean Oil
Tart Cherry - Abstract:
- Obesity is a major health concern in the United States and the rest of the developed world. Currently, more than 35% of adults and 15% of children in the U.S. are obese. The treatment of obesity-related illnesses accounts for $200 billion or more than 20% of total healthcare expenditures in the U.S. every year. Several diseases have been linked to obesity including cardiovascular disease, type-2 diabetes mellitus and non-alcoholic fatty liver disease (NAFLD). Nearly a quarter of adults in the U.S. have NAFLD. NAFLD is characterized by the accumulation of excess lipids in the liver in the absence of excessive alcohol consumption. Steatosis can progress to non-alcoholic steatohepatitis in which hepatocytes become inflamed, and fibrosis develops. In a small number of cases, severe fibrosis can lead to cirrhosis, liver failure, and death. Dietary interventions offer a safer and more affordable means of treating obesity and its related pathologies compared to interventions such as medication or surgery. Previous research has shown that a large number of foods have physiological activities beyond their nutritional value. In this thesis, we investigated the efficacy of tart cherries, soy protein concentrate, and high-oleic soybean oil in treating obesity and its related pathologies. The objectives of this project were to: 1.) determine if substituting a fiber-rich soy protein concentrate into a high-fat fed mouse diet prevents the development of obesity and NAFLD 2.) determine if substituting high-oleic soybean oil into a high-fat fed mouse diet prevents the development of obesity and NAFLD 3.) determine if tart cherries reduce the severity of obesity and its related inflammation in vivo 4.) determine if a tart cherry derived extract is capable of mitigating inflammation in TNF-α-stimulated human colonic epithelial cells Previous research has indicated that dietary supplementation with soy protein may mitigate the severity of NAFLD. Several studies have shown that replacing dietary saturated fatty acids with monounsaturated fatty acid (MUFA) may also ameliorate NAFLD. We examined the efficacy of dietary supplementation with soy protein concentrate (SPC), high-oleic soybean oil (HOS), and the combination to reduce markers of fatty liver disease and its associated inflammation in a high-fat (HF) induced NAFLD mouse model. Male C57BL/6J mice were given experimental diets ad libitum. The HF diets consisted of 60% kcal from lard; the HOS diets consisted of 20% kcal from lard and 40% kcal from high-oleic soybean oil, and diets supplemented with SPC replaced one-third of the casein with soy protein. Mice fed SPC had reduced visceral adiposity, hepatic steatosis, and markers of inflammation compared to casein-fed control mice. Mice fed high-oleic soybean oil gained significantly less weight and visceral adipose but had increased expression of several inflammatory markers. Several studies have shown that tart cherry (TC) products may mitigate symptoms of obesity and obesity-related inflammation. Tart cherries contain large amounts of anthocyanins and proanthocyanidins which have antioxidant and anti-inflammatory properties. We examined the effects of supplementing 1% tart cherry powder into a diet-induced obesity mouse model. Mice were provided ad libitum access to either a HF or a HF+TC diet for 18-weeks. No differences in weight gain or visceral adiposity were observed between the treatment groups. Mice fed the HF+TC diet had a slightly lower hepatic expression of inflammatory markers monocyte chemoattractant protein-1, interleukin (IL)-1ß, IL-6 and tumor necrosis factor (TNF)-α. We also examined the effects of a tart cherry extract (TCE) on colonic inflammation in vitro. Inflammation was stimulated in HT29 colonic epithelial cells with TNF-α and treated with TCE. Inflammation was measured as the concentration of IL-8 secreted by the cells and normalized to viability. The TCE had a small anti-inflammatory effect at higher concentrations when applied simultaneously with TNF-α. In conclusion, we have found that both a fiber-rich soy protein concentrate and tart cherry powder may be effective in mitigating the effects of obesity-related inflammation and NAFLD in a diet-induced obesity mouse model. We also found that high-oleic soybean oil may be pro-inflammatory in the same model. Further research will evaluate the constituent compounds of these foods to identify the key active components.