Location: Food Components and Health Laboratory
2014 Annual Report
Objectives
Diet is a lifestyle factor that is fairly easy to change and can have a significant impact on health. The human diet contains thousands of bioactive food components which have a multitude of physiologic actions, some of which can interrupt processes in the development of a host of chronic diseases. The goal of this project plan is to enhance the understanding of biological actions of food-based bioactive compounds to improve their efficacy in promoting health and preventing disease. We have organized the research team to broadly address the main factors affecting health benefits of dietary bioactive compounds: how much is in the food (content), how much we absorb from the food and how well we retain it (bioavailability/metabolism/elimination), and how the bioactive compounds work in the body (mechanisms of action). With respect to content, we intend to address agricultural practices that impact the amount of bioactive compounds present in crops and how to extend the shelf life of agricultural products. With respect to bioavailability, metabolism, and elimination, we intend to study both phenotypic and genotypic characteristics of individuals that impact the body’s nutrient handling. With respect to mechanisms of action, we will address reduction of risk for cancer, as well as other obesity related diseases. Bioactive compounds will include polyphenols, carotenoids, and sulfur compounds, because all demonstrate promising health benefits, and work with these compounds capitalizes on previous progress in our laboratory.
Objective 1. Delineate bioavailability, pathways of metabolism, and rates of elimination of bioactive substances from common foods (e.g., polyphenols, sulfur compounds, and other compounds as appropriate), and identify characteristics of humans that influence the body’s utilization of those bioactive substances.
Objective 2. Determine the impact of bioactive substances from common foods (e.g., polyphenols, sulfur compounds, and other compounds as appropriate) on markers of cancer risk in human and cell models.
Objective 3. Elucidate efficacy of bioactive substances from common foods (e.g. polyphenols, sulfur compounds, and other compounds as appropriate) on risk factors for diseases related to obesity.
Objective 4. Determine the impact of food composition heterogeneity (as influenced by genetics, environment, and agricultural production) on the variability in response of biomarkers of chronic disease to consumption of specific bioactive substances and its interaction with an individual’s nutrigenomic profile.
Objective 5. Determine the impact of agriculture, food production, and post-harvest practices on bioactive component content and variability, nutrient-nutrient interactions, and shelf life, with emphasis on fruits and vegetables.
Approach
Epidemiological studies have shown that diets high in fruits and vegetables are associated with decreased risk of chronic diseases. However, the scientific foundation necessary to translate these epidemiological findings into dietary recommendations is weak. Studies will be conducted to determine the effect of postharvest processing on phytonutrient content. The initial focus of the postharvest studies will be leaf lettuce and tomatoes, and these studies will be expanded to include kale, spinach, swiss chard, and/or strawberries. Several studies will be conducted on phytonutrient (anthocyanins) bioavailability and metabolism. Methods will be developed to isotopically label quercetin in lettuce and isoflavones in soy. The influence of phytonutrients on biomarkers of chronic disease will be investigated, with an initial focus on phytonutrients found in garlic due to possible roles in cancer prevention. Genotyping will be included in clinical studies whenever sufficient scientific justification exists. This research will be conducted through plant growth and postharvest studies, human feeding trials, quantitative and qualitative chemistry, molecular biology, and kinetic mathematical modeling techniques. Information generated from this project can be used to develop recommendations for dietary intakes of phytonutrients that will improve health and reduce risk of chronic disease.
Progress Report
Progress was made for both objectives of this National Program 107 plan, focusing on Component 3 to provide a Scientific Basis for Dietary Guidance. Progress has been made addressing Problem Statement 1A (Determine Agricultural Practices that Influence the Nutritional Status of Americans), 3A (Improve the Scientific Basis for Updating National Dietary Standards and Guidelines), 3B (Identify Roles of Food, Food Components and Physical Activity in Promoting Health and Preventing Disease), and 4A (Understand the Causes and Effects of Obesity and Obesity-Related Disorders) through studies on polyphenol availability in lean and obese individuals.
Berries are a rich source of flavonoids, especially the bright pigments called anthocyanins. Animal studies have suggested that berry preparations or anthocyanin-rich berry extracts can reduce body fatness in animal studies. Berry powder added to a high fat diet and fed to rats resulted in lower fasting insulin, lower post-prandial glucose response, and less abdominal fat. In another study, mice fed purified blueberry anthocyanins had lower weight gains and body fatness than mice receiving no anthocyanins. Blueberry anthocyanins have been shown to decrease adiposity in mice fed a high fat diet and tart red cherry intake by rats decreased adiposity and markers of inflammation. One human study has been completed. In this study, volunteers consumed a high-fat American diet including 600 grams (4 servings) of blackberries daily, expected to provide 540 mg cyanidin-based anthocyanins (purple pigments) daily. During the control treatment period, volunteers consumed the same high-fat base diet, with the blackberries replaced with a control food (jello matched for calories and fiber). Metabolic fuel use, glucose metabolism, and insulin response were measured. Analyses are ongoing. In a second study, two primary objectives will be addressed: to assess the differential response in bioavailability and metabolic pathways between lean and obese individuals exposed to acute, short term (14 day), and long-term (10-week) consumption of polyphenol-rich fruits (blueberry and apple), and beverages (tea); and to determine the differential systemic and gut anti-inflammatory response between obese and lean individuals exposed to polyphenol-rich fruits (blueberry and apple), and beverages (tea). Approval for this study has been received and recruitment is ongoing. This research is continuing with the line of research from the terminated project 1235-51000-052-00D, and is done in conjunction with subordinate projects 1235-51000-056-01R and 1235-51000-056-03R.
Accomplishments
