Location: Food Components and Health Laboratory
2020 Annual Report
Objectives
Objective 1: Determine the genotype, phenotype and food matrix factors that influence absorption, distribution, metabolism or excretion of glucosinolates, phenolics, and other food components.
Objective 2: Determine how consumption of foods and food components, including but not limited to glucosinolates, phenolics, and carotenoids, modulate inflammatory and metabolic pathways that affect risk for cardiovascular diseases, diabetes, cancer, and other chronic disease.
Approach
U.S. agriculture provides us with myriad dietary components that 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 physiologic actions of diet-based bioactive compounds to improve their absorption and efficacy in promoting health and preventing disease. We have organized this project to address current and emerging nutrition issues while capitalizing on the experience and expertise of the research team assigned to this project. We will address the following factors for several different categories of food components and bioactives: how much of a dietary component we absorb from the food, how well we retain and utilize that dietary component, and how the bioactive compounds function in the body (mechanisms of action) to prevent the most significant modifiable health risks faced by American adults, including cardiovascular disease, diabetes, and cancer. Bioactive compounds will include polyphenols, carotenoids, and sulfur compounds from Brassica vegetables, because all demonstrate promising health benefits, and work with these compounds capitalizes on previous progress in our laboratory.
Progress Report
This report is for project 8040-51000-059-00D entitled “Absorption, Distribution, Metabolism and Excretion of Food Components and their Impact on Chronic Disease Risk.” The project contributes to National Program 107 and focuses on Component 1 Linking Agricultural Practices and Beneficial Health Outcomes, Component 3 (Scientific Basis for Dietary Guidance), and Component 4 (Prevention of Obesity and Obesity-Related Diseases) through human studies focusing on Brassica vegetables, whole grains and berries.
In support of research Objective 1, several studies with Brassica vegetables were initiated or completed. These studies focus phenotype and food matrix factors that influence the absorption, distribution, metabolism or excretion of glucosinolates. Studies were conducted with kale and broccoli, including different food preparation methods of broccoli that result in different food matrices. In addition, studies of whole grain wheat and whole grain oat also were conducted to advance progress toward Objective 1.
A study of the healthfulness of kale, a vegetable that has been increasing in popularity over the past decade, was completed. The dietary intervention with humans was initiated to identify the effects of kale consumption on xenobiotic metabolizing enzymes, to identify novel metabolites of indole glucosinolates in human blood and urine after consumption of kale, and to determine if kale consumption results in upregulation of myrosinase (an enzyme important for the conversion of kale glucosinolates into bioactive compounds) producing bacteria in the colon resulting in greater appearance of glucosinolate metabolites in blood and urine. Laboratory and statistical analyses of samples for determining changes to xenobiotic metabolizing enzymes and novel metabolites have been completed. It was found that consuming baby kale modifies detoxifying enzymes, reducing cancer risk. Xenobiotic metabolizing enzymes process (and detoxify) exogenous and endogenous metabolites, including procarcinogens, and prepares them for excretion from the body, thereby decreasing the risk of cancer. The diet containing kale increased CYP1A2 (a detoxification enzyme) activity compared to control. Further, conjugated bilirubin (used to remove compounds from the body) was reduced by the kale diet. The implications of these results for cancer risk will be clarified as the functions of xenobiotic metabolizing enzymes become better understood.
A study of cooked broccoli to determine if there is an effect of daily feeding and body mass index on isothiocyanates and isothiocyanate metabolites in blood and urine has progressed. Statistical analyses have been completed, and a new manuscript has been submitted to a peer reviewed journal.
Another study was conducted to improve understanding of the links between brassica vegetable consumption, and broccoli in particular, and cancer risk. A human feeding intervention was conducted to determine, using advanced non-targeted targeted metabolomic approaches, if metabolites of certain compounds from broccoli can be used as markers of broccoli consumption. Glucosinolate and indole metabolites were identified in blood and urine, including the identification of indole metabolites not previously reported in the scientific literature. The results of this research suggest that glucoraphanin and indole metabolites may serve as marker compounds for the intake of broccoli in people.
In addition, research continued on a study of broccoli snacks. Vegetable snack foods are becoming increasingly popular but little research has been done to investigate the effect of processing of vegetables on their bioactive compounds. Methods were developed for in-house preparation of the broccoli (freeze drying and roasting). The research protocol was developed, institutional review board approval was obtained, and the clinical trial was completed. Laboratory analyses were initiated.
A dietary intervention study was completed for a study of whole grain wheat and oats. This study will identify (using principal components analysis) if metabolites from whole wheat oats and wheat (5-n-alkylresorcinols, avenanthramides, saponins) in blood and urine can be used as dietary biomarkers of daily intake of whole grain wheat and whole grain oat. Analysis of samples is ongoing.
To advance progress in meeting Objective 2, a study on mixed berries was completed. Continuing on previous berry research, a new study was initiating to determine if insulin sensitivity (related to blood sugar metabolism) is improved by consuming whole mixed berries (blackberries, blueberries, cranberries, raspberries, and strawberries), mixed berry juice, or fiber.
To support progress for Objective 2, a study to measure the metabolizable energy value of pulses was initiated, and the dietary intervention was completed. Sample analyses is ongoing. This study builds on previous research that focused on the metabolizable energy value of tree nuts. In studies of tree nuts, metabolizable energy value of tree nuts was found to be up to 25% less than what is reported in USDA FoodData Central. This discrepancy is related to limited data and incorrect assumptions used in the methods for calculating the metabolizable energy value of tree nuts. Current research on pulses (specifically chickpeas and lentils) will determine if similar errors exist in nutritional databases for pulses as for tree nuts.
Also in support of Objective 2, research was conducted to better understand the link between flavan-3-ol consumption and reduction of risk for heart disease and type 2 diabetes. Flavan-3-ols are a class of naturally occurring polyphenolic compounds found primarily in tea and cocoa whose consumption has been associated with reduced cardiometabolic risk which includes outcomes (including death) from coronary heart disease, stroke, hypertension, and type 2 diabetes. A systematic review and meta-analysis of published research studies was conducted to determine if there is consistent evidence that higher flavan-3-ol intake, irrespective of dietary source, reduces cardiometabolic risk. After careful identification of the studies and evaluation of their quality, in studies using good methodologies there are improvements in markers of risk including cholesterol, blood pressure, insulin sensitivity. Further, there is moderate evidence flavan-3-ol and monomer intakes were associated with reduced risk of cardiovascular disease, coronary heart disease, stroke and type 2 diabetes. Available evidence supports a beneficial effect of flavan-3-ol intake on cardiometabolic outcomes, and this information will be useful in developing dietary guidance.
Accomplishments
1. Broccoli consumption modifies gut micobes in lean people. Cruciferous vegetables are a good source of dietary fiber and bioactives, and can be metabolized by gut microbes, which are increasing linked to improved health outcomes. ARS researchers at the Beltsville Human Nutrition Research Center, Beltsville, Maryland, conducted a dietary intervention study to determine the impact of broccoli consumption on the gut microbes of healthy adults. Broccoli consumption changed the kinds of microbes in the gut, and affected processes related to energy metabolism. The effects of broccoli consumption were most pronounced in lean people. This study shows that broccoli consumption alters the composition of the human gut microbes, especially in lean individuals.
2. Berry consumption improves insulin sensitivity. Berries contain several compounds, such as flavonoids and fiber, that may have beneficial effects on insulin sensitivity and blood sugar regulation, possibly reducing risk for type 2 diabetes. ARS researchers at the Beltsville Human Nutrition Research Center, Beltsville, Maryland, studied the ability of mixed berries (blackberries, blueberries, cranberries, raspberries, and strawberries) to improve insulin sensitivity. The combined berry preparations resulted in a lower serum insulin area under the curve. This result suggests the potential for mixed berry preparations to improve post-prandial insulin response.
Review Publications
Charron, C.S., Novotny, J.A., Jeffery, E., Kramer, M.H., Ross, S., Seifried, H. 2019. Consumption of baby kale increased cytochrome P450 1A2 (CYP1A2) activity and influenced bilirubin metabolism in a randomized clinical trial. Journal of Functional Foods. 64:103624. https://doi.org/10.1016/j.jff.2019.103624.
Solverson, P.M., Henderson, T.R., Debelo, H., Ferruzzi, M.G., Baer, D.J., Novotny, J.A. 2019. An anthocyanin-rich mixed-berry intervention may improve insulin sensitivity in a randomized trial of overweight and obese adults. Nutrients. 11:2876. https://doi.org/10.3390/nu11122876.
Kaczmarek, J.L., Liu, X., Charron, C.S., Novotny, J., Jeffery, E.H., Seifried, H.E., Ross, S.A., Miller, M.J., Swanson, K.S., Holscher, H.D. 2019. Broccoli consumption affects the human gastrointestinal microbiota. Journal of Nutritional Biochemistry. 63:27-34. https://doi.org/10.1016/j.jnutbio.2018.09.015.
Sun, J., Charron, C.S., Novotny, J.A., Peng, B., Yu, L., Chen, P. 2019. Profiling glucosinolate metabolites in human urine and plasma after broccoli consumption using non-targeted and targeted metabolomic analyses. Food Chemistry. 309:125660. https://doi.org/10.1016/j.foodchem.2019.125660.
Raman, G., Avendano, E., Chen, S., Wang, J., Matson, J., Gayer, B., Novotny, J.A., Cassidy, A. 2019. Dietary intakes of flavan-3-ols and cardiometabolic health: systematic review and meta-analysis of randomized trials and prospective cohort studies. American Journal of Clinical Nutrition. 110:1067-1078. https://doi.org/10.1093/ajcn/nqz178.
