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ARS Home » Northeast Area » Beltsville, Maryland (BHNRC) » Beltsville Human Nutrition Research Center » Food Components and Health Laboratory » Research » Research Project #435982

Research Project: Strategies to Alter Dietary Food Components and Their Effects on Food Choice and Health-Related Outcomes

Location: Food Components and Health Laboratory

2020 Annual Report

Objective 1: Determine how changes in dietary food components macro and micronutrients composition affect taste, palatability, food choice and health. Objective 2: Investigate the effect of food processing methods on nutrient intake and disease risk reduction. Objective 3: Determine how foods and food components alter food and energy intake (measured over 2 months).

United States (U.S.) agriculture produces a bountiful array of healthful foods to support the nutritional needs of the American population, providing us vast options to use diet to support health and reduce risk of chronic disease. However, healthful foods are useless if they are not selected for consumption. The U.S. Department of Agriculture’s (USDA) What We Eat in America dietary survey has demonstrated that Americans are not following the Dietary Guidelines, but rather are eating too much salt, sugar, and protein, and falling short on fruits and vegetables. A complex array of factors influences food selection and consumption, including taste/palatability, satiety, convenience, healthfulness, and emotional/psychological factors. This project plan aims to improve understanding of these drivers of food intake and health consequences of consuming certain foods of concern. We will conduct two human feeding interventions to target different factors influencing food selection and consumption. In one study, we will investigate different methods for altering food preference, through either gradual or rapid alterations in the diet. In another study, we will provide a satiating food item twice per day, then measure all other food selected and consumed. We will also evaluate emotional and psychological factors throughout the food selection study. Finally, recognizing that consumers struggle with the balance between convenience and healthfulness, we will evaluate health effects of raw vs. processed meat, to see whether selection of this processed convenience food has negative health consequences. This research will offer paradigms for approaches to improve dietary choices by Americans, and provide a scientific basis for dietary recommendations and nutrition policy.

Progress Report
This report is for project #8040-51530-011-00D entitled “Strategies to Alter Dietary Food Components and Their Effects on Food Choice and Health-Related Outcomes.” 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 Objective 1, several studies with Brassica vegetables were initiated or completed. These studies focused on 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 wheat also were conducted to advance progress toward Objective 1. A study of kale 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. 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 interpretation is ongoing. 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 initiated 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.