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ARS Home » Northeast Area » Beltsville, Maryland (BHNRC) » Beltsville Human Nutrition Research Center » Food Components and Health Laboratory » Research » Research Project #426314

Research Project: Metabolism and Molecular Targets of Macro and Micro Food Components in the Development and Management of Obesity and Chronic Diseases

Location: Food Components and Health Laboratory

2019 Annual Report


Objectives
Diet is a modifiable factor that can influence the multitude of chronic health disorders that face the U.S. adult population, including type 2 diabetes, cardiovascular disease, some cancers, arthritis, endothelial dysfunction, and others. Through the experiments planned for this project, we will attempt to improve the understanding of the influence of diet on chronic disease. We will investigate direct effects of diet on cardiometabolic profile and additionally factors that influence weight gain, which increases risk for chronic disease. Objective 1. Determine the energy content of specific foods in the context of a mixed diet, and the absorption, metabolism and impact on biomarkers for health promotion of these foods or their macro and micro components. Objective 2. Determine the influence and interaction of the composition of food intake and exercise on glucoregulation, cardiometabolic profile, and metabolic flexibility (fuel management). Objective 3. Determine the extent to which the day-to-day variation in daily voluntary food intake, measured over at least 3 months, is related to diet composition, physical activity, and changes in physiological and metabolic markers related to energy balance, satiety and hunger.


Approach
Diet is a modifiable lifestyle factor that can influence the multitude of chronic diseases faced by an increasing proportion of the U.S. population, including type 2 diabetes, hypertension, vascular dysfunction, cardiovascular disease, cancer, and arthritis. Moreover, the widespread global prevalence of these diseases threatens the quality of life and places additional stresses on an already overburdened health care system. This project, through highly controlled human feeding studies, will target specific factors which influence risk for and development of chronic disease. First, research will be conducted to improve accuracy of the energy value of foods, which can impact weight gain, a risk factor for chronic disease. Second, research will be conducted to investigate dietary factors that can influence cardiometabolic profile, i.e. risk for cardiovascular disease, stroke, or diabetes. Third, we will study how diet influences voluntary food intake, again impacting weight gain, a risk factor for chronic disease. The outcomes of this research will provide a better understanding of 1) the energy content of specific foods in the context of a mixed diet, and the absorption, metabolism and impact on biomarkers for health promotion of these foods or their components, 2) dietary and lifestyle influences on diabetes and cardiovascular disease risk, and 3) the extent to which the day-to-day variation in daily voluntary food intake is related to diet composition. This research will fill knowledge gaps in the metabolism of macro and micro food components related to the development and management of obesity and chronic diseases, and provide a scientific basis for dietary recommendations and nutrition policy.


Progress Report
This is the final report for the project 8040-51530-010-00D entitled “Metabolism and Molecular Targets of Macro and Micro Food Components in the Development and Management of Obesity and Chronic Diseases” which terminated in January 2019. This project plan is linked to the 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 human studies investigating calorie absorption, energy metabolism, sugar metabolism, food intake regulation, and factors related to risk for cardiovascular disease, diabetes and obesity. During the final year of this project, data from a study on voluntary food intake was collated, and daily energy (calorie) and nutrient intake was determined over the course of two 3-week periods of free-choice (voluntary) food intake. These data are helping us understand how different dietary components affect free-choice calorie consumption, contributing to progress for Objective 3. Also, during the final year of this project, a study of men and women consuming mixed berries (strawberries, blueberries, blackberries, red raspberries, cranberries), was conducted to determine how berry consumption affects glucose (blood sugar) metabolism. All of these berries contain anthocyanins, a class of red, blue, and purple hues in plants, and are one of the main classes of compounds gaining substantial attention in regard to obesity. Studies have found that rodents consuming a high fat diet gain less weight when also consuming these colorful pigments. This study includes dietary treatments to help identify which components of berries (fiber or anthocyanins) may be responsible for their observed metabolic effects. This research expands on an earlier study of men consuming blackberries. Over the five-year span of this project, significant progress has been made in meeting the objectives of this project. For Objective 1, the energy value was determined for almonds, walnuts, and cashews. These studies found that the calorie content listed on the food label (the metabolizable energy content) of these nuts is 17% to 25% higher than what was measured in this series of studies. Further, it was established from these studies that processing of almonds (roasting, chopping or grinding) further alters the calorie content - roasting and chopping or grinding increases the calorie content. There are several significant and impactful outcomes of this research. First, a new method was developed to determine the calorie (energy) content of foods (in this case nuts) when they are fed as part of a diet. This new methodology has not existed previously, and builds on research that was conducted in the late 1890s and early 1900s that is still the basis for food labeling. Second, the impact of food processing on calorie content of nuts was established. Third, these data have provided nut growers, processors, and the food industry, with more accurate data with which to better inform consumers. Based on the success of this research, the research will be expanded to other plant-based foods in the new project 8040-51530-011-00D. For objective 2, initial studies were completed that improved analysis of calorimetry (breath gas) data as a means to measure metabolic state. This research impacted the field by providing scientists better tools to determine metabolic fuel use and energy expenditure with much greater accuracy. Subsequently, these tools were applied to studying metabolic flexibility in the elderly. Results from this research provided guidance to clinicians on how and when to prescribe minimal intensity exercise to the elderly in order to decrease insulin resistance, and improve blood sugar and metabolic fuel use in this sedentary population. Additional research was completed with berries, including blackberries and mixed berries, to investigate the effect of berries on glucose metabolism. Results from these studies, demonstrating improvement in how the body metabolizes glucose after consumption of blackberries, provide a scientific basis for dietary guidance, and impact dietary recommendations. Objective 3 focused on voluntary food intake. Progress was made toward meeting this objective. A study was completed to determine if consumption of mixed nuts influences food intake and choice. Included in this study were measures to determine how personality characteristics affect food choice, including mood, stress, tendency to seek approval, tendency to avoid criticism, tendency toward food cravings, and approach to food intake control. Data analyses from this study is continuing in the new project. In conclusion, significant progress has been made in meeting the research objectives of the project during the past 5 years. Because of the importance of these research objectives and their impact thus far, additional research will be conducted to further advance these objectives, as well as objectives focused on new research directions, as described in the new project 8040-51530-011-00D.


Accomplishments
1. Consumption of cashew nuts does not change risk factors for coronary heart disease. Consumption of most tree nuts is associated with a reduced risk for cardiovascular and coronary heart disease. Given this evidence, the Food and Drug Administration has authorized a qualified health claim for nuts stating that their consumption may reduce the risk of heart disease. However, cashews nuts have been explicitly restricted from using this qualified health claim. ARS researchers at the Beltsville Human Nutrition Research Center, Beltsville, Maryland, conducted a controlled-dietary intervention and found that there are no changes in blood cholesterol or other markers associated with cardiovascular or coronary heart disease after consumption of cashew nuts. These results support the Food and Drug Administration’s decision to exclude cashew nuts from the qualified health claim. Importantly, cashew nut consumption did not increase risk for cardiovascular or coronary heart disease. These data fill a void in knowledge and are of interest to nut producers, processors and to consumers who wish to make informed decisions regarding their diet and health.

2. The metabolizable energy content of cashews is lower than stated on food labels. There is no published research on the calorie content of cashews, and their calorie content is extrapolated from other tree nuts, and those data are over 100 years old. If these data are inaccurate, then food labels will not provide accurate information to consumers. ARS researchers at the Beltsville Human Nutrition Research Center, Beltsville, Maryland, discovered that the calorie content of cashews is 17% lower than what is found using the current method for measuring calories for food labeling (a calculation using the Atwater factors). This discrepancy between the measured calorie content of cashews and the value estimated by use of the Atwater factors (and used for food labeling) is similar to the discrepancy for walnuts and almonds. Some consumers avoid these nutrient-dense nuts over concern that they contain excessive calories. The current research with cashews, coupled with previous research with walnuts and almonds demonstrates that the calories in these nuts are significantly lower than previously known. The food industry is updating food labels so consumers will have more accurate information on the calorie content of their food.

3. Blackberry consumption increases fat oxidation and improves insulin sensitivity. Two-thirds of Americans can be classified as overweight or obese, leading to increased risk for cardiovascular disease, diabetes, cancer, and other morbidities. Dietary approaches offer solutions to weight loss and improved health without negative side effects. Anthocyanins, a class of red, blue, and purple hues in plants, are one of the main classes of compounds gaining substantial attention in regard to obesity. ARS researchers at the Beltsville Human Nutrition Research Center, Beltsville, Maryland, conducted a feeding study in which overweight and obese men consumed blackberries every day for a week. The results show that blackberry consumption increased both fat burning (oxidation) and also improved sugar (glucose) metabolism. These results will be used by health practitioners to provide dietary recommendations that are science-based.


Review Publications
Baer, D.J., Novotny, J. 2019. Consumption of cashew nuts does not influence blood lipids or other markers of cardiovascular disease in humans: a randomized controlled trial. American Journal of Clinical Nutrition. 109:269-275. https://doi.org/10.1093/ajcn/nqy242.
Solverson, P.M., Rumpler, W.V., Leger, J.L., Redan, B.W., Ferruzzi, M.G., Baer, D.J., Castonguay, T.W., Novotny, J. 2018. Blackberry feeding increases fat oxidation and improves insulin sensitivity in overweight and obese males. Nutrients. 10. https://doi.org/10.3390/nu10081048.
Baer, D.J., Novotny, J. 2018. Metabolizable energy from cashew nuts is less than that predicted by Atwater factors. Nutrients. 11:33. https://doi.org/10.3390/nu11010033.