Glucose Metabolism

SucroMet is designed to evaluate how adding two commonly used sweeteners-sucrose (table sugar) and sucralose (a low-calorie sweetener)-at low and high doses may influence glucose regulation, including insulin resistance and fasting plasma glucose, in adults aged 18 to 65 years with normal weight, overweight, or obesity. The low-dose intervention consists of 5% of the Estimated Energy Requirement (EER) from sucrose or 5 sucralose tablets per day (approximately 33.35 mg/day of sucralose). The high-dose intervention consists of 10% of EER from sucrose or 10 sucralose tablets per day (approximately 66.7 mg/day of sucralose). These doses maintain the planned 1:2 exposure ratio between the low- and high-dose intervention groups. Before the intervention begins, participants' habitual dietary intake is assessed and, when necessary, minor dietary adjustments are made to support a stable overall eating pattern while maintaining energy intake. Participants then complete a four-week run-in period during which these recommendations are followed, and dietary records are used to verify dietary stability before the intervention starts. Participants will consume the assigned sweetener incorporated into foods or beverages that they already consume as part of their habitual diet, without substantial changes to their usual eating patterns. The intervention includes two consecutive 12-week phases, one involving solid food intake and the other involving liquid intake, separated by a two-week washout period. This design allows evaluation of the effects of sweetener type, dose, and mode of consumption. The primary outcomes are changes in glucose regulation, including fasting plasma glucose and insulin resistance assessed by HOMA-IR. Secondary outcomes include changes in body composition, anthropometric measurements, blood pressure, routine biochemical parameters, gut microbiota composition, DNA methylation patterns in peripheral blood cells, and biomarkers related to inflammation, oxidative stress, and metabolomic profiles measured in blood and urine. Participants will attend scheduled study visits for anthropometric assessments, dietary evaluations, and biological sample collection. Blood, urine, and stool samples will be obtained at baseline and after each intervention phase. The study aims to address the following questions: 1. Do metabolic responses to sucrose and sucralose, including changes in insulin resistance (HOMA-IR) and fasting plasma glucose, differ according to participants' body mass index (BMI)? 2. Do low and high doses of sucrose and sucralose differentially affect glucose regulation, body composition, and metabolic health? 3. Does the mode of intake (solid versus liquid) influence changes in gut microbiota composition? 4. Are changes in DNA methylation patterns in peripheral blood cells associated with the consumption of sucrose and sucralose at different doses and in different forms? 5. Do different doses of sucrose and sucralose influence biomarkers related to inflammation, oxidative stress, and metabolomic profiles?

As part of the mandatory annual assessment of physical fitness, soldiers are required to complete a standardized military march. A total of 100 healthy volunteer participants will be recruited from soldiers serving at the Bundeswehr Hospital Ulm. During this march, physiological and metabolic parameters will be assessed. At baseline, anthropometric data and information on medical history, lifestyle, and fitness status will be collected, including a validated questionnaire on physical activity. Blood and urine samples will be obtained to determine routine laboratory and metabolic parameters, and body composition will be assessed using bioelectrical impedance analysis. In addition, selected sensors will be applied to continuously record physiological data. Participants will then complete a 6 km march carrying 15 kg of equipment. After completion of the march, sensors will be removed and additional blood and urine samples will be collected to evaluate metabolic responses to physical exertion, including catecholamine levels.

In a crossover design, 8 participants will receive caloric drinks containing stable isotopes. In one arm of the study, participants will consume 6 hourly drinks containing two stable isotopes. Repeated blood, breath, urine, and muscle biopsies will be taken. In the second arm, participants will consume 1 drink containing 75g glucose, labeled with two stable isotopes of glucose. Periodic blood and breath will be taken over three hours.

Natriuretic Peptides (NP) are hormones produced by the heart, and they have a wide range of favorable metabolic benefits. Lower levels of these hormones are associated with an increased likelihood of the development of diabetes and poor cardiometabolic health. Obese and Black individuals have \~30% lower levels of NP and are at a greater risk of developing cardiovascular (CV) events as compared to lean and White counterparts. Some people have common genetic variations that cause them to have \~20% lower NP levels. Similar to other low NP populations, these individuals with low NP genotype (i.e., carrying a common genetic variation called rs5068) are at a greater risk of developing cardiometabolic diseases. By understanding the NP response following the exercise challenge and the glucose challenge in individuals with genetically lower NP levels will help us understand how to improve cardiometabolic health in them.

In this study the investigators will investigate the acute effects of increasing alanine exposure on metabolic parameters in healthy participants. Participants will participate in one study day. After initial baseline blood samples, a three-hour intravenous infusion with glucagon will be initiated. The infusion rate will be increased every 30 minutes.

Our goal in this study is to further refine StandUPTV, an application designed to reduce SST in adults in our first study (ASU IRB # STUDY00012109), for the StandUPTV Habits program. This program aims to establish a non-sedentary habit triggered by an alert from the StandUPTV application after participants engage in approximately 30 minutes of SST in the evening.

The goal of this clinical trial is to establish the relationship between macronutrient food intake and the resulting blood and intersticial fluid (ISF )levels of small molecule markers, as well as, validate wearable optical readers and data fusion algorithms to accurately predict individual-specific macronutrient availability in real time. The study involves 1 screening visit of approximately 2 hours and up to 4 study days of approximately 14 hours. Subjects will be asked to arrive in the fasted state on all study days. Fasting prior to screening is not required. On the screening visit, body weight, height, and body composition by Dual-energy X-ray absorptiometry (DXA) will be measured. In addition, habitual dietary intake, physical activity level (PASE), and quality of life (SGRQ-C) will be assessed.