A Randomized, Cross-Over Clinical Trial to Evaluate the Acute Effects of Mixed Flavonoid and Caffeine Ingestion on Energy Expenditure and Fat Oxidation in Healthy Adult Women
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 25
- 试验地点
- 2
- 主要终点
- 24-hour energy expenditure (kilocalories/minute) from continuous respiratory exchange measurements (oxygen consumption, carbon dioxide production) in a metabolic chamber
研究概览
简要总结
The purpose of this study is to compare the effect of ingesting caffeine and mixed flavonoids (4 capsules, split between breakfast and lunch) on energy expenditure and fat oxidation in a metabolic chamber with 20 women (non-obese, healthy, ages 20-47 years, pre-menopausal). We hypothesize that based on the existing literature, ingestion of a double dose of the caffeine-mixed flavonoid supplement compared to placebo will increase fat oxidation and increase 24 h energy expenditure by about 75 kilocalories.
详细描述
This study will utilize a randomized, double-blind, cross-over design, comparing acute ingestion of the mixed flavonoid supplement (MF) compared to placebo control (PC) in healthy, non-obese, pre-menopausal women. The study will consist of two 24-hour study periods spent in the recently renovated indirect room calorimeter (i.e., metabolic chamber) at the University of North Carolina Chapel Hill Nutrition Research Institute (UNC NRI). The 24-hour study periods in the metabolic chamber will be 4 weeks apart. Primary outcome measures will be 24-hour energy expenditure (EE), resting metabolic rate (RMR), sleeping metabolic rate (SMR), substrate utilization from the respiratory quotient (RQ), and physical activity energy expenditure (AEE).
Following recruitment and eligibility assessment, study participants will be randomly assigned to complete either the mixed flavonoid (MF) or the placebo control (PC) study day. After a 4-week washout, study participants will cross over and complete the alternative treatment. A method of randomly permuted blocks will be generated using web-based randomization software (www.randomization.com) resulting in 10 study participants receiving MF during the first week, and 10 study participants receiving the PC during the first week. Study participants will consume 2 MF or PC capsules 30 min before breakfast, and 2 MF or PC capsules 30 min before lunch. During both study days, study participants will be fed in energy balance (i.e., energy intake will be matched to energy expenditure).
-
Experimental Study Participants: Using data generated previously in the UNC NRI metabolic chamber, a sample size calculation with 80% power revealed that 15-20 study participants would be needed to detect a 50 kcal difference in 24-h EE. To account for attrition, 25 study participants will be recruited via mass advertisement throughout the local area. Pre-menopausal women will be chosen because this is a target population of the sponsor.
-
Pre-Study Baseline Testing Eligibility will be determined in the outpatient clinical suite at the UNC NRI. Body composition (fat mass and fat free mass (FFM)) will be determined via dual energy x-ray absorptiometry (DXA) (GE Lunar iDXA; Milwaukee, WI). Body mass index (BMI, kg/m2) will be calculated for measured height and weight. Resting metabolic rate (RMR) will be estimated using a FFM-based equation [418 + (20.3 FFM)] (J Appl Physiol 1993;75:2514-2520). This estimated RMR will be used to calculate total dietary energy intake while in the metabolic chamber: RMR x physical activity level (PAL) of 1.3, and then adjusted using measured data (details provided below). A small blood sample will be obtained at this time and T3, T4, and TSH levels assessed through the clinical lab at the Lab Corp (Burlington, NC). A urine pregnancy test will be performed.
-
Indirect calorimetry: The metabolic chamber at the Nutrition Research Institute in Kannapolis, NC is an open-circuit, whole room indirect calorimeter. The CO2 and O2 analysers are differential, with full scale readings set for 0%-1%. O2 consumption, CO2 production, EE and RQ are recorded each minute. EE is calculated using an abbreviated Weir's formula (VO2 X 3.941) + (VCO2 X 1.106), where VO2 is the volume of oxygen consumed in L/minute and VCO2 is the volume of carbon dioxide released in L/minute. RQ is calculated as VCO2/VO2. Area under the curve (AUC) will be calculated using RQ data for the four hours following breakfast, lunch and dinner as well as sleeping hours between midnight and 6:00 am. Spontaneous physical activity will be measured each minute using a total room sensor. To calculate resting metabolic rate (RMR), EE will be plotted against the activity motion sensor output (each averaged over 30 minutes), and the y-intercept of the linear regression taken as EE in the inactive state. RMR will be multiplied by 1440 minutes to extrapolate to 24 hours. Twenty-four hour sleeping metabolic rate (SMR) will be determined as the lowest mean EE (kJ/minute) measured over 3 consecutive hours between midnight and 6:30 am and multiplied by 1440 minutes. Diet induced thermogenesis (DIT) will be calculated by subtraction of SMR from RMR. Activity induced EE (AEE) will be calculated as the difference between 24 hour EE and RMR.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Treatment
- 盲法
- Double (Participant, Investigator)
盲法说明
Flavonoid and placebo capsules
入排标准
- 年龄范围
- 20 Years 至 47 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •Women, ages 20 to 47 years
- •Body mass index (BMI) between 18.5 and 33 kg/m2 (normal weight, overweight, mild obesity)
- •Weight during the past 6 months has been somewhat stable (+/- 12 lbs)
- •Low-to-moderate caffeine intake, defined as consuming on average: less than 3 servings per day of coffee (each about 8 fl. oz.) and/or energy drinks with caffeine; less than 3 soft drinks with caffeine and tea per day
- •Premenopausal (self-report)
- •Willingness to maintain habitual diet and physical activity patterns, and not lose weight throughout the study period
- •Understands and agrees to all study procedures and signs the form providing informed consent to participate in the study
- •Willingness to report and maintain normal schedule of hormonal therapy including oral contraceptive pills, hormonal IUD, Nuva Ring, or DepoProvera injections.
- •Normal thyroid function as determined from a blood sample collected during pre-study baseline testing.
- •Not pregnant as determined by a urine pregnancy test during pre-study baseline testing and prior to the second chamber session, and not planning to become pregnant during the study.
- •Willingness to avoid vigorous exercise the day before each metabolic chamber session (e.g., intense running, cycling, swimming for 30 minutes and longer).
排除标准
- •Taking medications for or suffering from a medical condition that may impact results related to metabolism (e.g. thyroid disorders, diabetes, mental disorders such as anxiety or depression, heart disease, arthritis, cancer).
- •Heavy exerciser (defined as more than 300 minutes per week of moderate to vigorous exercise within the last two weeks)
- •Thyroid hormone levels outside of the normal laboratory reference range
- •Pregnant or lactating, or planning to become pregnant during the study
- •Recent use of antibiotics (within last two weeks)
- •History of smoking during the six months prior to study
- •Recent signs or symptoms of infection, including cold or flu-like symptoms (within last 2 weeks)
- •Conditions or diseases the investigator believes would interfere with ability to provide consent, comply with the study protocol, which might confound the interpretation of the study results or put the person at undue risk. These include the disease list above and other health problems that would make it difficult to comply with two 24-hour periods of confinement in the metabolic chamber such as panic disorder, cardiac arrhythmias, musculoskeletal disorders such as low back pain and osteoarthritis, and gastrointestinal disorders including reactions to supplements with caffeine and vitamin C, and food allergies.
- •Inability or unwillingness to consume the foods that will be included in the provided meals when staying in the chamber
- •History of drug or alcohol abuse (>5 standard drinks per day)
- •Taking herbal supplements or medications that may influence metabolism within 14 days prior to the study, including supplements containing bitter orange, guarana, fucoxanthin, and green coffee bean, and medications such as Meridia, Xenical, LipoRidAM, Advantra-Z, NuPhedrine, and Slim-
- •Current consumption (or unwilling to stop intake 2 weeks prior) of flavonoid supplements, or a heavy consumer of green tea (>3 cups per day)
- •Near-daily use of tablets containing caffeine (e.g., NoDoz) (or unwillingness to stop 2 weeks prior to the study).
- •High intake of caffeine from coffee, tea, energy drinks with caffeine, and soft drinks containing caffeine (or unwillingness to reduce intake for 2 weeks prior to the study and during the 4-week study).
- •Prone to panic attacks when confined in a small room, especially when consuming caffeine.
研究组 & 干预措施
Placebo
Placebo capsules
干预措施: Placebo (Dietary Supplement)
Flavonoid, caffeine
Flavonoid, caffeine capsules
干预措施: Flavonoid, caffeine (Dietary Supplement)
结局指标
主要结局
24-hour energy expenditure (kilocalories/minute) from continuous respiratory exchange measurements (oxygen consumption, carbon dioxide production) in a metabolic chamber
时间窗: 24 hours
Energy expenditure (kilocalories) over 24 h in metabolic chamber with oxygen consumption and carbon dioxide production analyzers whereby energy expenditure is calculated from respiratory exchange data (oxygen consumption, carbon dioxide production) using standard equations
次要结局
- 24-hour fat oxidation (fat grams oxidized per minute) from continuous respiratory exchange measurements (oxygen consumption, carbon dioxide production) in a metabolic chamber(24 hours)