Glycemic Index and Brain Function
The Effects of Dietary Glycemic Index on Brain Function
研究概览
详细说明
Most individuals have great difficulty following reduced calorie diets because they experience increased hunger. This process is regulated by specific brain areas. Though many psychological and environmental factors are involved, physiological effects of diet may have a significant impact. The postprandial rise in blood glucose, quantified by the glycemic index (GI), is of particular interest. High GI meals elicit hormonal events that limit availability of metabolic fuels, causing hunger and overeating, especially in people with high insulin secretion.
Our aim is to examine how postprandial changes after high versus low GI meals affect hunger and brain function in areas of intake control. Specifically, we speculate that obese individuals will demonstrate functional changes in brain areas of intake control and increased hunger after a high versus low GI meal.
We will recruit obese, young adults and quantify their insulin secretion during a 2-hour oral glucose tolerance test. A brief practice MRI session will serve to familiarize the subjects with the scanning process. During the two test sessions, standardized test meals with high versus low GI will be given in a randomized, blinded cross-over design. Serial blood levels of hormones, metabolic fuels, and metabolites will be correlated with perceived hunger, and a perfusion MRI scan will be performed to assess brain activation during the late postprandial phase, at the nadir of blood sugar and insulin levels (4 hours postprandial).
This work will inform an integrated physiological model relating peripheral postprandial changes to brain function and hunger. In addition, findings may provide evidence of a novel diet-phenotype, in which baseline clinical characteristics can be used to predict which weight loss diet will work best for a specific individual. Metabolite profiling might shed light on the mechanisms linking diet composition to brain function, and provide feasible clinical markers of the identified phenotype to facilitate translation into practice.
研究类型
注册 (实际的)
阶段
- 不适用
联系人和位置
学习地点
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Massachusetts
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Boston、Massachusetts、美国、02215
- Beth Israel Deaconess Medical Center
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Boston、Massachusetts、美国、02115
- Children's Hospital Boston
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Boston、Massachusetts、美国、02215
- Brigham and Women's Hospital
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参与标准
资格标准
适合学习的年龄
接受健康志愿者
有资格学习的性别
描述
Inclusion criteria
- Males age 18 to 35 years
- BMI less than or equal to 25 for age and gender
Exclusion criteria
- weight > 300 lbs
- largest body circumference > 144cm
- body shape incompatible with MRI scanner or equipment
- MRI exclusion criteria
- large fluctuations in body weight (5% over preceding 6 months, 2.5% during the study)
- known medical problems that may affect metabolism or hormones
- diabetes mellitus (fasting plasma glucose ≥126 mg/dL)
- other abnormal laboratory screening tests
- taking any medications or dietary supplements that might affect body weight, appetite, or energy expenditure
- smoking or illicit substance abuse
- high levels of physical activity (>30 minutes per day, > 4days per week)
- currently following a weight loss diet
- allergies or intolerance to eggs, vanilla extract, equal, canola oil, milk, cornstarch, corn syrup
学习计划
研究是如何设计的?
设计细节
- 主要用途:治疗
- 分配:随机化
- 介入模型:交叉作业
- 屏蔽:四人间
武器和干预
参与者组/臂 |
干预/治疗 |
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有源比较器:Low GI
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Subjects will be instructed to consume a liquid test meal with a low GI over 5 minutes after baseline laboratory evaluations.
The low and high GI meal contain similar amounts of milk, oil, dried egg whites, equal, and vanilla extract.
The low GI meal corn-starch as a carbohydrate.
Both meals have similar macronutrient composition (60% carbohydrate, 15% protein, 25% fat), micronutrient profiles, physical properties, palatability and sweetness.
The high vs. low GI meals have a predicted difference in GI of 90 vs. 40, and consistent with this prediction, a pilot study in obese young adults found a 2.2-fold difference in glycemic response (p<0.001).
The test meals will provide 25% of individual daily energy requirements.
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实验性的:High GI
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Subjects will be instructed to consume a liquid test meal with a high GI over 5 minutes after baseline laboratory evaluations.
The low and high GI meal contain similar amounts of milk, oil, dried egg whites, equal, and vanilla extract.
The high GI meal contains corn-syrup as a carbohydrate.
Both meals have similar macronutrient composition (60% carbohydrate, 15% protein, 25% fat), micronutrient profiles, physical properties, palatability and sweetness.
The high vs. low GI meals have a predicted difference in GI of 90 vs. 40, and consistent with this prediction, a pilot study in obese young adults found a 2.2-fold difference in glycemic response (p<0.001).
The test meals will provide 25% of individual daily energy requirements.
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研究衡量的是什么?
主要结果指标
结果测量 |
大体时间 |
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Blood Flow in Brain Areas of Intake Control.
大体时间:4 hours postprandial
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4 hours postprandial
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次要结果测量
结果测量 |
措施说明 |
大体时间 |
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Subjective Hunger Rating
大体时间:Every 30 minutes for 5 hours.
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Every 30 minutes for 5 hours.
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Blood Glucose Level
大体时间:Every 30 minutes for 5 hours.
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Every 30 minutes for 5 hours.
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Blood Insulin Level
大体时间:Every 30 minutes for 5 hours
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Every 30 minutes for 5 hours
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Blood Glucagon Level
大体时间:Every 30 minutes for 5 hours.
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Every 30 minutes for 5 hours.
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Blood Growth Hormone Level
大体时间:Every 30 minutes for 5 hours.
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Every 30 minutes for 5 hours.
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Blood Epinephrine Level
大体时间:Every 30 minutes for 5 hours.
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Every 30 minutes for 5 hours.
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Blood Fatty Acids Level
大体时间:Every 30 minutes for 5 hours.
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measuring metabolite profiles
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Every 30 minutes for 5 hours.
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合作者和调查者
调查人员
- 研究主任:Belinda S Lennerz, MD, PhD、Boston Children's Hospital
- 首席研究员:David Alsop, PhD、Beth Israel Deaconess Medical Center
出版物和有用的链接
研究记录日期
研究主要日期
学习开始
初级完成 (实际的)
研究完成 (实际的)
研究注册日期
首次提交
首先提交符合 QC 标准的
首次发布 (估计)
研究记录更新
最后更新发布 (估计)
上次提交的符合 QC 标准的更新
最后验证
更多信息
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Low GI的临床试验
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Clinical Nutrition Research Centre, Singapore完全的肥胖 | 2型糖尿病 | 糖尿病前期