Grains Reduce Adiposity and Improve Nutrition Study (GRAINS) Increased Whole Grain Intake - Beneficial Effects on Visceral Adiposity, Vascular Function and Glucose Metabolism/Insulin Resistance
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 54
- 试验地点
- 2
- 主要终点
- Body Composition
研究概览
简要总结
Whole grain intake beneficially affects body weight, body fat and glucose metabolism, and the investigators' previous work has shown that a high whole grain intake significantly reduced body fat in the abdominal region as measured by dual energy X-ray absorptiometry (DEXA) compared to a refined grain intake. Additional research is needed with regard to the mechanisms by which whole grains may affect visceral adiposity and the adipokines, which have been associated with risk for insulin resistance and type 2 diabetes. Therefore the proposed study aims to address these issues and in addition, includes exploratory work with adipocytes in cell culture to evaluate the effects of whole grains on adipocyte function.
Hypothesis:
There will be a greater reduction in visceral adiposity, indicators of insulin resistance (HOMA score), improvement in inflammatory status and improvement in adipokine levels after six weeks of a weight stable period and after six weeks of weight loss in subjects consuming 6-9 servings compared to 0 servings of whole grains per day.
详细描述
Including whole grains as part of a heart-healthy diet has been shown to be beneficial in decreasing body weight and body fat. The beneficial effects of whole grains on body weight may be explained by the larger volume and relatively low energy density of whole grain food thus leading to increased satiation. Reducing visceral fat is of particular importance as visceral adiposity has been associated with increased risk for metabolic diseases and cardiovascular disease.
The proposed study is a randomized, 2-parallel arm controlled feeding study. Subjects will be fed one of two weight maintenance diets (refined grain and whole grain) for 6 weeks, followed by a 6 week controlled weight loss period where subjects are fed the same diets, but at a reduced calorie level, designed to elicit weight loss (~2 lbs per week). Diets for both groups will have the same nutrient profile (percent of calories from fat, protein, carbohydrates, etc.); however, the whole grain (WG) group will substitute whole grains for refined grains in their grain intake (breads, tortillas, cereals, etc.). The WG group will be expected to take in 6-9 servings of whole grains per day on both diets. Plasma endpoints will be measured at baseline and at the end of the 6-week diet periods. Blood samples also will be taken at the mid-point of each period and held for analysis if deemed appropriate after initial data is reviewed. Endo-PAT will be conducted at baseline and at the end of each diet period as well as DEXA and MRI testing.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- None
入排标准
- 年龄范围
- 35 Years 至 55 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •BMI > 25 to < 42
- •Waist circumference of > 40 inches for males and > 35 inches for females and having one other of the criteria for metabolic syndrome will be recruited
- •In this population, we will also accept the following:
- •LDL-C < 175 mg/dL
- •HDL-C > 25 mg/dL
- •Triglycerides < 400 mg/dL
- •All subjects will be required to meet one specific criteria for metabolic syndrome beyond increased waist circumference
排除标准
- •Have insulin-dependent diabetes
- •Are pregnant or expecting to be pregnant, lactating in the last 6 months
- •Are taking NSAIDS or other medications known to affect inflammatory markers or drugs affecting glucose metabolism
- •Blood pressure lowering medications are acceptable if the person has controlled BP at screening, <140/90 mmHg.
结局指标
主要结局
Body Composition
时间窗: Week 6 and 12 - End of diet period 1 and 2
To assess regional changes in body fat deposition, subjects will undergo a dual energy X-ray absorptiometry (DXA) scan at baseline (beginning of study) and end of each intervention period. Waist circumference measurements also will be taken at this time to track how much fat is lost from the abdominal area of the body.
次要结局
- Abdominal obesity(Week 14 - End of diet period 2)
- Fasting glucose(Time 0, week 6 and week 14 - Baseline end of each diet period)
- Resting Metabolic Rate(Week 0 and week 14 - Baseline and end of diet period 2)
- Appetite Hormones(Week 0, week 6 and week 14 - Baseline end of each diet period)
- Endothelial Health(Week 0, week 6 and week 14 - Baseline end of each diet period)
- Plasma cytokines(Week 0, week 6 and week 14 - Baseline end of each diet period)