The Effects of Orange Juice on Insulin Sensitivity and Plasma Lipids
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 36
- 试验地点
- 2
- 主要终点
- Insulin sensitivity ('M' value)
研究概览
简要总结
The aim of this study is primarily to investigate the ability of antioxidants found in orange juice (OJ) to increase the body's sensitivity to the hormone insulin. Overweight or mildly obese women, who are otherwise healthy, will be recruited. The time commitment for subjects is ~14wks. Subjects will attend the laboratory on 5 occasions after fasting from midnight. The 1st is a medical screening. Laboratory visits 2 & 5 will take ~5hrs and will be separated by 3 months, during which time subjects will consume 250ml of an orange drink (either OJ or an orange flavoured control drink) once a day. During visits 2 & 5, subjects will have a scan to assess their %body fat using a low-dose x-ray machine, and have their insulin sensitivity measured using a technique called a 'Glucose Clamp'. During the 3hr glucose clamp, subjects receive an infusion of the hormone insulin and a glucose solution directly into their blood stream, with insulin sensitivity determined from the amount of glucose required to maintain blood glucose at normal levels. In addition, a small sample of fat tissue (about the size of a haricot bean) will be taken from underneath the skin of the belly. Subjects will record their food intake for 3-days in weeks 3, 7 and 11 of consuming the drink, and come to the lab for visits 3&4 during weeks 4&8. Laboratory visits 3&4 repeat measurements taken in the 1st (screening) visit.
详细描述
Background:
Overweight and mild obesity are associated with insulin resistance and mild elevations in lipid risk factors which are not usually sufficiently abnormal to merit treatment. Such people are encouraged to lose weight to reduce their risk of progressing to type 2 diabetes and coronary heart disease, but there is clearly a potential role for dietary modifications to maximize any potential benefit of this weight loss. Flavonoids are known to have vascular effects which might enhance substrate delivery to metabolically active tissues, and thus improve insulin sensitivity. There are many different dietary sources of flavonoids, with fruits such as apples, berries and citrus being rich sources. However, some researchers have expressed concern that a high dietary intake of 100% juice may contribute to the development of insulin resistance, obesity and the Metabolic Syndrome (Bazzano, Li et al. 2008), although this is not universally accepted (Fujioka, Greenway et al. 2006; O'Neil and Nicklas 2008). To date, there have been no studies investigating the effects of citrus fruits on indices of cardio-metabolic health in people who are presently healthy but are at risk of developing some features of the Metabolic Syndrome.
Aims:
To investigate the effects of orange juice (OJ) intake on insulin sensitivity, appetite hormones, blood pressure and plasma lipids. In addition we aim to investigate any gene expression changes associated with OJ consumption, in particular in adipose tissue.
Experimental protocol and methods:
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- Single (Participant)
入排标准
- 年龄范围
- 18 Years 至 55 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •pre-menopausal or post-menopausal and taking HRT
- •BMI 27-35kg/m2
- •HOMA-IR value > 1.5
排除标准
- •pregnant or breast feeding,
- •any metabolic or endocrine abnormalities,
- •clinically significant abnormalities on screening,
- •fasting glucose > 6.0mmol/l,
- •taking medication other than the contraceptive pill or HRT
- •herbal supplement use,
- •food allergies/intolerances related to the investigational product (citrus juices, fructose)
- •daily consumption of >100ml citrus juices
结局指标
主要结局
Insulin sensitivity ('M' value)
时间窗: after 3 months' intervention
Insulin sensitivity (mg glucose disposal from the blood/kg body weight/min)calculated from glucose disposal during a hyperinsulinemic, euglycemic glucose clamp
次要结局
- Glucose Oxidation rate(after 3 months' intervention period)
- High Density Cholesterol(after 3 months' intervention)
- Low density cholesterol(after 3 months' intervention)
- Gene expression in adipose tissue(after 3 months' intervention)
研究者
Elizabeth Simpson
Senior Research Fellow
University of Nottingham