Effect of Fructose on Metabolic Control in Humans: A Series of Systematic Reviews and Meta-analyses to Provide Evidence-based Guidance for Nutrition Guidelines Development
试验速览
- 阶段
- 不适用
- 发起方
- 入组人数
- 1
- 试验地点
- 1
- 主要终点
- Blood Pressure (BP) Analysis
研究概览
简要总结
Diabetes and heart associations continue to discourage high intakes of dietary fructose, a constituent part of the sucrose molecule that is found in fruits and vegetables as a natural sugar and in some processed foods and beverages as an added sweetener. The concern relates to its ability to increase certain blood fats and cholesterol, which increase the risk of cardiovascular disease. The evidence for an adverse effect of fructose on these risk factors, however, is inconclusive. To improve the evidence on which nutrition recommendations for fructose are based, the investigators therefore propose to study the effect of fructose on blood fats, cholesterol, sugars, blood pressure, and body weight, by undertaking a systematic synthesis of the data taken from all available clinical studies in humans. This technique has the strength of allowing all of the available data to be pooled together and differences to be explored in groups of different study participants (healthy humans of different sex, weight, and age and in those with diseases which predispose to disturbances in metabolism, such as diabetes) with dietary fructose in different forms, doses, and with differing durations of exposure. The findings generated by this proposed knowledge synthesis will help improve the health of consumers through informing recommendations for the general public, as well as those at risk of diabetes and cardiovascular disease.
详细描述
Background: Fructose has been implicated in chronic disease guidelines. The American Heart Association (AHA) and American (ADA), Canadian (CDA), and European (EASD) Diabetes Associations discourage dietary fructose at high intakes (>15-20% energy), citing its ability to aggravate blood lipids. The American Heart Association (AHA) and the World Health Organization (WHO) recommend reduced consumption (<5-7% and <10% energy, respectively) of added sugars, especially as high fructose corn syrup in sugar sweetened beverages, to decrease the risk of weight gain. These concerns, however, are based on inconsistent intervention data in humans. There is also paradoxical evidence that small, catalytic doses of fructose at a level obtainable from fruit (<10-g/meal) may improve glycemic control in humans.
Objective: To improve evidence-based guidance for fructose recommendations, the investigators propose conducting a series of 7 systematic reviews and meta-analyses of controlled feeding trials to assess the effect of oral fructose on cardiometabolic risk in humans. The first 6 systematic reviews and meta-analyses will each be conducted on a different area of cardiometabolic risk: (1) lipids, (2) glycemic control, (3) body weight, (4) uric acid, (5) blood pressure, and (6) non-alcoholic fatty liver (NAFL). The seventh meta-analysis will investigate the effect of small, "catalytic" doses of fructose at a level obtainable from fruit (<10-g/meal) on all areas of cardiometabolic risk.
Design: The planning and conduct of the proposed meta-analyses will follow the Cochrane handbook for systematic reviews of interventions. The reporting will follow the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.
Data sources. MEDLINE, EMBASE, CINAHL and The Cochrane Central Register of Controlled Trials (Clinical Trials; CENTRAL) will be searched using appropriate search terms, supplemented by manual, hand searches of bibliographies.
Study selection: We will include controlled feeding trials investigating the effect of fructose in isocaloric exchange for other carbohydrate sources (isocaloric trials) or added to a control diet as a source of excess energy (hypercaloric trials) on cardiometabolic risk factors in humans. Studies that are <7-days diet duration, lack a control, or do not provide viable endpoint data will be excluded. To isolate the effects of fructose, we will also exclude trials in which fructose was administered exclusively as sucrose (bound fructose) or high-fructose corn syrup (42% to 55% of free fructose), except where these sweeteners were the comparator.
研究设计
- 研究类型
- Observational
入排标准
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Trials in humans
- •Oral fructose intervention
- •Suitable control (i.e. another carbohydrate source in isocaloric exchange for fructose or a control diet which is compared with the same diet supplemented with excess energy from fructose)
- •>= 7-days diet duration
- •Viable endpoint data
排除标准
- •Non-human studies
- •IV or parenteral fructose
- •High fructose corn syrup or sucrose intervention (except where these are the comparators)
- •Lack of a suitable control
- •< 7-days diet duration.
- •No viable endpoint data
结局指标
主要结局
Blood Pressure (BP) Analysis
时间窗: January 2012
Analyses: 1. Systolic BP, diastolic BP, and mean arterial pressure (MAP)
"Catalytic" Fructose Across Cardiometabolic Endpoints Analysis
时间窗: January 2012
Analyses: 1. Lipids, glycemic control, body weight, blood pressure, and uric acid
Non-Alcoholic Fatty Liver (NAFL) Analysis
时间窗: June 2012
Analyses: 1. Imaging and spectroscopy endpoints of liver fat (Liver ultrasound \[US\], computed tomography \[CT\], magnetic resonance imaging \[MRI\], or magnetic resonance spectroscopy \[MRS\]) and biomarkers of hepatocellular injury (transaminases \[ALT, AST, GGT\])
Body Weight Analysis
时间窗: November 2011
Analyses: 1. Body weight
Uric Acid Analysis
时间窗: February 2012
Analyses: 1. uric acid
Lipid Analysis
时间窗: June 2012
Analyses: 1. Fasting lipids (triglycerides, HDL-cholesterol \[C\], LDL-C, apo-B, total-C:HDL-C ratio, apo-B:apo-A1 ratio, non-HDL-C) 2. Postprandial lipids (peak, mean, and area under the curve \[AUC\] triglycerides)
Glycemic Control Analysis
时间窗: June 2012
Analyses: 1. Glycated blood proteins (HbA1c, fructosamine, glycated albumin), glucose, and insulin in people with diabetes 2. Glycated blood proteins (HbA1c, fructosamine, glycated albumin), glucose, and insulin in people without diabetes 3. Insulin sensitivity (Euglycemic-hyperinsulinemic clamp, frequent sampling intravenous glucose tolerance test \[FSIGT\], Homeostasis model assessment of insulin resistance \[HOMA-IR\], oral glucose tolerance test insulin sensitivity index \[OGTT-ISI\])
次要结局
未报告次要终点
研究者
John Sievenpiper
Adjunct Research Fellow
University of Toronto