None listed
Conditions
Brief summary
The vascular endothelium plays an important role in the regulation in several important bodily processes, including arterial tone, thrombosis, and inflammation. Dysfunction in the endothelium can lead to the development of atherosclerotic lesions, a pathophysiological link to acute cardiovascular disorders. A common condition associated with endothelial dysfunction is obesity. Current research suggests that the mechanism of obesity-induced endothelial dysfunction may be multifactorial, as excess adipose tissues has been shown to induce several metabolic changes which have the potential to interfere with normal endothelial function. A recent meta-analysis (Joris, P J et al. 2015) of human studies on the effects of weight loss on FMD of the brachial artery reported that weight loss increased FMD vs. control by 3.29%. It also estimated that each 10kg decrease in body weight increased fasting FMD by 1.11%. Researchers highlighted that effects may depend on subject characteristics, type of weight-loss treatment, and dietary composition. Within the studies included in the meta-analysis, increases in FMD were larger in the higher weight-loss group when subjects consumed low-fat diets compared with low-carbohydrate diets. What has not been investigated however, in this meta-analysis or indeed in any RCT to date, is whether the impact of changed dietary composition (and resulting hypocaloric conditions) through intermittent energy restriction results in a change in FMD. Accordingly, the current study is designed to investigate the effect of intermittent energy restriction on endothelial function, relative to habitual intakes. This research will add value to the scientific field by adding to the existing literature targeting intermittent energy restriction and its potential health benefits. primary aim of this study is to investigate the effect of two fasting days compared to two ad libitum eating days on blood vessel function. Secondary aim is to determine changes in, serum lipids, plasma glucose and insulin. We hypothesize that individuals will have similar endothelial function following two fasting days compared to two ad libitum eating days.
Interventions
In a randomized cross-over study including 32 adults men and women an intermittent energy restriction regime asking participants to follow a very low calorie diet (2100kJ for women and 2500kJ for men) for two days per week before returning to their normal eating habits for the other 5 days will be prescribed. This is commonly known as the 5:2 diet. Participants will be asked to attend the Sansom Institute for Health Research Clinical Trials Facility on four separate occasions. Body height (once
In a randomized cross-over study including 32 adults men and women an intermittent energy restriction regime asking participants to follow a very low calorie diet (2100kJ for women and 2500kJ for men) for two days per week before returning to their normal eating habits for the other 5 days will be prescribed. This is commonly known as the 5:2 diet. Participants will be asked to attend the Sansom Institute for Health Research Clinical Trials Facility on four separate occasions. Body height (once only), body weight & and blood vessel function (using techniques of applying blood pressure cuffs to you upper arm and thigh and an ultrasound of the artery above your elbow) will be measured as part of an initial screening visit participants will also meet with a dietitian who will assess eligibility for the study & provide information about the diet. Dietary compliance will be measured via weighed food diary (weighing everything you eat) for the duration of each fast day during the trial (8 days). The fasting days are required to be consecutive, and the 5:2 regime is to be followed continuously for 4 weeks. Visit 2 will occur two weeks later and will involve a check in with the dietitian to check dietary compliance. The following week participants will be asked to return for a visit following 2 fast days or 2 ad libitum eating days (this will be discussed in visit 2) for assessment of weight and blood vessel function. Visit 4 they will return for measurements as taken in visit 3 following the reverse dietary condition. The order of assessment for visits 3 and 4 is randomised using an online randomisation generator. Participants will also have their liver size measured via ultrasound at the baseline and last visit of the trial. The study runs for a total of 4 weeks.
Sponsors
University of South Australia
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Blinded (masking used) (Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
BMI > 18.5 kg/m Aged 18 - 75 years Not pregnant or breast feeding Participant reports they are healthy or have type 2 diabetes managed by diet alone or stable dose metformin
Exclusion criteria
Drinking more than 5 standard drinks per day and unable/unwilling to stop Participant reports they are unwell Participating in any ongoing dietary studies Eating out more than once a fortnight and unable/unwilling to stop for the duration of the study
Outcome results
None listed