None listed
Conditions
Brief summary
A key defect in type 2 diabetes (T2D) is the impaired ability to respond to insulin and remove circulating glucose and store it in muscle. We have recently established that long-term and high dose vitamin C supplementation improves insulin sensitivity in muscle in people with T2D to a degree which is clinically significant. Therefore, this cheap and safe supplement is likely to be an effective adjunct therapy to complement current standard care and control excess blood glucose levels. Therefore, the aim of this project is to investigate whether antioxidant vitamin C supplementation results in a clinically significant improvement in glycaemic control in people with T2D. Forty males and females with T2D (aged 45-75 yrs) will be recruited and undergo placebo and vitamin C (0.5g twice daily) in a double-blind, randomized, cross-over manner. Outcome measures will be conducted at the beginning (baseline) and end of each 4 month treatment and involve a visit at each of these times to the Clinical Research Laboratory at Deakin University. There will be a 4 week washout between treatments, so total involvement will be 9 months. Participants will be asked to complete a 4-day food and physical activity diary the week prior to each laboratory visit. Participants will have their height, weight and blood pressure measured and a DXA scan to measure body composition. Participants will be fitted with an accelerometer to measure physical activity and a Continuous Glucose Monitoring (CGM) system to monitor interstitial blood glucose. The following morning they will visit the laboratory in a fasted state and have a blood sample taken and eat a healthy breakfast provided by us. The accelerometer and CGM will be worn at home by participants, and (blinded) measurements will occur over a continuous 48-hour period while participants eat pre-prepared healthy meals provided by us.
Interventions
People with type 2 diabetes will undergo supplementation with oral capsules of ascorbic acid (0.5g twice daily) and placebo for four months each in a double-blind, randomized, cross-over manner. A four-week wash-out period will separate the different interventions. At the start and end of each four-month intervention, participants will undergo a number of measurements. These measurements include whole-body dual-energy X-ray absorptiometry (DXA) to measure body composition, and a fasting blood sa
People with type 2 diabetes will undergo supplementation with oral capsules of ascorbic acid (0.5g twice daily) and placebo for four months each in a double-blind, randomized, cross-over manner. A four-week wash-out period will separate the different interventions. At the start and end of each four-month intervention, participants will undergo a number of measurements. These measurements include whole-body dual-energy X-ray absorptiometry (DXA) to measure body composition, and a fasting blood sample to measure plasma ascorbic acid, glucose, insulin, lipids and HbA1c. At the start and end of each four-month intervention, participants will also be fitted with a continuous glucose monitor (CGM) for measurement of postprandial glucose and an accelerometer to objectively measure physical activity. CGMs and accelerometers will be worn and provide measurements over a continuous 48h-period at each time point. A diet of pre-packaged and fresh nutrient-controlled foods will be provided to participants for these 48h. For the four days prior each laboratory visit, participants will complete a 4-day food diary and physical activity survey to monitor consistency of nutrient intake and physical activity during the study duration. Capsule compliance during the study duration will be encouraged through regular weekly phone calls and/or SMS contact. In addition, actual capsule compliance will be measured at the end of treatments by determining the percentage of capsules consumed relative to the expected number that should be consumed during the treatment period.
Sponsors
Dr Glenn Wadley
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
45 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
(i) Type 2 diabetes with glycaemic control that is modest (HbA1c between 7.0% and 9.0%); (ii) aged 45-75 years; (iii) body mass index < 35 kg/m2; (iv) blood pressure <160/90 mmHg.
Exclusion criteria
(i) Having a major medical illness in addition to Type 2 diabetes; (ii) taking >2000 mg metformin per day) or more than 2 different diabetes medications or on insulin therapy; (iii) smokers; (iv) taking vitamin supplements other than those provided by us during the trial
Outcome results
None listed