None listed
Conditions
Brief summary
Preliminary evidence suggests that low-carbohydrate (LC) diets appear safe for use in type 1 diabetes (T1D) and may be effective for certain subgroups of this clinical population. However, the available body of research is limited and there is still a lack of consensus regarding the efficacy of LC diets for improving T1D management. Since there are a multiplicity of lifestyle factors impacting T1D management, and with consideration that all individuals have their own personal needs and preferences, an interventional study that uses participants as their own controls and investigates a patient-led dietary approach will be of important clinical relevance. Therefore, a within-patient interventional study investigating a LC diet with an adaptive carbohydrate prescription (25-75 g/day) will be undertaken in adults with T1D in an outpatient setting. The aim of this research is to assess the efficacy of a LC diet in adults with T1D. Our primary objective is to determine the effects of a LC diet (25-75 g/day) on clinical markers of T1D management including HbA1c, glycaemic variability, frequency of hypoglycaemia, total daily insulin, and quality of life. We expect that a LC diet will result in improved T1D management compared to habitual diets higher in carbohydrates.
Interventions
This is a 28-week single arm within-participant intervention study involving a 4-week control period, a 12-week intervention period and a 12-week follow-up.
This study will investigate a 12-week low-carbohydrate (LC) diet with an adaptive carbohydrate prescription. The prescription will start at 50 g of digestible carbohydrate per day for the first 4 weeks, then it can be adapted (increased or decreased) within a broader range of 25-75 g/day according to individual blood glucose levels and pers
This is a 28-week single arm within-participant intervention study involving a 4-week control period, a 12-week intervention period and a 12-week follow-up. This study will investigate a 12-week low-carbohydrate (LC) diet with an adaptive carbohydrate prescription. The prescription will start at 50 g of digestible carbohydrate per day for the first 4 weeks, then it can be adapted (increased or decreased) within a broader range of 25-75 g/day according to individual blood glucose levels and personal preference. Participants will meet individually with the study dietitian for a total of six 1-hour fortnightly sessions to receive dietary instruction, strategies and education. All six diet sessions will be delivered via Telehealth (Zoom video conferencing). Participants will be required to test their blood glucose levels at least six times daily, in accordance with standard diabetes management practices, using whatever method(s) they usually use to test glucose. The dietitian will review participants' dietary intake (via diet history or Easy Diet Diary mobile App tracking) and blood glucose levels to monitor adherence to the intervention throughout the study. The purpose of this study is to investigate a LC dietary intervention. However, it is not possible to make major changes to the dietary management of T1D without considering the subsequent required change(s) to insulin management. As such, all participants will be supported by a member of their usual diabetes care team and provided with an information pack (developed by the study diabetes educator, dietitian, physician and endocrinologist) at the beginning of the study that contains suggested guidelines for insulin management on a LC diet. The information pack includes resources relating to general considerations for insulin management on a LC diet; blood glucose self-monitoring; managing hypoglycaemia; and managing sick days. For safety purposes, participants will be required to self-monitor either urine or blood ketones regularly throughout the intervention period using their usual method(s) of measuring ketones. Participants will be required to measure their ketones at least twice per week, and more under certain circumstances (e.g., if feeling unwell) as per standard of care diabetes practices. Prior to starting the dietary intervention, participants will undertake a 4-week control period where they will be asked to maintain their usual dietary intakes and diabetes management practices. They will be provided with basic diet- and diabetes-related education by the dietitian, including information on carbohydrate counting, food label reading, blood glucose monitoring and managing hypoglycaemia. Once participants have completed the 4-week control period, they will start the intervention period immediately.
Sponsors
The University of Sydney
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
• Adults aged 18-70 yrs • Residing within Australia • Previously diagnosed T1D (confirmed with specialist letter/correspondence, diabetes duration greater than or equal to 6 months, using multiple daily injections of insulin and/or insulin pump) • Suboptimal glycaemic control (HbA1c greater than 7.0%) • BMI 18.5-39.9 kg/m2 • Habitual dietary intake contains more than 150 g/day of total carbohydrates (assessed by a 24-hour diet recall collected by study dietitian) • Independent free-living, able to understand study requirements, speak and understand fluent English, and both physically and cognitively able to provide their informed consent • Willing and able to self-monitor blood glucose levels using both finger-prick and/or continuous blood glucose monitoring devices on a daily basis • Willing and able to learn and utilise dietary carbohydrate and protein counting skills • Willing and able to titrate insulin dosages according to their dietary carbohydrate (and/or protein) intake in consultation with a member of their usual diabetes care team • Owns and can competently use an iOS or Android mobile device that is able to receive text messages/calls and download free mobile applications from the App Store or Google Play • Has access to and can competently use a computer, mobile or tablet device with internet connection for uploading data onto REDCap and for Zoom conferencing • Be willing to visit an Australian Clinical Labs collection centre (https://www.clinicallabs.com.au/location/) on four separate occasions throughout the study
Exclusion criteria
• HbA1c equal to or less than 7.0% • Underweight (BMI less than 18.5 kg/m2) or class III obesity (BMI greater than or equal to 40 kg/m2) • Habitual use of an automated insulin delivery system to control blood glucose levels • Habitual adherence to a fixed insulin regimen such that they are not confident in titrating insulin dosages according to their dietary intake. • Previously diagnosed hypo unawareness • Non-English speaking or unable to understand English • Previous medical diagnosis of cognitive impairment and/or mental illness (not including depression and anxiety) • Using medication to manage depression and/or anxiety and medications have been increased within the last three months • Current physical impairment or disability that limits individual capacity to communicate with researchers and/or use the mobile application Easy Diet Diary (e.g., blind/vision impaired/deaf/speech impaired) • Habitual dietary intake contains equal to or less than 150 g/day of total carbohydrates • Usual dietary intake strictly excludes animal-based protein (e.g., vegan diet) • Undertaken major change(s) to their insulin delivery method and/or glucose monitoring method within the last three months, of which they are unfamiliar (e.g., switched from injections to insulin pump and has never used pump before, or from multiple daily finger pricks to CGM and has never used CGM before) • Recent pregnancy or lactation (within the last six months) • Planning to get pregnant within the next 12 months • Self-identifies as current or recent smoker (within the last 6 months) • Significant weight change (+/- 10% body weight) within the last three months • Previous weight loss surgery • History of malignancy (other than non-melanoma) • History of thalassemia or other haemoglobinopathy • Pre-existing anaemia • Recent blood transfusion (within the last three months) • A known family history of premature heart disease, including having a first-degree male relative (i.e., father or brother) or a first degree female relative (i.e., mother or sister) who had a heart attack, stroke or was diagnosed with cardiovascular disease before the ages of 55 or 65, respectively • Previously diagnosed familial hypercholesterolaemia • Previously diagnosed gastrointestinal disease (not including irritable bowel syndrome [IBS], coeliac disease or stable treated inflammatory bowel disease [IBD]), liver disease (including liver cirrhosis; not including fatty liver), chronic kidney disease (CKD; eGFR less than 60), respiratory disease (not including stable treated asthma), thyroid disease (including goitre; not including stable treated hyper- or hypothyroidism) or cardiovascular disease (including coronary heart disease, heart failure, cardiomyopathy, congenital heart disease, peripheral vascular disease and stroke; not including hyperlipidaemia or hypertension) • Previously diagnosed neurological disorder (including high-frequency episodic migraine [10-14 headache days per month], chronic migraine [greater than or equal to 15 headache days per month], epilepsy, dementia, multiple sclerosis and Parkinson’s disease; not including low frequency migraines [less than 10 headache days per month]) • Previously diagnosed with a clinical eating disorder (including anorexia nervosa, bulimia nervosa or binge eating disorder) (within the last five years) • Existing patient of Mrs Amy Rush (Credentialled Diabetes Educator), Dr David Lim (Medical Doctor), Dr Kevin Lee (Endocrinologist) or Ms Jessica Turton (Accredited Practising Dietitian)
Outcome results
None listed