Very-low-carbohydrate diets can improve blood sugar control in type 1 diabetes, with low rates of hypoglycaemia and other complications, according to an online patient survey. The researchers, led by Dr Belinda Lennerz and Dr David Ludwig of Boston Children's Hospital, now call for controlled clinical trials of this approach.
The patients were drawn from TypeOneGrit, a Facebook community of people with type 1 diabetes committed to a very-low-carb diet as recommended by the book Dr Bernstein's Diabetes Solution (Dr Richard Bernstein is a co-author on the study).
Of 493 people who took the survey, 316 provided enough information to be included in the analysis. For 138 of these participants, the researchers were able to confirm diabetes diagnosis, blood-sugar control measures, metabolic health measures and other outcomes with health care providers or through review of medical records. Forty-two percent of participants were children.
Participants reported an average daily carbohydrate intake of 36 grams, or about 5% of total calories (for comparison, the American Diabetes Association recommends about 45% of calories come from carbohydrates). Self-reported haemoglobin A1c values – the primary measure of blood-sugar control – averaged in the normal range, at 5.67% (the target is below 7% and prevailing levels average 8.2%).
Participants required lower-than-average doses of insulin (mean, 0.40 U/kg/day), and those for whom data were available had favourable measures of insulin sensitivity and cardiometabolic health, such as low triglyceride levels and high HDL cholesterol levels.
Safety concerns have been raised about very-low-carb diets in type 1 diabetes, primarily that they increase the risk of hypoglycaemia, or dangerous drops in blood sugar. However, in the study, rates of hospitalisation for hypoglycaemia (1%), diabetic ketoacidosis (2%) and other diabetes complications were lower than those generally reported for type 1 diabetes populations.
More than 80% of survey respondents were satisfied or very satisfied with their diabetes management. Yet about a quarter said they did not discuss the very-low-carb diet with their diabetes care providers, some citing concerns about being criticised or even being accused of child abuse.
The study authors note that severe carbohydrate restriction is actually a very old approach in type 1 diabetes.1 Before the discovery of insulin, it extended children's lives, sometimes for years. Once insulin was introduced, carb restriction fell out of practice.
But the authors believe very-low-carbohydrate diets deserve further study in type 1 diabetes. Since this study was observational in nature and not controlled, they call for randomised clinical trials to rigorously test the diet's safety and efficacy.
Lennerz and Ludwig emphasise that the results of this study, by themselves, do not justify a change in diabetes management. They strongly suggest that anyone with diabetes make dietary changes only with the supervision of a diabetes care provider.
Abstract
Objectives: To evaluate glycemic control among children and adults with type 1 diabetes mellitus (T1DM) who consume a very low–carbohydrate diet (VLCD).
Methods: We conducted an online survey of an international social media group for people with T1DM who follow a VLCD. Respondents included adults and parents of children with T1DM. We assessed current hemoglobin A1c (HbA1c) (primary measure), change in HbA1c after the self-reported beginning of the VLCD, total daily insulin dose, and adverse events. We obtained confirmatory data from diabetes care providers and medical records.
Results: Of 316 respondents, 131 (42%) were parents of children with T1DM, and 57% were of female sex. Suggestive evidence of T1DM (based on a 3-tier scoring system in which researchers took into consideration age and weight at diagnosis, pancreatic autoimmunity, insulin requirement, and clinical presentation) was obtained for 273 (86%) respondents. The mean age at diagnosis was 16 ± 14 years, the duration of diabetes was 11 ± 13 years, and the time following a VLCD was 2.2 ± 3.9 years. Participants had a mean daily carbohydrate intake of 36 ± 15 g. Reported mean HbA1c was 5.67% ± 0.66%. Only 7 (2%) respondents reported diabetes-related hospitalizations in the past year, including 4 (1%) for ketoacidosis and 2 (1%) for hypoglycemia.
Conclusions: Exceptional glycemic control of T1DM with low rates of adverse events was reported by a community of children and adults who consume a VLCD. The generalizability of these findings requires further studies, including high-quality randomized controlled trials.
Authors
Belinda S Lennerz, Anna Barton, Richard K Bernstein, R David Dikeman, Carrie Diulus, Sarah Hallberg, Erinn T Rhodes, Cara B Ebbeling, Eric C Westman, William S Yancy, David S Ludwig
[link url="https://www.sciencedaily.com/releases/2018/05/180507074218.htm"]Boston Children’s Hospital material[/link]
[link url="http://pediatrics.aappublications.org/content/early/2018/05/03/peds.2017-3349"]Pediatrics abstract[/link]