karppaus.info

Abstract
Objective To determine the efficacy and safety of low carbohydrate diets (LCDs) and very low carbohydrate diets (VLCDs) for people with type 2 diabetes.

Design Systematic review and meta-analysis.

Data sources Searches of CENTRAL, Medline, Embase, CINAHL, CAB, and grey literature sources from inception to 25 August 2020.

Study selection Randomized clinical trials evaluating LCDs (<130 g/day or <26% of a 2000 kcal/day diet) and VLCDs (<10% calories from carbohydrates) for at least 12 weeks in adults with type 2 diabetes were eligible.

Data extraction
Primary outcomes were remission of diabetes (HbA1c <6.5% or fasting glucose <7.0 mmol/L, with or without the use of diabetes medication), weight loss, HbA1c, fasting glucose, and adverse events. Secondary outcomes included health related quality of life and biochemical laboratory data. All articles and outcomes were independently screened, extracted, and assessed for risk of bias and GRADE certainty of evidence at six and 12 month follow-up. Risk estimates and 95% confidence intervals were calculated using random effects meta-analysis. Outcomes were assessed according to a priori determined minimal important differences to determine clinical importance, and heterogeneity was investigated on the basis of risk of bias and seven a priori subgroups. Any subgroup effects with a statistically significant test of interaction were subjected to a five point credibility checklist.

Results
Searches identified 14 759 citations yielding 23 trials (1357 participants), and 40.6% of outcomes were judged to be at low risk of bias. At six months, compared with control diets, LCDs achieved higher rates of diabetes remission (defined as HbA1c <6.5%) (76/133 (57%) v 41/131 (31%); risk difference 0.32, 95% confidence interval 0.17 to 0.47; 8 studies, n=264, I2=58%). Conversely, smaller, non-significant effect sizes occurred when a remission definition of HbA1c <6.5% without medication was used. Subgroup assessments determined as meeting credibility criteria indicated that remission with LCDs markedly decreased in studies that included patients using insulin. At 12 months, data on remission were sparse, ranging from a small effect to a trivial increased risk of diabetes. Large clinically important improvements were seen in weight loss, triglycerides, and insulin sensitivity at six months, which diminished at 12 months. On the basis of subgroup assessments deemed credible, VLCDs were less effective than less restrictive LCDs for weight loss at six months. However, this effect was explained by diet adherence. That is, among highly adherent patients on VLCDs, a clinically important reduction in weight was seen compared with studies with less adherent patients on VLCDs. Participants experienced no significant difference in quality of life at six months but did experience clinically important, but not statistically significant, worsening of quality of life and low density lipoprotein cholesterol at 12 months. Otherwise, no significant or clinically important between group differences were found in terms of adverse events or blood lipids at six and 12 months.

Conclusions
On the basis of moderate to low certainty evidence, patients adhering to an LCD for six months may experience remission of diabetes without adverse consequences. Limitations include continued debate around what constitutes remission of diabetes, as well as the efficacy, safety, and dietary satisfaction of longer term LCDs.

Published today in the British Medical Journal (BMJ), scientists found that after six months, patients who followed a low carb diet containing less than 26 per cent of daily calories from carbohydrates achieved greater rates of type 2 diabetes remission than those who followed other diets traditionally recommended for managing the disease.

Professor Grant Brinkworth, contributing author to the study and CSIRO Research Scientist, said the findings showed those who better adhered to the low carb dietary approach had the greatest health improvements.

"Building on existing research, this study underscores that a low carb diet can achieve greater weight loss and is more effective in reducing diabetes medication and improving blood glucose control," Professor Brinkworth said.

"However, this study has gone one step further in showing the low carb dietary approach to be effective in driving type 2 diabetes into remission.

"We know that lifestyle factors such as what we eat play a major part in determining our risk to type 2 diabetes. The good news is these lifestyle choices are within our control to change."

Diabetes has become one of the greatest global health challenges of the 21st century.

Worldwide it is estimated that one in 11 adults have diabetes and that it is responsible for approximately 11 per cent of deaths annually.

Type 2 diabetes is the most common form of the disease, with 90-95 per cent of all cases.

Study co-lead Dr Joshua Goldenberg, National University of Natural Medicine, Helfgott Research Institute in Oregon, said the study was the first systematic review to examine the safety and efficacy of low carb diets in adults and to assess remission rates of type 2 diabetes.

"We used the most robust scientific methods to examine the combined effects of 23 published clinical trials from across the world, involving 1357 participants, including additional data from five of those clinical trials on markers of blood sugar status," Dr Goldenberg said.

"By examining the totality of evidence on the effects of low carb diets against clinical targets, this study will help clinicians and patients to better understand how this dietary approach can be used to treat type 2 diabetes, which remains a significant and worsening problem worldwide, despite numerous pharmaceutical developments.

"The results of this study suggest low carb diets could be considered an effective alternative, while monitoring and adjusting diabetes medication as needed."

Professor Brinkworth said the findings underlined the need for diet support tools.

"These results show low carb diets can be a really effective dietary approach for type 2 diabetes management, however, the challenge is to provide patients with easy-to-use support tools and convenient product solutions to help them adhere to it long-term to gain these greater health improvements," Professor Brinkworth said.

"In the future, having clearer a definition of type 2 diabetes remission and more rigorous studies examining the long-term safety and satisfaction of low carb diets will also help to confirm the strength of this therapeutic approach."