Low Glycemic Diet Improves A1c, Other Risk Factors in Diabet
A diet rich in vegetables and low in carbs — a so-called low glycemic index (GI) diet ? is associated with clinically significant benefits beyond those provided by existing medications for people with type 1 and type 2 diabetes, compared with a higher glycemic diet, findings from a new meta-analysis show.

This study aimed to inform the update of the European Association for the Study of Diabetes clinical practice guidelines for nutrition therapy.

Eligibility criteria for selecting studies Randomised controlled trials of three or more weeks investigating the effect of diets with low glycaemic index (GI)/glycaemic load (GL) in diabetes.

The primary outcome was glycated haemoglobin (HbA1c). Secondary outcomes included other markers of glycaemic control (fasting glucose, fasting insulin); blood lipids (low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), non-HDL-C, apo B, triglycerides); adiposity (body weight, BMI, waist circumference), blood pressure (systolic blood pressure (SBP) and diastolic blood pressure (DBP)), and inflammation (C reactive protein (CRP)).

Two independent reviewers extracted data and assessed risk of bias. Data were pooled by random effects models. GRADE (grading of recommendations assessment, development, and evaluation) was used to assess the certainty of evidence.

-- 29 trial comparisons were identified in 1617 participants with type 1 and 2 diabetes who were predominantly middle aged, overweight, or obese with moderately controlled type 2 diabetes treated by hyperglycaemia drugs or insulin.

-- Low GI/GL dietary patterns reduced HbA1c in comparison with higher GI/GL control diets.

-- Reductions occurred also in fasting glucose, LDL-C, non-HDL-C, apo B, triglycerides, body weight, BMI, and CRP, but not blood insulin, HDL-C, waist circumference, or blood pressure.

-- A positive dose-response gradient was seen for the difference in GL and HbA1c and for absolute dietary GI and SBP.

-- The certainty of evidence was high for the reduction in HbA1c and moderate for most secondary outcomes, with downgrades due mainly to imprecision.

Conclusively, this synthesis suggests that low GI/GL dietary patterns result in small important improvements in established targets of glycaemic control, blood lipids, adiposity, and inflammation beyond concurrent treatment with hyperglycaemia drugs or insulin, predominantly in adults with moderately controlled type 1 and type 2 diabetes. The available evidence provides a good indication of the likely benefit in this population.

Source: https://www.bmj.com/content/374/bmj.n1651