Low GI Foods Significantly Reduce Blood Sugar in Diabetes Patients

Low glycemic index foods found to be helpful in lowering A1C and blood sugar in diabetic patients

Changes in diet to a low glycemic diet are associated with small but meaningful improvements in lowering blood sugar, weight, cholesterol, and other risk factors found in diabetic patients. These findings are a part of a recent study done in the BMJ. In addition, Mayo Clinic did an article highlighting why a low GI diet may be effective and why other healthy alternatives could do the same job as a low GI diet. Finally, a study done in 2008 in BMC nutritional journal highlighted scientific literature that shows a low GI diet has favorable effects on rapid weight loss and a decrease in fasting glucose levels.

Low GI diet and its effects on glycemic control have been studied for 15+ years to help show how this diet can have significant impacts on diabetic patients and helping with some of the significant challenges they face. GI diets consist of assigning a number to carbohydrate-containing food according to how much it will increase the blood sugar; it’s simply a carb counting mechanism to guide food choices. Low GI increase blood glucose 1-55 mg/dl, medium: 56-69 mg/dl, and high 70 mg/dl and higher. The improvements in cholesterol, blood sugar, and weight loss showed more progress with the low GI diet than oral glycemic lowering drugs and insulin therapy. Twenty-seven randomized control trials with publications up to May 2021 that investigated the effects of a low GI diet in diabetic patients were used to conduct this study. 1617 Patients with type 1 and 2 diabetes that were overweight or obese. Primary outcomes were A1c. Secondary outcomes were fasting glucose, fasting insulin, LDL, HDL, body weight, BMI, waist circumference, Blood Pressure, and inflammation (CRP). Trials used were conducted in outpatient settings in Canada, Australia, France, the USA, Israel, and Mexico. The median follow-up duration was 12 weeks, the glycemic control average was 7.7%, and treated with hyperglycemic drugs (69%), insulin (14%), or a mix of both (7%).

The primary outcome HbA1c compared with controlled diets P <0.001 with a statistical significance at P<0.10, showing that the GI diet was significant in lowering the A1c better than control diets. Secondary outcomes reductions in non-HDL P=0.002, small decreases in LDL P=<0.001. Fasting glucose, body weight, BMI, and CRP were reduced in the low GI diet. While blood insulin, HDL, waist circumference, and blood pressure showed no significant reductions compared to controlled diets. Ultimately, results can conclude that a low GI diet shows significant improvements in glycemic control as seen in the primary outcome A1C and secondary outcomes blood lipids, adiposity, and inflammation beyond what hyperglycemic drugs and insulin concurrent treatment.

The evidence for this study shows that this may be more beneficial in middle-aged adults with moderately controlled type 1 and 2 diabetes, which also poses a weakness of the study results. Because this study failed at showing a reduction in waist circumference and blood pressure, we could benefit from a full trial where the secondary outcomes of this study are tested again against other control diets. There are plenty of clinical trials done proving low GI diets significantly helps diabetic patient with glucose and A1C control. Studies like this have shaped conversations healthcare teams provide recommendations to patients on control of their A1C and blood glucose levels. Canada diabetes guidelines include specific recommendations and guides on low GI eating to help control blood sugar. More studies should be done to test the benefit of the low GI diet on older and less controlled diabetic patients.

Practice Pearls:

• Low GI diet studies show significant reductions in A1c and blood glucose levels
• Patients who are middle-aged with moderately controlled diabetes may benefit more from this study
• Other essential factors such as weight loss and cholesterol-lowering, which can directly impact cardiovascular events, were also shown to be improved with a low GI diet.

1. ChiavaroliL, Lee D, Ahmed A, Cheung A, Khan T A, Blanco S et al. Effect of low glycaemic index or load dietary patterns on glycaemic control and cardiometabolic risk factors in diabetes: systematic review and meta-analysis of randomised controlled

trialsBMJ  2021;  374 :n1651 doi:10.1136/bmj.n1651

2. Radulian G, Rusu E, Dragomir A, Posea M. Metabolic effects of low glycaemic index diets.Nutr J. 2009;8:5. Published 2009 Jan 29. doi:10.1186/1475-2891-8-5

 Erica Hicks, PharmD Candidate 2022, South College School of Pharmacy