While low-carb diets are often recommended for people being treated for diabetes, little evidence exists on whether eating fewer carbs can impact the blood sugar control of those with diabetes or prediabetes who aren't treated by medications.
Now, according to new research from Tulane University, a low-carb diet can help those with unmedicated diabetes – and those at risk for diabetes – lower their blood sugar.
About the study
The six-month trial enrolled 150 individuals, average age 59, with HbA1c levels in the range of prediabetes and diabetes (6.0 to 6.9 per cent) who were not being treated by diabetes medication. Most participants (130) had prediabetes.
A hemoglobin A1c (HbA1c) test measures your average blood sugar level over the past three months.
The Canadian Diabetes Association considers a HbA1c of 6.0 to 6.4 per cent in the prediabetes range. According to the American Diabetes Association, a HbA1c of 5.7 to 6.4 per cent indicates prediabetes. Both organizations use a HbA1c of 6.5 per cent or more to diagnose diabetes.
The study compared two groups: one assigned to a low-carb diet and another that continued with their usual diet. After six months, the low-carb diet group had greater drops in hemoglobin A1c, a marker for blood sugar levels, when compared with the group who ate their usual diet. It’s used to diagnose prediabetes and diabetes, as well as help guide diabetes management.
The low-carbohydrate diet group also lost weight and had lower fasting glucose levels.
"The key message is that a low-carbohydrate diet, if maintained, might be a useful approach for preventing and treating Type 2 diabetes, though more research is needed," said lead author.
Type 2 diabetes comprises more than 90% of cases of diabetes in Canada and the United States. Type 2 diabetes can severely impact quality of life with symptoms such as blurred vision, numb hands and feet, and overall tiredness. It can also cause other serious health problems like heart disease, vision loss and kidney disease.
Findings important for those with prediabetes
The results are especially important for those with prediabetes whose A1c levels are higher than normal but below levels that would be classified as diabetes. Approximately 96 million Americans have prediabetes and more than 80% of those with prediabetes are unaware, according to the CDC. It’s estimated that 22% of Canadians have prediabetes.
Those with prediabetes are at increased risk for Type 2 diabetes, heart attacks or strokes and are usually not taking medications to lower blood sugar levels, making a healthy diet more crucial.
The study involved participants whose blood sugar ranged from prediabetic to diabetic levels and who were not on diabetes medication. Those in the low-carb group saw A1c levels drop 0.23% more than the usual diet group, an amount considered "modest but clinically relevant."
Importantly, fats made up around half of the calories eaten by those in the low-carb group, but the fats were mostly healthy monounsaturated and polyunsaturated fats found in foods like olive oil and nuts.
The study doesn't prove that a low-carb diet prevents diabetes.
But it does open the door to further research about how to mitigate health risks of those with prediabetes and diabetes not treated by medication.
Source: JAMA Network Open, October 26, 2022.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.