Case studies: High-carb plant-based diets improve type 1 diabetes
Published in the Journal of Diabetes & Metabolism, both case studies followed individuals with type 1 diabetes who adopted plant-based diets rich in whole carbohydrates, including fruits, vegetables, whole grains, and legumes. The patients' health care teams tracked their blood sugar control, heart disease risk factors, and other health measurements before and after the diet change.
One case study followed a female patient who was diagnosed with type 1 diabetes in 2018. At the time, her A1c (average blood glucose level over the past 3 months) was 8.7%. She initially adopted a low-carbohydrate (less than 30 grams of carbohydrate per day), high-fat diet that was high in meat and dairy. Her blood sugar stabilised but she required more insulin per gram of carbohydrate consumed.
Her total cholesterol also increased from 175 to 221 mg/dL. In January 2019, she switched to a plant-based diet, eliminating dairy products, eggs, and meat. The patient was able to decrease her insulin dosage, maintain her A1c level at 5.4%, and drop her cholesterol level to 158 mg/dL.
"This study challenges the misconception that carbs are the enemy when it comes to diabetes," says study author Hana Kahleova, MD, PhD, director of clinical research at the Physicians Committee. "The patient in this case study experienced the opposite: Adding more healthful carbohydrates to her diet stabilized her glycemic control, reduced her insulin needs, and boosted her overall health."
The other individual - a 42-year-old man who had been diagnosed with type 1 diabetes at age 25 - eliminated animal products from his diet and switched to a whole food, plant-based diet. He increased his consumption of carbohydrates from 150 grams to 400-450 grams per day.
After adopting a carbohydrate-rich plant-based diet, he lost weight, required less insulin, and reduced his A1c from 6.2% to a range between 5.5-5.8%.
As a next step, the authors suggest that randomised clinical trials are needed to verify the case studies' findings, assess their generalizability, and quantify the effectiveness of plant-based diets in the management of type 1 diabetes.
Previous studies have found that low-fat, plant-based diets can improve glycemic control and be beneficial for those with type 2 diabetes. Research has also shown that those eating a plant-based diet have approximately half the risk of developing type 2 diabetes, compared with non-vegetarians.
The report explains the understood mechanisms of action: "High-fat diets may inhibit glucose utilisation, as the result of a downregulation of the genes required for mitochondrial oxidative phosphorylation in skeletal muscleand by increasing serum endotoxin levels, thus leading to insulin resistance.
"In contrast, a high-carbohydrate, high-fiber diet may increase postprandial metabolism and improve glucose disposal through an increase in insulin signaling, resulting in GLUT4 translocation. Therefore, a highcarbohydrate, high-fiber diet seems to increase insulin sensitivity and enhance glucose oxidation in type 1 diabetes."
Dr. Kahleova concludes: "Decades of research has proven that a plant-based diet can be beneficial for those with type 2 diabetes. Now, these groundbreaking case studies are offering hope that the same may be true for those with type 1 diabetes."
Source: Journal of Diabetes and Metabolism
Kahleova. H., et al
"Plant-Based Diets for Type 1 Diabetes"
