Low-fat vegan diet beneficial for improving cardiometabolic health in type 1 diabetes patients: Study

The researchers found that a low-fat vegan diet — high in carbohydrates and fiber and moderate in protein — increases insulin sensitivity, reduces insulin requirement, and improves glycemic control in individuals with type 1 diabetes versus a conventional portion-controlled diet.

"In the vegan group, total and LDL cholesterol and blood urea nitrogen to creatinine ratio decreased. A1C decreased in both groups," the researchers reported in Clinical Diabetes. 

Hana Kahleova, Physicians Committee for Responsible Medicine, Washington, DC, and colleagues aimed to compare the effects of a low-fat vegan diet (without carbohydrate or portion restriction) to those of a portion-controlled diet in people with T1D. This trial comes at a crucial juncture, considering the rising prevalence of T1D globally and the persistent challenges associated with its management.

The effects of a low-fat vegan diet were compared with a conventional portion-controlled, carbohydrate-controlled diet in 58 patients with T1D (age, ≥ 18 years) who had been receiving stable insulin treatment for the past 3 months.

Participants were randomly assigned to receive either the vegan diet (n = 29), comprising grains, vegetables, fruits, and legumes, or the portion-controlled diet (n = 29) that reduced daily energy intake by 500-1000 kcal/d in overweight participants while maintaining a stable carbohydrate intake.

The study's primary clinical outcomes included glycemic control (A1c), insulin sensitivity, and insulin requirement (total daily dose of insulin). Other assessments included the blood urea nitrogen, body weight, blood lipid profile, and blood urea nitrogen-to-creatinine ratio.

18 participants in the vegan diet group and 17 in the portion-controlled group completed the study.

The study led to the following findings:

• In the vegan group, the total daily dose of insulin decreased by 12.1 units/d and insulin sensitivity increased by 6.6 g of carbohydrate per unit of insulin on average, with no significant changes in the portion-controlled diet group.
• Participants on the vegan diet had lower levels of total and low-density lipoprotein cholesterol and blood urea nitrogen and a lower blood urea nitrogen-to-creatinine ratio, whereas both vegan and portion-controlled groups had lower A1c levels.
• Body weight decreased by 5.2 kg in the vegan group; there were no significant changes in the portion-controlled group.
• For every 1-kg weight loss, there was a 2.16-unit decrease in the insulin total daily dose and a 0.9-unit increase in insulin sensitivity.

"This study provides substantial support for a low-fat vegan diet that is high in carbohydrates and fiber, low in fat, and moderate in protein" and suggests the potential therapeutic use of this diet in type 1 diabetes management, the researchers wrote.

Reference:

Hana Kahleova, Tatiana Znayenko-Miller, Karen Smith, Cyrus Khambatta, Robby Barbaro, Macy Sutton, Danielle N. Holtz, Mark Sklar, Desiree Pineda, Richard Holubkov, Neal D. Barnard; Effect of a Dietary Intervention on Insulin Requirements and Glycemic Control in Type 1 Diabetes: A 12-Week Randomized Clinical Trial. Clin Diabetes 2024; cd230086. https://doi.org/10.2337/cd23-0086