Cut down on carbohydrate in the dietary therapy of type 2 diabetes: Mechanisms of effective therapy by selective choice of macronutrients

Publikation: Bog/antologi/afhandling/rapportPh.d.-afhandlingForskning

  • Mads Gustav Juul Skytte
Nutritional therapy is recognized as a first-line therapeutic intervention in patients with type 2 diabetes (T2D). However, dietary recommendations are ambiguous and no clear consensus exists regarding the macronutrient distribution of the diabetes diet. Currently, the Danish diabetes dietary guidelines recommend a macronutrient distribution of 45-60 energy percent (E%) from carbohydrates, 10-20 E% from protein and <35 E% from fat. Carbohydrate-restriction has been suggested as a viable nutritional treatment to improve glycemic control, although meta-analyses have revealed receding or absent long-term effect. Most feeding studies are, however, influenced by a concomitant weight-loss which makes it difficult to evaluate the effects of an eating pattern unconfounded by the beneficial effects of a weight-loss. Therefore, we investigated the effects of a conventional diabetes (CD) diet and an iso-energeticcarbohydrate-reduced high-protein (CRHP) diet during 6 weeks of full meal provision aiming at wei ght stability in patients with type 2 diabetes. Whereas the macronutrient distribution of the CD diet was in accordance with the current Danish diabetes guidelines (carbohydrates 50 E%/proteins 17 E%/fat 33 E%), the CRHP diet was reduced in carbohydrates to 30 E% and increased in proteins and fat to 30 E% and 40 E%, respectively. After 6 weeks of treatment, the CRHP diet improved glycemic control by reducing HbA1c by 6.2 (± 0.8) mmol/mol whereas the CD diet reduced HbA1c by 0.8 (± 1.0) mmol/mol. After 6 weeks of treatment, carbohydrate-restriction reduced 24-hour mean glucose by 13% and a mixed meal test revealed that postprandial glucose and insulin excursions were lower on the CRHP diet, as compared to the CD diet. We also found a significant difference between diets in terms of hepatic fat fraction. Hepatic fat fraction was reduced by 2.4 (-7.8 to -1.0) % following 6 weeks of CRHP dietary treatment. The CRHP diet also reduced fasting triglycerides, total cholesterol and non-HDL-cholesterol but increased urinary excretion of 8- oxoGuo, a marker of oxidative RNA modifications. Collectively, a CRHP diet, compared to a CD diet, improved metabolic control and lipid profiles but increased a marker of oxidative stress in patients with T2D receiving 6 weeks of full food provision. In conclusion, carbohydrate-restriction is an efficient short-term nutritional strategy in the management of T2D, but the long-term efficacy, safety and feasibility of the diet merit further investigation.
ForlagDepartment of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen
StatusUdgivet - 2020

ID: 240641512