From the Guidelines
Protein can be converted into glucose through gluconeogenesis, but it does not significantly increase plasma glucose concentration in healthy individuals or those with controlled type 2 diabetes. This is because the glucose produced from protein is not entirely released into the general circulation, as evidenced by a study published in Diabetes Care 1. The study found that when subjects with type 2 diabetes ingested 50g of protein, only 2g of glucose appeared in the circulation, despite the potential for 11-13g of glucose to be produced from the deaminated protein.
Key Points
- Protein ingestion stimulates insulin secretion, which can affect glucose output by the liver, depending on the insulin-to-glucagon ratio 1.
- In individuals with type 1 or type 2 diabetes, the glucagon response to protein is greater than in nondiabetic subjects, which can impact glucose production and blood sugar levels 1.
- The addition of protein to a meal does not slow the absorption of carbohydrate or change the postprandial peak glucose response in type 1 diabetic subjects, according to one study 1.
- The rate of restoration to euglycemia after hypoglycemia is not different when treatment is given with carbohydrate or carbohydrate plus protein in type 1 diabetic subjects, as shown in another study 1.
Clinical Implications
The conversion of protein to glucose is an important consideration in the management of blood sugar levels, particularly for individuals with diabetes. However, the evidence suggests that protein ingestion does not significantly increase plasma glucose concentration in healthy individuals or those with controlled type 2 diabetes. Therefore, protein can be a useful component of a meal plan for individuals with diabetes, as it can help stimulate insulin secretion and provide a sense of fullness and satisfaction, without causing a significant increase in blood glucose levels.
From the Research
Protein Conversion to Glucose
- Protein can be converted to glucose through the process of gluconeogenesis, which is a metabolic pathway that generates glucose from non-carbohydrate sources such as amino acids 2, 3, 4.
- This process is essential for maintaining blood glucose levels within a narrow range, especially during periods of metabolic stress such as starvation 2.
- The conversion of protein to glucose is a slow process that occurs over a period of hours, allowing glucose to be disposed of if presented for utilization slowly and evenly over a long time period 5.
Factors Influencing Protein Conversion to Glucose
- The presence of adequate insulin is necessary for protein to be metabolized and converted to glucose 5.
- A high-protein diet can increase gluconeogenesis, leading to an increase in endogenous glucose production 3, 6.
- The type and amount of protein ingested can influence the metabolic response, including the stimulation of insulin and glucagon secretion 4.
Mechanisms of Protein-Induced Gluconeogenesis
- The small intestine plays a role in gluconeogenesis, producing glucose that is detected in the portal vein and initiates a nervous signal to the hypothalamic nuclei regulating energy homeostasis 6.
- Protein diets can induce satiety effects indirectly via intestinal gluconeogenesis and portal glucose sensing, leading to the activation of brain areas involved in the regulation of food intake 6.