The 'early' postprandial glucagon response is related to the rate of gastric emptying in type 2 diabetes

Intra-pancreatic fat is associated with high circulating glucagon and GLP-1 concentrations following whey protein ingestion in overweight women with impaired fasting glucose: A randomised controlled trial

AIM

Intra-pancreatic fat deposition (IPFD) while hypothesised to impair beta-cell function, its impact on alpha-cells remains unclear. We evaluated the association between IPFD and markers of pancreatic cells function using whey protein.

METHODS

Twenty overweight women with impaired fasting glucose (IFG) and low or high IPFD (<4.66% vs ≥4.66%) consumed 3 beverage treatments: 0 g (water control), 12.5 g (low-dose) and 50.0 g (high-dose) whey protein, after an overnight fast, in randomised order. Blood glucose, insulin, C-peptide, glucagon, gastric-inhibitory polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and amylin were analysed postprandially over 4 h. Incremental area-under-the-curve (iAUC), incremental maximum concentration (iCmax), and time to maximum concentration (Tmax) for these were compared between IPFD groups using repeated measures linear mixed models, also controlled for age (pcov).

RESULTS

iAUC and iCmax glucose and insulin while similar between the two IPFD groups, high IPFD and ageing contributed to higher postprandial glucagon (iAUC: p = 0.012; pcov = 0.004; iCmax: p = 0.069; pcov = 0.021) and GLP-1 (iAUC: p = 0.006; pcov = 0.064; iCmax: p = 0.011; pcov = 0.122) concentrations.

CONCLUSION

In our cohort, there was no evidence that IPFD impaired protein-induced insulin secretion. Conversely, IPFD may be associated with increased protein-induced glucagon secretion, a novel observation which warrants further investigation into its relevance in the pathogenesis of dysglycaemia and type-2 diabetes.

Serum alanine transaminase is predictive of fasting and postprandial insulin and glucagon concentrations in type 2 diabetes

The liver plays a key role in glucose homeostasis. Serum liver enzyme levels, including alanine transaminase (ALT), aspartate transaminase (AST) and gamma-glutamyl transferase (GGT), are reportedly predictive of the risk of type 2 diabetes (T2D). However, the link between the liver enzyme profile and metabolic derangements in T2D, particularly the secretion of both insulin and glucagon, is not clear. This study evaluated its relationships with glycemia, insulin and glucagon both during fasting and after an oral glucose load or a mixed meal in T2D. 15 healthy and 43 T2D subjects ingested a 75 g glucose drink. 86 T2D subjects consumed a mixed meal. Venous blood was sampled for measurements of blood glucose and plasma insulin, C-peptide and glucagon. Blood glucose, plasma insulin, C-peptide and glucagon concentrations, both fasting and after oral glucose, correlated directly with ALT, while fewer and weaker correlations were observed with GGT or AST. Subgroup analysis in T2D subjects ascertained that plasma insulin, C-peptide and glucagon concentrations after oral glucose were higher with increasing ALT. Similar findings were observed in the T2D subjects who received a mixed meal. In conclusion, serum liver enzyme profile, particularly ALT, reflects dysregulated fasting and nutrient-stimulated plasma insulin and glucagon concentrations in T2D.

A systematic review exploring the mechanisms by which citrus bioflavonoid supplementation benefits blood glucose levels and metabolic complications in type 2 diabetes mellitus

BACKGROUND

Citrus bioflavonoids are polyphenolic compounds that are derived from citrus fruits and vegetables. Although they are well known for their powerful antioxidant properties, their effects on glycemic control are not well understood. This review aims to highlight the potential benefits of using citrus bioflavonoids in patients with type 2 diabetes mellitus and its metabolic complications, as well as the medicinal effects of known subclasses of naturally occurring citrus bioflavonoids.

METHODS

In this systematic review, a survey of studies was conducted from January 2012 to February 2023 using various databases (PubMed, Medline, Google Scholar, and Scopus) to determine the effects of citrus bioflavonoid supplementation on reducing oxidative stress, improving lipid profiles, and glycemic index in patients with diabetes mellitus, as well as the proposed mechanisms of action.

RESULTS

The results of the survey indicate that citrus bioflavonoids may have a positive impact on reducing oxidative stress levels in patients with type 2 diabetes mellitus. In addition to reducing oxidative stress, citrus bioflavonoids may also have a positive impact on other markers of diabetes. For example, studies have shown that they can reduce non-enzymatic protein glycation, which is a process that occurs when glucose molecules bind to proteins in the body.

CONCLUSION

The reduction in oxidative stress that can be achieved using citrus bioflavonoids may help to maintain antioxidant levels in the body, thereby reducing the severity of diabetes and its complications. These findings suggest that citrus bioflavonoids may be a useful complementary therapy for patients with diabetes.