Management of gestational diabetes mellitus via nutritional interventions:The relevance of gastric emptying

Gestational diabetes mellitus(GDM)represents one of the most common medical complications of pregnancy and is important to the well-being of both mothers and offspring in the short and long term.Lifestyle intervention remains the mainstay for the management of GDM.The efficacy of nutritional approaches(e.g.calorie restriction and small frequent meals)to improving the maternal-neonatal outcomes of GDM was attested to by Chinese population data,discussed in two articles in recent issues of this journal.However,a specific focus on the relevance of postprandial glycaemic control was lacking.Postprandial rather than fasting hyperglycaemia often represents the predominant manifestation of disordered glucose homeostasis in Chinese women with GDM.There is now increasing appreciation that the rate of gastric emptying,which controls the delivery of nutrients for digestion and absorption in the small intestine,is a key determinant of postprandial glycaemia in both health,type 1 and 2 diabetes.It remains to be established whether gastric emptying is abnormally rapid in GDM,particularly among Chinese women,thus contributing to a predisposition to postprandial hyperglycaemia,and if so,how this influences the therapeutic response to nutritional interventions.It is essential that we understand the role of gastric emptying in the regulation of postprandial glycaemia during pregnancy and the potential for its modulation by nutritional strategies in order to improve postprandial glycaemic control in GDM.

Whey protein: The “whey” forward for treatment of type 2 diabetes?

A cost-effective nutritional approach to improve postprandial glycaemia is attractive considering the rising burden of diabetes throughout the world. Whey protein, a by-product of the cheese-making process, can be used to manipulate gut function in order to slow gastric emptying and stimulate incretin hormone secretion, thereby attenuating postprandial glycaemic excursions. The function of the gastrointestinal tract plays a pivotal role in glucose homeostasis, particularly during the postprandial period, and this review will discuss the mechanisms by which whey protein slows gastric emptying and stimulates release of gut peptides, including the incretins. Whey protein is also a rich source of amino acids, and these can directly stimulate beta cells to secrete insulin, which contributes to the reduction in postprandial glycaemia. Appetite is suppressed with consumption of whey, due to its effects on the gut-brain axis and the hypothalamus. These properties of whey protein suggest its potential in the management of type 2 diabetes. However, the optimal dose and timing of whey protein ingestion are yet to be defined, and studies are required to examine the long-term benefits of whey consumption for overall glycaemic control.

Upper gastrointestinal function and glycemic control in diabetes mellitus

Recent evidence has highlighted the impact of glycemic control on the incidence and progression of diabetic micro- and macrovascular complications, and on cardiovascular risk in the non-diabetic population. Postprandial blood glucose concentrations make a major contribution to overall glycemic control, and are determined in part by upper gastrointestinal function. Conversely, poor glycemic control has an acute, reversible effect on gastrointestinal motility. Insights into the mechanisms by which the gut contributes to glycemia have given rise to a number of novel dietary and pharmacological strategies designed to lower postprandial blood glucose concentrations.

Development of innovative tools for investigation of nutrient-gut interaction

The gastrointestinal tract is the key interface between the ingesta and the human body.There is wide recognition that the gastrointestinal response to nutrients or bioactive compounds,particularly the secretion of numerous hormones,is critical to the regulation of appetite,body weight and blood glucose.This concept has led to an increasing focus on“gut-based”strategies for the management of metabolic disorders,including type 2 diabetes and obesity.Understanding the underlying mechanisms and downstream effects of nutrient-gut interactions is fundamental to effective translation of this knowledge to clinical practice.To this end,an array of research tools and platforms have been developed to better understand the mechanisms of gut hormone secretion from enteroendocrine cells.This review discusses the evolution of in vitro and in vivo models and the integration of innovative techniques that will ultimately enable the development of novel therapies for metabolic diseases.

Quality of colonoscopy performed by medical or surgical specialists and trainees in five Australian hospitals

BACKGROUND Ensuring colonoscopy procedure quality is vital to the success of screening and surveillance programmes for bowel cancer in Australia. However, the data on the performance of quality metrics, through adequate adenoma detection, bowel preparation, and procedure completion rates, in the Australian public sector is limited. Understanding these can inform quality improvement to further strengthen our capacity for prevention and early detection of colorectal cancer.AIM To determine the quality of colonoscopy in Australian teaching hospitals and their association with proceduralist specialty, trainee involvement, and location.METHODS We retrospectively evaluated 2443 consecutive colonoscopy procedure reports from 1 January to 1 April, 2018 from five public teaching tertiary hospitals in Australia(median 60 years old, 49% male). Data for bowel preparation quality,procedure completion rates, and detection rates of clinically significant adenomas, conventional adenomas, and serrated lesions was collected and compared to national criteria for quality in colonoscopy. Participating hospital, proceduralist specialty, and trainee involvement indicators were used for stratification. Data was analysed using Chi-squared tests of independence, MannWhitney U, One-way ANOVA, and multivariate binary logistic regression.RESULTS Fifty-two point two percent(n = 1276) and 43.3%(n = 1057) were performed by medical and surgical proceduralists respectively, whilst 29.8%(n = 728) involved a trainee. Inadequate bowel preparation affected 7.3% of all procedures. The procedure completion rate was 95.1%, which increased to 97.5% after adjustment for bowel preparation quality. The pooled cancer, adenoma, and serrated lesion detection rates for all five hospitals were 3.5%, 40%, and 5.9% respectively. Assessed hospitals varied significantly by patient age(P < 0.001), work-force composition(P < 0.001), adequacy of bowel preparation(P < 0.001), and adenoma detection rate(P < 0.001). Two hospitals(40%) did not meet all national criteria for quality, due to a procedure completion rate of 94.5% or serrated lesion detection rate of 2.6%. Although lower than the other hospitals, the difference was not significant. Compared with surgical specialists, procedures performed by medical specialists involved older patients [65 years(inter-quartile range, IQR 58-73) vs 64 years(IQR 56-71);P = 0.04] and were associated with a higher adenoma detection rate [odds ratio(OR) 1.53;confidence interval: 1.21-1.94;P < 0.001]. Procedures involving trainee proceduralists were not associated with differences in the detection of cancer, adenoma, or serrated lesions, compared with specialists, or according to their medical or surgical background. On multivariate analysis, cancer detection was positively associated with patient age(OR 1.04;P < 0.001) and negatively associated with medical compared to surgical proceduralists(OR 0.54;P = 0.04). Conventional adenoma detection rates were independently associated with increasing patient age(OR 1.04;P < 0.001), positively associated with medical compared to surgical proceduralists(OR 1.41;P = 0.002) and negatively associated with male gender(OR 0.53;P < 0.001).CONCLUSION Significant differences in the quality of colonoscopy in Australia exist, even when national benchmarks are achieved. The role of possible contributing factors, like procedural specialty and patient gender need further evaluation.