1.
Intake of Lactobacillus reuteri improves incretin and insulin secretion in glucose-tolerant humans: a proof of concept.
Simon, MC, Strassburger, K, Nowotny, B, Kolb, H, Nowotny, P, Burkart, V, Zivehe, F, Hwang, JH, Stehle, P, Pacini, G, et al
Diabetes care. 2015;(10):1827-34
Abstract
OBJECTIVE Ingestion of probiotics can modify gut microbiota and alter insulin resistance and diabetes development in rodents. We hypothesized that daily intake of Lactobacillus reuteri increases insulin sensitivity by changing cytokine release and insulin secretion via modulation of the release of glucagon-like peptides (GLP)-1 and -2. RESEARCH DESIGN AND METHODS A prospective, double-blind, randomized trial was performed in 21 glucose-tolerant humans (11 lean: age 49 ± 7 years, BMI 23.6 ± 1.7 kg/m(2); 10 obese: age 51 ± 7 years, BMI 35.5 ± 4.9 kg/m(2)). Participants ingested 10(10) b.i.d. L. reuteri SD5865 or placebo over 4 weeks. Oral glucose tolerance and isoglycemic glucose infusion tests were used to assess incretin effect and GLP-1 and GLP-2 secretion, and euglycemic-hyperinsulinemic clamps with [6,6-(2)H2]glucose were used to measure peripheral insulin sensitivity and endogenous glucose production. Muscle and hepatic lipid contents were assessed by (1)H-magnetic resonance spectroscopy, and immune status, cytokines, and endotoxin were measured with specific assays. RESULTS In glucose-tolerant volunteers, daily administration of L. reuteri SD5865 increased glucose-stimulated GLP-1 and GLP-2 release by 76% (P < 0.01) and 43% (P < 0.01), respectively, compared with placebo, along with 49% higher insulin (P < 0.05) and 55% higher C-peptide secretion (P < 0.05). However, the intervention did not alter peripheral and hepatic insulin sensitivity, body mass, ectopic fat content, or circulating cytokines. CONCLUSIONS Enrichment of gut microbiota with L. reuteri increases insulin secretion, possibly due to augmented incretin release, but does not directly affect insulin sensitivity or body fat distribution. This suggests that oral ingestion of one specific strain may serve as a novel therapeutic approach to improve glucose-dependent insulin release.
2.
A randomized cross-over study of the metabolic and hormonal responses following two preoperative conditioning drinks.
Awad, S, Fearon, KC, Macdonald, IA, Lobo, DN
Nutrition (Burbank, Los Angeles County, Calif.). 2011;(9):938-42
Abstract
OBJECTIVE Preoperative conditioning with carbohydrate-based drinks attenuates postoperative insulin resistance and leads to clinical benefits. The use of metabolic conditioning agents such as glutamine and antioxidants, in addition to carbohydrate, may benefit patients undergoing major surgery, because glutamine and antioxidant supplementation have been shown to improve gastrointestinal perfusion, immune function, morbidity, and gluco-metabolic control in critically ill patients. We investigated the postprandial responses after ingestion of a clear carbohydrate drink (CCD) containing 50 g of carbohydrate (preOp, Nutricia, Trowbridge, UK) and that of another drink containing 50 g of carbohydrate, 15 g of glutamine, and antioxidants (ONS; Fresenius Kabi, Bad Homburg, Germany). METHODS Twelve overnight-fasted healthy male subjects ingested one of the drinks in a randomized, double-blinded, cross-over manner, after which blood was sampled for 360 min for measurement of glucose, insulin, glucagon, non-esterified fatty acids, β-hydroxybutyrate and glutamine. RESULTS The means ± standard errors for age and body mass index of participants were 21 ± 0.9 y and 23.2 ± 0.5 kg/m(2). After CCD ingestion, glucose and insulin concentrations peaked within 40 min (8.4 ± 0.4 mmol/L and 43.9 ± 3.8 mIU/L, respectively) and returned to baseline at 80 min (glucose 4.9 ± 0.3 mmol/L) and 140 min (insulin 5.5 ± 0.5 mIU/L). After ONS ingestion, peak glucose and insulin concentrations occurred within 40 min but were of a lower magnitude (6.6 ± 0.1 mmol/L and 29.6 ± 2.9 mIU/L, respectively). Glucose concentrations after ONS were higher than after CCD at 100 min. CONCLUSION Peak insulin and glucose concentrations were higher after CCD ingestion; in contrast, responses after ONS ingestion were "blunted" and prolonged.