This study aimed to investigate the effects of small doses of intact and hydrolyzed whey protein co-ingested with mixed-nutrient breakfast and lunch meals on postprandial glycemic and appetite responses in men with type 2 diabetes. In a randomized, single-blind crossover design, 11 men with type 2 diabetes attended the laboratory on three mornings and consumed either intact whey protein (15 g), hydrolyzed whey protein (15 g), or a placebo (control) immediately before mixed-macronutrient breakfast and lunch meals, separated by 3 hours. Blood samples were collected periodically, and interstitial glucose was measured during and for 24 hours after each trial. Subjective appetite was assessed using visual analog scales.
The results showed that total postprandial glycemia area under the curve was reduced by 13% ± 3% after breakfast following the intact whey protein when compared with control (P < 0.05). Hydrolyzed whey attenuated early glucose after breakfast when compared with control (P < 0.05). Glycemia was improved post-lunch after the intact whey protein only when compared with control (P < 0.05). Greater satiety was observed after the intact whey protein only after both meals when compared with control (P < 0.05). Insulin concentrations increased after both the intact and hydrolyzed whey protein, showing strong positive correlations with increases in valine and isoleucine (P < 0.05). Incretin and appetite regulatory hormone responses were similar across trials (P > 0.05).
In conclusion, the consumption of a small 15-g dose of intact whey protein immediately before consecutive mixed-macronutrient meals improves postprandial glycemia, stimulates insulin release, and increases satiety in men with type 2 diabetes.
This study investigated the effects of consuming a premeal shot containing a low dose of whey protein (WP) on free-living glycemic control in people with type 2 diabetes. In a randomized, placebo-controlled, single-blind crossover design, 18 insulin-naive individuals with type 2 diabetes consumed a ready-to-drink WP shot (15 g of protein) or a nutrient-depleted placebo beverage 10 min before breakfast, lunch, and dinner over a 7-day free-living period. Free-living glucose control was measured by blinded continuous glucose monitoring. The results showed that premeal WP supplementation reduced the prevalence of daily hyperglycemia by 8%±19% and increased the time spent in euglycemia by 9%±19%. Mean 24-hour blood glucose concentrations were 0.6±1.2 mmol/L lower during WP compared with placebo. Similar improvements in glycemic control were observed during the waken period with premeal WP supplementation, whereas nocturnal glycemic control was unaffected. Supplemental compliance/acceptance was high (>98%), and no adverse events were reported. The study suggests that consuming a premeal WP shot containing 15 g of protein before each main meal may help improve glycemic control in people with type 2 diabetes.