Department of Family Relations and Applied Nutrition, University of Guelph, Guelph, ON, Canada N1G 2W1.
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8.
J Dairy Sci. 2019 Aug;102(8):6766-6780. doi: 10.3168/jds.2019-16358. Epub 2019 Jun 20.
This study describes the effects on glycemic response and the underlying mechanisms of action of increasing the protein concentration and decreasing the casein-to-whey ratio in milk when consumed with a high glycemic breakfast cereal. Twelve healthy men and women, aged 18 to 30 yr and with a body mass index of 20 to 24.9 kg/m, consumed (in random order) milk beverages (250 mL) containing either 3.1 or 9.3% protein and casein-to-whey ratios of either 80:20 or 40:60. We measured postprandial appetite, glucose, regulatory hormones, and stomach emptying rate over 200 min, as well as food intake at an ad libitum meal at 120 min. Although pre-meal appetite was suppressed to a greater extent with milk beverages that had high (9.3%) compared with regular (3.1%) protein content, food intake was similar among all 4 treatments. Pre-meal mean blood glucose was lower with beverages that had high rather than regular milk protein content, with the lowest glucose peaks after the high milk protein treatment with the 40:60 casein-to-whey ratio. Pre-meal insulin and C-peptide levels were not affected by milk protein content or casein-to-whey ratio, but pre-meal glucagon-like peptide 1 was higher after the treatment containing high milk protein and the 40:60 casein-to-whey ratio, and pre-meal cholecystokinin was higher after the treatments containing high milk protein content. Plasma paracetamol response was also lower after the treatments containing high compared with regular milk protein content. When consumed with carbohydrate, milk beverages with high protein content and (to a lesser extent) a decreased casein-to-whey ratio lowered postprandial glycemia through insulin-independent mechanisms, primarily associated with delayed stomach emptying.
本研究描述了在食用高血糖早餐谷物时，增加牛奶中的蛋白质浓度和降低酪蛋白与乳清比例对血糖反应的影响及其潜在作用机制。12 名年龄在 18 至 30 岁、体重指数在 20 至 24.9kg/m 的健康男性和女性随机饮用（250 毫升）含有 3.1%或 9.3%蛋白质和酪蛋白与乳清比例分别为 80:20 或 40:60 的牛奶饮料。我们在 200 分钟内测量了餐后食欲、血糖、调节激素和胃排空率，以及在 120 分钟时进行的自由进食餐的食物摄入量。尽管高（9.3%）蛋白含量的牛奶饮料比普通（3.1%）蛋白含量的牛奶饮料能更显著地抑制餐前食欲，但所有 4 种处理的食物摄入量相似。高蛋白牛奶饮料的餐前平均血糖较低，而高蛋白质处理的血糖峰值最低，乳清比例为 40:60。餐前胰岛素和 C 肽水平不受牛奶蛋白含量或酪蛋白与乳清比例的影响，但高蛋白质和乳清比例为 40:60 的处理后，餐前胰高血糖素样肽 1 水平较高，而高蛋白质处理后，餐前胆囊收缩素水平较高。含高蛋白质含量的处理后，血浆对乙酰氨基酚的反应也较低。当与碳水化合物一起食用时，高蛋白质含量和（在较小程度上）降低酪蛋白与乳清比例的牛奶饮料通过非胰岛素依赖机制降低了餐后血糖，主要与胃排空延迟有关。
