Age and Sex Interact to Determine the Effects of Commonly Consumed Dairy Products on Postmeal Glycemia, Satiety, and Later Meal Food Intake in Adults

Background: Dairy consumption reduces postprandial glycemia and appetite when consumed with carbohydrates. Objectives: The objective was to test the effects of frequently consumed dairy products, age, and sex on glycemia, appetite, and food intake. Methods: In a randomized, unblinded, crossover design, 30 older [60-70 y; BMI (kg/m2): 18.5-29.9] and 28 young (20- 30 y; BMI: 18.5-24.9) adults consumed 500 mL of a calorie-free control (water), skim milk and whole milk, 350 g Greek yogurt, and 60 g cheddar cheese. Food intake at an ad libitum meal was measured 120 min later. Glycemia, appetite, and gastric hormone responses were measured premeal (15-120 min), within-meal (120-140 min), and postmeal (140- 170 min). Effects of treatment, age, and sex and their interactions were analyzed using ANOVA followed by Tukey's post hoc test. Results: All forms of dairy, compared with water, decreased postmeal glycemia, premeal appetite, and meal intake (P < 0.0001). Premeal glucose, insulin, and glucagon-like peptide 1 increased, and ghrelin decreased, but effects of dairy differed with age and sex. Older adults had 10% higher pre- and postmeal glucose (P < 0.01). Premeal appetite suppression per 100 kcal of treatments was more after yogurt than other dairy, but overall appetite suppression was less in older adults than in young adults and in males than in females (P < 0.05). Pizza intake was reduced by 175 kcal after yogurt and cheese and by 82 kcal after milks compared to water (P < 0.001). Mealtime reduction for treatment calories averaged 62% after yogurt and cheese but was less at 33% after milks (P < 0.05). Compensation was less in older (33%) than in young (63%) adults (P < 0.03). Conclusions: Dairy products consumed in usual forms before a meal stimulatemetabolic responses leading to reduced premeal appetite, later food intake, and postmeal glycemia, but their effects differ in magnitude and with the sex and age of adults. J Nutr 2021;151:2161-2174.