This study investigates the effects of dairy breakfasts (2% cow's milk, 2% Greek yogurt, cheese) and a non-dairy breakfast (soy beverage) on satiety and post-meal blood glucose. Each participant will receive every treatment in this crossover design study.
Regular consumption of dairy is associated with better body composition and lower incidences of type 2 diabetes and obesity. This may be due to dairy's ability to increase satiety and decrease post-prandial glycemia. However, most clinical studies have only investigated isolated dairy proteins (whey and casein) and the effects of whole dairy products, consumed as part of a meal, remain unclear. Additionally, the effect of dairy type and form remain to be further investigated. Therefore, this study will test the effects of dairy products when consumed with a high glycemic index breakfast on satiety and post-prandial glycemia. Thirty healthy older males and females (60-70 years, BMI 18.5-30.0 kg/m2) will be recruited for the randomized, unblinded, crossover study. Participants will fast overnight, and at baseline will consume 1) 2% milk (250 mL), 2) soy beverage (250 mL), 3) plain 2% Greek yogurt (175 g), 4) cheddar cheese (30 g), or 5) water (250 mL - control). Treatments will be consumed along with 2 pieces of white toast with strawberry jam, except for the water control which will be consumed alone. All breakfast meals will be isocaloric and water will be given with the yogurt (75 mL) and cheese (220 mL) to compensate for fluid content. At 0 (baseline), 15, 30, 45, 60, 90, 120, 150, 180, (pre-meal period) and 210 minutes (post-meal period) blood will be collected for glucose analysis and subjective appetite ratings completed. Insulin will be analyzed every 30 minutes. Between 180-200 minutes, an ad libitum lunch will be provided to assess food intake.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
29
Department of Nutritional Sciences, University of Toronto
Toronto, Ontario, Canada
Blood Glucose
Blood glucose (mmol/L) is measured using finger prick capillary blood samples
Time frame: 0-210 minutes
Subjective Appetite
Subjective appetite ratings are obtained from four 100 mm visual analogue scale (VAS) questions assessing "Desire to Eat", "Hunger", "Fullness" and "Prospective Food Consumption". The average of all four VAS is calculated to obtain the average appetite score for statistical analysis.
Time frame: 0-210 minutes
Insulin
Blood insulin (μU/mL) is measured using finger prick capillary blood samples
Time frame: 0-210 minutes
Food Intake
Food at an ad libitum lunch meal consisting of a dish of rice, meatballs, and tomato sauce will be weighed to determine food intake based on nutrition information provided by the manufacturers.
Time frame: 180-200 minutes
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