Metabolic diseases are on the rise globally, with type 2 diabetes and obesity at the forefront. It’s important to find a way to reduce the risk of these diseases and to be able to effectively manage them. One way to do this is through developing effective dietary strategies. It has been found that both whey and casein proteins which are derived from milk affect blood glucose levels and satiety after a meal. Therefore, scientists from the University of Guelph in collaboration with the University of Toronto examined the effects of a casein-to-whey protein ratio and total protein concentration of milk consumed with cereal at breakfast on blood glucose concentrations, appetite ratings and subsequent food intake.
=Q=
In this randomised, controlled, double-blinded study of 32 young healthy adults, researchers asked the participants to fast and consume 250 ml of milk in three types of protein concentrations: 80:20 casein-to-whey protein ratio (normal milk); or 40:60 (modified high protein); or control (water with whey permeate). Participants consumed milk with two servings of oat-based breakfast cereal. Blood glucose concentrations were determined from finger-prick blood samples and appetite was assessed using visual analog scales. Participants then consumed a pizza lunch and both blood glucose and appetite were assessed following the lunch meal.
The researchers found that milk consumed with a high-carbohydrate diet at breakfast reduced blood glucose even after lunch and the effect was greater with high-protein milk. They also found that high-protein milk reduced the post-lunch appetite in participants. Milk with higher whey protein concentration significantly decreased pre-lunch blood glucose compared to normal milk, whereas normal milk reduced pre-lunch appetite.
When whey and casein proteins naturally present in milk are digested, gastric hormones are released that slow digestion and increases feelings of fullness. Digestion of whey proteins achieves this effect more quickly, whereas casein proteins provide a longer lasting effect.
This study shows that consuming a high-carbohydrate breakfast with high-protein milk could be a potential dietary strategy to manage blood glucose levels and reduce appetite. It also emphasises the importance of having milk at breakfast to slow down the digestion of carbohydrates and to help maintain a healthy blood sugar level.
Source: Journal of Dairy Science
