Does partial reduction of added sugar in chocolate milk and yogurt benefit glycaemic response?
Mount Saint Vincent University
Commercially available dairy products such as chocolate milk, or yogurt have added sugar (5.5% or higher of total calories) that contributes to a higher energy density of these products. The objective of this study was to investigate whether chocolate milk and yogurt with reduced sugar content have any benefits on blood glucose (BG) control in humans. We hypothesized that chocolate milk and yogurt formulated with the reduced level of added sugar will benefit mean glycaemic response of these products. Methods: Ten male and ten female aged 19-35 completed a cross-over, single-blinded, randomized study attending five sessions with one week washout between the sessions. The treatments were randomly assigned and included a serving of chocolate milk (250ml) with 3.3% (C3.3%) and 5.5% added sugar (C5.5%), a serving of yogurt (175g) with 3.3% (Y3.3%) and 5.5% added sugar (Y5.5%), and water control (250ml). Blood samples were collected and the subjective appetite rating and feeling of physical comfort were recorded at 0, 15, 30, 45, 60, 90, and 120 min. Ad libitum food intake (FI) was measured with a pizza meal at 120 minutes. The changes in blood glucose, appetite and physical comfort parameters over time were analyzed with two-way ANOVA, and food intake, blood glucose and appetite AUCs, and the palatability of the treatments and pizza meal were analyzed with one-way ANOVA. The TukeyKramer post-hoc test was used for pairwise comparisons. Results: There was an effect of a treatment on blood glucose iAUC0-120min (P=0.0025). The treatments with C3.3%, C5.5% and Y5.5% resulted in a higher BG iAUC0-120min compared to water control (P<0.05), while the treatment with Y3.3% led to a similar BG iAUC0-120min as the water control (P>0.05). Additionally, all the dairy treatments resulted in a similar BG iAUC0-120min (P>0.05). All caloric treatments resulted in reduced subjective appetite compared to water control over two hours (P<0.05). There was no effect of a treatment on cumulative FI over two hours; however, there was an effect of a treatment (P=0.02) on ad libitum FI with pizza meal at 120 min. The treatments with C3.3% led to reduced FI compared to water control (P=0.02) and a similar trend was observed for the treatment with Y3.3% (P=0.05). All treatments resulted in a similar subjective rating of energy, fatigue, thirst physical and comfort parameters (P>0.05). Conclusion: The treatments with chocolate milk and yogurts with full and reduced added sugar content result in a similar glycaemic response over two hours. However, the reduction of added sugar in yogurt results in BG response similar to water control and tended to lower ad libitum FI compared to water control, while chocolate milk with reduced added sugar content results in a lower ad libitum FI compared to water control. Both chocolate milk and yogurt with reduced sugar content similarly suppress subjective appetite over two hours as their full sugar counterparts, and do not cause any physical discomfort. The reduction of added sugar does not negatively impact the sensory properties of chocolate milk and yogurt. Although the reduction of added sugar in chocolate milk and yogurt does not cardinally impact postprandial glycaemic response, both chocolate milk and yogurt with reduced added sugar content possess with unique metabolism that may position them as potential functional products for metabolic control.