Tea-induced calmness: Sugar-sweetened tea calms consumers exposed to acute stressor

Abstract

The food and beverage industry has been increasingly replacing sugar with non-nutritive sweeteners in their sweetened products to control or reduce total calories. Research comparing the effect of nutritive and non-nutritive sweeteners on emotional state of participants exposed to acute stressors is still limited. This study aimed to determine the effect of drinking tea sweetened with either a nutritive sweetener (sugar) or a non-nutritive sweetener (sucralose or stevia) on emotional state, in terms of calmness and pleasantness, of participants exposed to an acute stressor. Effects of acute stress on sweetness intensity and overall liking of tea beverages were also determined. Results showed that the possibility of tea-induced calmness, calculated as the difference between calmness ratings after and before drinking a tea sample, was established on stress session in the sugar-sweetened tea. Overall liking, but not the sweetness intensity, of the sugar-sweetened tea was affected by acute stress. In conclusion, this study provides empirical evidence that the consumption of tea sweetened with nutritive sweetener, but not with non-nutritive sweetener, has calming effect on consumers with acute stress, suggesting that this effect may not be due to the sweet taste of sugar, but due to the caloric nature of the sweetener.

Figure 1

(A) Comparisons of POMS rating of individual negative moods (annoyed, anxious, stressed, tensed) on “No-stress day” and “Stress day”. (B) Comparison of POMS rating of individual positive moods (calm, cheerful, relaxed) between “No-stress day” and “Stress day”. A Wilcoxon Signed-Rank test was used for data analysis. **and ***represent a significant difference at P < 0.01 and P < 0.001, respectively. Error bars represent standard error of mean.

Figure 2. Comparisons of tea-induced calmness between “No-stress day” and “Stress day” for stevia-sweetened tea (SVT), sucralose-sweetened tea (SCT), sugar-sweetened tea (SGT), and unsweetened tea (UST).

Tea-induced calmness is calculated as the difference between calmness ratings after and before drinking tea sample. A Wilcoxon Signed-Rank test was used for data analysis. N.S. represents no significant difference at P < 0.05. *Represents a significant difference at P < 0.05. Error bars represent standard error of mean.

Figure 3. Comparisons of tea-induced pleasantness between “No-stress day” and “Stress day” for stevia-sweetened tea (SVT), sucralose-sweetened tea (SCT), sugar-sweetened tea (SGT), and unsweetened tea (UST).

Tea-induced pleasantness is calculated as the difference between calmness ratings after and before drinking tea sample. A Wilcoxon Signed-Rank test was used for data analysis. N.S. represents no significant difference at P < 0.05. Error bars represent standard error of mean.

Figure 4. Comparisons of sweetness intensity between “No-stress day” and “Stress day” for stevia-sweetened tea (SVT), sucralose-sweetened tea (SCT), sugar-sweetened tea (SGT), and unsweetened tea (UST).

A Wilcoxon Signed-Rank test was used for data analysis. N.S. represents no significant difference at P < 0.05. Error bars represent standard error of mean.

Figure 5. Comparisons of overall liking between “No-stress day” and “Stress day” for stevia-sweetened tea (SVT), sucralose-sweetened tea (SCT), sugar-sweetened tea (SGT), and unsweetened tea (UST).

A Wilcoxon Signed-Rank test was used for data analysis. N.S. represents no significant difference at P < 0.05. *Represents a significant difference at P < 0.05. Error bars represent standard error of mean.