Sex Differences in Salivary Oxytocin and Cortisol Concentration Changes during Cooking in a Small Group

Abstract

Background: Oxytocin (OT), a neuropeptide, has positive effects on social and emotional processes during group activities. Because cooking is an integrated process in the cognitive, physical, and socio-emotional areas, cooking in a group is reported to improve emotion and cognition. However, evidence for efficacy in group cooking has not been well established at the biological level. Methods: To address this shortcoming, we first measured salivary levels of OT and cortisol (CORT), a biomarker of psychological stress, before and after group cooking for approximately 1 h by people who know each other in healthy married or unmarried men and women. We then compared the initial OT and CORT concentrations with those during individual non-cooking activities in isolation. Results: Baseline OT concentrations before group and non-group sessions did not significantly differ and OT levels increased after both types of activity in men and women. In men, however, the percentage changes of OT levels in the first over the second saliva samples were significantly small during cooking compared with those in individual activities. In women, however, such a difference was not observed. In contrast, the mean salivary CORT concentrations after group cooking were significantly decreased from the baseline level in both sexes, though such decreases were not significant after individual activity sessions. The sex-specific differences were marital-status independent. Conclusion: These results indicate that OT and CORT concentrations after two activity sessions by a familiar group changed in opposite directions in a sex-specific manner. This suggests that, because cooking is experience-based, we need to consider the sex-specific features of group cooking if we apply it for intervention.

Keywords: cooking; cortisol; group activity; in-group member; oxytocin; stress.

Figure 1

Oxytocin (OT) concentrations before and after a single group (cooking) or non-group (individual activity) session. OT levels are for the first (before) and second (after) salivary samples collected from nine men and nine women engaged in cooking in a group or in individual desk or bench work for approximately 1 h. p-values are for two-tailed Student’s t-tests: (A) individual activity by men, p = 0.2200, n = 46; (B) cooking by men, p = 0.8079, n = 55; (C) individual activity by women, p = 0.2935, n = 44; (D) cooking by women, p = 0.2086, n = 90.

Figure 2

Percentage changes in oxytocin levels before and after a single session. Percentage of oxytocin levels for the first (before) saliva over the second (after) saliva samples after each session. Saliva was collected during individual (non-cooking) and group (cooking) activities in men (A) and women (C). The average percentage of oxytocin levels for the first (before) saliva over the second (after) saliva samples in individual male (B) and female (D) participants. p-values are for two-tailed Student’s t-tests: (A) p = 0.0216 between individual activity (n = 44) and cooking (n = 55) in men; (B) p = 0.0492, between individual activity (n = 9) and cooking (n = 9) in men; (C) p = 0.1849 between individual activity (n = 44) and cooking (n = 90) in women; (D) p = 0.6373 between individual activity (n = 9) and cooking (n = 9) in women. Filled and open symbols represent married and single participants, respectively.

Figure 3

Cortisol concentrations before and after a single group (cooking) or non-group (individual activity) session. CORT levels are for the first (before) and second (after) saliva samples collected from five men and nine women engaged in cooking in group or in individual desk or bench work for approximately 1 h. p-values are for two-tailed Student’s t-tests: (A) individual activity by men, p = 0.0087, n = 17; (B) cooking by men, p = 0.0011, n = 26; (C) individual activity by women, p = 0.2074, n = 31; (D) cooking by women, p = 0.0049, n = 35.

Figure 4

Changes in cortisol levels before and after a single session. Percentage of CORT levels for the first (before) saliva over the second (after) saliva samples after each session. Saliva was collected at individual (non-cooking) and group (cooking) activities in men (A,B) and women (C,D). Average percentage of cortisol levels for the first (before) saliva over the second (after) saliva samples in individual participants. p-values are for two-tailed Student’s t-tests: (A) p = 0.2469 between individual activity (n = 17) and cooking (n = 26) in men; (B) p = 0.3022 between individual activity and cooking in 5 men; (C) p = 0.0385 between individual activity (n = 31) and cooking (n = 35) in women; (D) p = 0.4498 between individual activity and cooking in 9 women. Filled and open symbols represent married and single participants, respectively.