Effect of Polyphenol-Rich Dark Chocolate on Salivary Cortisol and Mood in Adults.

Catherine Tsang,Grace Farhat,Anna Bussu,Emad Al-Dujaili,Lindsay Hodgson

doi:10.3390/antiox8060149

Abstract

The aim of the present study was to investigate whether ingestion of polyphenol-rich dark chocolate improved salivary cortisol levels and subjective mood states in adults recruited from a health and social care setting. Twenty-six participants ingested 25 g/day of a high polyphenol dark chocolate (containing 500 mg of total flavonoids) or a similar amount of a control dark chocolate containing negligible flavonoids for four weeks. Twenty-four-hour salivary glucocorticoid levels (cortisol and cortisone) were measured by an enzyme-linked immunosorbent assay, and subjective mood was assessed using a validated Positive Affect and Negative Affect Schedule. Total daily cortisol, morning cortisol, and the cortisol/cortisone ratio were significantly reduced (p < 0.001) after ingestion of only the high polyphenol dark chocolate. There were no significant differences between groups for overall scores for positive affect and negative affect. No changes were observed after the control dark chocolate, or any other parameter measured. In conclusion, the findings from this small-scale study indicate lowering of salivary cortisol levels following polyphenol-rich dark chocolate in adults recruited from a health and social care setting. Such changes may be attributable to their ability to inhibit 11β-hydroxysteroid dehydrogenase type 1 activity and warrant further investigation.

Highlights

Chronic stress is an important risk factor for several psychophysical pathologies including cardiovascular disease (CVD), hypertension, insulin resistance, musculoskeletal illness, anxiety, and depression [1]
The HPA axis is activated during the stress response increasing cortisol levels, and prolonged activation may contribute to the onset of mood deterioration and affective disorders including anxiety and depression [11]
There were no significant differences between mean age and body mass, and no changes were observed in dietary intake for total fat, carbohydrate, protein or total energy intake

Summary

Introduction

Chronic stress is an important risk factor for several psychophysical pathologies including cardiovascular disease (CVD), hypertension, insulin resistance, musculoskeletal illness, anxiety, and depression [1]. Work-related or occupational stress is increasingly prevalent in the UK population, and contributes to an increased health and economic cost, sickness absence, high staff turnover, and early retirement [2]. Stress-related psychiatric syndromes, such as anxiety and depression, share common biological mechanisms that include the dis-regulation of the hypothalamic–pituitary–adrenal (HPA) axis [6,7,8,9,10]. The HPA axis is activated during the stress response increasing cortisol levels, and prolonged activation may contribute to the onset of mood deterioration and affective disorders including anxiety and depression [11]. Since prevention and management of risk factors linked to occupational stress are not yet adequately structured, and with no measure of long-term effectiveness on healthcare professions, it is essential to explore alternative strategies which are modifiable and accessible

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Conclusion