Ageing is accompanied by a steady increase of the stress hormone cortisol, which is why elderly people often feel less well than when they were young. But not if they eat about 40 cherries a day, advise researchers in Experimental Gerontology at the University of Extremadura.
Cherries as a superfood
Cherries are an exceptionally good source of phenols, which is why producers of superfoods have more than an average interest in products based on cherries that can, for example, improve the quality of sleep or help muscles to recover after a marathon or an eccentric workout.
Researchers at the University of Extremadura gave subjects the equivalent of 18 cherries twice a day for 5 subsequent days. To be precise, the Spaniards used a patented extract of cherries from the Jerte Valley. Each dose supplied 1580 mg phenols plus 2 mg tryptophan, 27 nanograms serotonin and 16 nanograms melatonin. On another occasion, the subjects were given a placebo for 5 days.
The Spaniards worked with a total of 30 subjects; 10 of these were between the ages of 20-30 (Young), 10 between 35-55 (Middle-Aged) and 10 between 65-85 (Old).
As the figure below shows, the amount of cortisol dropped in the subjects’ urine during the days on which they were given a supplement.
The young subjects didn’t notice much effect from the supplement, but the other two groups did. Their Trait and State Anxiety Scores were reduced; in other words, the cherry supplement made them less nervous, fretful and tense.
The subjects also produced more serotonin as a result of the supplement. The figures below show the results for the Middle-Aged and the Old groups, but the figures for the Young group are not very different.
The results of the study are in agreement with what we presently know about stress. That is, the way in which stress stimuli affect an organism depends on the concentration of neurotransmitters in the brain. If the brain produces little serotonin when there are stress stimuli, the production of cortisol will increase. The more serotonin made by the brain, the less the concentration of cortisol will increase as a result of the stress stimuli.
The consumption of a Jerte Valley cherry product in humans enhances mood, and increases 5-hydroxyindoleacetic acid but reduces cortisol levels in urine.
Jerte Valley cherries contain high levels of tryptophan, serotonin, and melatonin. These molecules have been shown to be involved in mood regulation. It has been suggested that a complex inter-relationship between brain serotonin, circulating levels of cortisol (the major stress hormone), and the hypothalamus-pituitary-adrenal axis exists in the regulation of stress responses, where cortisol and serotonin act as markers of mood disturbances. Moreover there is growing evidence that altered HPA activity is associated with various age-related pathologies. The present study evaluated the effect of the ingestion of a Jerte Valley cherry-based product, compared to a placebo product, on urine cortisol and 5-hydroxyindoleacetic acid (5-HIAA) levels, and on mood in young, middle-aged, and elderly participants.
Cortisol and 5-HIAA acid levels were measured by commercial enzyme-linked immunosorbent assay kits. The mood state profile was analysed using a visual analogue scale and the state-trait anxiety inventory.
Our findings showed that the ingestion of the Jerte Valley cherry product decreased urinary cortisol and increased urinary 5-HIAA levels in all the experimental groups. Moreover, the cherry product was able to lessen anxiety status in the middle-aged and elderly participants, and enhanced subjective mood parameters, particularly family relationships in young participants, and frame of mind and fitness in both middle-aged and elderly subjects.
The consumption of the Jerte Valley cherry product may protect against stress and act as a mood enhancer by increasing serotonin availability to the organism, particularly with advancing age.
Copyright © 2012 Elsevier Inc. All rights reserved.
PMID: 22583983 [PubMed – indexed for MEDLINE]