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      Effects of tryptophan-rich breakfast and light exposure during the daytime on melatonin secretion at night

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          Abstract

          Background

          The purpose of the present study is to investigate effects of tryptophan intake and light exposure on melatonin secretion and sleep by modifying tryptophan ingestion at breakfast and light exposure during the daytime, and measuring sleep quality (by using actigraphy and the OSA sleep inventory) and melatonin secretion at night.

          Methods

          Thirty three male University students (mean ± SD age: 22 ± 3.1 years) completed the experiments lasting 5 days and 4 nights. The subjects were randomly divided into four groups: Poor*Dim (n = 10), meaning a tryptophan-poor breakfast (55 mg/meal) in the morning and dim light environment (<50 lx) during the daytime; Rich*Dim (n = 7), tryptophan-rich breakfast (476 mg/meal) and dim light environment; Poor*Bright (n = 9), tryptophan-poor breakfast and bright light environment (>5,000 lx); and Rich*Bright (n = 7), tryptophan-rich breakfast and bright light.

          Results

          Saliva melatonin concentrations on the fourth day were significantly lower than on the first day in the Poor*Dim group, whereas they were higher on the fourth day in the Rich*Bright group. Creatinine-adjusted melatonin in urine showed the same direction as saliva melatonin concentrations. These results indicate that the combination of a tryptophan-rich breakfast and bright light exposure during the daytime could promote melatonin secretion at night; further, the observations that the Rich*Bright group had higher melatonin concentrations than the Rich*Dim group, despite no significant differences being observed between the Poor*Dim and Rich*Dim groups nor the Poor*Bright and Rich*Bright groups, suggest that bright light exposure in the daytime is an important contributor to raised melatonin levels in the evening.

          Conclusions

          This study is the first to report the quantitative effects of changed tryptophan intake at breakfast combined with daytime light exposure on melatonin secretion and sleep quality. Evening saliva melatonin secretion changed significantly and indicated that a tryptophan-rich breakfast and bright light exposure during the daytime promoted melatonin secretion at this time.

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          Most cited references20

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          The basic physiology and pathophysiology of melatonin.

          Melatonin is a methoxyindole synthesized and secreted principally by the pineal gland at night under normal environmental conditions. The endogenous rhythm of secretion is generated by the suprachiasmatic nuclei and entrained to the light/dark cycle. Light is able to either suppress or synchronize melatonin production according to the light schedule. The nycthohemeral rhythm of this hormone can be determined by repeated measurement of plasma or saliva melatonin or urine sulfatoxymelatonin, the main hepatic metabolite. The primary physiological function of melatonin, whose secretion adjusts to night length, is to convey information concerning the daily cycle of light and darkness to body physiology. This information is used for the organisation of functions, which respond to changes in the photoperiod such as the seasonal rhythms. Seasonal rhythmicity of physiological functions in humans related to possible alteration of the melatonin message remains, however, of limited evidence in temperate areas in field conditions. Also, the daily melatonin secretion, which is a very robust biochemical signal of night, can be used for the organisation of circadian rhythms. Although functions of this hormone in humans are mainly based on correlative observations, there is some evidence that melatonin stabilises and strengthens coupling of circadian rhythms, especially of core temperature and sleep-wake rhythms. The circadian organisation of other physiological functions could depend on the melatonin signal, for instance immune, antioxidative defences, hemostasis and glucose regulation. Since the regulating system of melatonin secretion is complex, following central and autonomic pathways, there are many pathophysiological situations where the melatonin secretion can be disturbed. The resulting alteration could increase predisposition to disease, add to the severity of symptoms or modify the course and outcome of the disorder.
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            Further validation of actigraphy for sleep studies.

            Actigraphy is generally compared to polysomnography (PSG), which has been considered the gold standard for sleep studies. The objective of the present study was to evaluate the concordance between PSG and two previously proposed algorithms (Cole et al, 1992; Sadeh et al, 1994) to analyze actigraphic recordings. The minute-by-minute agreement rate was evaluated through calculation of sensitivity, specificity, and accuracy. Regarding the sleep parameters, the concordance was performed through the Bland and Altman technique. A night of adaptation to the sleep laboratory followed by simultaneous polysomnographic and actigraphic recordings throughout the night. 21 healthy volunteers. A sleep laboratory None. Ninety-one percent of all PSG epochs were correctly identified by both algorithms, and this accuracy is reasonably satisfactory. The actigraphy was a sensitive method, with values of 99% and 97% for Cole's and Sadeh's algorithms, respectively. However, actigraphy had a low specificity: 34% and 44% for Cole's and Sadeh's algorithms, respectively. The Bland and Altman technique showed that actigraphy systematically overestimated Sleep Latency, Total Sleep Time and Sleep Efficiency while it underestimated Intermittent Awakenings. The results of this study show the utility of actigraphy as a useful method for assessment of sleep, despite its limitations regarding identification of waking epochs during sleep. The Bland and Altman concordance technique was revealed to be a powerful tool to evaluate how well actigraphy agreed with polysomnography. This technique, combined with calculations of sensitivity and specificity, appears to be the most adequate procedure for the assessment of concordance.
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              Actigraphy validation with insomnia.

              Actigraphy, a method of inferring sleep from the presence or absence of wrist movement, has been well validated against polysomnography in trials with people without insomnia. However, the small amount of literature on validation with insomniacs has revealed an actigraphy bias toward overscoring sleep. The current validation trial with insomniacs used the largest number of subjects to date in such research and attracted participants with diverse demographic characteristics. People with insomnia slept 1 night in the laboratory while simultaneously being monitored by polysomnography, actigraphy (high-sensitivity algorithm of the Mini Mitter AW64 Actiwatch), and morning sleep diary. Sleep disorders center. Participants were 57 volunteers from the community, 26 men and 31 women, ranging in age from 21 to 87 years. All participants satisfied conservative criteria for insomnia. The sample included subjects with primary insomnia, subjects with comorbid insomnia, and hypnotic users with current insomnia complaints. N/A. Actigraphy was successfully validated on 4 measures of sleep pattern--number of awakenings, wake time after sleep onset, total sleep time, and sleep efficiency percentage--based on nonsignificant mean differences and significant correlation between actigraphy and polysomnography. Sleep-onset latency with actigraphy was not significantly different from polysomnography but was weakly correlated with polysomnography. Hypnotic use contributed to actigraphic overscoring of sleep. Actigraphy proved to be a satisfactory objective measure of sleep on 4 of 5 sleep parameters, but these results are specific to this particular instrument using this particular algorithm and should not be construed as a blanket endorsement of actigraphy for measuring insomnia.
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                Author and article information

                Contributors
                fukushige.haruna.66r@st.kyoto-u.ac.jp
                fukuda@fwu.ac.jp
                tanaka.mizuho.62.v@st.kyoto-u.ac.jp
                09ule05@mb2.fwu.ac.jp
                spitz_czech@yahoo.co.jp
                tsumura@junshin-c.ac.jp
                kondo@gz.sekisuihouse.co.jp
                haratets@kochi-u.ac.jp
                wakamura@hs.med.kyoto-u.ac.jp
                morita@fwu.ac.jp
                Journal
                J Physiol Anthropol
                J Physiol Anthropol
                Journal of Physiological Anthropology
                BioMed Central (London )
                1880-6791
                1880-6805
                19 November 2014
                19 November 2014
                2014
                : 33
                : 1
                : 33
                Affiliations
                [ ]Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, 53, Shogoin, Kawahara-cho, Sakyo-ku, Kyoto 606-8507 Japan
                [ ]Department of Environmental Science, Fukuoka Women’s University, 1-1-1, Kasumigaoka, Higashi-ku, Fukuoka, 813-8529 Japan
                [ ]Department of Living Environmental Science, Fukuoka Women’s University, 1-1-1, Kasumigaoka, Higashi-ku, Fukuoka, 813-8529 Japan
                [ ]Laboratory of Environmental Physiology, Graduate School of Integrated Arts and Sciences, Kochi University, 2-5-1, Akebonocho, Kochi, 780-8520 Japan
                [ ]Department of Food and Nutrition, Junshin Junior College, 1-1-1, Chikushigaoka, Minami-ku, Fukuoka 815-8510 Japan
                [ ]Comprehensive Housing R & D Institute, Sekisui House Ltd, 6-6-4, Kabutodai, Kizugawa-city, Kyoto 619-0224 Japan
                Article
                83
                10.1186/1880-6805-33-33
                4247643
                25407790
                90e87c46-38ef-4b21-a044-705cd5d794b9
                © Fukushige et al.; licensee BioMed Central Ltd. 2014

                This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

                History
                : 21 May 2014
                : 23 October 2014
                Categories
                Original Article
                Custom metadata
                © The Author(s) 2014

                Anthropology
                bright light exposure,circadian rhythm,melatonin,sleep,tryptophan
                Anthropology
                bright light exposure, circadian rhythm, melatonin, sleep, tryptophan

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