Acute effects of the very low carbohydrate diet on sleep indices
ABSTRACT We compared the effect of short-term consumption of a very low carbohydrate (VLC) diet over 48 h to a control mixed diet on sleep indices in healthy, non-obese men.
This study employed a repeated-measure design where subjects were given isocaloric (2400 kcal) diets and matching evening test meals (4 h before usual bed-time), which were either mixed low-fat, high carbohydrate (15.5%, 12.5% and 72% of energy from protein, fat and carbohydrate, respectively) or VLC (38%, 61% and < 1% of energy from protein, fat and carbohydrate, respectively). Polysomnographic testing was performed on the familiarization and control night, 4 h after the first VLC test meal (acute phase) and 48 h (ketosis phase) following commencement of the VLC diet.
Fourteen healthy, non-obese men (aged 18-35 years; body mass index 23.4 +/- 1.9 kg/m(2)) who were good sleepers took part in the study.
Objective sleep was recorded using a computerized sleep system. Urine ketone level was monitored with reagent strips before the evening test meals and at bed-time on the control night, during the VLC acute and ketosis phases. Blood glucose level was measured with a glucometer before the evening test meal until 120 min following the meal. Hunger and fullness were assessed immediately after the meal until bed-time with Likert scales.
The proportion of rapid-eye movement (REM) sleep to total sleep time was significantly reduced at the VLC acute and VLC ketosis when compared to the control night (P = 0.006; n = 11 and P = 0.05; n = 14, respectively). The percentage of slow wave sleep (SWS) significantly increased for both the VLC acute (17.7 +/- 6.7) and ketosis (17.8 +/- 6.1) phases compared to control (13.9 +/- 6.3), P = 0.02 for both phases.
In healthy, good sleepers, the VLC diet over the short-term promotes increases in the percentage of SWS (deep sleep stage 4) and a reduction in the percentage of REM sleep ('dreaming' sleep) compared to the control mixed diet. The sleep changes may be linked to the metabolism of the fat content of the VLC diet.
- SourceAvailable from: Maria Pilar Terrón
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- ". While the total amount of carbohydrates may influence the architecture of sleep, it does not affect the duration. However, the evidence on whether carbohydrates positively impact sleep quality is not completely consistent, since consuming carbohydrate meals with high or low glycaemic loads seems not to affect any polysomnographically determined sleep index . On the contrary, some components of the typical human diet, such as vitamin B12, improve alertness and concentration and reduce the daytime sleepiness phase . "
ABSTRACT: Free radicals and oxidative stress have been recognized as important factors in the biology of aging and in many age-associated degenerative diseases. Antioxidant systems deteriorate during aging. It is, thus, considered that one way to reduce the rate of aging and the risk of chronic disease is to avoid the formation of free radicals and reduce oxidative stress by strengthening antioxidant defences. Phytochemicals present in fruits, vegetables, grains, and other foodstuffs have been linked to reducing the risk of major oxidative stress-induced diseases. Some dietary components of foods possess biological activities which influence circadian rhythms in humans. Chrononutrition studies have shown that not only the content of food, but also the time of ingestion contributes to the natural functioning of the circadian system. Dietary interventions with antioxidant-enriched foods taking into account the principles of chrononutrition are of particular interest for the elderly since they may help amplify the already powerful benefits of phytochemicals as natural instruments with which to prevent or delay the onset of common age-related diseases.Oxidative Medicine and Cellular Longevity 06/2013; 2013:729804. DOI:10.1155/2013/729804 · 3.36 Impact Factor
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- "In small children (n = 594), teenage girls (n = 126), and in a small study of 30 Greek women, a trend was observed toward longer sleep duration, with subjects consuming more energy from fat, whereas in other large studies with adolescents (n = 240) and adults (n = 459 and n = 2828), short sleep duration was correlated with increased fat intake [8,10–13,47,58]. Studies of high-fat, low-carbohydrate diets have not observed marked differences but only a remote trend on sleep duration, but also some influence on the relation of non-REM and REM sleep as described above   . "
ABSTRACT: Sleep, much like eating, is an essential part of life. The mechanisms of sleep are only partially clear and are the subject of intense research. There is increasing evidence showing that sleep has an influence on dietary choices. Both cross-sectional and epidemiologic studies have demonstrated that those who sleep less are more likely to consume energy-rich foods (such as fats or refined carbohydrates), to consume fewer portions of vegetables, and to have more irregular meal patterns. In this narrative review, we pose the opposite question: can ingested food affect sleep? The purpose of this review is to discuss the evidence linking diet and sleep and to determine whether what we eat and what kind of nutrients we obtain from the food consumed before bedtime matter. In addition, scientific evidence behind traditional sleep-promoting foods such as milk and some herbal products is briefly described. These are reviewed using data from clinical trials, mostly in healthy subjects. In addition, we discuss the possible mechanisms behind these observations. Lastly, we summarize our findings that emerging evidence confirms a link between diet and sleep. Overall, foods impacting the availability of tryptophan, as well as the synthesis of serotonin and melatonin, may be the most helpful in promoting sleep. Although there are clear physiological connections behind these effects, the clinical relevance needs to be studied further.Nutrition research 05/2012; 32(5):309-19. DOI:10.1016/j.nutres.2012.03.009 · 2.59 Impact Factor
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ABSTRACT: To construct a practical system using a mobile manipulator, a new mobile manipulator with exchangeable active/passive joints has been developed by authors. In the mobile manipulator, passive joints play an important role in absorbing the mobile positioning error and reducing the internal force passively. By utilizing the exchangeable active/passive joints, a control algorithm. for automatic insertion of a long pipe based only on the angular information of the passive joints is proposed. By implementing the algorithm to the mobile manipulator, the insertion task was performed successfully. The proposed control algorithm is described and the experimental results are shown in this paperSystems, Man, and Cybernetics, 2001 IEEE International Conference on; 02/2001