PDF | Unlabelled: Islamic Ramadan is a day fast in which food, fluids, medications, drugs and smoking are The majority of health-specific findings related to Ramadan fasting are mixed. New perspectives on chrononutrition. Article. The primary finding of this meta-analysis was that after Ramadan fasting, low- density lipoprotein (SMD = , 95 % CI = . Islamic rules for Muslims is fasting during Ramadan. New perspectives on chrononutrition. Chrononutrition (Part 2): Breakfast-skipping and Diet Timing . Ramadan studies often show that people lose weight when they can only eat.

Author: Dolrajas Zululrajas
Country: Monaco
Language: English (Spanish)
Genre: Business
Published (Last): 2 September 2005
Pages: 493
PDF File Size: 10.10 Mb
ePub File Size: 9.1 Mb
ISBN: 174-7-93948-446-2
Downloads: 62203
Price: Free* [*Free Regsitration Required]
Uploader: Kazitilar

Chrononutrition against Oxidative Stress in Aging

To receive news and publication updates for Oxidative Medicine and Cellular Longevity, enter your email address in the box below. This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 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.

Understanding the aging process has gained in importance with people’s increasing life expectancy. Chronological age is the strongest predictor of chronic diseases, and the scientific community is searching for protective agents that can contribute to preventing or delaying the onset of many age-related diseases. The complexity of the holistic systems of which living cells form a part makes it difficult to distinguish between the causes and consequences of aging.

Indeed, it is still unknown whether this process derives from a single or multiple causes [ 1 ]. Theories of aging are mainly divided into those assuming that aging is genetically encoded and those assuming that it is due to a decline in maintenance mechanisms and exponential accumulation of molecular damage resulting in degeneration and dysfunction at the cellular level [ 2 ].

Among the latter theories, the free radical theory of aging also known as oxidative stress theory put forward by Harman in [ 3 ] has received extensive support. It posits that the organism’s deterioration resulting from increasing longevity is above all a consequence of the persistent accumulation of free radical mediated damage to essential molecules. This accumulation gradually compromises cell and tissue function, and eventually the entire function of the organism itself [ 4 ]. Within this theory, some authors argue that aging results from damage caused by free radicals to nuclear DNA, while others argue that it is a result of alterations to, and progressive loss of, mitochondria as a result of the mutilation of their DNA, thus reducing their biological effectiveness [ 1 ].

Indeed, mitochondrial DNA lacks polyamines or protective histones and, thus, is more susceptible than nuclear DNA to oxidative damage. Mutations are, therefore, more likely to take place in the mitochondrial genome of differentiated cells [ 5 ].

Curiously, healthy elderly individuals can have oxidative stress levels that are similar to those of young adults [ 6 ], or at least comparable in terms of antioxidant defences [ 7 ]. This suggests that oxidation is not inevitable in aging. It is commonly argued that aging is not a genetically controlled process but an interaction between environment and genes [ 8 ].

Psychological stress and lifestyle factors appear to have an impact on the level of oxidation [ 910 ]. Stress has been the most extensively studied negative factor in the brain’s vulnerability to aging.

In contrast, positive environmental factors such as a healthy diet can lead to improvements in aging [ 11 ]. Indeed, chrononutritikn is estimated that a third of all cancer deaths in the United States could be avoided through appropriate dietary modification [ 12 ].

Changes curononutrition dietary behaviour, such as increased consumption of fruits, vegetables, and grains, are a practical strategy for significantly reducing the incidence of chronic diseases.


Phytochemicals chrononutritioj bioactive nonnutrient compounds present in fruits, chrononutritiin, grains, and other plant foods. They have been linked to reductions in the risk of major oxidative stress-induced diseases [ 13 ]. Numerous investigations have shown a strong link between dietary intake of phytochemicals and reduced risk of cancer and cardiovascular disease worldwide. Thus, a prospective study in Finland involving men and women ages 15—99 years found an inverse association between the intake of flavonoids and the incidence of cancer [ 14 ].

As well as flavonoids, other phenylpropanoids, isoprenoids, and indoleamines, particularly the indole melatonin, merit particular attention due to their biological activities [ 15 ].

Melatonin is the principal neurohormone secreted at night by the vertebrate pineal gland. It is an important component of the body’s internal timekeeping system [ 16 ].

In particular, it is a signal of darkness chrononutriiton encodes time of day and length of day information for the brain [ 17 ]. A conceptual difficulty in melatonin research is that, while it is a signal of darkness, it has different functional consequences depending on the given species’ time of peak activity. In nocturnal species, it is associated with arousal and physical activity.

French book helps Muslims stay slim during Ramadan

In diurnal species, it is associated with sleep and rest [ 16 ]. In diurnal animals, the onset of melatonin secretion is closely associated with the timing of sleep propensity. It also coincides with decreases in core body temperature, alertness, and performance [ 18 ]. In this respect, the efficacy of melatonin supplementation to combat sleep disorders is well known, especially in the elderly with their marked reduction in melatonin production [ 16 ]. This hormone has a broad spectrum of physiological effects [ 20 ].

These include, but are not limited to, chronobiological, immunomodulatory, neuroendocrine, and antioxidant activities Figure 1. All of these may contribute to the observed anti-aging potency of this natural agent [ 21 ].

Related to its antioxidant activities, melatonin acts as a potent antioxidant and free radical scavenger [ 22 — 25 ]. It not only scavenges the especially toxic hydroxyl radicals, but also performs indirect antioxidant actions via its ability to stimulate antioxidative enzymes [ 26 ].

Melatonin diminishes free radical formation at the mitochondrial level by reducing the leakage of electrons from the electron transport chain [ 27 ]. Increasing the levels of circulating melatonin, either directly by exogenous administration or indirectly by including vegetables rich in this compound in the diet, enhances the individual’s antioxidant status [ 28 — 31 ].

It also stimulates a number of antioxidative enzymes which metabolize reactive products to innocuous agents. As well as for diseases in which there is an elevated production of free radicals, this may have implications for aging since production of this pineal indole wanes with increasing age.

Indeed, some authors speculate that its loss contributes to the aging process [ 4 ]. Some components of foods possess biological activities which influence circadian rhythms in humans.

A central target of current chronobiological research is how nutrients can alleviate or even prevent diseases. In the present review, we shall focus on the potential use of chrononutrition as a novel dietary strategy to counteract the deleterious actions of free radicals and reactive species on physiological systems during aging. We humans are immersed in an environment characterized by repetitive rhythmic cycles [ 32 ].

Conditions that are modified by different temporal cycles include organic efficiency, pathologies and the pharmacokinetics, pharmacodynamics, and efficacy of drugs. This phenomenon of rhythmicity extends to all classes of living beings, whether animals or plants, and at all levels of organization molecules, cells, tissues, and organs.

Chronobiology is the discipline that studies the nature and function of biological rhythms, defined as the recurrence of any event within a biological system at roughly regular intervals [ 34 ]. The human body’s biological clocks, for example, are controlled by synchronization with signals from the external environment [ 35 ].

The entire spectrum of biological rhythms covers an extremely wide range of frequencies [ 36 ]. All organisms, however, present circadian rhythms. These are biological processes that have an endogenous, entrainable oscillation of about 24 hours. The internal synchronization provided by circadian clocks may be altered by many factors, one of which is aging.

The aging process leads to a situation of chronobiological imbalance that results in shortening the period and reducing the amplitude of the oscillator, loss of the circadian rhythm itself, appearance of an ultradian pattern, and internal desynchronization [ 3940 ].

During aging, any disturbance or imbalance in the relationship between the circadian and homeostatic systems may lead to the impairment of numerous physiological processes. Antioxidant systems also deteriorate during aging.


Elderly individuals, therefore, become more vulnerable to pathological conditions related to oxidative stress and may require an extra supply of dietary antioxidants to combat free radicals [ 41 ]. These are all compounds with powerful antioxidant properties [ 232947 ]. The administration of tryptophan increases the availability of serotonin in the brain [ 4648 ].

Melatonin levels are consequently elevated as well [ 49 ]. Besides being an antioxidant, melatonin also has oncostatic, immunomodulatory, anti-inflammatory, and chronobiotic properties [ 50 — 52 ]. Given this context, the administration of tryptophan and melatonin in accordance with the needs of elderly subjects may contribute to readjusting any disturbances they have in their circadian rhythms.

Knowledge of the nature and function of biological rhythms is of practical as well as theoretical interest. This is reflected in the growing number of applications of chronobiology published in the recent health sciences literature. One such novel area of research is chronopharmacology. This is focused on the design and evaluation of drug delivery systems that release a bioactive agent at a rhythm matching the biological requirements of the treatment of a given disease [ 53 ].

Applying the knowledge of circadian function and regulation to the relevance of disease has enabled a chronobiology-based approach in the timing of administration of conventional drugs in order to synchronize the rhythms in disease activity with the efficacy of a particular drug, thus allowing for its optimal efficacy in the patient.

Other recent applications of chronobiology include chronopathology, chronotherapy, and chrononutrition, all aimed at reducing the need for invasive methods in therapeutic interventions, and therefore are of unquestionable importance Figure 2. Our eating schedules are dictated not only by food supply, hunger, and satiety, but also by convenience and social habits and pressures. Feeding behaviour is the first element to consider in an organism’s nutritional process.

The vast majority of studies have focused on examining the homeostatic regulation of the quantity and quality of food ingested. The hypothalamus is the main neural structure involved. It acts in close correlation with the release of such hormones as cholecystokinin CCKleptin, ghrelin, and insulin. Temporal aspects of this regulation have been far less studied [ 54 ].

Meal timing can affect many physiological processes. Since these are functions with a circadian rhythmicity, they deteriorate during aging with the weakening of overt circadian patterns [ 20 ]. That meal timing has major effects on the body has led to the conviction that, in choosing food, it is not only convenient to consider its nutritional value, but also its capacity to promote or hinder the normal functioning of the circadian cycle’s control systems Table 1.

Similar authors to follow

In humans, alterations have been detected in the overall expression of daily rhythms when food intake is limited to the usual period of rest i. Nutrients and phytochemicals play an essential part in the regulation of such circadian functions as sleep.

Compared with a control chronoonutrition high in carbohydrates and low in fat, a very low carbohydrate, fat-rich diet has been found to reduce the proportion of rapid eye movement REM sleep recorded by polysomnography.

But it also increased the percentage of deep slow-wave NREM sleep [ 55 ]. 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 [ raamadan ].

On the contrary, some components of the typical human diet, such as vitamin B12, improve alertness and concentration and reduce the daytime sleepiness phase [ 56 ]. Since some nutrients can entrain the circadian rhythm, diet design must take meal timing into account as well as the quantity and quality of the foods. In particular, the time of day at which food is consumed directly influences certain metabolic and hormonal factors—glucose, free fatty acids, glucocorticoids, and thyroid hormones, among others [ 57 ].

These ideas can be subsumed under the concept of chrononutrition. This concept reflects that it is not only the content of food, but also the time of ingestion and the interactions of its nutritional chrononutrittion which naturally contribute to the proper functioning of the circadian system.