Health Impact of Fasting in Saudi Arabia during Ramadan: Association with Disturbed Circadian Rhythm and Metabolic and Sleeping Patterns

et al. (2014) Health Impact of Fasting in Saudi Arabia during Ramadan: Association with Disturbed Circadian Rhythm and Metabolic and Sleeping Patterns. PLoS ONE 9(5): e96500. doi:10.1371/journal.pone.0096500 Health Impact of Fasting in Saudi Arabia during Ramadan: Association with Disturbed Circadian Rhythm and Metabolic and Sleeping Patterns Ghada M. Ajabnoor Suhad Bahijri Anwar Borai Altaf A. Abdulkhaliq Jumana Y. Al-Aama George P. Chrousos Kottarappat N. Dileepan, University of Kansas Medical Center, United States of America Background: Muslims go through strict Ramadan fasting from dawn till sunset for one month yearly. These practices are associated with disturbed feeding and sleep patterns. We recently demonstrated that, during Ramadan, circadian cortisol rhythm of Saudis is abolished, exposing these subjects to continuously increased cortisol levels. Hypothesis: Secretory patterns of other hormones and metabolic parameters associated with cortisol, and insulin resistance, might be affected during Ramadan. Protocol: Ramadan practitioners (18 males, 5 females; mean age 6SEM = 23.1661.2 years) were evaluated before and two weeks into Ramadan. Blood was collected for measurements of endocrine and metabolic parameters at 9 am (61 hour) and again twelve hours later. Results: In Ramadan, glucose concentration was kept within normal range, with a significant increase in the morning. Mean morning concentration of leptin was significantly higher than pre-Ramadan values (p = 0.001), in contrast to that of adiponectin, which was significantly lower (p,0.001). These changes were associated with increased insulin resistance in morning and evening. Concentrations of hsCRP were lower during Ramadan than those during regular living conditions, however, normal circadian fluctuation was abolished (p = 0.49). Even though means of liver enzymes, total bilirubin, total protein and albumin were all decreased during Ramadan, statistically lower means were only noted for GGT, total protein, and albumin (p = 0.018, 0.002 and 0.001 respectively). Discussion: Saudi Ramadan practitioners have altered adipokine patterns, typical of insulin resistance. The noted decreases of hsCRP, liver enzymes, total protein, and albumin, are most likely a result of fasting, while loss of circadian rhythmicity of hsCRP is probably due to loss of circadian cortisol rhythm. Conclusions: Modern Ramadan practices in Saudi Arabia, which are associated with evening hypercortisolism, are also characterized by altered adipokines patterns, and an abolished hsCRP circadian rhythm, all likely to increase cardiometabolic risk. - Funding: This project was supported by the deanship of research at King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia under grant number (HiCi/14326-2) as part of a main research study conducted by the Saudi Diabetes Study Research Group. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. The combined inputs of the master circadian clock in the suprachiasmatic nucleus (SCN) of the hypothalamus and of the rhythmic behaviors of the rest/sleep vs. wake and feeding vs. fasting states control the overall temporal organization of the neuroendocrine system, as well as other behavioral and physiologic systems, along the 24-hour day [1,2]. Conversely, the peripheral clocks and the above rhythmic states may influence neuroendocrine tempos independently of the direct control of the central circadian clock [3]. The overwhelming evidence that the circadian and metabolic systems are linked together at molecular, cellular and behavioral levels has fueled great interest in the possible roles of circadian disorganization in obesity, diabetes and other cardiometabolic disorders [46]. Adequate sleep duration is vital for cardiovascular health, while inadequate duration of quality sleep is specifically associated with increased cardiovascular morbidity [79]. On the other hand, intermittent fasting (IF; reduced meal frequency) and caloric restriction (CR) enhance cardiovascular and brain functions and improve several risk factors for coronary artery disease and stroke, including a reduction in blood pressure and increased insulin sensitivity [10]. Therefore, the obligatory fasting from dawn to sunset during the month of Ramadan for all healthy Muslims is believed to bring health benefits. Indeed, studies on Ramadan practitioners worldwide support this belief [1114]. However, Ramadan fasting in the Kingdom of Saudi Arabia, unlike other Muslim and Arab countries, is associated with profound changes in sleeping and feeding patterns, with an almost complete reversal of the rest/sleep vs. wake cycle and restriction of food intake to night-time only. We already reported the effects of these life-style changes on glucose homeostasis, as well as insulin and cortisol secretion patterns, the latter characterized by a complete loss of circadian rhythmicity [15]. However, other circadian hormonal and metabolic effects of Ramadan on insulin tissue sensitivity, in particular the adipokines leptin and adiponectin, have been studied little and questions remain. Here we studied Ramadan-related changes of leptin and adiponectin, both of which regulate appetite and affect metabolic pathways and insulin sensitivity, growth hormone (GH), which influences insulin sensitivity, and hsCRP, a measure of systemic smoldering inflammation, as well as associated changes in acute reactants and liver function. Subjects and Methods Study Design We employed samples of the population studied in our earlier report described in brief below [15]. The same subjects were studied at different times to avoid variability between groups at baseline and to decrease sample size. Based on laboratory quality control data, and reference ranges for intended measurements, sample size was calculated to avoid type II statistical error [16], and was found to be 18.7. This was increased further to account for drop-outs, and the total number of recruited subjects was 25. The protocol was approved by the Committee on the Ethics of Human Research at the Faculty of Medicine- King Abdulaziz University. Twenty-three of the recruited volunteer healthy subjects (18 males, 5 females), aged 1842 years; completed the study. Written informed consent was obtained in all cases. Volunteers were studied twice, during their regular life (Shaaban) before, and again 1015 days into fasting period (Ramadan). They were instructed to have meals as usual on the day of testing, and to record their usual sleeping and waking times for the previous three days. This was because changes in quantity, quality or timing of meals, as well as in sleeping pattern, are expected to affect measured parameters, such as circulating concentrations of glucose, insulin, cortisol, leptin and adiponectin. More details about study protocol, (...truncated)