Ramadan diet restrictions modify the circadian time structure in humans. A study on plasma gastrin, insulin, glucose, and calcium and on gastric pH

Implications of Ramadan Fasting in the Setting of Gastrointestinal Disorders

Intermittent fasting is an increasingly popular dieting technique with many well-studied benefits, such as permitting weight loss in obese patients, lowering low-density lipoprotein cholesterol (LDL-C) levels and triglyceride levels, and optimizing circadian rhythms. A special type of intermittent fasting occurs during Ramadan, when Muslims worldwide fast daily from dawn to sunset for a month. Ramadan fasting has demonstrated several health benefits, including improving the gut microbiome, modifying gut hormone levels, and lowering proinflammatory markers such as cytokines and blood lipids. Although fasting has many health benefits, fasting during Ramadan may aggravate chronic medical conditions. We aim to review the literature devoted to Ramadan fasting and its effects on Muslim patients with gastrointestinal (GI) disorders, such as Inflammatory bowel disease (IBD), peptic ulcer disease (PUD), upper GI bleeding (UGIB), gastroesophageal reflux disease (GERD), and liver conditions. We will discuss recommendations for diet and medication compliance during Ramadan in the recommended pre-Ramadan counseling sessions. In this study, we used PubMed to research journals using the key terms "Ramadan," "intermittent fasting," and "gastrointestinal diseases." The current literature studying the impact of Ramadan on gastrointestinal disorders shows that patients with IBD have a minimal risk of disease exacerbation, although older men with ulcerative colitis (UC) were more prone to exacerbation during fasting. Patients with duodenal ulcers were at a higher risk of hemorrhage after Ramadan fasting. Although with mixed results, studies show patients with liver disease demonstrated improvements in liver enzymes, cholesterol, and bilirubin after Ramadan. Physicians should offer pre-Ramadan counseling to educate patients on the risks of fasting and encourage shared decision-making. To facilitate more definitive discussions between the physician and a Muslim patient, clinicians should seek a deeper understanding of how Ramadan fasting affects certain health conditions and offer accommodations, such as diet and medication adjustments.

The Association between Acute Myocardial Infarction-Related Outcomes and the Ramadan Period: A Retrospective Population-Based Study

Fasting throughout the Muslim month of Ramadan may impact cardiovascular health. This study examines the association between the Ramadan period and acute myocardial infarction (AMI)-related outcomes among a Muslim population. The data were retrospectively extracted from a tertiary hospital (Beer-Sheva, Israel) database from 2002–2017, evaluating Muslim patients who endured AMI. The study periods for each year were: one month preceding Ramadan (reference period (RP)), the month of Ramadan, and two months thereafter (1840 days in total). A comparison of adjusted incidence rates between the study periods was performed using generalized linear models; one-month post-AMI mortality data were compared using a generalized estimating equation. Out of 5848 AMI hospitalizations, 877 of the patients were Muslims. No difference in AMI incidence between the Ramadan and RP was found (p = 0.893). However, in the one-month post-Ramadan period, AMI incidence demonstrably increased (AdjIRR = 3.068, p = 0.018) compared to the RP. Additionally, the highest risk of mortality was observed among the patients that underwent AMI in the one-month post-Ramadan period (AdjOR = 1.977, p = 0.004) compared to the RP. The subgroup analyses found Ramadan to differentially correlate with AMI mortality with respect to smoking, age, sex, diabetes mellitus, and hypertension, suggesting the Ramadan period is a risk factor for adverse AMI-related outcomes among select Muslim patients.

Impact of religious fasting on metabolic and hematological profile in both dyslipidemic and non-dyslipidemic fasters

BACKGROUND/OBJECTIVES

Religious fasting (RF) is practiced annually by millions of Christian and Muslim followers worldwide. Scarce data exist on the impact of RF on the metabolic and hematological profile of individuals with or without dyslipidemia.

SUBJECTS/METHODS

The present study included: (i) 60 Greek Orthodox participants, 30 with dyslipidemia and 30 without dyslipidemia, who abstained from meat, fish and dairy products for seven consecutive weeks, and (ii) 15 young, non-dyslipidemic Muslim participants abstaining totally from food and liquid from dawn till sunset during 30 days. Biochemical (iron, ferritin, vitamin B12, calcium, low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC), triglyceride and fasting glucose) and hematological (hemoglobin, hematocrit) serum blood test results of study participants were measured pre- and post- RF (at weeks 0 and 7 for Orthodox participants and at weeks 0 and 4 for Muslim participants).

RESULTS

In dyslipidemic and non-dyslipidemic Orthodox participants, a significant reduction of fasting glucose, HDL, LDL and TC levels was found post-RF. Hemoglobin, hematocrit, iron and ferritin levels were significantly increased, while post-RF vitamin B12 and calcium levels were substantially decreased. Subanalysis between dyslipidemic and non-dyslipidemic Orthodox participants revealed a greater decrease of cholesterol levels in the former. In Muslim participants, triglyceride, LDL and total cholesterol levels were increased post-RF (all p values < 0.05).

CONCLUSIONS

Our study adds to the existing literature evidence about the significant impact of RF on metabolic and hematological profiles of Orthodox and Muslim followers. The prevention of calcium and B12 deficiency during Orthodox RF by supplement consumption as well as the protection from dehydration and dysregulation of lipid metabolism during Ramadan RF should concern both clinicians and dietician nutritionists. Nevertheless, studies with larger sample size and/or long-term follow-up are warranted before reaching definite conclusions about the effects of RF on human health.

Does Ramadan Observance Affect Cardiorespiratory Capacity of Healthy Boys?

Studies raising the issue of the effects of Ramadan observance (RO) on boys' 6-min walk test (6MWT) data are rare. The studies, which did not include control groups of non-fasters, presented contradictory results. This study aimed to compare the 6MWT data (6-min walk distance [6MWD; m, %predicted], heart rate [HR; bpm, % of maximal predicted HR]), oxy-hemoglobin saturation (Oxy-sat; %), systolic and diastolic blood pressures (SBP and DBP, respectively; mmHg) determined at rest (_Rest and at the end _End of the test) of a group of 22 healthy fasting boys (age: 12 to 15 years) with an age-matched non-fasting group (n = 10). The 6MWTs were performed during three experimental conditions (ECs): Pre-Ramadan, Mid-Ramadan, and Post-Ramadan. The two groups' 6MWT data for each EC were compared, and repeated factorial analysis of variance (2 groups vs. 3 ECs) was performed. Both groups had similar values of 6MWD (m, %predicted), HR_Rest or HR_End (bpm, % of maximal predicted HR), Oxy-sat_Rest, Oxy-sat_End, SBP_Rest, and DBP_Rest during the three ECs. Compared to the non-fasting group, the fasting group had significantly higher SBP_End (121 ± 10 vs. 130 ± 11) and DBP_End (72 ± 6 vs. 78 ± 7) determined during the Mid-Ramadan EC. No significant interactive effects of the groups (2) vs. ECs (3) was found for the 6MWD (%predicted; p = .809), HR_Rest (%, p = .555), HR_End (%, p = .964), Oxy-sat_Rest (p = .336), Oxy-sat_End (p = .389), SBP_Rest (p = .708), SBP_End (p = .548), DBP_Rest (p = .277), and DBP_End (p = .096). To conclude, in boys, RO does not impact the 6MWD, HR, or Oxy-sat, but it has minimal impact on the SBP_End and DBP_End.

Effects of Ramadan fasting on serum lipid profile

INTRODUCTION

Ramadan is the ninth month in the lunar Islamic calendar and lasts for about 29-30 days. It is mandatory for all adult individuals of the Islamic faith to fast during the holy month of Ramadan. During this period, healthy Muslims do not eat or drink (i.e., total abstinence from food and fluids) and refrain from tobacco, daily from pre-dawn until dusk (21). Very few studies in the recent years have been conducted on this subject and for primary care physicians, it is of great help in understanding the physiological changes that occur in various populations with different rituals in Muslims.

MATERIALS AND METHODS

The present study included healthy adult male Muslim volunteers from different mosques in and around Jammu city. The number of subjects in the study was 100. Blood samples from all 100 subjects were collected twice during the study-once in the week prior to the beginning of Ramadan and then again in the last week of Ramadan (from 98 subjects as 2 subjects opted out). Following biochemical parameters were taken into consideration: (a) Serum total cholesterol (b) Serum triglycerides (c) Serum HDL cholesterol.

RESULTS

It was observed that compared to pre-fasting levels, total cholesterol (TC) and triglycerides (TG) were significantly decreased (P = 0.000) and high-density lipoprotein cholesterol (HDL-C) level had significantly increased (P = 0.000).

CONCLUSION

This study showed a reduction in total cholesterol and triglycerides along with a rise in levels of HDL-C, which had beneficial effects on lipid profile post Ramadan fasting period.

Oxidant and antioxidant parameters in people who fast during Ramadan, and those who do not

BACKGROUND

Objectives: The main aim of this study was to compare, by a new automated colorimetric method, oxidant and anti-oxidant status of those who fast during Ramadan and those who do not. For this purpose, total oxidant status (TOS), total anti-oxidant capacity (TAC) levels and oxidative stress index (OSI) were analysed. By doing this, we hope to examine whether fasting has any beneficial effect on human health.

MATERIALS AND METHODS

Fifty seven people were included in this study. Of these, 30 people had been fasting during the month of Ramadan for at least ten years, but 27 had never fasted in their life. On the 15^th day of Ramadan, blood samples were obtained from both groups after 12 hours of fasting.

RESULTS

The TAC levels of the fasting group (1.29±0,19) was quite higher than the non-fasting group (1,09±0,16) [EIC2][ICD3] [ICD4](p< 0.001). Similarly, in the fasting group TOS level and the OSI (respectively 12,77±2,23 and 1,01±0,25) was quite lower [EIC5][ICD6][ICD7] than in the non-fasting group (respectively 14,15±2,04 and 1,33±0,30), (p<=0.019 and p<0.001, respectively).These findings show that the TOS level of non-fasting group was high. This oxidative stress might cause various illnesses. Therefore, fasting could play a significant part in health-protection by increasing total anti-oxidant capacity.

Recurrent circadian fasting (RCF) improves blood pressure, biomarkers of cardiometabolic risk and regulates inflammation in men

Background

The effects of fasting on health in non-human models have been widely publicised for a long time and emerging evidence support the idea that these effects can be applicable to human practice.

Methods

In an open label longitudinal follow-up, a cohort of 78 adult men (aged 20 to 85 years) who fasted for 29 consecutive days from sunrise to sunset (16 h fasting—referred to as recurrent circadian fasting) in Pakistan, were studied. The primary outcomes of the fasting study was weight loss/recovery and the associated changes in blood pressure and circulating levels of surrogate markers linked to organ and system functions—including cardiovascular, metabolic and inflammation. Post-fasting outcomes include the regulation of physiological biomarkers.

Results

Recurrent circadian fasting with weight loss reduced blood pressure (140.6 vs. 124.2 mmHg) and markers of cardiovascular risk (~ 4-fold for resistin; triglycerides: p < 0.0001). Reduced glycemia (p < 0.0001) and the associated changes in the regulation of ketosis (β-hydroxybutyrate) were accompanied by a metabolic shift (PPARβ, osteoprotegerin), suggesting the involvement of the different physiological systems tested. Elevated orexin-A levels (p = 0.0183) in participants indicate sleep disturbance and circadian adaptation. All participants had CRP level < 2 mg/l during the fasting period and a similar trend was observed for TNFα. While most SASP molecules were decreased after the fasting period, heightened levels of IL-8 and IL-6 suggest that some inflammatory markers may be elevated by recurrent circadian fasting. Importantly, older adults reveal similar or more substantial benefits from fasting.

Conclusions

Recurrent circadian fasting is beneficial at the cardiometabolic and inflammatory levels, especially for at-risk individuals—this is contingent on compliance towards the recommended dietary behaviour, which controls carbohydrate and caloric intake. These benefits from fasting may be particularly beneficial to older adults as they often exhibit abnormal cardiovascular, metabolic and inflammatory signatures.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-2007-z) contains supplementary material, which is available to authorized users.

Eating Late Negatively Affects Sleep Pattern and Apnea Severity in Individuals With Sleep Apnea

STUDY OBJECTIVES

This study aimed to analyze the association between habitual meal timing and sleep parameters, as well as habitual meal timing and apnea severity in individuals with obstructive sleep apnea (OSA).

METHODS

Patients in whom mild to severe OSA was diagnosed were included in the study (n = 296). Sleep parameters were analyzed by polysomnography. Dietary pattern was obtained by a food frequency questionnaire and meal timing of the participants. Individuals with OSA were categorized by meal timing (early, late, and skippers).

RESULTS

Dinner timing was associated with sleep latency (β = 0.130, P = .022), apnea-hypopnea index (AHI) (β = 1.284, P = .033) and poor sleep quality (β = 1.140, P = .015). Breakfast timing was associated with wake after sleep onset (WASO) (β = 3.567, P = .003), stage N1 sleep (β = 0.130, P < .001), and stage R sleep (β = -1.189, P = .001). Lunch timing also was associated with stage N1 sleep (β = 0.095, P = .025), sleep latency (β = 0.293, P = .001), and daytime sleepiness (β = 1.267, P = .009). Compared to early eaters, late eaters presented lower duration of stage R sleep and greater values of sleep latency, WASO, stage N1 sleep, and AHI, in addition to increased risk of poor sleep quality and daytime sleepiness (P < .005).

CONCLUSIONS

Late meal timing was associated with worse sleep pattern and quality and apnea severity than early meal timing. Despite some of these results having limited clinical significance, they can lead to a better understanding about how meal timing affects OSA and sleep parameters.

Circadian Rhythm and Sleep Disruption: Causes, Metabolic Consequences, and Countermeasures

Circadian (∼24-hour) timing systems pervade all kingdoms of life and temporally optimize behavior and physiology in humans. Relatively recent changes to our environments, such as the introduction of artificial lighting, can disorganize the circadian system, from the level of the molecular clocks that regulate the timing of cellular activities to the level of synchronization between our daily cycles of behavior and the solar day. Sleep/wake cycles are intertwined with the circadian system, and global trends indicate that these, too, are increasingly subject to disruption. A large proportion of the world's population is at increased risk of environmentally driven circadian rhythm and sleep disruption, and a minority of individuals are also genetically predisposed to circadian misalignment and sleep disorders. The consequences of disruption to the circadian system and sleep are profound and include myriad metabolic ramifications, some of which may be compounded by adverse effects on dietary choices. If not addressed, the deleterious effects of such disruption will continue to cause widespread health problems; therefore, implementation of the numerous behavioral and pharmaceutical interventions that can help restore circadian system alignment and enhance sleep will be important.

Effects of Ramadan intermittent fasting on North African children's heart rate and oxy-haemoglobin saturation at rest and during sub-maximal exercise

Aim:

To examine the effects of Ramadan intermittent fasting (RIF) on the heart rate (HR) and oxyhaemoglobin saturation levels (oxy-sat) of boys at rest and during a six-minute walking test (6MWT).

Methods:

Eighteen boys (age: 11.9 ± 0.8 years, height: 153.00 ± 8.93 cm, body mass: 55.4 ± 18.2 kg), who fasted the entire month of Ramadan in 2012 for the first time in their lives, were included. The experimental protocol comprised four testing phases: two weeks before Ramadan (pre-R), the end of the second week of Ramadan (R-2), the end of the fourth week of Ramadan (R-4), and 10 to 12 days after the end of Ramadan (post-R). During each phase, participants performed the 6MWT at approximately 15:00. HR (expressed as percentage of maximal predicted HR) and oxy-sat (%) were determined at rest and in each minute of the 6MWT.

Results:

R-4 HR values were lower than those of (1) pre-R (in the second minute), (2) R-2 (in the first and second minutes), and (3) post-R (in the first, second, fourth, fifth and sixth minutes). R-2 oxy-sat values were higher than those of pre-R (in the third minute) and those of post-R (in the fifth minute). Post-R oxy-sat values were lower than those of pre-R and R-4 in the fifth minute. These oxy-sat changes were not clinically significant since the difference was less than five points.

Conclusion:

In non-athletic children, their first RIF influenced their heart rate data but had a minimal effect on oxy-sat values.

Knowledge, beliefs and attitudes of Muslim footballers towards Ramadan fasting during the London 2012 Olympics: a cross-sectional study

OBJECTIVES

Muslims observe fasting during the month of Ramadan by abstaining from eating and drinking from dawn to sunset. Available literature shows that although several studies have been conducted on athletes to determine the effects of Ramadan fasting in terms of physical fitness and performance, little data are available regarding the knowledge, beliefs and attitudes of athletes (particularly footballers) towards Ramadan fasting during high-level competitions. This study explored the knowledge, beliefs and attitudes towards Ramadan fasting among football players participating in the London 2012 Olympics football tournament.

DESIGN

Cross-sectional study.

SETTINGS

Team training facility.

PARTICIPANTS

54 Muslim footballers participating in the London Olympics, 2012 OUTCOME MEASURES: Each participant was asked to complete a pre-validated structured questionnaire to assess knowledge, beliefs and attitudes regarding Ramadan fasting and their intention to fast during London 2012.

RESULTS

Of the 54 participating athletes, 21(39%) reported that they intended to fast during Ramadan, but not on a match day. This attitude differed across three teams interviewed -83%, 15% and 0%-showing cross-cultural variation. Overall, there was a lack of knowledge among footballers regarding the effects of Ramadan fasting on sleep and performance; around 30% of athletes gave incorrect responses. This knowledge was independent of their decision to fast on non-competition days (p>0.05).

CONCLUSIONS

This is the first study to describe the knowledge, beliefs and attitudes towards Ramadan fasting among athletes from Muslim-majority countries participating in a high-level competition. Appropriate knowledge can ensure optimum performance for athletes during Ramadan fasting. Coaches, family members and friends also in possession of this knowledge can provide moral support to the players.

24-Hour Measurement of Gastric pH in Rural South Africa

Background. Previous studies have established norms of 24-hour gastric pH profiles for western countries. This study was designed to establish the pattern for a rural African population with a high incidence of oesophageal cancer. Methods. After lower oesophageal manometry a probe was placed 10 cm distal to the lower oesophageal sphincter. We carried out 24-hour ambulatory monitoring of gastric pH on 59 healthy subjects. This was satisfactorily completed on 26 female and 18 male (age 21–64, median 35) subjects in the Transkei region of South Africa. Results. The mean 24 hour gastric pH was 2.84 and the mean night-time pH was 3.7. 40 volunteers recorded a night-time pH reaching over 4. 33 volunteers recorded a night-time pH over 7. Night-time alkalinisation was present for 136.4 minutes (25th centile 22.8, 75th centile 208.1) at pH4 or over, and 79.3 (2.5, 122.7) minutes at pH7 or over. Episodes of rapid alkaline rise were 17 (10, 47). 21.1% of these occurred while supine. 35 of 36 tested subjects were positive for H. pylori IgG. Conclusion. Gastric alkalinisation is common in Transkei, at a higher pH than that reported in other studies, and is sustained longer. Nighttime alkalinisation is frequent. This suggests a high level of duodenogastric reflux.

Impact of Ramadan on clinical and microbiologic parameters of patients seen at a diarrheal hospital in urban Dhaka, Bangladesh, 1996-2012

Ramadan is a month in the Islamic calendar when Muslims fast during daylight hours. We used data from the surveillance system of the International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka Hospital in Dhaka, Bangladesh, a predominantly Muslim country, to compare the etiology and clinical presentation of patients who presented with diarrhea during Ramadan to that of control periods, defined as the 30 days immediately before Ramadan. The proportion of infecting pathogens was largely the same, although Shigella spp. were less likely to be identified during Ramadan. Clinical presentations during Ramadan among adult Muslim diarrheal patients were also comparable to those admitted during control periods. A subgroup of cholera patients who presented after sunset during Ramadan had a shorter duration of diarrhea and higher prevalence of severe thirst, drowsiness, and severe dehydration. Our findings suggest that Ramadan has few effects on the profile of enteric pathogens and clinical features of adults seeking medical care for diarrhea.

Effects of Ramadan fasting on cardiovascular risk factors: a prospective observational study

Background

Previous research has shown that Ramadan fasting has beneficial effects on cardiovascular risk factors, however there are controversies. In the present study, the effect of Ramadan fasting on cardiovascular risk factors has been investigated.

Method

This is a prospective observational study that was carried out in a group of patients with at least one cardiovascular risk factor (including history of documented previous history of either coronary artery disease (CAD), metabolic syndrome or cerebro-vascular disease in past 10 y). Eighty two volunteers including 38 male and 44 female, aged 29–70 y, mean 54.0 ± 10 y, with a previous history of either coronary artery disease, metabolic syndrome or cerebro-vascular disease were recruited. Subjects attended the metabolic unit after at least 10 h fasting, before and after Ramadan who were been fasting for at least 10 days. A fasting blood sample was obtained, blood pressure was measured and body mass index (BMI) was calculated. Lipids profile, fasting blood sugar (FBS) and insulin, homocysteine (hcy), high-sensitivity C-reactive protein (hs-CRP) and complete blood count (CBC) were analyzed on all blood samples.

Results

A significant improvement in 10 years coronary heart disease risk (based on Framingham risk score) was found (13.0 ± 8 before Ramadan and 10.8 ±7 after Ramadan, P <0.001, t test).There was a significant higher HDL-c, WBC, RBC and platelet count (PLT), and lower plasma cholesterol, triglycerides, LDL-c, VLDL-c, systolic blood pressure, body mass index and waist circumference after Ramadan (P <0.05, t test). The changes in FBS, insulin,Homeostasis Model Assessment Insulin Resistance (HOMA-IR), hcy, hs-CRP and diastolic blood pressure before and after Ramadan were not significant (P >0.05, t test).

Conclusions

This study shows a significant improvement in 10 years coronary heart disease risk score and other cardiovascular risk factors such as lipids profile, systolic blood pressure, weight, BMI and waist circumference in subjects with a previous history of cardiovascular disease.

Effects of fasting during ramadan month on cognitive function in muslim athletes

Purpose

Our study aimed to profile the effect of fasting during the Ramadan month on cognitive function in a group of healthy Muslim athletes.

Methods

Eighteen male athletes underwent computerized neuropsychological testing during (fasting) and after (non-fasting) Ramadan. Diet was standardized, and tests were performed at 0900h and 1600h to characterize potential time-of-day (TOD) interactions. Psychomotor function (processing speed), vigilance (visual attention), visual learning and memory, working memory (executive function), verbal learning and memory were examined. Capillary glucose, body temperature, urine specific gravity, and sleep volume were also recorded.

Results

Fasting effects were observed for psychomotor function (Cohen's d=1.3, P=0.01) and vigilance (d=0.6, P=0.004), with improved performance at 0900h during fasting; verbal learning and memory was poorer at 1600h (d=-0.8, P=0.03). A TOD effect was present for psychomotor function (d=-0.4, P<0.001), visual learning (d=-0.5, P=0.04), verbal learning and memory (d=-1.3, P=0.001), with poorer performances at 1600h. There was no significant fasting effect on visual learning and working memory.

Conclusions

Our results show that the effect of fasting on cognition is heterogeneous and domain-specific. Performance in functions requiring sustained rapid responses was better in the morning, declining in the late afternoon, whereas performance in non-speed dependent accuracy measures was more resilient.

Impact of caloric and dietary restriction regimens on markers of health and longevity in humans and animals: a summary of available findings

Considerable interest has been shown in the ability of caloric restriction (CR) to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE) consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF) consists of two interchanging days; one day, subjects may consume food ad libitum (sometimes equaling twice the normal intake); on the other day, food is reduced or withheld altogether. Dietary restriction (DR) - restriction of one or more components of intake (typically macronutrients) with minimal to no reduction in total caloric intake - is another alternative to CR. Many religions incorporate one or more forms of food restriction. The following religious fasting periods are featured in this review: 1) Islamic Ramadan; 2) the three principal fasting periods of Greek Orthodox Christianity (Nativity, Lent, and the Assumption); and 3) the Biblical-based Daniel Fast. This review provides a summary of the current state of knowledge related to CR and DR. A specific section is provided that illustrates related work pertaining to religious forms of food restriction. Where available, studies involving both humans and animals are presented. The review includes suggestions for future research pertaining to the topics of discussion.

Effect of Acute Maximal Exercise on Circulating Levels of Interleukin-12 during Ramadan Fasting

PURPOSE

The purpose of this study was to examine the effects of Ramadan fasting on circulating levels of interleukin-12 (IL-12) after a brief maximal exercise.

METHODS

NINE SUBJECTS PERFORMED A WINGATE TEST ON THREE DIFFERENT OCCASIONS: (i) the first week of Ramadan (1WR), (ii) the fourth week of Ramadan (4WR), and (iii) three weeks after Ramadan (AR). Blood samples were taken before, immediately and 60 min after the exercise. Plasma concentrations of IL-12 were measured using enzyme-linked immunosorbent assay. Variance analysis revealed no significant effect of Ramadan on P(peak) and P(mean) during the three testing periods.

RESULTS

Considering the effect of Ramadan on plasma concentrations of IL-12, analysis of the variance revealed a significant Ramadan effect (F((2,) (16))=66.27; P < 0.001) as well as a significant time effect (F((2,) (16))= 120.66; P < 0.001). However, no significant (Ramadan × time) of test interaction (F((4,) (32))=2.40; P>0.05). For all measures, IL-12 levels were lower during 1WR and 4WR in comparison with AR (P < 0.05). Considering the exercise effects, IL-12 levels measured immediately after the exercise were significantly higher than those measured before and at 60 minutes after the exercise (P < 0.001).

CONCLUSIONS

These results suggest that an acute intense exercise-induced IL-12 response is modified by daytime fasting and modifications in sleep schedule during Ramadan.

Nocturnal gastroesophageal reflux revisited by impedance-pH monitoring

Background/Aims

Impedance-pH monitoring allows detailed characterization of gastroesophageal reflux and esophageal activity associated with reflux. We assessed the characteristics of nocturnal reflux and esophageal activity preceding and following reflux.

Methods

Impedance-pH tracings from 11 healthy subjects and 76 patients with gastroesophageal reflux disease off acid-suppressive therapy were analyzed. Characteristics of nocturnal supine reflux, time distribution and esophageal activity seen on impedance at 2 minute intervals preceding and following reflux were described.

Results

Patients had more nocturnal reflux events than healthy subjects (8 [4-12] vs 2 [1-5], P = 0.002), with lower proportion of weakly acidic reflux (57% [35-78] vs 80% [60-100], P = 0.044). Nocturnal reflux was mainly liquid (80%) and reached the proximal esophagus more often in patients (6% vs 0%, P = 0.047). Acid reflux predominated in the first 2 hours (66%) and weakly acidic reflux in the last 3 hours (70%) of the night. Most nocturnal reflux was preceded by aboral flows and cleared by short lasting volume clearance. In patients, prolonged chemical clearance was associated with less esophageal activity.

Conclusions

Nocturnal weakly acidic reflux is as common as acid reflux in patients with gastroesophageal reflux disease, and predominates later in the night. Impedance-pH can predict prolonged chemical clearance after nocturnal acid reflux.