Saudi Journal of Kidney Diseases and Transplantation

: 2007  |  Volume : 18  |  Issue : 3  |  Page : 349--354

Fasting the month of Ramadan by Muslims: Could it be injurious to their kidneys?

Hala S El-Wakil1, Iman Desoky2, Nashaat Lotfy3, Ahmed G Adam1,  
1 Nephrology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
2 Biochemistry Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
3 Radiology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt

Correspondence Address:
Hala S El-Wakil
Nephrology Department, Faculty of Medicine, Alexandria University, Alexandria


Ramadan is the ninth lunar month of the Islamic calendar. During Ramadan, Muslims abstain from food and drink from dawn to sunset (fasting) to express their gratitude to God; eating and drinking is permitted only at night. Muslims typically consume two meals each day, one after sunset, and the other just before dawn. The effect of fasting during the month of Ramadan on patients with renal impairment is still a matter of controversy. This is a prospective study performed on 15 predialysis chronic kidney disease (CKD) patients and six healthy volunteers as control. They were studied during two phases: when the subjects were drinking and eating freely before the start of Ramadan, and a second phase toward the end of Ramadan. We estimated glomerular filtration rate (GFR) using DTPA dynamic renal scan, and tubular cell damage by measuring the level of N-acetyl-B-D- glucosaminidase (NAG). The change in glomerular filtration rate was -6.56 ± 31.10 in the CKD group compared to 9.58 ± 30.10 in the control group with no significant difference between them (p= 0.43). However, the urinary NAG percentage change was found to be significantly higher in the CKD patients compared to the control group (236 ± 332, -49.1 ± 60.1 respectively p= 0.03). There was a significantly positive correlation between the NAG values and the change in the blood glucose level (p=0.001), hence diabetic CKD patients should be meticulously followed during Ramadan fasting. In conclusion, fasting Ramadan may have injurious effect on the renal tubules in CKD patients. Larger studies are recommended to determine the extent of tubular injury and renal function in CKD patients during Ramadan fasting.

How to cite this article:
El-Wakil HS, Desoky I, Lotfy N, Adam AG. Fasting the month of Ramadan by Muslims: Could it be injurious to their kidneys?.Saudi J Kidney Dis Transpl 2007;18:349-354

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El-Wakil HS, Desoky I, Lotfy N, Adam AG. Fasting the month of Ramadan by Muslims: Could it be injurious to their kidneys?. Saudi J Kidney Dis Transpl [serial online] 2007 [cited 2020 Apr 7 ];18:349-354
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The month of Ramadan is the ninth lunar month of the Islamic calendar. Ramadan fasting is one of the five pillars of Islam. Fasting extends from dawn until sunset.

During this period, the individual must abstain from eating, drinking or taking any nutritive materials through any route. Islam allows the break of fasting for certain groups of people including ill persons. [1]

During Ramadan, fasting Muslims tend to alter their dietary habits. This involves changes in eating times and content of food, in addition to fluid deprivation. [2],[3] It is fairly well known that fluid deprivation causes volume con­traction and renal hypoperfusion. The latter may cause renal dysfunction and aggravate existing renal impairment. [4]

During fasting, different pathophysiological mechanisms may contribute to the progression of renal disease. Plasma insulin like growth factor (IGF-I) was found to be decreased by fasting and increased by re-fasting. [5]

Physicians caring for Muslim patients are frequently consulted about various aspects of Ramadan. Unfortunately, there is little scien­tific information in the medical literature on this subject. The effect of fasting during the month of Ramadan on patients with renal impairment is still a matter of controversy.

The aim of the present study was to assess the clinical and biochemical changes that occur during the fasting month in patients with chronic kidney disease (CKD) in the predialysis stage and to localize whether the injury is glomerular and / or tubular.

 Patients and Methods

We studied 15 CKD patients with creatinine clearances below 60 ml/min were recruited from the nephrology clinic in Alexandria Main University Hospital, Alexandria, Egypt, during the month of Ramadan, November 2001. Six healthy volunteers were included in the study and served as a control group.

The mean age was 53.0 + 15.6 years, ranged from 23-82 years. Nine women and six men were included. Only twelve patients completed the study. The cause of CKD was diabetes mellitus in 21.4% patients, hypertension in 21.4%, chronic pyelonephritis in 21.4%, chronic glomerulonephritis in 14.2%, poly­cystic kidney disease in 14.2% and obstructive uropathy in 7.14%.

All patients fasted during Ramadan at least the previous two years and during the study period; all fasted from dawn until sunset. We excluded patients who were below 20 years of age, or had chronic liver disease, advanced cardiac disease, acute infection, or diabetes insipidus.

The evaluation of the patients was conducted in two phases in matched situations:

1. Pre-Ramadan phase: during which the patients were allowed to drink and eat freely.

2. Ramadan Phase: near the end of the month of Ramadan.

Clinical evaluation of the patients included meticulous current and past medical history, and physical examination. The laboratory investigations included blood urea nitrogen, serum creatinine, serum electrolytes, serum albumin, blood glucose, serum cholesterol, and triglycerides (Hitachi 902 automatic bioche­mical analyzers using Roche Bioche-mical Diagnostic reagents) in addition to 24 hour urine protein excretion, and N-acetyl-D-gluco­saminidase (NAG) as a marker for tubular cell damage that was reported as the NAG/ creatinine ratio in urine.

Glomerular filtration rate (GFR) was measured with the Technetium 99m Stannous Diethylene Triamine Penta Acetic acid (DTPA) renography for the estimation of total as well as split renal functions in all the patients; GE STARCAM 400 A Gamma Camera connected to a GE computer calculated the GFR two to three minutes after the injection of isotope using Gates' method. [7]

 Statistical Analysis

Data were analyzed using the statistical package SPSS version 9.0 for windows. Qualitative variables were expressed as number and percentage, while quantitative variables were expressed as mean ± standard deviation (SD). Wilcoxon ranks test (Z-value) was used for comparison of qualitative variables, and Mann-Whitney test was used (MWZ) for comparison of means, when the paired t-test was not appropriate. Spearman's rank correlation coefficient (r) was used to measure the mutual relationship between two normally distributed data. The level of significance was selected as P [10] Rashed demonstrated that fasting during Ramadan did not show any significant medical problems on health. [11]

Our results showed no significant difference in mean blood pressure change among CKD patients in comparison to the healthy persons. These findings are matched with the results of Perk et al.[12]

Our results showed significantly higher serum potassium levels during Ramadan fasting among CKD patients. This could be attributed to the traditional breakfast with large amounts of dates, apricot juice and coffee, all of which are rich in potassium. This would provide over 80 mmol of potassium during one meal. Similar changes have been found in patients on chronic hemodialysis, [13] and in renal transplant recipients.[14]

Our results showed that GFR did not change significantly in CKD patients during Ramadan. This data is different to that of Al Muhanna [15] who found a transient reduction of the calculated creatinine clearance in CKD patients who recovered two weeks after Ramadan. The difference may be attributed to more advanced renal failure in their series in comparison to ours.

Though our study did not include transplant patients, others reported stable renal function with fasting during Ramadan in donors and recipients of renal allografts after the first year of transplantation if associated with normal renal functions. [16] Moreover, similar data were obtained for renal transplant recipients with normal as well as impaired renal functions.[17]

Renal tubular injury, as assessed by increased urinary NAG, tended to increase in our study CKD group. This could be explained by the vulnerability of the tubules to hemody-namic changes, especially in the diseased kidneys. The Malaysian group studied many tubular functions among healthy persons during Ramadan fasting. They found that tubular dys­functions that might occur during fasting were temporary and the body rapidly adapted to fasting, and finally there were no adverse effects on renal function among normal persons. This was attributed to the regimen of altered meal times and activity during Ramadan.[18]

Tubular injury correlated significantly with poor glycemic control among our CKD patients. Hence, diabetic predialysis patients should be meticulously followed during Ramadan fasting. Khatib et al [19] found a trend towards better glycemic control following Ramadan fasting, while dyslipidemia in pre­Ramadan patients was sustained or even worsened following Ramadan fasting. More­over, diabetic patients with CKD were defined as high risk patients, while those sustaining poor glycemic control were consi-dered very high risk patients. [20] The EPIDIAR study emphasized the need for intensive education of patients before fasting during Ramadan, in addition to close monitoring of blood glucose. This challenge is more apparent in diabetic patients with CKD. [21]

We conclude from this small study that Ramadan fasting may be injurious to renal tubules, but only for those with CKD. Larger studies are recommended to determine the extent of tubular injury and renal function in CKD patients during Ramadan fasting.


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