According to Gram Research analysis of a 2026 Egyptian study of 138 hemodialysis patients, fasting during Ramadan did not worsen bone health markers over the month. Blood levels of calcium, phosphorus, and parathyroid hormone stayed stable, and no bone-related adverse events were reported. Longer studies are still needed.
A new study followed 138 adults on hemodialysis, a treatment that filters the blood when the kidneys can no longer do it, at four dialysis centers in Egypt. Some patients fasted for all of Ramadan, some fasted only on non-dialysis days, and others did not fast. Researchers measured blood minerals and bone-related markers at the start and end of the month. According to Gram Research analysis, fasting did not worsen mineral and bone markers, and levels of calcium, phosphorus, and parathyroid hormone stayed stable. Potassium dropped in all groups, and no meaningful rise in dialysis complications, such as low blood pressure or low blood sugar, was found. One bone marker differed between groups, but that difference disappeared after accounting for age, sex, body weight, and time on dialysis. Because the study was observational and relatively small, larger studies with longer follow-up are still needed.
Key Statistics
A 2026 multi-center cohort study of 138 hemodialysis patients in Egypt found that calcium, phosphorus, magnesium, and parathyroid hormone levels stayed stable during Ramadan fasting.
In the same 2026 study, levels of FGF23, sclerostin, and TRAP5b increased in all fasting groups during Ramadan, while Klotho decreased in every group, with no significant differences between fasting and non-fasting patients after adjustment.
The 2026 study found no significant change in dialysis-related complications, such as low blood pressure and low blood sugar, before versus after Ramadan among 138 hemodialysis patients.
The Quick Take
- What they studied: The researchers wanted to know whether fasting during Ramadan, the Islamic month when many people don’t eat or drink from sunrise to sunset, affects blood chemistry and bone health in people who receive hemodialysis.
- Who participated: 138 adults aged 18 to 85 who had been on hemodialysis for at least six months. They came from four dialysis centers in Dakahlia, Egypt, and their medical conditions were stable.
- Key finding: Fasting was not linked to worse bone health markers. Calcium, phosphorus, magnesium, and parathyroid hormone stayed stable in all groups. One bone marker showed a difference between groups before adjustment for other factors, but that difference was not statistically significant after adjustment (adjusted P = 0.229).
- What it means for you: If you are on hemodialysis and fast during Ramadan, this study suggests your bone and mineral levels did not worsen over the month. Talk with your kidney care team before fasting, because the study only looked at a short period under medical supervision.
The Research Details
This was a prospective observational cohort study, which means researchers followed a group of people over time and recorded what happened without assigning them to fast or not fast. Participants were sorted into three groups based on their fasting habits: people who did not fast, people who fasted only on days they did not have dialysis, and people who fasted for the full month of Ramadan.
Researchers collected health information, including dialysis details, weight gain between treatments, and any problems that happened during dialysis sessions. Blood samples were taken at the beginning and end of Ramadan. These samples were tested for standard chemistry values and for markers of bone activity, including alkaline phosphatase, FGF23, sclerostin, Klotho, and TRAP5b.
The team compared how each marker changed from the start to the end of Ramadan across the three groups. They then adjusted the results for age, sex, body mass index, and how long each person had been on dialysis, so that these factors would not distort the comparison.
Patients on hemodialysis are at higher risk of weak bones and mineral imbalances, so changes in fasting habits could matter for their health. Because this study followed the same patients at two points in time, it can show how their blood levels actually changed during the month. Comparing three fasting groups also helps reveal whether fasting itself made a difference.
The study followed patients from several centers and tracked a wide range of blood markers, which adds useful detail. However, it was observational, so it cannot prove cause and effect. The groups were not randomly assigned, and the study was not designed or sized to measure safety. The short timeframe also means it cannot show long-term effects on bones. The authors say larger controlled studies are needed, and that caution is appropriate.
What the Results Show
The main question was whether fasting changed bone and mineral health over Ramadan. Across all three groups, levels of calcium, phosphorus, magnesium, and intact parathyroid hormone (a hormone that controls calcium balance) stayed stable. This suggests that fasting did not disrupt these key minerals in this group of patients.
Serum potassium, a mineral that affects heart rhythm, dropped by a similar amount in all groups. Sodium and albumin, a blood protein, rose slightly in people who fasted for the full month. These changes were modest, and the researchers did not find a meaningful difference between the groups for potassium.
For bone markers, FGF23, sclerostin, and TRAP5b increased in all groups, while Klotho decreased in all groups. These shifts happened whether or not people fasted, which suggests they may be related to the dialysis treatment or the passage of time rather than to fasting itself. Before adjustment, one marker called BSAP appeared to rise in non-fasting patients while staying flat or slightly falling in fasting patients. That difference disappeared once the researchers accounted for age, sex, body mass index, and dialysis history.
Dialysis-related problems, including low blood pressure during treatment and low blood sugar, did not change significantly before or after Ramadan. The researchers also reported no clinically important bone-related side effects. This is reassuring, but the study was not designed to detect rare or serious safety problems, so the finding should be read with that limit in mind.
Earlier research on fasting in people with kidney disease has raised concerns about dehydration, changes in blood chemistry, and possible strain on the body. This study adds information specifically about bone and mineral markers in people on hemodialysis, an area that has been studied less. Its results are consistent with the idea that stable, medically supervised patients may handle fasting without major short-term changes in these markers.
The study had several limitations. It was observational, so people chose their own fasting patterns, and those who fasted may have differed from those who did not in ways the researchers could not fully measure. The sample of 138 people is moderate in size, and the study only followed patients for about one month. Bone health changes often take months or years to show up, so this study cannot reveal long-term effects. The researchers also noted that the study was selected for clinically stable patients, so the results may not apply to everyone on dialysis.
The Bottom Line
Based on this study, there is moderate evidence that Ramadan fasting did not cause short-term harm to bone or mineral markers in stable hemodialysis patients under medical supervision. Because the study was small and short, this should be viewed as an early signal rather than a final answer. Patients who want to fast should discuss their plans with their nephrologist and dialysis team first, and should monitor for warning signs such as dizziness, weakness, or unusual fatigue.
This research is most relevant to adults receiving maintenance hemodialysis who are considering fasting during Ramadan, and to the clinicians who advise them. People with other kidney conditions, those who are not on dialysis, or those with unstable health should not assume these results apply to them. Anyone with diabetes, heart problems, or low blood pressure should also get individual medical advice before fasting.
This study only tracked changes over about one month, so it can describe what happened during Ramadan but not what happens over years. Any effects on bone strength would usually take months or longer to appear, and they would need to be measured with bone density tests and long-term follow-up. Patients should expect ongoing checkups rather than quick changes.
Frequently Asked Questions
Is it safe for people on hemodialysis to fast during Ramadan?
A 2026 study of 138 hemodialysis patients in Egypt found no significant rise in dialysis complications during Ramadan. Blood minerals and bone markers stayed stable, but the study was short and not designed to measure safety, so patients should consult their nephrologist first.
Does fasting during Ramadan affect bone health in dialysis patients?
A one-month study of 138 dialysis patients found that fasting did not worsen bone and mineral markers. Calcium, phosphorus, and parathyroid hormone stayed stable. Effects on bone strength take longer to appear, so researchers say longer studies are needed.
What blood levels change during Ramadan fasting for people on dialysis?
In a 2026 Egyptian study of 138 hemodialysis patients, potassium dropped in all groups, while sodium and albumin rose slightly in full fasters. Bone markers FGF23, sclerostin, and TRAP5b increased, and Klotho decreased, whether or not patients fasted.
Should I talk to my kidney doctor before fasting during Ramadan?
Yes is not required here, so the answer is this: always discuss fasting with your nephrologist and dialysis team before Ramadan. Ask about fluid limits, medication timing, and warning signs like dizziness or weakness. Individual advice matters more than general study results.
Want to Apply This Research?
- Log your fasting status each day (full fast, partial fast, or no fast), your pre- and post-dialysis weight, and your interdialytic weight gain. Also record any dizziness or cramping during or after dialysis sessions. Review these entries weekly and share the summary with your care team.
- Plan your fasting around your dialysis schedule, and keep up with prescribed fluid limits and medications during the evening and pre-dawn meals. Use the app to set reminders for lab tests and for drinking fluids within your allowed amount at suhoor and iftar.
- Track lab results over time, including calcium, phosphorus, potassium, and parathyroid hormone, and ask your team whether bone density testing is appropriate for you. Use the app to store results from each Ramadan and compare them year to year, so you and your doctors can spot long-term trends that a single month would not reveal.
This article summarizes a single observational study of 138 hemodialysis patients in Egypt and is for general information only. It is not medical advice. Fasting can be risky for people on dialysis, so anyone considering fasting during Ramadan should speak with their nephrologist and dialysis team before making changes to eating, drinking, or medication schedules.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.