Today’s Journal Club article was sent to me by a good friend who came across it while researching the impact of eating during dialysis. Bananas AND eating during dialysis – yes! What a research combo!
The full reference for this article can be found here: Quan, Zilin, et al. “Effect of banana intake on serum potassium level in patients undergoing maintenance hemodialysis: A randomized controlled trial.” International Journal of Nursing Sciences 11.2 (2024): 197-204.
Why did the authors conduct this study?
The authors highlight that most nutrition guidelines for people receiving dialysis recommend limiting fruit to prevent/manage hyperkalemia. However, these guidelines may inadvertently result in the pendulum swinging to far to the other side, causing hypokalemia. According to the authors, the prevalence of hypokalemia among people receiving hemodialysis is:
- 0.4-11% before dialysis
- 54.5% after dialysis
The concern with hypokalemia is the potential for cardiac arrythmias and increased mortality. The authors also highlighted that arrythmias during dialysis may be more common than (certainly myself) realized, highlighting that studies among people wearing defibrillators during dialysis reported rates to be as high as 70%. It is possible that cause of these arrythmias is flucations in serum potassium levels during the dialysis session.
What was the primary study question?
Does consuming bananas during hemodialysis prevent hypokalemia and impact health outcomes?
Serum potassium values were evaluated:
- Before starting dialysis
- 2 hours into dialysis
- 4 hours into dialysis
- Before the next dialysis run
The specific health outcomes were:
- Blood glucose levels
- Hypotension
- Muscle Cramps
- Chest Tightness
- Vital Signs
Who was included in the study?
122 maintenance dialysis patients participated. Participants were:
- Between the ages of 18-80
- Had been on dialysis for at least one year
- Had adequate dialysis access (no concerns with dialysis adequacy)
- Not have any contra-indications to eating bananas (GI symptoms, allergies, dysphagia etc)
- Not expected to experience diarrhea or hypotension during dialysis
- Not be taking any potassium-altering medications (what specific meds wasn’t clearly defined)
Important points about this inclusion criteria: Who these results can’t be applied to
For the most part this inclusion criteria is pretty standard and describes a fairly average dialysis population. However there are two key things here that could make interpreting their results somewhat challenging. First, people who “could have” diarrhea or hypotension during dialysis weren’t included. This is one of the key reasons that eating during dialysis is often discouraged, so they have intentionally selected a group of people from the dialysis unit who were less prone to these symptoms. So this study can’t answer if eating bananas is safe for people who are experiencing intra-dialytic hypotension or GI symptoms.
This study also excluded people who were taking potassium altering medications. While they didn’t provide a list of these medications in the paper, this likely includes any RAASi (which include things like ACE inhibitors, MRAs – spironolactone or fineronone). So if your patients are on these medications, the results of this study may not apply to them either.
What did they do?
This study had two groups – an intervention group and a control group.
The intervention group received 250g of banana at the start of dialysis and were advised to eat it within the first 1 hour of their dialysis session. Participants were on a baseline low potassium diet and the authors reported that the total daily potassium intake for participants remained below 3000mg per day.
How much is 250g bananas? According to the Canadian Nutrient File: 23cm of banana = ~150g, while 15cm of banana = ~100g of banana. So this means people had to eat 48cm of bananas! That’s like a foot and a half of bananas! The authors reported that this provided 640mg of potassium.
The control group was restricted from eating anything during dialysis. They were given low potassium diet education and were asked to avoid eating high potassium foods prior to dialysis.
What happened to the potassium levels?
The group who ate the bananas had higher potassium values than the group who did not eat the bananas. The mean values provided by the authors are in the table below. No group had hyperkalemia. The control group had a higher incidence of hypokalemia and arrythmias compared to the intervention group.
| Group | Baseline | 2 hours into HD | 4 hours into HD | Before next HD run |
| Intervention | 4.8 | 3.9 | 3.5 | 4.7 |
| Control | 4.6 | 3.6 | 3.3 | 4.5 |
The difference in the potassium values were statistically significantly different between groups and from baseline at 4 hours into HD.
What’s cool about this study?
This simple study looked at the impact of eating bananas during HD session for people who start HD with normokalemia. The authors reported that the group who didn’t have bananas had a higher incidence of hypokalemia and arrythmias compared to the group that ate the bananas.
What this study doesn’t tell us?
This study does not tell us what would happen if you added bananas during dialysis for people who started HD with hyperkalemia. This study also doesn’t tell us about adding bananas to a liberal potassium diet as the total potassium in the diet (for both the intervention and control) was less than 3000mg per day.
The authors of this study did not tell us anything about the potassium concentration of the dialysis bath. So we don’t know if adjusting the bath would have changed the incidence of hypokalemia for participants.
We also only have potassium values up to 4 hours into dialysis and then at the next dialysis session. We don’t know what happened to the potassium values in the interim.
Take Aways
I liked this study, I thought the simple design has great clinical utility and it showed positive results for our patients. The key take aways for me were:
- That having bananas in the first hour of dialysis could help prevent hypokalemia and arrythmias.
- Consuming 640mg of potassium from bananas was associated with a greater increase in potassium levels than not consuming anything at all. This suggests the bananas had an increasing impact on serum potassium values, so there is a potential that if people who had hyperkalemia ate bananas their potassium values might go higher – though admittedly, that wasn’t explicitly tested in this study.
