Date of publication: November 24, 2015

Expert Perspectives

Expert round table (Part 4): optimizing protein and phosphorus intake in dialysis patients?

In the fourth of our expert round table videos, recorded prior to the ERA-EDTA 2015 Congress, our experts discuss how to optimize both protein and phosphorus intake in their dialysis patients. Topics covered include:

  • Phosphorus-to-protein ratio and the impact of additives
  • Helping patients transition between seemingly contradictory dietary advice in NDD-CKD and dialysis
  • Appropriate use of supplements
  • The role of the renal team in patient education and support

The COMPACT expert panel comprises Drs Stuart Sprague, Kam Kalantar-Zadeh, Angel De Francisco & Adrian Covic.

If we can help [our elderly patients] to control phosphorous, by educating them about phosphorous-to-protein ratio, by educating them about phosphorous absorbability and the control of phosphorous, and yet allow them to eat adequate, proper nutrition … then I think we have achieved win-win-win.

– Professor Kamyar Kalantar-Zadeh



Dr De Francisco

A question which I consider very important in order to educate not only patients but doctors as well, is how we want to control hyperphosphataemia. Sometimes we discuss about reducing the protein intake or sometimes how to reduce the phosphate which is in the additives. If we reduce [patients’] protein intake, then we [create a] risk for malnutrition. How can we balance that particular indication?

Dr Kamyar Kalantar-Zadeh

Good question. Actually, I think [with] what we have done traditionally, we have deprived some of our patients of the needed protein intake. Dialysis patients, they require an average of 1.2 to 1.4 grams per kilogram body weight of protein per day.

To achieve this amount of protein, which is above the average of what we eat, requires the amount of food or a diet that will inevitably have also some high amount of phosphorous. Therefore, traditionally, we have been dealing with contradictory advice.

At the same time we’re saying that dialysis patients require high protein intake and at the same time, we have no choice but to restrict the amount of phosphorous in the diet, which leads to then less protein intake. This is the area where we can take advantage of phosphorous binders.

Dr Sprague

You bring up an interesting point that I think most nephrologists and many patients struggle with. As you said, dialysis patients need more protein intake than the average individual, let alone the patient with CKD, who actually [may be] restricting their protein, sometimes at the direction of their clinician, sometimes [based on] their lone research, saying that “If I decrease my protein intake, I’ll slow my progression of disease.”

Then, they get to dialysis and I find that it’s very hard to educate them or convince them that they have to take more protein, and I think many clinicians don’t appreciate that they do need a higher protein level. The problem is, which you alluded to, is the quality of the protein they take in.

Unfortunately, I don’t think we do a good job in educating them on what’s high quality protein with low inorganic phosphate content as opposed to high quality protein that doesn’t have this inorganic phosphate. I think that’s really problematic. Again, we try to bring our dietician into the realm to really sit down and do that.

Another issue which troubles me, and I don’t know the answer, is there’s been this big use now of these protein supplements during dialysis. It was Nepro and now there’s LiquaCel and stuff. What’s your sense on how does that help? Does that replace having good dietary protein?

Dr Kalantar-Zadeh

Very good points. I feel that nothing would replace natural food and nothing is more important than having access to being able to eat and enjoy. We nephrologists have traditionally approached our patients in a way that we have sort of been harassing them [as to] why they are eating more.

As you said, we have to deal with several challenges here. One is that when a patient transitions to dialysis, we have to educate this patient at the same time that now this is the time that you have to take more protein than less.

At the same time, while we are dealing with that challenge we are also telling them that “You have to take less phosphorous.” As you said, nowadays, we know that inorganic phosphorous that is added to the food is even more easily absorbable.

We’ve got to try hard to avoid those sources of foods such as processed food or food with additives. Then, we still have to deal with the natural food, natural protein that has phosphorous. The phosphorous is 40% – 60% absorbable.

No matter what we do, we still have the challenge of phosphorous being associated with high protein intake. Again, this is where we need to find the best approach for these sort of patients. If we can help them to achieve that high protein-intake goal of 1.2 to 1.4 grams per kilogram per day. Yet to maintain phosphorous within the range that is recommended, below 5.5 milligrams per deciliter –

Dr De Francisco

[While] avoiding malnutrition.

Dr Kalantar-Zadeh

Then we have avoided malnutrition and we have also controlled phosphorous.

Dr De Francisco

What were you thinking, Adrian?

Dr Covic

Just to fine tune the discussion, I agree, first of all, with the majority of the points discussed. Just to fine tune it, I want to make two points.

First is the fact that there are very strong French data showing that even if patients are getting good nutrition, even if their phosphorous is in the, let’s say, normal/high, just a little bit above what we perceive as the upper level, their survival is actually similar to the normal.

My first point and my first whole message would be that I would be worried, really, by the very high values. We still have to prove that bringing phosphorous to normal levels is actually beneficial. Particularly to the second point, which you mentioned, Angel, that we are getting an aging population, very old patients, some of them with a lot of comorbidities. Their lifespan and life expectancy is what, six months to 1.6 years and 1.6 months?

With those patients, I would be really reluctant to enforce this dietary recommendation. I’ll just leave them to free diet plus whatever wonder phosphate binder would be. A wonder phosphate binder would be a very low pill burden with a good tolerability and I would forget about diet in those elderly patients.

Dr De Francisco

Anyway, I think that the final comment on this is just to emphasise how important nutrition is, how important protein is (the right protein nutrition), and how important it is to educate our patient to avoid the inorganic phosphate which is contained in the additives.

Dr Sprague

It is. I want to get back, which I’m surprised, Kam, you didn’t bring up, but if I remember correctly, you came up and published the concept of the phosphate/protein ratio with foods, which I don’t think is taken on. But I do think that shouldn’t that concept be brought to the forefront and nephrologists really understand that or at least dieticians really understand, that we should be counselling patients to have foods that have low phosphate-to-protein ratios or the index, I think, is what you called that?

Dr Kalantar-Zadeh

Yes. Thank you for bringing this up. I think it’s still an important index. This so-called phosphorous or phosphate-to-protein ratio, in fact, was suggested by KDOQI, not by any of us. Therefore, this is a relatively established concept.

What has maybe changed or evolved in between is that in addition to phosphorous-to-protein ratio of a given food, what is also important is the phosphorous absorbability, based on the proportion of inorganic versus natural phosphorous. Also based on the proportion of vegetable-based phosphorous versus meat phosphorous.

These are all areas that have evolved in between and have made the phosphorous-to-protein ratio a little bit more complex. Going back to liberalizing food for certain ages or certain people including elderly dialysis patients, I completely agree and I’m supportive of that.

I would like my elderly patients to continue to enjoy life, as [maintaining] a quality of life is very important. If we can help them to control phosphorous, to educate them about phosphorous-to-protein ratio, to educate them about phosphorous absorbability and the control of phosphorous, yet allow them to eat adequate, proper nutrition and help them to keep phosphorous closer to the normal, to the target range, then I think we have achieved win-win-win.

Dr Covic

I think that this discussion brings us to the point that we need a teamwork approach. There are a lot of information you are alluding to which should be given by the dietician because, of course, we as doctors, we should approach the patient, but can you believe a patient that he will take advantage only from the medical advice?

It should be a dietician, it should be the nurses, it should be really a team effort from this point of view. Otherwise, I don’t think we are going to succeed.

Dr Kalantar-Zadeh

That’s actually a very important point, a multi-disciplinary approach. Physicians or nephrologists, they can’t win the battle if they just go as the only health care professional to the patient, as you astutely alluded to here. We need dieticians, we need nurses, we need the entire dialysis clinic staff to be supportive too. They have to be also educated in this regard and they have to provide the same education about everything that we discussed, right? What do you think?

Dr Sprague

I absolutely agree. I think that’s an approach that we try to do in our facility. I’ve been impressed, at least, in the United States, the dieticians do take an active role, but they have to do it in concert with the physicians.

The truth is, which you’ve suggested, even the technicians and the other care members can help reinforce this concept of nutrition and phosphate and taking binders, because they interact with the patients on a regular basis while they’re on dialysis. That reinforcement could be very beneficial.

Dr Covic

Can I ask one other question? You were mentioning supplements. Many of my patients are asking me about alpha-ketoglutarate and this kind of approach. Would you think it’s an important one?

Dr Sprague

My personal bias has been against supplements in cans … but I know right now in the United States, because of thresholds of serum albumin of 4.0, which has become a criteria of CMS and the score card that dialysis facilities are scored on, they’re really pushing these LiquaCel, in particular in the facilities I go to, or Nepro or other high-protein supplements.

I think they’re a very poor substitute and I think we’re giving the patients the wrong message to say that they could drink these supplements and not have good nutrition. Personally, I feel very much against the supplements. I’d be curious as how Kam feels on that.

Dr Covic

Supplements, I was mentioning really the keto-analogues.

Dr De Francisco

I don’t think we have a randomised control trial for that.

Dr Covic


Dr De Francisco

That’s the fashionable approach, whatever it is. Rational, rational, but without any kind of –

Dr Kalantar-Zadeh

I think supplements certainly have their own place and indication, however, as you, again, suggested, we should give high priority to patients, a natural way of food intake, which is associated with, again, higher quality of life and better patient satisfaction.

Supplements are indicated when we cannot achieve that. As long as there are opportunities here to help patients to move to that direction, I think, as you wisely suggested, we should really not quickly switch to use of supplement.

Again, we need also to educate ourselves and the old way of approaching patients to ask them to control phosphorous by avoiding high-protein diet.

Which probably has led to certain cases of malnutrition or maybe some of the patients with low serum albumin levels. If we can find a way for these patients to enjoy natural food with adequate protein while we help them with phosphorous balance and phosphorous control, then I think we have achieved more.

See also the previous expert round table videos:

September 9th, 2015; Expert round table (Part 1): what are the biggest challenges clinicians face in controlling serum phosphorus in dialysis patients?

September 16th, 2015; Expert round table (Part 2): the importance of adherence, nutrition and treatment individualization

September 22nd, 2015; Expert round table (Part 3): role of new markers of mineral & bone metabolism

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