I recently attended a meeting to hear nephrologist Kamyar Kalantar-Zadeh MD, MPH, PhD, give a talk entitled “A balanced approach to phosphorus balance.” He began to tell attendees that European patients choose their dialysis clinic based on the meals they serve during the treatment. Imagine that.

The late Bernard Charra, MD, who was in charge of a dialysis clinic in Tassin, France, used to serve patients multiple-course meals––and wine––during their eight-hour, overnight hemodialysis treatments. So while U.S. clinics see eating during dialysis as an infection control or choking risk, other countries seem to understand the value.

Read also: Following the renal diet: A nephrologist’s perspective 

What we need to control

Kalantar reviewed the elements of the renal diet, including:

  • Getting the right amounts of calories and protein
  • Limiting certain nutrients, like sodium, potassium, phosphorus, and fluids

He pointed out that 20-78% of patients are noncompliant with these diet restrictions. “Renal diets are arguably the most restrictive for any patient group and many of the restrictions contradict recommendations for healthy eating,” he said.

Would you follow these rules?

Dr. Kalantar stated my views exactly when he said, “The renal diet is awful – what can [patients] eat?” The renal dietitian struggles to convince the patient to consume enough protein; studies have shown that over half of dialysis patients receive less than the recommended protein intake (at least 1.0 g/kg/day). Kidney Dialysis Outcomes Quality Initiative guidelines recommends 1.0 to 1.2 g/kg/day.

An increase in dietary phosphorus per gram of protein leads to an increase in mortality, he said. He encouraged the audience to prescribe the strongest phosphate binder to help decrease the pill burden. Interestingly, he also encouraged letting the patients eat during dialysis and then take the strongest binder with the meal. He recommended two new iron-based binders that may help with this.

  • chewable sucroferric oxyhydroxide. This has less pill burden and less absorbable iron
  • ferrous citrate has more absorbable iron. Sucroferric oxyhydroxide maintenance dose maintained serum phosphorus < 5.0 mg/dl with significantly fewer pills. No serum ferritin changes were observed from baseline after 52 weeks on Sucroferric oxyhydroxide, Dr. Kalantar reported.

Surprisingly, no serious adverse events were observed for patients eating during dialysis.  In hypoalbuminemic hemodialysis patients, high-protein meals during dialysis, combined with a potent phosphorus binder, are safe and increase serum albumin while controlling phosphorus.

Dr. Kalantar collaborates frequently with Christian Shinaberger, MPH, PhD, whose doctoral thesis was entitled, “Should serum phosphorus be controlled by decreasing dietary protein in dialysis patients?” In an article in the American Journal of Clinical Nephrology (2008), Dr. Shinaberger and colleagues said that a decline in serum phosphorus with concomitant decline in protein intake is associated with increased death risk. They also found that controlling phosphorus while maintaining high dietary protein intake may be associated with the best survival in hemodialysis patients.

Protein counts

At the same meeting was Adamasco Cupisti, MD, from the University of Pisa, Italy. He suggested that the nutritional goal for ESRD patients is to give the right amount of protein but with the lowest phosphorus load as possible. He agreed that a conflict exists between protein and phosphorus intake. In Europe, they suggest boiling meat and poultry sources of protein to decrease the bioavailability of phosphorus. Boiling reduces the mineral content. When the meeting was over, I approached him and told him our patients don’t like to cook––so getting them to boil the animal sources of protein before they prepare it would be difficult.  He encouraged more phosphorus from plant foods as there is less bioavailability with less effective load of phosphorus.

Some of the large dialysis providers show lab results that indicate the “nPCR” (the normalized protein catabolic rate) should be 0.8 to 1.2 g/kg/day. The trick is to eat the right amount of protein but with the lowest phosphorus load as possible. The organic phosphorus, in animal proteins such as meat, poultry, dairy and fish, is about 60% absorbed. Organic phosphorus in plant proteins found in nuts and beans is 20-40% absorbed while phosphate containing preservatives that are added to beverages, processed foods and “fast foods” are 100% absorbed. Dr. Cupisti said.

Make it easy

My job as a renal dietitian is to provide super easy recipes that patients can prepare with the least amount of energy. So a peanut butter (smooth or crunchy) and jelly sandwich might just make a good meal after all. Or how about some beans and rice for a snack? One egg white has only 5 mg of phosphorus – the yolk adds 80 mg of phosphorus. An omelet with 4 egg whites (pure protein) and one yolk would be high in protein, cheap and easy to make.

Conclusion

Dr. Kalantar would agree that paying more attention to dietary, non-protein restriction, e.g., fast food and high additive foods, is important. Ask dialysis patients to eat more protein––including during dialysis, he agrees––while paying more attention to the phosphorus/protein ratio. Among the two new iron-based binders, sucroferric oxyhydroxide has less pill burden and less absorbable iron, whereas ferrous citrate has more absorbable iron. Likewise, the non-dietary serum phosphorus control should be reinforced––using phosphorus binders more diligently and using phosphorus binders that are potent with the least pill burden.

My job as a nutritionist is to teach the patient to look at ingredients and avoid anything with “phos” on the label.  It is truly a herculean task to figure it out.  Dietitians are trained to look at the overall diet and help patients individualize meal plans. According to a team at the Rogosin Institute led by Sharon M. Moe, MD, the focus should be on Good Food First and the recognition that food is as critical as medications in the management of patients with chronic kidney disease. In order to achieve this change, there must be an emphasis on the A,B,C, and Ds of kidney nutrition health:

  1. Access to affordable, fresh foods
  2. Back to basics
  3. Cooking: You can do it!
  4. Deliver information a patient can understand

In short, Dr. Moe said, we need to make good food and nutrition “cool, fun, funky and fresh.”1

References

  1. Moe S. et al. Food as medicine: No more renal “diet.”  ASN Kidney News, Oct/Nov.2016