Abstract: TH-PO1039

Can CKD Patients Estimate Phosphate Content (PC) in the Food Correctly?

Session Information

Category: Mineral Disease

  • 1201 Mineral Disease: Ca/Mg/PO4

Author

  • Taborsky, Petr, Fresenius Medical Care, Praha, Czechia
Background

Hyperphosphatemia has been identified as a risk factor for survival of CKD patients. Food is the main source of increased serum phosphate in CKD. Patients are advised to control the amount of absorbed phosphate by phosphate binders. Reasonable PC estimate is a prerequisite for successful treatment with phosphate binders and for their adequate dosing.

Methods

Phosphate and protein content of 53 popular food items available on the market in Czech Republic were measured using standard chemical methods. Five typical Czech meals were prepared by nutritional specialist using recipes recommended for dialysis patients. The identical meals were purchased fresh in restaurant or frozen in supermarket and phosphate and protein content of all meals were measured. Virtual menu consisting of meal photos and short descriptions including information on the meal origin was compiled, nutrition facts were blinded. 23 predialysis patients CKD stage 3-5 were asked during their regular visit in nephrology clinic to go over the menu and put together the three days diet corresponding to their kidney function. Importance of low PC in the diet was repeatedly stressed. All patients were previously instructed in renal diet by nutrition specialist using the standard protocol. The optimal diet and the "worst" choice (the lowest and the highest possible content of phosphate) were calculated for comparison.

Results

Calculated PC in dietary regimens ranged from 730 to 1780 mg per day, all diets contained at least 60 g of protein per day. Phosphate to protein ratio in food varies much widely: from 9 mg/g in non-processed beef to 85 mg/g in some brands of spread cheese. PC in home-made meals was 1.2 to 2 times lower than in ready-to-eat meals. Food products labeled as "for children" contained less phosphate. Mean PC in diet chosen by patients was 1420 mg per day ranging from 920 to 1690 mg of phosphate per day. Difference in PC was done mainly by individual preferences of some sorts of dairy products and manufactured pastries.

Conclusion

PC is extremely variable, even within the same sort of food. For ordinary patient without special training the correct estimation of PC in food is very difficult even impossible. Traditional education based on close correlation between protein and PC in food should be changed because of widespread use of phosphate-containing additives.