Restricting Dietary Protein and Phosphorus May Improve CKD-MBD

Very low protein intake was not superior to traditional low protein diets, however.
Very low protein intake was not superior to traditional low protein diets, however.

Limited scientific evidence suggests that dietary interventions such as calcium-enriched bread and low phosphorus/protein consumption can provide some benefit for patients with chronic kidney disease-mineral and bone disorders (CKD-MBD), a new review finds.

Zhuangzhu Liu, MD, of Guangdong Provincial Hospital in Guangzhou, China, and colleagues examined 9 randomized trials of dietary interventions for CKD-MBD.  The interventions included calcium-enriched bread, a low phosphorus diet, a low protein diet, a very low protein diet, post-hemodialysis supplements, and a low lipid diet. CKD stage varied among the 634 participants. None of the studies examined cardiovascular events or fractures.

Calcium-enriched bread (vs. calcium acetate) increased serum calcium (mean difference 0.16 mmol/L), decreased serum phosphorus (-0.41 mmol/L), and decreased the calcium-phosphate product (-0.62 mmol2/L2), according to results published in the Cochrane Database of Systematic Reviews.

Low phosphorus diets decreased serum phosphorus in 2 of 3 studies. The other showed a low phosphorus diet plus lanthanum carbonate decreased fibroblast growth factor 23 (FGF-23) only. One study also looked at mortality and reported no differences.

Very low protein intake (0.3–0.4 g protein/kg/day) was not better than a low protein diet (0.8-0.6 g protein/kg/day) at lowering phosphorus, increasing calcium, and decreasing alkaline phosphatase. Parathyroid hormone levels were significantly lower with a very low protein diet, however.

Compared with a normal diet, post-hemodialysis supplements did not increase serum phosphorus. A low lipid diet also provided no meaningful benefit over statin therapy.

The studies were low quality and “suboptimal,” the investigators acknowledged. They encouraged large, well-designed randomized controlled trials of dietary interventions (including combination approaches) for patients with CKD-MBD that examine crucial end points such as cardiovascular events, fractures, and mortality. Future studies should also report adverse events such as protein-energy malnutrition, hypophosphatemia, and hyper- and hypocalcemia.

Source

  1. Liu, Z; Su, G; Guo, X; et al. Cochrane Database of Systematic Reviews 2015; doi: 10.1002/14651858.CD0110350.pub2.
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