The Superfoods in Renal Disease

By Himani Puri Program Incharge, Renal Nutrition India, An IAPEN

India core group

Nuts and oilseeds by virtue of their compositions are nutrient dense foods rich in good quality protein, unsaturated fatty acids, fiber, minerals, and bioactive compounds like tocopherols, phytosterols, phenolic compounds, etc (1) They beneficially impact health outcomes in many conditions like coronary heart disease (2,3), gallstones (4), cancer (5), etc but there is limited evidence to suggest beneficial effects in CKD (6). The high mineral content of nuts and seeds especially potassium, phosphorus, and magnesium has led to their restrictive recommendation in chronic kidney disease (CKD) (7)

Phosphorus

The absorption of dietary phosphorus is based on its type (organic vs inorganic) and source (animal vs plant) The nuts (a plant-based source of phosphorus) though containing organic phosphorus, are considered to have lower bioavailability because they are present in the form of phytates (8). Patient-centric plantdominant low-protein diet (PLADO) of 0.6–0.8 g/kg/day with>50% plant-based sources, in nondialysis CKD patients may be useful in correcting metabolic acidosis and hyperphosphatemia (9, 10) Furthermore, nuts are usually consumed raw, and so, it is unlikely that they might contribute to the dietary phosphorus burden in CKD (<30% is absorbed in uncooked food).

Potassium

In advanced chronic kidney disease (CKD), progressive decline in kidney function may lead to an increased risk for high serum potassium levels (hyperkalemia) (11). The high potassium content of the nuts and seeds may be another potential risk of hyperkalemia has always been one of the concerns in CKD management

However, growing evidence suggest that a plant-based diet, which includes consumption of high-potassium foods, may prevent the development of CKD in individuals with relatively preserved or normal kidney function (12)

A recent KDIGO consensus report recognized the validity of dietary potassium restriction for managing acute hyperkalemia; but, the report also hypothesized that too much of restriction of dietary potassium in lieu of prevention of hyperkalemia in CKD may deprive patients of the benefits of a high-potassium diet (13) So the recommendations for dietary potassium for patients with CKD and hyperkalemia should be highly individualized (14). On the other hand, a lower dietary potassium intake might lead to worse survival in nondialysis dependent and dialysis-dependent CKD patients (15)

While nuts are considered a healthy food in the general population, there has been a paucity of research examining the impact of nut consumption upon outcomes in patients with CKD And therefore more research needs to be done with regards to usage and efficacy of nuts and seeds in renal disease patients and the recommendations need to individual based