Table 3.

Open issues in oral nutritional supplementation in dialysis.

	Pros	Cons- Unclear
Interference with depuration	Concomitant dialysis may make it possible to reduce the risk of fluid overload; if meals or snacks are given at the start of treatment, excess phosphate or potassium can be removed during the dialysis session.	We lack data on interference with dialysis efficiency. Low tolerance (hypotension) can lead to shortened dialysis time, or reduced blood flow and dialysis efficiency.
Long-term effects	Small studies report good results in selected patients.	Long-term advantages are not clear in pooled data, possibly due to the heterogeneity of indications and populations.
Tolerance	Good, unless the patient develops hypotension during or immediately after the meal.	Old studies suggest withholding food during dialysis. However, high- protein, high-fat meals were often supplied, and weight loss was often considerable.
Losses during dialysis	Probably minimal.	No clear contraindication.
Additives and preservation agents	Widely used in industrial food processing to reduce contaminations and enhance duration.	Very little studied; while phosphate and potassium containing additives are usually avoided less is known about other substances and trace elements. This is a question that needs further study.