Why does the renal diet limit some healthy foods?

When a person starts on dialysis, one of the diet contradictions is that all the sudden some foods that were forbidden are on the ‘ok to eat’ list and foods that were healthy to eat end up on the ‘limit or avoid’ list.

What’s going on?
The answer has something to do with potassium and phosphorus. For a normal, healthy diet, experts recommend eating whole grain foods, beans and nuts (these are naturally very high in potassium and phosphorus). They also encourage people to eat more fruits and vegetables–a great source of potassium.

When the kidneys stop working, potassium and phosphorus build up in the blood because the kidneys no longer remove them. High levels are unsafe, so to keep levels down the diet has to limit foods that are high in potassium and phosphorus. In addition to a low phosphorus diet, medications that bind phosphorus so it can’t be absorbed, help keep phosphorus down.

Foods that were previously viewed as less healthy like refined cereals, white bread, white rice, fruits canned in syrup, extra fats and sugars are better choices for a hemodialysis diet because the potassium and phosphorus content is lower in these foods compared to foods that are healthy choices for the general population.