Supporting someone on dialysis

This is where families do the most damage with the best intentions. The instinct is to take away everything on a photocopied list of forbidden foods. That instinct is out of date, and it is dangerous.

There is no single kidney diet. Current nutrition guidance moved deliberately away from blanket restriction towards advice individualised to blood results, dialysis modality and remaining kidney function (KDOQI Nutrition in CKD, 2020). Blanket restriction produces a miserable, narrow diet and it produces malnutrition, and malnutrition kills far more people on dialysis than an occasional banana does.

So the goal is not a safe list. The goal is to get a renal dietitian, take them a real food diary and the latest blood results, and cook to the plan they give you. What follows is what to understand so that conversation is a good one.

If you change one thing in the whole kitchen, change the salt. Guidance is less than 2,300 mg of sodium a day, which is roughly under 5 to 6 g of salt (KDOQI Nutrition in CKD, 2020).

Here is why it matters more than any other single lever. Salt drives thirst. Thirst drives drinking. Drinking drives the weight they put on between sessions. That weight has to be dragged off in four hours, and dragging it off fast is what causes the blood pressure crashes, the cramps, and the washed-out feeling afterwards. The most useful fluid advice is almost never "drink less". It is "eat less salt, and you will want to drink less".

Most salt is not in the salt cellar. It is in processed and takeaway food, bread, cured and processed meat, stock cubes, sauces, crisps and salted snacks. Cooking from scratch is the single highest-yield thing a household can do, and it benefits everybody at the table.

This one catches families out badly, so read it twice. Before dialysis, protein is often restricted. Once dialysis starts, protein needs to go up, roughly doubling, to about 1.0 to 1.2 g per kg of ideal body weight per day for people on haemodialysis and on peritoneal dialysis (KDOQI Nutrition in CKD, 2020). Dialysis removes amino acids, and peritoneal dialysis loses protein directly into the drained fluid.

People who carry the old pre-dialysis low-protein rules into dialysis become malnourished. If the household has spent two years carefully keeping the meat off his plate, that has to change on the day dialysis starts, and it should change on the dietitian instruction, not on ours.

Fish is excellent protein and it is the Seychelles staple. It is not free of potassium or phosphorus, so portion size still matters, but do not let anyone talk them out of protein.

Phosphate builds up in kidney failure, and over time it pulls calcium out of bone and deposits it in blood vessels, the heart and the eyes, which raises the risk of heart attack and stroke. It also drives the itching (National Kidney Foundation).

The most useful fact about phosphate is that not all of it is equal. Phosphate added to food as a preservative or a texture agent is almost completely absorbed. Natural phosphate from plants such as beans, nuts and grains is bound up and poorly absorbed, and the phosphate in animal foods sits in between (National Kidney Foundation).

So cutting the processed food with phosphate additives is far higher-yield than cutting the lentils. Read ingredient labels and look for anything containing "PHOS". Dark colas, processed cheese, processed and enhanced meats and convenience foods are the usual culprits.

And never solve a phosphate problem by cutting protein. The highest-phosphate foods are often the highest-protein foods, and they need the protein. That is precisely why phosphate binders exist.

Potassium sits in a narrow safe window. Too high can cause a dangerous heart rhythm, and too low is also dangerous. But current guidance does not set a universal limit: it says intake should be individualised to keep the blood level in the normal range (KDOQI Nutrition in CKD, 2020).

And it depends enormously on the modality, which almost nobody tells families. People on haemodialysis, especially across the long weekend gap, are the group genuinely at risk of a high potassium. People on peritoneal dialysis often run low, and some are told to eat more potassium, not less (NIDDK). Getting this backwards is a real risk in a household that has absorbed the standard advice from somewhere else.

A cooking technique that genuinely helps, if the dietitian has asked you to lower potassium: boil vegetables and starchy staples in a large volume of water and throw the water away. It leaches potassium out. We are not going to publish a percentage, because we could not verify one for the local staples, and your dietitian can tell you how much it is worth in your case.

One warning that matters in any kitchen, and especially in a self-catering apartment or a rented villa: most low-sodium salt substitutes are potassium chloride. They are marketed as the healthy option and they are hazardous in kidney failure. Read the label.

Renal diet leaflets are written for temperate countries. They warn about potatoes and bananas and say nothing about the food that is actually on a Seychellois table, which is why we have set out the numbers below.

Coconut is the headline. Coconut water is sold everywhere as a natural health drink, and for someone on dialysis it is a double hit: it is a fluid, and it is a potassium load. Coconut milk hides the same potassium inside a curry, where it is invisible on the plate.

Breadfruit and cassava are traditional staples and they are high in potassium, breadfruit being roughly in avocado territory. Neither appears on any imported diet sheet.

The good news is real and worth saying: not all tropical fruit is a problem. Papaya, mango and pineapple are all lower in potassium than a banana, and pineapple is notably low. There is more to say yes to here than most people think.

We are not going to give you a number. Fluid allowances are individual: they depend on how much urine they still pass, their dialysis modality and schedule, and their blood results, and the renal team sets it. Anyone on the internet who gives you a millilitre figure is guessing about your household.

What we can tell you is that fluid is not only drinks. Soup, gravy, sauces, ice, jelly, ice cream, yoghurt and juicy fruit all count, and so do melons, grapes, oranges and tomatoes (NIDDK). In a resort or at a family lunch, the iced drinks, the sorbet and the fruit platter are exactly the trap.

And the heat here is not a licence to drink more. Kidney Care UK is explicit that there is no one-size-fits-all advice on fluid in hot weather, and that fluid restrictions, diuretics and blood pressure medicines must never be changed without the kidney team, even in extreme heat. Heat cuts both ways: sweating plus fluid removal can tip someone into dehydration and collapse, while drinking to thirst in tropical heat can tip them into fluid overload. It is a conversation with the unit, and the answer is theirs, not ours.