Diet and fluids after a kidney transplant

After years of counting potassium and watching phosphate, one of the first questions after a kidney transplant is what you can eat now. The answer is usually more generous, though not unlimited. This page gathers what UK and US public bodies say about food safety, healthy eating, weight, salt, potassium, phosphate, fluids and grapefruit, and ends with questions to confirm with a renal dietitian (a specialist in food and kidney health). Practice differs between transplant centres, and the rules you are given in the first weeks may be stricter or looser than what is written here, so your own transplant team has the final word.

More freedom, with some limits that remain

The National Kidney Foundation says that after a transplant most patients have more freedom with their diet, while healthy choices and food safety remain important. It adds that the anti-rejection medicines you take will also affect what you can and cannot eat. Those medicines lower the immune system's activity, and the Cambridge University Hospitals leaflet says this makes you more likely to catch infections, including those from food. The medicines are explained in immunosuppressant medicines after a transplant.

Food safety

Cambridge University Hospitals names listeria, salmonella and E. coli as the risks, and notes that listeria can cause no symptoms in some people. It also points out that vomiting can mean you cannot keep down your immunosuppressive medicine, which can raise the risk of rejection.

The leaflet gives practical habits from shop to table: eat food within its use-by or best-before date, wash hands and produce, use separate chopping boards for raw and cooked food, and make sure reheated food is piping hot. It also advises a fridge at 5°C or lower and a freezer at minus 18°C or lower. The National Kidney Foundation adds that salad bars and food buffets are best avoided when eating out.

On eating out, Cambridge University Hospitals advises avoiding restaurants and takeaways in the first six to eight weeks. Trips abroad bring their own food questions, covered in travel and vaccines after a transplant.

Some foods carry more risk. The leaflet says a list of them should be avoided strictly for the first six months, and that after six months, if kidney function is good, the team is happy and anti-rejection medicine has not been increased, they no longer need to be avoided. Basic food safety continues for the lifetime of the transplant. The table shows examples from that list.

Examples of higher-risk foods and alternatives, from Cambridge University Hospitals

Food	The leaflet says to avoid	Alternative it suggests
Milk and yoghurt	Unpasteurised milk and yoghurt, and probiotic or "bio" yoghurt drinks	Pasteurised milk and yoghurt that does not describe itself as bio or probiotic
Eggs	Raw or undercooked eggs and dishes containing raw egg	Hard-boiled eggs, shop-bought mayonnaise
Fruit and vegetables	Unwashed produce, and salad from delis or salad bars	Washed fresh produce, cooked or tinned vegetables

The full list is longer. If vomiting, diarrhoea or fever follows a doubtful meal, signs of rejection and infection to report sets out what sources say about contacting the team.

Grapefruit and other interactions

This is the rule where the sources agree almost word for word. The National Kidney Foundation lists grapefruit and grapefruit juice, pomegranate and pomegranate juice, and Seville oranges as foods to avoid, noting that ordinary oranges are fine in moderation. Cambridge University Hospitals gives the same three, says they interfere with the levels of anti-rejection medicine, and suggests checking products such as mixed fruit juices. The National Kidney Foundation warns that some citrus-flavoured drinks contain grapefruit extract.

Supplements and herbal products carry a similar caution. The National Kidney Foundation says to talk to your transplant doctor or pharmacist before starting any new supplement or herbal product, and names St John's wort, echinacea, ginseng, feverfew and some herbal teas. The American Kidney Fund adds that over-the-counter supplements, especially those containing potassium or magnesium, should be checked with the team first.

Weight after a transplant

Weight gain is common. Cambridge University Hospitals says early gain is likely to be fluid retention after the operation, while longer-term gain can come from steroids such as prednisolone raising appetite, relaxed dietary restrictions and lower activity. The National Kidney Foundation agrees that a better appetite is common.

The concern is what happens next. The National Kidney Foundation says controlling weight lowers the chance of heart disease, diabetes and high blood pressure, and suggests high-fibre foods, lean meats, non-fat dairy and mostly water to drink. Cambridge University Hospitals links a healthy weight to a lower risk of new-onset diabetes after transplant, since anti-rejection medicine and steroids may raise blood sugar. Activity is covered in exercise after a kidney transplant. If weight worries you, Cambridge University Hospitals suggests asking your GP about weight management services, and the Foundation suggests asking your doctor for a dietitian referral.

Salt

Salt is one of the few restrictions that often stays. The National Kidney Foundation says most people still need to limit it, though it differs between people, because transplant medicines, especially steroids, may make the body hold on to fluid and salt makes that worse. Extra fluid raises blood pressure, which is very important to control. Your doctor will decide how much sodium is best for you, and it lists cured meats, canned soups, ready meals and salted snacks among the high-salt foods.

Cambridge University Hospitals recommends a no-added-salt approach and suggests pepper, herbs, spices, lemon juice and vinegar instead.

Potassium and phosphate

Cambridge University Hospitals says that with a successful transplant the previous potassium restriction is relaxed, and that a dietitian can advise how to reintroduce foods such as bananas, coffee, nuts and chocolate, gradually, for example one new item a day in small portions. It adds that some people with delayed graft function (a kidney that is slow to start working) may need to keep a low-potassium diet, usually only in the short term.

On phosphate, the same leaflet says phosphate binders are stopped after a kidney transplant and that a phosphate restriction should no longer be needed.

Fluids

The sources we opened say much less about fluids than about food, and none gives a daily amount. The National Kidney Foundation says it is important to keep the new kidney hydrated, so drink plenty of water and limit drinks with caffeine. How much is right depends on how well the kidney is working and on other health factors, so that figure belongs to your team. If you have been told to limit fluids, follow that instruction until they say otherwise.

Healthy eating day to day

Cambridge University Hospitals points to the Eatwell Guide, with the balance judged over a day or a week rather than at every meal. It suggests at least five portions of fruit and vegetables a day, and, because long-term steroid use can weaken bones, three to four portions of calcium-rich foods a day. For people with diabetes, the National Kidney Foundation recommends three balanced meals a day and working with the doctor and dietitian on blood sugar.

What to confirm with a renal dietitian

NIDDK, the US National Institute of Diabetes and Digestive and Kidney Diseases, says people with a transplant have more choices than on dialysis, but should work with a dietitian on a plan that can change with medicines, test results, weight and blood pressure (NIDDK). Worth asking about:

• Which foods and supplements to avoid with your particular medicines.
• Whether and when your potassium restriction can be relaxed, and how to reintroduce foods.
• How much salt is right for you, given your blood pressure.
• Whether any fluid limit applies, and how much to drink otherwise.
• Which higher-risk foods your centre asks you to avoid, and for how long.

The short version

A transplant usually widens what you can eat, but food hygiene, salt, weight and a short list of interacting foods such as grapefruit still matter. Potassium and phosphate limits often ease, though your dietitian decides when and how. For anything the sources leave open, including how much to drink, ask your renal dietitian and transplant team.