Diet taboos for kidney failure

There is no universal list of dietary taboos for patients with renal failure. The core principle is to "follow the stratification of kidney function, follow the complications, and follow the treatment plan." All blanket "no salt, no meat, no soy products" are wrong.

I have been in the nephrology follow-up group for almost two years, and I have seen too many patients who have fallen into the trap. The one who impressed me the most was a 62-year-old man who had just been diagnosed with a creatinine of 150 and a GFR of 58. I didn’t know where he read a post saying that he had to go vegetarian because he had poor kidneys. He stopped eating meat, eggs, and milk, and ate steamed buns and vegetables every day. His creatinine did not drop during the three-month review, and his albumin dropped to 31g/L. His legs were so swollen that he couldn’t even pull up his pants, which made his kidney function even worse.

The controversy over protein intake has actually been raging for almost ten years. The early view was that once renal failure is diagnosed, the sooner protein restriction is better, the better, which can reduce the metabolic burden on the kidneys. ； The current internationally accepted KDIGO guidelines recommend that patients with a GFR above 30 can eat high-quality protein normally, as long as they do not eat too much protein. Wait until the GFR drops below 30, and then follow the standard limit of 0.6-0.8g per kilogram of body weight. Some domestic clinicians are more conservative. When encountering patients with a GFR of around 45 who already have proteinuria, they will recommend appropriately reducing protein intake in advance. Both options are supported by large sample clinical data. There is no absolute right or wrong. Just follow the rhythm of your own treatment.

In addition to the controversy over protein, more people are stepping on the pitfalls of salt. Many family members think that if the kidneys are not good, they should completely avoid salt. They don’t even dare to add soy sauce, oyster sauce, and light soy sauce when cooking. The patient’s food is so bland that he can’t even eat. On the contrary, he cannot keep up with his nutrition. In fact, as long as there is no high blood pressure or edema, it is perfectly fine to control it to 3-5g of salt per day (about half a beer bottle cap). For patients who have undergone dialysis and do not have edema, the salt limit can even be relaxed to 6g. On the contrary, those patients who secretly eat cured bacon, pickles, and processed snacks often have their creatinine rise by dozens of units the next day after eating one meal. I have seen patients who secretly ate two pieces of cured fish during the New Year and went to the emergency department directly because of water and sodium retention and heart failure.

Oh, by the way, there is also the ever-present problem of soy products. It used to be said that plant proteins are not easy to metabolize and patients with kidney failure must not touch them. Now the latest research has classified soy protein isolate as high-quality protein. As long as the total protein intake does not exceed the standard, it is perfectly fine to eat a piece of tofu and drink a cup of soy milk occasionally. However, some doctors consider that the phosphorus and potassium content of soybeans is generally higher than that of chicken, fish, eggs, and milk. For patients who have not yet undergone dialysis and whose GFR is lower than 30, they will recommend animal protein to be preferred. Soy products can satisfy their cravings occasionally, and there is no need to compete with each other.

There are also many people who dare not touch high-potassium fruits such as bananas, oranges, and kiwis once they are diagnosed with kidney failure. It is really unnecessary. Only patients whose blood potassium is higher than 5.5mmol/L or whose GFR is lower than 20 need to strictly limit potassium. I once met a 28-year-old young man who stopped eating all fruits and vegetables as soon as he was diagnosed with renal failure. He ate white rice and fried winter melon every day. After half a month, he was so weak that he could not walk due to potassium deficiency. When he went to the hospital for a review, his blood potassium was only 2.8, and he was scolded by the doctor.

As for those food supplements that claim to "tonify the kidneys", you need to be even more careful. Black sesame paste, black bean porridge, and chicken stewed with cordyceps flowers are all hard-hit areas with high levels of phosphorus and potassium. I once saw an aunt who believed in her neighbor's folk prescription and drank black bean porridge every day to replenish her kidneys. After a month of drinking, her blood potassium soared to 6.2, and she was sent to the emergency room to lower her potassium, which almost caused arrhythmia.

In fact, after all is said and done, there really aren’t that many black and white taboos when it comes to diet for kidney failure. Don’t search for a list on the Internet and apply it to yourself, and don’t listen to the patient next door who says you can’t eat anything and don’t dare to touch anything. After all, everyone’s kidney function stage, whether they have dialysis, whether they have high blood pressure and hyperkalemia, and other complications are different. Find your attending or a specialized nephrology nutritionist to calculate how much protein and salt you can eat every day, and whether you should limit potassium and phosphorus. It is more reliable to eat accordingly. For patients with kidney failure, long-term malnutrition is more harmful to the kidneys than eating two more bites of meat.