Diet taboos for renal insufficiency

The daily salt intake should not exceed 3g. Unless there are special circumstances, avoid high-phosphorus and high-potassium processed foods. Eat high-quality protein, not too much or too little. Don't drink "tonic soups" such as thick broth and bone soup if you can. The rest of the taboos should be determined based on your glomerular filtration rate (eGFR) stage and whether you have comorbidities such as edema, high potassium, and high uric acid. Blindly following the trend of taboos can lead to accidents.

I met a 56-year-old Chen during a follow-up visit in the nephrology department last year. He was diagnosed with stage 3b chronic renal failure and his eGFR was only 42. Originally, his creatinine was stable, but I heard from neighbors in the community that "if your kidneys are not good, you need to drink more bone soup to replenish your kidneys." "I made bone soup at home every day and drank two large bowls at a time. After drinking it for half a month, I was itchy and couldn't sleep all night. There were blood marks all over my arms. When I went to the hospital, I found that my blood phosphorus was more than twice the normal value, and my creatinine increased by 27%.

Don't tell me, there are really too many family members who drink bone soup who believe that "what you eat is what you eat". This point is now controversial: the experience of the older generation believes that bone soup nourishes people and nourishes the kidneys, but the modern renal nutrition guide clearly states that the phosphorus and purine in the bones People with impaired kidney function cannot excrete it if it is boiled in soup. Either the high phosphorus causes itchiness and calcification of blood vessels, or the high uric acid causes gout. All of these will put a burden on the kidneys. If you really want to supplement nutrition, it is better to eat two mouthfuls of stewed lean meat, which is more effective than drinking ten bowls of soup.

Another common misunderstanding is that many people think that if I don’t eat pickles, it means I am controlling salt. It’s not that simple.

Last time, there was a 28-year-old girl with nephritis and a creatinine of 122. The doctor asked her to control her salt. She did not put pickles in her meals at home every day, but she ordered takeout to go with it. Braised chicken, spicy hotpot, and braised food took turns. After three months of review, her creatinine rose to 161, which made her cry. Later, I gave up taking out food and bought a 2g salt-limited spoon. I put a maximum of one and a half spoons in every day when cooking. I checked again after half a year and found that the creatinine dropped back to 118, which was very stable.

I would also like to say here that the old view in the past was that if you have bad kidneys, you should completely ban salt. This is no longer recommended now: as long as you don’t have severe general edema or refractory hypertension, you don’t need to eat salt-free rice at all. Salt within 3g is just enough for your body’s needs. If you really don’t eat any salt at all, you will easily become low in sodium and your body will be so soft that you can’t even walk, which is not conducive to your condition.

When it comes to nutritional supplements, protein is the most controversial.

Two years ago, I met a 62-year-old aunt with stage 2 kidney failure. She heard someone say that "eating protein will increase the burden on the kidneys." She didn't dare to touch a bite of meat or an egg. She drank white porridge and vegetables every day. After half a year, her albumin was only 28g/L. Her feet were so swollen that she couldn't even put on cotton-padded shoes, and her creatinine increased from 130 to 170. Later, she went to the nutrition department and asked her to eat 1 boiled egg, 2 taels of lean pork, and a cup of 100ml pure milk every day. After two months, the swelling completely disappeared and the creatinine dropped back to 142.

In the past, the old guidelines required patients with renal failure to eat only 0.6g per kilogram of body weight per day. Now the latest KDIGO guidelines have been relaxed to 0.6-0.8g. The core is to eat high-quality protein - that is, eggs, milk, lean meat, fish and other animals. Protein, there is another taboo that was loosened now: the older generation said that you should not eat soy products if your kidneys are not good. Current research has found that soy protein is actually high-quality protein. As long as the total amount is controlled, it is okay to eat a piece of tofu and drink a cup of soy milk occasionally. It does not need to be beaten to death. Of course, if your creatinine rises quickly after taking it, don’t hesitate and just stop.

As for the frequently asked questions, are foods high in potassium and phosphorus such as bananas, oranges, spinach, and mushrooms absolutely not to be touched? Neither.

If your eGFR is still above 60 and you have no history of hyperkalemia, it is perfectly fine to eat two pieces of sugar orange in winter and half a piece of watermelon in summer. You don’t have to make yourself suffer. But if your eGFR has dropped below 30, or you have had high potassium in the past, you really need to keep your mouth shut. I met an old man in the emergency department before. I bought sugar oranges at home in the winter. He was greedy and ate half a stick. That night, he felt panicked and out of breath. When he was sent to the hospital, his blood potassium was checked to 6.8mmol/L, and he was immediately arranged for emergency dialysis. It was too risky.

Oh, by the way, there is another invisible high-phosphorus expert that everyone easily overlooks: the additives in various processed foods, such as cola, milk tea, processed meat, and meatballs in instant hot pots. The human body absorption rate of the inorganic phosphorus in them can reach 90%. It is much scarier than the natural phosphorus in food. If you can't avoid it, don't eat it.

To be honest, diet with renal insufficiency is never a torture of "you can't eat this and you can't eat that". The core is a question of "quantity". If you eat something that others cannot touch, you may be fine if you eat a small amount. If you eat something that others can eat, you may have an accident if you take one more bite. If you are really unsure, it is much more reliable to find your own attending doctor or nephrology nutritionist to come up with an individualized diet plan than to read a random list of taboos online.