Diet taboos for polycystic kidney disease

The core dietary taboos for patients with polycystic kidney disease can be summarized as "two less, one avoidance, and one dynamic": consume less food that increases the metabolic burden on the kidneys, consume less ingredients that may stimulate abnormal growth of cysts, and avoid substances that are clearly nephrotoxic. All dietary requirements must be dynamically adjusted according to the stage of kidney function. There is no one-size-fits-all absolute fasting list.

A while ago, I met a 30-year-old male patient in the outpatient clinic. Polycystic kidney disease was diagnosed in the work unit, and the kidney function was completely normal. I went back and searched the taboo list on the Internet, and stopped all soy products, eggs, milk, and even meat. He only boiled cabbage with rice. Within 20 days, he came for a follow-up visit because of hypoalbuminemia and edema. His face was so swollen that his eyes almost narrowed into slits. He said that he was afraid that eating the wrong food would aggravate the cysts, and he ended up starving himself to the hospital first.

Speaking of which, I have to mention the most controversial issue of soy products. Nowadays, you can still find a lot of statements on the Internet that "You must not eat tofu with polycystic kidney disease." This is actually an old concept in the early years - it used to be that plant proteins had many metabolic waste products and would increase the burden on the kidneys, so patients with kidney disease were required to avoid eating tofu. However, the chronic kidney disease guidelines issued by KDIGO in recent years have already updated this conclusion: If the kidney function is still in the compensatory stage and there are no problems with proteinuria or elevated creatinine, eating soy products (such as tofu, soy milk, natto) in moderation will have a smaller metabolic burden than eating red meat (pork, beef, and sheep) every day. As long as the total daily protein amount is controlled at 0.8-1.0g per kilogram of body weight, there will be no problem. Of course, if you have progressed to the stage of renal failure, whether it is animal protein or plant protein, you must strictly follow the doctor's advice to control the intake. There is no saying that no one is "better" than the other.

It is currently recognized by academic circles that the dietary factor that has the greatest impact on the progression of polycystic kidney disease is actually high salt, which is also the easiest pitfall for most patients. I have seen too many patients whose cysts grew very slowly when checked every year. As a result, after retirement, they had nothing to do but pickle pickles and make soy pork at home every day, and eat pickled radish with every meal. In less than two years, their creatinine doubled, and their cysts became larger than before. It’s not that you can’t touch a bite of pickled vegetables. During the Chinese New Year, I made soy duck at home. It’s perfectly fine to satisfy your cravings with a pair of chopsticks. I’m afraid you’ll think “it’s okay to eat a little anyway” and eat every meal. If your daily salt intake exceeds 6g (about the amount of a beer bottle cap), in the long run, your blood pressure will increase, the burden on your kidneys will increase, and the cysts will naturally grow faster. By the way, many people think "I don't put much salt in cooking", but the invisible salt in the potato chips, plums and takeaways you usually eat has already exceeded the standard. You should also pay attention to these hidden pitfalls.

As for high purine and high animal fat intake, there is no need to make it an absolute fast. If your uric acid and blood lipids are normal, going out for a seafood barbecue or a bowl of Laohuo soup with friends on the weekend will basically not have any impact as long as it is not a sudden change. But if you already have hyperuricemia or high blood lipids, you need to control it appropriately - after all, uric acid crystals deposited in the kidneys will aggravate kidney damage, and it will be even worse for patients with polycystic kidney disease. Oh, by the way, it is really recommended to drink less alcohol, especially beer. In addition to being high in purines, it will also stimulate the epithelial cells of the cyst wall to secrete cyst fluid and accelerate the growth of the cyst. This is a conclusion that is basically uncontroversial in the academic community.

One pitfall that must be avoided is nephrotoxic substances. This is non-negotiable. Don’t try random folk remedies and ancestral secret recipes with unknown ingredients. An aunt once thought that “taking some Chinese medicine can eliminate cysts” in polycystic kidney disease, so she found a doctor in the countryside to prescribe a bunch of medicines, which contained Panax notoginseng. Within a month of taking it, she suffered acute kidney injury and induced hepatic veno-occlusive disease. It took her more than half a month to be rescued in the hospital. Also, when you have a cold or a headache, don’t take antipyretic analgesics such as ibuprofen and acetaminophen casually. If you need to take medicine, tell your doctor about your history of polycystic kidney disease and ask the doctor to prescribe you medicine with less nephrotoxicity. This is more important than any dietary taboos.

There are also many people asking about drinking water, which also depends on the situation. For patients with early-stage polycystic kidney disease, no edema, and normal urination, it is actually recommended to drink more water, about 2000ml a day, to dilute the urine, which can reduce the probability of urinary tract infection and kidney stones, which is beneficial to the kidneys. But if you have reached the stage of renal insufficiency and have swollen legs, chest tightness, and oliguria, you need to control the amount of water you drink. Drinking too much will not be excreted, but will increase the burden on the heart and kidneys. Don't listen to the "uniform recommendations" on the Internet, just follow your own review results.

In fact, among the patients with polycystic kidney disease I have come into contact with, many have normal kidney function after living for seventy or eighty years. Many people scare themselves and either dare not eat anything or do not avoid anything, which makes them prone to problems. There is no need to act like an ascetic when it comes to diet. Grasp the word "moderate", check your kidney function and kidney ultrasound regularly every six months, and adjust your diet according to your own indicators. This is more useful than saving ten taboo lists on the Internet.