Dietary taboos for membranous nephropathy

Daily salt intake should be strictly controlled within 3g (lower for edema and massive proteinuria), high-quality protein intake should be controlled at 0.8-1.2g/kg/day based on body weight, avoid excess, and resolutely avoid nephrotoxic foods with high additives, high purine, and high fat. The scope of contraindications will be different for patients with different disease stages and whether they have abnormal renal function. There is no need to apply unified standards regardless of the situation.

A while ago, a 28-year-old man was admitted to the outpatient clinic. His membranous nephropathy has been in clinical remission for just one year. He felt that he was getting better. So he and his friends went to a late-night snack stall and showed off 20 skewers of roasted lamb, half a portion of pickled radish, and drank two bottles of cold beer. When he woke up the next day, his eyelids were swollen to a slit, and the urine proteinuria test returned to 3+. The 24-hour urinary protein quantification soared to 4.2g. The medicine he had taken for more than half a year was like taking the medicine in vain. Many people think that the top priority for kidney disease is protein. In fact, salt is the number one "invisible killer". Don’t underestimate this 3g of salt, which is about the amount of a beer cap. The takeaways, pickles, processed snacks and even many so-called “healthy” meal replacements you usually eat contain more invisible sodium than you can imagine. I once met an aunt who didn't dare to touch pickles every day, so she liked to chew two soda crackers as a snack. As a result, the edema kept coming back and forth. Later, when I looked at the ingredient list, I found that the sodium content of every 100g of soda crackers was 600 mg. She ate four or five soda crackers a day, which accounted for almost 1/3 of the daily salt intake. No wonder the indicator was not stable. By the way, I have to mention here that when the edema is particularly severe and the 24-hour urine protein exceeds 4g, the doctor may ask you to eat a salt-free diet for a short period of time. At this time, do not even touch invisible salts such as soy sauce, oyster sauce, and chicken essence. Of course, if you have been in clinical remission for more than 2 years and all indicators are normal, it is okay to relax to 4-5g of salt occasionally. It does not need to be so stuck that eating will not be fun and it will affect your immunity.

In addition to invisible salt that is easily overlooked, how to eat protein is probably the most frequently asked question by patients with membranous nephropathy. This has also been controversial in the field of nephrology for many years. In the early days, everyone thought that leaking protein had to be replenished, and that one should eat more eggs and drink more milk. The current mainstream view is that if the kidney function is normal and the proteinuria is not too much (less than 3.5g in 24 hours), it is enough to eat 0.8-1.0g of high-quality protein per kilogram of body weight every day. If there is a period of massive proteinuria, it can be appropriately increased to 1.0-1.2g, but it must not exceed 1.2g, otherwise the excess protein will leak out of the kidneys and increase the filtration burden. Of course, some doctors will recommend that patients with refractory membranous nephropathy who are not sensitive to hormones should appropriately relax their protein intake to avoid severe hypoalbuminemia. However, the premise is that the renal function is completely normal, and the indicators of urinary protein and plasma albumin must be regularly monitored. You cannot increase the amount casually.

Here I would also like to talk about the issue of soy products that everyone has been arguing about for a long time. Many people say that people with kidney disease cannot eat soy products. In fact, it is not a one-and-done thing. The protein of the three soybeans, soybeans, black beans, and green beans, is high-quality protein. The amino acid ratio matches the needs of the human body very well. If you include it in the total daily protein, it is completely edible. I have a patient who did not dare to eat a bite of tofu before. After listening to our suggestions, he eats stewed tofu twice a week, 2 taels each time. His indicators do not fluctuate at all, and he is more energetic than before. On the contrary, the protein of miscellaneous beans such as mung beans and red beans is not high-quality plant protein and contains a lot of metabolic waste. Patients with renal insufficiency should avoid eating it as much as possible.

There are also several types of things that you should try not to touch no matter what stage you are at: processed foods with a large amount of preservatives and flavorings, such as ham sausages, canned foods, carbonated drinks, etc. The phosphorus and food additives in them need to be metabolized by the kidneys. The kidneys of patients with membranous nephropathy are inherently more fragile than ordinary people, so they should do as little extra burden as possible. There are also high-fat animal offal, fat meat, margarine, etc. Patients with membranous nephropathy are already prone to hyperlipidemia, and the risk of thrombosis is several times higher than that of ordinary people. If you eat too much, the blood lipids will increase, and the risk of thrombosis will also increase, so you should not do it. Oh, by the way, there are also folk prescriptions and health products with unknown ingredients, especially the traditional Chinese medicine pills that claim to "radically cure kidney disease". Many of them contain nephrotoxic ingredients. In clinical practice, there are really many patients who suffer from kidney failure after taking folk prescriptions. Don't gamble with your kidneys. Don’t believe in the saying “what you eat is what you eat to replenish your waist”. I have seen many patients drink pork loin soup to replenish their waists. In the end, their uric acid and blood lipid levels soared, which worsened their condition.

If you already have elevated creatinine and renal insufficiency, then there is one more taboo, which is to limit potassium and phosphorus. Try to eat as little high-potassium foods as bananas, oranges, mushrooms, and seaweed, and control the amount of high-phosphorus foods such as processed meats, milk tea, and nuts. But if your kidney function has always been normal, there is no need to deliberately avoid these. Many patients dare not eat anything, and end up with low potassium and low sodium malnutrition, which is not conducive to recovery.

In fact, when it comes down to it, there are really not so many rigid rules about the diet of membranous nephropathy. I have seen old patients who have been in remission for more than ten years, and it is okay to eat weak ice cream occasionally. I have also seen young people who have just relapsed after eating and drinking. The core thing is not to put unnecessary burden on the kidneys, and not to eat too much and make their quality of life extremely low. If you are really not sure whether you can eat it or not, bring your food records to your attending doctor for your next check-up. This is much more reliable than the messy unified contraindication list you can search online.