Diet taboos for urinary stones

Drinking less than 2000ml of water per day and eating a high-salt and high-sugar diet for a long time.

Let’s talk about a case I just encountered last week. A 28-year-old Internet programmer had a 0.4cm calcium oxalate stone during a physical examination. He went home and drank all spinach and soy products. Even the milk he drank every day was replaced by sugar-free soy milk. After three months of review, the stone was not smaller. On the contrary, the low-calcium diet led to more free oxalate acid absorption in the intestines, and he also suffered from leg cramps due to calcium deficiency.

In fact, this is also a misunderstanding among many patients today. They search the entire Internet for "what should not be eaten with urinary stones" without caring about the composition of their stones. After all, there are several types of urinary stones. Calcium oxalate stones account for the highest proportion, uric acid stones are linked to gout, and infectious stones are linked to urinary tract infections. The taboo foods are not bad at all.

Take calcium oxalate stones as an example. The academic community currently has two different guidance directions: the traditional view is that the intake of high-oxalate foods such as spinach, amaranth, strong tea, chocolate, and rhubarb should be strictly limited to avoid excessive oxalic acid concentration in the urine to form crystals.； However, in recent years, more and more clinical studies have also pointed out that as long as they are not patients with hyperoxaluria, ordinary patients with calcium oxalate stones do not need to completely avoid eating high-oxalate foods. Instead, they can eat them with high-calcium foods - such as spinach and tofu stew. The oxalic acid combines with calcium in the intestines to form calcium oxalate that is not absorbed by the human body. It is excreted directly with the feces and does not end up in the urine. On the contrary, it is safer than eating spinach alone.

Of course, if you find out that your 24-hour urinary oxalic acid excretion is far above the standard, you still have to listen to the doctor's instructions to strictly control oxalic acid, and don't force yourself to do it.

After talking about calcium oxalate stones, which account for 80%, let’s talk about uric acid stones, which are becoming more and more common among young people. In the past few years, eight out of ten of the patients I have met have a long-term habit of eating late night snacks, drinking beer, and eating seafood. Last month, there was an old football fan who stayed up late every day during the World Cup and served crayfish and ice beer. He had gout and refused to go to the hospital. Later, he came to the emergency department with rolling back pain and was found to have a 0.6cm uric acid stone lodged in his ureter. The pain made him shed tears. The core taboo for this type of patients is high-purine foods: animal offal, shelled seafood, thick broth, and beer. They should definitely eat less of these, but they don’t dare to eat soy products even in the rain. Studies have already shown that processed tofu and soy milk have lost most of their purines during the production process. Patients with stable uric acid control can eat it two or three times a week without any problem, and they don’t need to be beaten to death.

Oh, by the way, there is another rumor that has been circulating for more than ten years that needs to be clarified: Many people are afraid to drink mineral water when they have stones, saying that the minerals in it will aggravate the stones. They really think too much - the calcium and magnesium ions in the mineral water are not as much as if you drink a sip of milk and eat half a piece of tofu. There is no need to buy pure water to drink, it is a waste of money. Some people think that drinking milk tea and carbonated drinks can also be considered as rehydration. Don’t be silly. Drinks with high sugar and high phosphorus will only accelerate the formation of crystals in the urine. I once met a girl born in the 2000s who didn’t like to drink boiled water. She drank three cups of iced milk tea a day and developed three stones in six months. In the end, she was so painful that she couldn’t undergo minimally invasive surgery.

As for patients with infectious stones, most of them contain magnesium ammonium phosphate. This type of stone is more likely to grow in alkaline urine, so don’t follow the trend of drinking soda or eating too many citrus foods to over-alkalinize the urine. Don’t believe the “drinking cranberry juice can dissolve stones” posted on the Internet. According to current research, cranberry juice can at most slightly reduce the risk of urinary tract infection. Moreover, most commercially available cranberry juice adds a lot of sugar. Drinking too much will step on the red line of high sugar, which is not worth the candle.

In the past few years of follow-up in the urology department, I have seen too many people who either ate too much for half a year and had stones that grew to 1cm and needed surgery. I also saw people who dared not eat anything and ended up losing more than ten pounds and still lacked calcium. To be honest, the dietary adjustment for urinary stones is really not that complicated. After the lithotripsy or surgery, the stones were sent for examination. , you can check the ingredients for tens of dollars, adjust your diet according to the results, touch the water glass more often, and don't wait until you are thirsty before drinking water - after all, urine is like the water in the kettle at home. When there is enough water, the impurities are washed away, and thick scale will form when the water is boiled dry. The same principle applies to stones.