Tofu and kidney stones are not related to each other, why do they always turn into one? Today, let’s talk about kidney stones and tofu. Kidney stones are caused by the abnormal accumulation of some crystalline substances (such as calcium, oxalic acid, uric acid, cystine, etc.) and organic matrix (such as matrix A, acidic mucopolysaccharides, etc.) in the kidneys. Adult kidney stones are mainly calcium oxalate and calcium urate. The mechanism of kidney stone formation is more complex, but the production of stones is mainly related to three factors: low water intake and slow urine flow; increased oxalate and uric acid content in the body and the acidic internal environment of the body. Laymen always think that stones are related to eating more (purines) and moving less (sedentary), in fact, the core factors of kidney stone formation are still some internal factors, such as the local alkalinization ability of the kidneys and the tubular concentration ability is abnormal, as well as the ability of the kidneys to excrete calcium decreases, and so on. Congenital developmental abnormality or acquired injury of renal tubules are often important triggers leading to the above phenomena. Why do some people always talk about tofu and kidney stones? It may be due to the fact that tofu contains oxalic acid and calcium, which are easily misunderstood by laymen as the culprits of kidney stones. Here’s what you need to know about tofu. The main raw material of tofu is soybean, which is a very nutritious food. Soybeans, also known as “meat grown in the ground”, play a very important role in supporting the health of our bodies. The main components of tofu are as follows: 1. Energy The process of tofu is to extract the proteins from soybeans and solidify them. Therefore, tofu contains a large amount of protein, with 9.2 grams of protein per 100 grams of tofu. The protein in tofu is a high-quality protein containing a variety of amino acids, including many essential amino acids needed by the human body, and the protein in tofu is easily digested and absorbed by the human body. In addition, tofu contains a small amount of carbohydrates and fat, is a low-energy food. 2, vitamins per 100 grams of tofu contains vitamin B1 0.05 mg, vitamin B2 0.02 mg, vitamin E 8.4 mg, in addition, there are niacin, folic acid, etc.. 3, minerals In addition to the original minerals in soybeans, there is also a part of the production process as a coagulant added. Every 100 grams of tofu contains calcium 105 mg, magnesium 63 mg, iron 1.5 mg, zinc 0.74 mg, potassium 106 mg, in addition to copper, phosphorus, selenium and other minerals beneficial to the human body. 4, phytochemicals Mainly isoflavones, saponins, etc., with a certain degree of cardiovascular protection, immunomodulatory effects. I have been on the kidney disease patients can eat soy products with or without detailed elaboration, the conclusion is certain, the vast majority of kidney disease patients can eat normal (except allergies). Recently, many kidney stone patients repeatedly asked me whether they can eat tofu, because I heard that kidney stone patients can eat tofu will cause stone aggravation. In fact, this conclusion is a pseudoscience and must be clarified. Tofu is one of the most widely and popular cooking ingredients made from soybeans, green beans and black beans, processed by soaking, grinding, filtering, cooking, adding fine, coagulation and molding. Tofu and tofu products have a higher protein content than soybeans, and tofu protein is a complete protein, not only contains eight essential amino acids, and its ratio is close to the human body needs, nutritional efficiency is higher. Tofu in the coagulation molding process need to add a small amount of brine, the latter is made from seawater or salt lake water salt, residual in the salt pond mother liquor, the main ingredients are magnesium chloride, calcium sulfate, calcium chloride and sodium chloride, etc., taste a little bitter, evaporated and cooled precipitation of magnesium chloride crystals, also known as brine block. Northern people often use this as a coagulant for tofu, because the brine can make the protein in the soybean milk into a gel, the water analyzed, with salt brine as a coagulant made of tofu, hardness, elasticity and toughness, the folk will often be the finished product of such practices of the tofu known as the old tofu, or northern tofu, hard tofu. Due to traditional methods of making tofu using brine mostly salt brine (magnesium chloride) and gypsum brine (calcium carbonate), which has been considered to contain toxic substances eaten more bad, so the vast majority of brine used now is made from the original juice of tofu when the water is made after fermentation. In fact, neither magnesium chloride nor calcium carbonate will not adversely affect the human body, on the contrary, many patients with renal insufficiency, but also by taking calcium carbonate tablets for a long time, in order to reduce intestinal phosphorus absorption to protect the human body’s renal function and the function of other organs from the damage of phosphorus. Therefore, no special circumstances, kidney stone patients can normally eat tofu and other soy products. Prevention of kidney stones is best to do the following: 1, drink more water The U.S. recommendation is 12 cups a day (one cup is 240 ml) or more. Because drinking more water, more urine, it will dilute the calcium oxalate and other minerals, to avoid their crystallization precipitation. Conditional people preferred soda, both to achieve the purpose of hydration, but also can alkalize the urine, to prevent stone formation. 2, eat less animal protein too much animal protein intake, will increase the calcium in the urine, thus increasing the formation of calcium oxalate, calcium phosphate. 3, eat less salt Salt will also affect the excretion of calcium, increase the calcium content in the urine. 4, eat less oxalic acid-rich foods, such as spinach, peanuts, chocolate, asparagus, etc. In fact, most vegetables and fruits also contain oxalic acid. However, these foods are often nutrient-rich foods as well, so it is not appropriate to overemphasize limiting them. For oxalic acid to form stones, it needs to reach the urine where it combines with calcium. If oxalic acid-rich foods are cooked and eaten together with calcium-rich foods, they may combine in the gut, making it difficult to be absorbed, and they won’t make it to the urine to become stones. From this point of view, the legendary “spinach and tofu together”, not only does not lead to stones, but also help to avoid stones. It should also be emphasized that there are some traditional Chinese medicines that are rich in oxalic acid, such as rhubarb, ginseng, Panax ginseng, Radix et Rhizoma Ginseng, Radix et Rhizoma Polygoni Multiflori, etc. Long-term users need to regularly check whether there are crystals in the kidney tissue, and discontinue the use of these medicines if necessary.