It is said that tea has a high oxalic acid content and frequent tea drinking can cause kidney stones! This is not the case. Tea does contain oxalic acid, which is related to the occurrence of kidney stones, but the tea polyphenols, caffeine, tea polysaccharides and tea pigments in tea can effectively prevent the occurrence of stones.
From another perspective, drinking tea also consumes a lot of water, which is also helpful in preventing kidney stones.
Tea has a history of thousands of years of drinking in my country and is a healthy drink. In the relationship between drinking tea and kidney health, people believe that the oxalic acid contained in tea is a high-risk factor for the formation of calcium oxalate kidney stones.
However, some studies have mentioned that tea polyphenols, caffeine, tea polysaccharides and tea pigments in tea can effectively inhibit the formation of kidney stones. The mechanism is related to diuresis, antioxidants to reduce cell damage, inhibition of adhesion between crystals and renal tubular epithelial cells, lowering blood uric acid levels, regulating intestinal microorganisms and metabolic syndrome.
A large prospective study from Shanghai, China found that men who drink green tea for a long time have a lower risk of kidney stones than men who never drink tea, and there is a trend that the risk of kidney stones decreases with increasing monthly tea drinking. There are also epidemiological surveys that have found that increasing tea drinking reduces the risk of kidney stones.
Therefore, it is recommended to choose spring green tea, and the brewing time should not exceed 5 minutes, which can minimize the intake of oxalic acid, and at the same time obtain more tea polyphenols, which can better inhibit the formation of kidney stones. If you like to drink black tea, you can add some milk to reduce the excretion of urinary oxalic acid.
As for the so-called strong tea and weak tea, it is just a relative term, and there is no unified definition at present. For example, 5 grams of tea leaves are soaked in a small amount of water for a long time, and 5 grams of tea leaves are soaked in more water for the same time. Although the concentrations of the two are different, if you drink all of them, the intake ingredients are the same.
So as long as the amount of tea leaves is certain, there is no need to worry about the concentration of tea water. The key is that it is not bitter and you can accept it.
From the existing research, we don’t need to worry too much about drinking tea causing kidney stones. Long-term moderate drinking of tea has a preventive effect on the formation of kidney stones.
Some studies have mentioned that drinking ≥240 ml of tea per day may be associated with a 16% reduction in the risk of kidney stone formation. There are also documents that mention that the longer the duration of tea drinking, the better the preventive effect. Tea consumption ≥20 cup-year can reduce the risk of kidney stones by 20%, while <20 cup-year is meaningless. Cup-year is the product of the number of cups of tea consumed per day (120ml as a cup) and the number of years of tea drinking. For example, drinking 2 cups of tea per day for 10 years can reduce the risk of kidney stones by 20%.
In addition, we also drink a lot of water while drinking tea, and adequate drinking water is also helpful in preventing kidney stones.
The occurrence of kidney stones is closely related to unreasonable diet, such as high-protein diet, high-purine diet, high-oxalate diet, high-salt diet, etc.
1. High-protein diet
It will increase the content of calcium, uric acid and oxalic acid in urine and decrease the content of urine pH and citrate. Increased calcium, uric acid and oxalic acid in urine can promote stone formation; while citrate is an inhibitor of stone formation, and decreased urine pH will also promote the formation of calcium oxalate crystals.
2. High-purine diet
The metabolic end product of purine is uric acid. A large intake of high-purine diet will not only increase the excretion of uric acid in urine, making it easy to form uric acid stones; it will also increase the formation of endogenous oxalic acid, thereby increasing the risk of calcium oxalate stone formation.
3. High-oxalate diet
Oxalic acid is one of the important factors in the formation of kidney stones. Oxalic acid combined with calcium will form calcium oxalate crystals, increasing the risk of stones.
4. High-salt diet
Eating more salt means consuming more sodium. A large intake of sodium salt can increase the excretion of calcium and cystine in urine, reduce the excretion of citrate in urine, increase urine pH, and thus increase the risk of stones.
In addition, some bad habits, such as not liking to drink water, taking medicine indiscriminately, often holding urine for a long time, staying up late, smoking, etc., will also increase the risk of kidney stones.
1. Eat less sauces and pickled foods
Usually, you should eat less sauces and pickled foods, and you should also eat less processed foods such as instant noodles, konjac, red sausage, Chinese sausage, spicy strips, etc. As for cooking salt, it is recommended to control it to no more than 5 grams per day, which is about less than 1 beer can cap.
2. Avoid excessive intake of animal protein
Although animal protein is high-quality protein, people who already have kidney stones need to control their intake to avoid increasing the burden on the kidneys. For animal food, you can choose white meat foods such as fish and poultry, and try to eat less red meat such as pork, beef, and lamb, generally 1 to 2 times a week, no more than 50 grams each time.
3. Drink enough milk
Milk is an important way for us to supplement calcium in our daily life. It is recommended that patients with stones use milk as the main source of dietary calcium, and it is recommended to drink 300 ml of milk every day.In recent years, a large number of studies have shown that a high calcium diet is associated with a reduced risk of stones. The possible mechanism is that high calcium binds oxalic acid in the intestine, reduces the absorption of oxalic acid and excretion in urine, and reduces the ratio of urine oxalic acid/calcium. In addition, dairy products may contain certain factors that inhibit stone formation.
4. Eat more fresh fruits and vegetables
Fresh fruits and vegetables contain nutrients such as dietary fiber, mineral potassium, and antioxidants, which are helpful in preventing and reducing kidney stones.
5. Limit foods with high oxalic acid
For foods with too high oxalic acid content, be sure to blanch them before eating to remove most of the oxalic acid, such as spinach, amaranth, water spinach, wild rice stem, winter bamboo shoots, etc.
6. Drink more water
Drinking more water is beneficial to patients with kidney stones. It can not only prevent stone formation, but also promote stone excretion. Drink at least 1500~1700 ml per day, preferably 2000~3000 ml, especially when the weather is hot or when doing strenuous physical activities.
Drinking tea frequently is not the main cause of kidney stones. To prevent kidney stones, you should pay more attention to eating less foods that are not friendly to the kidneys and changing bad eating and living habits.Such rumors often assert that specific behaviors or foods can cause specific health problems, such as drinking tea can cause kidney stones, rather than considering the complex causal relationship of other possible factors.
