Calcium salt crystals can form kidney stones, so is calcium supplementation safe? Will kidney stones occur?

An aunt left a message to Huazi, saying that she was old and had some osteoporosis, and the doctor recommended that she take calcium supplements. However, she also had kidney stones, and was worried that after taking calcium supplements, there would be more and more kidney stones, so she was in a dilemma. Huazi told her that kidney stones are mainly composed of 80% calcium oxalate stones, 10% uric acid stones, and some calcium phosphate stones. The rarer ones are cystine stones.

Although most kidney stones contain calcium, many people used to worry that calcium supplementation would increase the risk of kidney stones. But in fact, normal calcium supplementation does not increase the incidence of kidney stones.

1. Formation of kidney stones The most common type of kidney stones is calcium oxalate stones. As the saying goes, "it takes two to tango." Calcium alone cannot form stones. It must be salted with oxalate and then precipitated into crystals when the urine is concentrated to form stones.

The calcium in urine comes from the blood. The human body's blood calcium is stable. Regardless of whether calcium is supplemented or not, the urine will contain calcium. When it encounters a large amount of oxalic acid, it may form stones.

Therefore, the "culprit" of kidney stones is oxalic acid. When the body's oxalic acid metabolism is disordered and the oxalic acid in the urine increases, it is easy to combine with calcium to form salts and stones. Another common stone is uric acid stones, which are also caused by abnormal uric acid metabolism in the human body and increased uric acid in the blood. When the urine is concentrated, uric acid stones are easily formed.

2. Regular calcium supplementation is very safe. The human body's bone calcium is mainly composed of calcium, and the calcium in the human body is lost every day with sweat and urine, so it needs to be supplemented every day. Adults need to take in 800 mg of calcium every day, and the elderly have weaker absorption function and need to take in 1000 mg of calcium. However, the Chinese Residents' Dietary Health Survey shows that the amount of calcium obtained by adults in my country from their diet is less than 400 mg per day.

The human body needs to maintain a stable blood calcium level. If calcium is insufficient, osteoclasts will be used to break down bones and release calcium from the bones into the blood. In other words, normal calcium supplementation is only to make up for the body's "deficit" and will not affect blood calcium levels or increase the incidence of kidney stones.

3. How to prevent kidney stones 1. Ensure adequate water intake: Regardless of the cause of kidney stones, there is a prerequisite, which is urine concentration. Solutes such as calcium salts and uric acid dissolved in urine will precipitate to form stones. Therefore, ensuring adequate urine volume can prevent the occurrence of kidney stones. It is recommended to drink more than 2000 ml of water every day, divided into multiple times, and drink slowly in small sips.

2. Do not take excessive calcium supplements: Daily diet can provide some calcium, so do not blindly pursue excessive calcium intake. It is usually safe to supplement about 600 mg of calcium per day. If you take excessive calcium supplements, you may develop hypercalciuria, which may increase the risk of stones.

3. Reduce oxalic acid intake: Spinach, bamboo shoots, potatoes, beets, plums, strawberries, oranges and other foods contain a lot of oxalic acid, which will combine with calcium in urine to form calcium oxalate stones. Eat less of them. When eating vegetables, you can blanch them first, and a lot of oxalic acid will dissolve in the water to reduce intake. When eating vegetables, do not drink vegetable soup.

4. Reduce purine intake: People with hyperuricemia should pay attention to reducing the intake of meat, fish, animal offal and other foods. Because these foods contain more purine, uric acid will be generated after metabolism, which can easily lead to uric acid stones. People who take uric acid-lowering drugs usually need to drink more than 3000 ml of water every day to avoid the formation of stones by uric acid excreted through urine.

To sum up, the main cause of kidney stones is the abnormal metabolism of oxalic acid and uric acid in the body, and has little to do with calcium supplementation. As long as the amount of calcium supplementation is controlled and not excessive, it is safe. When supplementing calcium, increasing the amount of water and controlling the intake of oxalic acid and purine can also effectively prevent the occurrence of kidney stones. I am pharmacist Huazi, welcome to follow me and share more health knowledge.