Will drinking water with scale for a long time cause kidney stones? The answer is unexpected!

Friends who use kettles to boil water at home should have seen this phenomenon: the scale on a kettle that has been used for a long time is very difficult to clean. Many people are worried about "Will drinking water with scale for a long time cause kidney stones?" Yesterday, this topic once became a hot search on Weibo.

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Let’s talk about it in detail today.

Drinking scale-containing water for a long time will not cause kidney stones

Scale is formed by the interaction of calcium and magnesium ions and alkalinity in water during the boiling process. The main components are calcium carbonate and magnesium hydroxide. There are many minerals naturally present in water, among which calcium ions and magnesium ions are the most abundant.

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Generally speaking, the higher the content, the greater the hardness of the water, which is what we often call "hard water". When the hardness of water is higher than about 200 mg/L, it will cause scale to form in water plants, water distribution systems, pipe networks and kettles. The higher the temperature, the greater the scale content, which is why it is easier to form scale after boiling water.

Water with scale is usually very hard. The main components of scale are actually calcium carbonate and magnesium hydroxide, which are common substances and are very safe and will not harm human health.

World Health Organization "Guidelines for Drinking-water Quality (Fourth Edition)"

In fact, the World Health Organization (WHO)'s latest "Guidelines for Drinking Water Quality" clearly states that the concentration in drinking water is not high enough to have an impact on health, so no limit is set. There is currently no evidence that hard water can cause stones or other health problems. On the contrary, if you drink less water and eat more meat, the risk of urinary stones will be higher.

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Hard water is harmless to the human body. Calcium and magnesium are both essential elements for the human body, and most people have low calcium and magnesium intake. In this sense, hard water can also supplement some minerals. Of course, it is far from enough for daily needs. The right way to supplement minerals is still a balanced diet.

However, water that is prone to scale usually tastes bad, which is why many southerners find Beijing's tap water tastes bad after coming to Beijing. It is also difficult to clean and can burn the kettle. If you don't like it, you can install a water softener at home, or drink purified water, mineral water, or other water.

How to drink water more healthily?

1. Drink water in moderation

China's dietary guidelines recommend that the average adult drink 1500-1700 ml of water per day, of which about 800 ml can be obtained from food, so about 900 ml is still needed.

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Of course, this is a recommended amount and you don’t have to stick to it. You can adjust it according to your own situation. For example, if it is summer, or if you exercise a lot and sweat a lot, you should drink more water. The air in the north is dry, so you can also drink more water. Physical laborers or people who stay outdoors get thirsty quickly and drink a lot, so they can also drink more.

Some patients with chronic diseases should pay attention to drinking more water. For example, patients with urinary stones, hyperuricemia, gout, and diabetes should drink more water to reduce the risk of disease.

2. Drink water in small amounts and multiple times

Don’t drink water only when you feel thirsty. You should drink consciously and actively, in small amounts and multiple times. The elderly are especially sensitive and need to replenish water in a timely manner.

Drink a glass of water when you wake up in the morning, and try not to drink too much water before going to bed at night to avoid getting up frequently at night.

3. In special circumstances, pay attention to drinking more water, and choose electrolyte water appropriately.

People who do strenuous exercise, have high fever and diarrhea, have urinary stones, hyperuricemia, gout, and diabetes should drink more water, and can choose electrolyte water under the guidance of a doctor or nutritionist. People who are active or working in a high temperature environment (high temperature in summer) should drink more water, salt water, or electrolyte water containing potassium, sodium, etc.

References

[1] Lu Jinsuo, Chen Cheng, Li Xiong, et al. Analysis of scale problems in drinking water[J]. China Water & Wastewater, 2019, 35(08): 15-19. DOI: 10.19853/j.zgjsps.1000-4602.2019.08.004.

[2] Hou Jian. Harmful metal elements in scale are harmful to health [J]. Metal World, 2009(02):70.

[3] Tang Qingguo, Wang Lijuan, Liang Jinsheng, et al. Study on the formation and change of scale crystals[J]. Journal of Synthetic Crystals, 2009, 38(03): 602-607. DOI: 10.16553/j.cnki.issn1000-985x.2009.03.041.

[4]WHO Guidelines for Drinking-Water Quality (4th edition)

Planning and production

Author: Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center

Review | Zhong Kai, Researcher at the National Food Safety Risk Assessment Center

Planning丨Lin Lin

Editor: Jin Yufen