Are these 13 sayings about drinking water true or false? Let’s find out in one article today!

The all-mighty and caring greeting: "Drink more water"! Drinking water may seem like a trivial matter, but it is related to life.

March 22 to March 28 is China Water Week . Although everyone is quite familiar with drinking water, there are many rumors about drinking water, such as "yin and yang water cannot be drunk" and "mineral water is better than purified water", which makes it difficult to distinguish the truth from the false. This article sorts out 13 common sayings about drinking water. Let's find out the truth today.

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01

The more water you drink, the better?

Truth: Not really

Although "drinking more water" is good for health, it does not mean that the more you drink, the better. When water intake exceeds the kidney's ability to excrete water, it can lead to a decrease in body fluid concentration and plasma sodium ion concentration; blood dilution, a decrease in total plasma protein, hemoglobin, and hematocrit; an increase in the volume of intracellular and extracellular fluid, etc., leading to water intoxication. [1]

However, water intoxication is relatively rare in normal healthy people, and is more common in people with kidney disease, liver disease, congestive heart failure, etc.

Moreover, if you drink a lot of water in a short period of time but do not take in enough sodium, you may develop hyponatremia, which can cause nausea, vomiting, headache, memory loss, mental retardation, and even coma and death. This is more common in people who drink a lot of water after strenuous exercise but do not replenish electrolytes in time, such as marathon runners.

Besides, drinking too much water every day will affect your food intake and lead to reduced food intake, which may increase the risk of malnutrition.

So, how much water is appropriate to drink? According to the "Dietary Guidelines for Chinese Residents", in mild climates, men and women with light physical activity levels need to drink 1700 ml and 1500 ml of water per day respectively, such as boiled water, bottled water, packaged drinking water, natural mineral water, natural spring water, etc. If the temperature is high or there is a lot of physical activity, the amount of water you drink needs to be increased appropriately.

If you can't drink tasteless water, you can also drink light tea, lemon water, mint water, unsweetened mung bean soup and sour plum soup, etc.

02

Just drink water when you are thirsty?

Truth: It is not recommended to wait until you are thirsty to drink water.

When the body is dehydrated, the osmotic pressure receptors in the hypothalamus will sense the increase in the internal environment's osmotic pressure, and will transmit this signal to the cerebral cortex, allowing the brain to send a signal to tell us "The body is already dehydrated, hurry up and replenish water! It will be dangerous if you don't drink water."

So when we feel thirsty, our body is already in a state of obvious dehydration. It is best not to wait until you are thirsty to drink water. You should drink water regularly and regularly, or have a glass of water when you have nothing to do. Drink 200 ml each time. This amount is easy to drink without any burden.

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03

Can’t drink “Yin Yang Water”?

The truth: Drink it with confidence.

Folk rumor: "Drinking Yin and Yang water will cause diarrhea, so you can't drink the mixed water."

The so-called yin and yang water is actually a mixture of hot and cold water. This phenomenon is very common in life. After all, freshly boiled water is so hot that you can't drink it in a hurry. You can only add some cold water to cool it down. It's just a normal operation.

This kind of "yin and yang water" is completely drinkable and will not cause diarrhea, but the prerequisite is to ensure that both the cold water and the hot water are boiled water or bottled water that meets the sanitary indicators. As long as these conditions are met, there is no problem mixing water of different temperatures together and drinking it.

But if it is raw water, it is hard to say, because raw water has not been processed by high temperature and may contain pathogenic bacteria or parasites. It is not recommended to drink it. You may really get diarrhea if you drink it.

04

Will drinking water after a meal affect digestion?

Truth: No

Some people believe that drinking water after a meal will dilute stomach acid and affect food digestion. In fact, this is not the case. Stomach acid is not so easily diluted. For example, a foreign document mentioned that drinking water before, during, or after a meal will not affect digestion, but will help improve digestion. [2]

In addition, some studies have mentioned: If we consider it purely from a biochemical point of view, it would take nearly 2000 milliliters of water to cause changes in gastric juice, which is equivalent to three or four bottles of water. I guess no one would drink so much water at once after a meal.

Therefore, it is fine to drink a moderate amount of water after a meal. It will not affect digestion. Just remember to drink slowly and in small sips and don't drink too much.

05

Is mineral water better than purified water?

The truth: No, it depends on the situation.

Purified water is packaged drinking water that is processed from ordinary water by distillation, electrodialysis, ion exchange, reverse osmosis or other appropriate water purification processes. It contains almost no impurities such as minerals.[3] Mineral water is water that naturally emerges from deep underground or is collected through drilling. It contains a certain amount of minerals, trace elements or other ingredients and is uncontaminated within a certain area and prevents contamination by taking preventive measures.

Although drinking water contributes little to the human body's trace element nutrition, when the diet cannot obtain enough trace elements such as calcium, supplementing the mineral content from drinking water is also a way. Therefore, it is recommended that people who are deficient in trace nutrients can choose to drink mineral water. People with diseases such as urinary stones are recommended to drink purified water.

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06

Is the water in the drinking fountain safe?

The truth: No, it can be dirty.

The water in the water dispenser is indeed safe, provided that the dispenser is clean and sanitary and the water quality is up to standard. However, if a bucket of water is drunk for a long time or the water dispenser is not cleaned or disinfected for a long time, it may become unsafe and may increase the risk of disease.

When bottled water is stored in a sealed barrel or water dispenser for a long time, the activity of microorganisms in the water may cause the water quality to change after it comes into contact with air. Research results show that the longer the bottled water in a water dispenser is consumed, the more bacteria there are in the water in the barrel and in the water dispenser. It is best to drink the bottled water within 7 days after opening the lid. [4]

The contamination of the inner tank and the inner wall of the cold water valve of the water dispenser is the main reason for the excessive microbial content at the water outlet, and many people ignore the cleaning of the smart seat in the water dispenser, which is also prone to breeding bacteria.

Friends who use water dispensers at home must pay attention to disinfecting the water dispenser. It is generally recommended to disinfect it once every half a month to one month. The inner tank and cold water valve and other parts of the water dispenser should be cleaned every 7 days.

07

Is it easy to get kidney stones if you drink hard water?

The truth: Drink it with confidence.

The so-called hard water refers to water with a relatively high total concentration of calcium and magnesium. The higher the content, the harder the water. When the water contains a high content of minerals such as calcium and magnesium, scale will form on the bottom and wall of the kettle when boiling water.

Drinking this kind of water regularly does not necessarily mean you will get stones. To prevent stones, you still need to drink more water. Studies have shown that increasing water intake and urination can reduce the risk of kidney and urinary stones. [1]

Tips for removing scale: Try vinegar and baking soda.

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08

Can drinking water make you fat?

The truth: How is it possible!

The reason for gaining weight is that the calories consumed throughout the day are greater than the calories consumed, which leads to fat accumulation and gradually becomes "rounder". Water has no calories, whether it is hot water, cold water or warm water, their calories are 0.

Therefore, even if you drink a lot of water, you will not gain weight, unless you are drinking "sugar water".

09

Can drinking soda water treat high uric acid?

Truth: No treatment

Sodium bicarbonate is often used in clinical treatment of hyperuricemia, so some people think that drinking soda water can treat hyperuricemia. Although the soda water we often talk about is also a weak alkaline aqueous solution containing sodium bicarbonate, the content of sodium bicarbonate in soda water is very different from that of drugs and cannot play a therapeutic role.

However, drinking some soda water can increase the amount of water you drink, and of course plain water will have the same effect. my country's "Dietary Guidelines for Hyperuricemia and Gout Patients" recommends that people with hyperuricemia and gout need to drink 2,000 ml of water every day. Drinking more water can promote the excretion of uric acid. Another thing to note is that some soda water has a high sodium content. If you drink too much soda water, you should reduce your salt intake.

10

Should you drink light salt water in the morning?

Truth: Not recommended.

Many people are used to drinking a glass of light salt water in the morning, thinking that it can increase intestinal osmotic pressure, clean the stomach and intestines, and promote the discharge of stool. In fact, there is no such thing as "stool" in the human body, and there is no such concept as "stool" or "detoxification" in medicine.

A 300 ml cup of light salt water generally requires about 2 grams of salt. According to the recommendation of the "Dietary Guidelines for Chinese Residents", the daily salt intake of each person should be less than 5 grams. If you drink water in the morning, you will have already taken in nearly 2 grams of salt. The salt intake for the whole day is likely to exceed the standard, which can easily increase blood pressure and is not good for cardiovascular health.

Especially for those who already suffer from high blood pressure, heart disease and abnormal kidney function, they need to be more vigilant. Although it is not recommended to drink, you can gargle with light salt water to help freshen your breath.

11

Drinking honey water to treat constipation?

The truth: It may not work.

Drinking honey water to promote bowel movements is not useful for everyone. If you achieve the so-called laxative effect after drinking honey water, it means you have fructose intolerance.

Honey contains a lot of fructose, but some people's intestines absorb fructose slowly. In order to balance the osmotic pressure in the intestine, water will enter the intestinal cavity, and the stool volume will increase, thereby increasing stool excretion. Some people may also experience diarrhea!

Some people may say: "Even if honey water is useless for defecation, it can still provide some nutrition!"

Honey water has limited nutritional value. 75.6% of honey is sugar (including glucose and fructose), 22% is water, 2.3% is fat and protein, and less than 0.1% is vitamins and minerals. [5] Generally, only 1 teaspoon of honey water is used to make honey water, and the nutritional value is minimal. Not only does it have no health benefits, but drinking too much honey may even make you fat!

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12

Can boiling water thousands of times cause cancer?

Truth: No.

It is very common to boil water for many times in daily life. When a pot of water is left for a long time and becomes cold, you need to plug it in again to heat it up. Sometimes a pot of water needs to be boiled again three or four times. So some people worry that repeatedly boiling water will cause excessive nitrite and cause cancer?

Someone has done a related experiment: after boiling tap water 8 times, the nitrite content is only 3.38μg/L. [6] This is far from the nitrite content of drinking water quality stipulated in the "GB5749-2006 Drinking Water Hygiene Standard" of ≤ 1000μg/L, so there is no need to worry about it causing cancer. As long as the tap water itself is hygienic, it is safe to drink it after boiling it a few more times.

13

Is overnight water unhealthy?

The truth: Seal it tightly and drink it with confidence.

If you drink water boiled in the morning at night, people don't worry about it being unhealthy; but if you drink water boiled in the evening the next morning, some people worry about it being harmful to health. I don't understand why this is the case.

In fact, overnight water is relatively safe, as long as you cover the lid when not drinking it to prevent foreign objects from falling into it. But drinking water is just like eating food, take as much as you drink, and it is best not to leave it overnight.

See here

Why don’t you go and have a drink of water?

References:

[1] Chinese Nutrition Society. Dietary Guidelines for Chinese Residents[M]. People's Medical Publishing House. 2022

[2] https://hubpages.com/health/Drink-Water-While-Eating

[3] GB 19298-2014 National Food Safety Standard Packaged Drinking Water

[4] Li Xiaoxiao, Su Guanru, Wan Yingna, Shen Yuanyuan, Yang Jianjun. Analysis of the influence of water dispensers on the microbial contamination of drinking water[J]. Journal of Xi'an University of Arts and Sciences (Natural Science Edition), 2020, 23(04): 62-66.

[5] Yang Yuexin, Wang Guangya, Pan Xingchang. Editors. Chinese Food Composition Table. December 2009. 2nd edition.

[6] Wu Fei, Wang Hui, Shu Jingwei, Wang Anshuo, Chen Wenjun. Study on the correlation between residual chlorine and nitrite content in tap water and heating conditions[J]. Journal of Food Safety and Quality, 2017, 8(11): 4458-4462.

Author: Xue Qingxin, registered nutritionist

Review | Zhang Na, Associate Researcher, Doctoral Supervisor, Peking University School of Public Health

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