Is boiled water more than 16 hours old like a "chronic poison"? If you make these 5 water drinking mistakes, you may get sick!

As the saying goes, "Food is the most important thing for man, and water is the first priority for food." Maintaining adequate water intake every day plays a vital role in the health of human skin, blood vessels, and intestines.

◎ Maintain good skin: The skin is well hydrated, has a fast metabolism, is less likely to develop wrinkles and spots, and looks younger;

◎ Reduce respiratory diseases: The respiratory mucosa is relatively moist, and the secreted mucus helps reduce the invasion of pathogens;

◎ Smoother blood flow: Sufficient water helps blood flow smoothly and reduces the risk of thrombosis;

◎Prevent constipation: Sufficient water can prevent dry stools and constipation...

However, there have been many rumors circulating in life about drinking water, such as: boiled water cannot be drunk for more than 16 hours, drinking water with scale for a long time can easily cause kidney stones, drinking soda water can lower uric acid... Are these statements true or false?

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01

Boiled water also has a "shelf life"

Can’t drink after more than 16 hours?

Some people say: "Boiled water also has a 'shelf life'. If it exceeds 16 hours, E. coli will multiply and cause abdominal pain, diarrhea, fever and nausea, and it is no longer drinkable." In fact, there is no scientific basis for this statement , because E. coli cannot be transmitted through the air.

In this regard, researchers from Fuzhou University conducted a special experiment:

The researchers divided boiled water into two groups, with and without lids, and left them there for 5 hours, 8 hours, 11 hours, 14 hours, 15 hours, 16 hours and 17 hours respectively, and monitored whether the water contained E. coli.

The results showed that no matter whether there was a lid or not, there was no E. coli in the boiled water placed in each cup after the experimental time .

However, E. coli may contaminate water sources through feces, so it is best not to drink unsterilized water .

In addition, in the summer, the temperature is high and the humidity is high. If the water is not stored properly, it may be contaminated by flies, dust, etc., and may also contain other bacteria. It is best not to drink it, especially for children or people with fragile gastrointestinal tract.

02

Drinking scale-containing water for a long time

Prone to kidney stones?

After using the kettle at home for a period of time, there is often a layer of white scale on the bottom of the kettle. There is a rumor that "this is hard water, and drinking too much can easily cause kidney stones." Is this really true?

In fact, scale is mostly formed because the water contains more calcium and magnesium ions.

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China's "Drinking Water Hygiene Standard" stipulates that the total hardness of drinking water (calculated as calcium carbonate) should not exceed 450mg/L, which is equivalent to 180mg of calcium in 1L . Adults usually drink no more than 2L of water per day, and the reference daily calcium intake is 800mg, so the maximum tolerable intake is 2000mg.

It can be seen from this that normal drinking of water will not cause excess calcium in the body, nor will it induce kidney stones .

Secondly, drinking more water can dilute the concentration of calcium oxalate and calcium urate, which can help prevent the formation of kidney stones and even expel existing small stones.

03

Drink more soda

Can it regulate the acid-base constitution and lower uric acid?

Soda water, that is, water containing sodium bicarbonate, is weakly alkaline. There are rumors that drinking it regularly can change the internal environment of the body, correct the acidic constitution, and reduce the risk of disease; there are also rumors that it can reduce uric acid. What is the truth?

1. The acid-base constitution is a lie. The internal environment cannot be easily changed.

First of all, the "acid-base body type" is a lie. There is no such thing as diet or drinking water being able to regulate body type.

What's more, the human body has a complete fluid regulation system that can stabilize the pH value of the internal environment between 7.35-7.45 , which cannot be changed through food or water.

Therefore, for ordinary people, there is no need to deliberately pursue weak alkaline water. Maintaining good living and eating habits can maintain the acid-base balance of body fluids and boost health.

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2. It may be difficult to lower uric acid by drinking soda alone

Theoretically, soda water can alkalize urine, increase the solubility of uric acid, and promote uric acid excretion.

However, drinking soda water alone cannot lower uric acid levels, because the sodium bicarbonate content of soda water sold on the market is so low that it is almost negligible and is unlikely to change the pH of urine , let alone lower uric acid levels. [1]

Of course, for patients with high uric acid, it is not bad to drink some soda water in moderation. After all, drinking more water can promote the excretion of uric acid.

04

Drink more lemon water for whitening?

The effect is limited, and drinking it incorrectly can harm your health

There is a saying that "a white complexion hides a hundred flaws". Among various whitening methods, refreshing and delicious lemon water is particularly popular. But can drinking lemon water really whiten your skin?

1. Drinking lemon water for whitening has limited effect

People believe that lemons are rich in vitamin C, which can reduce skin melanin and have a certain whitening effect.

Indeed, vitamin C can inhibit the activity of tyrosinase, reduce the production of melanin from the root, and also lighten melanin, thereby brightening the skin tone.

But it is unscientific to talk about efficacy without considering dosage. The vitamin C content of lemon is about 22mg/100g, which is not very high, so it is difficult to achieve the whitening effect by just drinking a few slices of lemon in water every day .

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2. Drinking too much may cause stomach discomfort

Since soaking a few slices of lemon in water is of no use, can I soak a few more slices and drink more every day?

In fact, drinking too much blindly is not good - lemon is rich in fruit acid, citric acid, malic acid, etc. Excessive intake will irritate the gastric mucosa and cause stomach discomfort. People who already have underlying diseases such as gastritis and gastric ulcers should be especially careful .

In general, if you want to whiten your skin, it is better to do a good job of sun protection and ensure that you consume 300~500g of vegetables and 200~350g of fruits every day. You can also buy skin care products containing ingredients such as niacinamide, arbutin, and vitamin C.

05

Should I drink 8 glasses of water every day?

This amount is enough, but it varies among different groups of people.

The saying "drink 8 glasses of water a day" is widely circulated, and many people insist on doing it. But have you ever thought about how big a cup you should use for these 8 glasses of water? Obviously, this saying is not very accurate.

So how much is the right amount to drink every day? Is this standard suitable for everyone?

1. Daily water intake, this standard is enough

The "Dietary Guidelines for Chinese Residents (2022)" points out that adult men with low physical activity levels should drink 1700ml per day and adult women should drink 1500ml per day .

If the weather is hot, the air is dry, and you sweat a lot, you should increase your water intake according to the actual situation. You can pay attention to your urine. If it is light yellow, clear, and sufficient, it means that you are drinking enough water.

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2. These people should control their water intake

The above drinking water standards are for healthy people, but some special groups should be treated differently, such as:

◎ Patients who are taking medication to treat gastric ulcers : The medication contains substances such as sucralfate and aluminum hydroxide gel, which can protect the gastric mucosa. If you drink too much water, it may reduce the efficacy of the medication and be detrimental to recovery.

◎ Patients with chronic kidney disease : When kidney function is impaired, the water you drink cannot be excreted normally, so you need to control your water intake. Generally, the appropriate amount of water for the whole day (including drinking water and water in the diet) = 500ml + the amount of urine the previous day;

◎ Patients with heart failure : Drinking a lot of water will increase the amount of blood returning to the heart, thereby increasing the heart load and aggravating the condition. For patients with severe heart failure, the amount of water they drink should even be controlled within 800ml.

Notice:

The specific amount of water to drink should be based on the doctor's advice .

06

Remember the "3 Don'ts"

Learn the correct way to drink water

Drinking water may seem simple, but many people do it wrong. According to the "China Water and Life Quality Perception Survey Report", 95.3% of people in my country do not know how to drink water.

To drink water correctly, remember the following 3 points:

1. Don’t wait until you’re thirsty to drink water

Thirst is actually a clear sign of dehydration. As the body loses more water, it will be accompanied by darker urine, dry skin, chapped mouth and tongue, hoarseness, and general weakness.

As the perception function of the elderly is reduced, they should develop the habit of drinking water actively. It is recommended to drink water every half an hour, but do not drink too much each time, so as to avoid "water poisoning" caused by drinking a lot of water in a short period of time .

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2. Don’t drink too hot or too cold water

Overheated water (over 65°C) can scald the esophageal mucosa . If this continues for a long time, the esophageal mucosa will be repeatedly damaged and repaired, which can easily lead to cancer.

Ice water can easily irritate the gastrointestinal tract, causing abdominal pain, diarrhea and other discomforts. In special cases, it may also cause dangers. For example, drinking ice water in summer can easily cause excess heat to accumulate in the body, leading to heat stroke; drinking ice water can easily cause coronary artery spasm in patients with three highs, inducing angina pectoris or even myocardial infarction.

3. Do not use juice or drinks as a substitute

Many people always think that "boiled water is too bland and tasteless" and prefer to use fruit juice or beverages instead. However, they contain high sugar content, and excessive consumption can easily increase the risk of obesity, diabetes, gout and other diseases, so it is better to drink less .

For example, a study found that the intake of sugary drinks was positively correlated with the risk of gout, and drinking sugary drinks increased the risk of hyperuricemia by 35%. [2]

References:

[1] China Internet Joint Rumor Refutation Platform. “True Knowledge: Can Drinking Soda Water Lower Uric Acid?” 2021-05-13.

[2] Soraiya Ebrahimpour-koujana, Parvane Saneeib, Bagher Larijanic, et al. Consumption of sugar sweetened beverages and dietary fructose in relation to risk of gout and hyperuricemia: a systematic review and meta-analysis[J]. Critical reviews in food science and nutrition, 2020, 60(1):1-10.

Review｜Li Nannan Director of Hunan Science Writers Association, Deputy Director of Research and Publicity Department of Hunan Science and Technology Association, Second-level Researcher, Chinese Science Writer (Medical Field)

Source: I am a great doctor official account

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