World Kidney Day | The secrets of drinking water can no longer be hidden

March 11 is World Kidney Day. Drinking water in moderation is an important factor in protecting kidney health. So what are the ways to keep water, the source of life that we cannot live without? The following 5,000-word dialogue-style popular science article is definitely worth reading and saving.

Do those fancy waters really have miraculous effects?

Niu Niu: To be honest, I still don’t understand how to buy the many packaged drinking water on the market.

Binghai: In a word, just clean is good.

Niu Niu: What about mineral water, mineral water, ice spring water, glacier water, magnetized water, and weak alkaline water?

Binghai: It’s a long story. First of all, most of those functional waters, such as magnetized water and weak alkaline water, have been advertised for their health benefits, but they are actually useless commercial gimmicks. Especially weak alkaline water, which claims that the human body is weakly alkaline, so drinking weak alkaline water is healthier, which is simply nonsense.

Niu Niu: How can this be nonsense? Aren’t there many businesses that still advertise that their water is weakly alkaline?

Binghai: This kind of publicity is actually skirting the advertising law, making you think that weak alkaline water has some benefits. It is similar to a salt factory saying "Salt from the East China Sea", but in essence it is no different from other salts. In fact, in the "National Food Safety Standard for Packaged Drinking Water" (GB 19298-2014) officially implemented in 2016, the "pH value" indicator was removed because it has no effect on health. However, my country's drinking water hygiene standards have set the pH to 6.5~8.5. Within this limit, it is fine whether it is alkaline or acidic.

Niu Niu: What about magnetized water and various types of health water?

Binghai: Ineffective, all ineffective, all are gimmicks of merchants, I can say it so absolutely. Because there is no evidence that drinking water has health benefits. According to the "National Food Safety Standard General Rules for Pre-packaged Food Packaging" (GB 7718): the product name of packaged drinking water shall not be labeled with "activated water", "small molecular cluster water", "functional water", "energy water" and other unscientific content. If one day the World Health Organization or relevant national departments announce that any of these waters have health benefits, please tell me. But before that, any propaganda about health functions is hooliganism.

Niu Niu: Then I want to question, aren’t there many mineral waters on the market, are they ineffective?

Binghai: It has no health benefits. First of all, the national standard has cancelled the term "mineral water". Although you can still find a lot of results if you search "mineral water" on Taobao, if you look closely at their packaging, without exception, they do not say "mineral water" or "mineralized water", but are changed to "Mou Yue", "Mou Chang" and other special names that are unclear and impressive. Its essence is to add some minerals to pure water. You only need to look at its ingredient list to see it at a glance: it usually says "drinking pure water" plus some additives such as "magnesium sulfate, zinc sulfate, calcium chloride, potassium chloride".

Niu Niu: That’s not right. If they have no effect, why add these additives? Are they for preservation?

Binghai: It is useful, but it is not for health care, but to improve the taste. For example, sometimes some people feel a little bitter in their mouths after drinking very pure water, so you can add some compliant additives, which can even make them feel that the water is slightly sweet. In fact, according to mandatory regulations, this kind of water with added minerals must be marked with words such as "food additives added to adjust the taste" near the product name. If you look carefully, those so-called "mineral waters" actually have this sentence.

Niu Niu: So is mineral water the same as them?

Binghai: They are different. If you are referring to natural mineral water, it is subject to the National Food Safety Standard for Drinking Natural Mineral Water (GB 8537). Some water such as groundwater and glacier water are also of this type.

Niu Niu: Wouldn’t natural water without food additives be better?

Ice Sea: Natural water certainly contains some natural minerals, but they also have no additional benefits to human health.

Niu Niu: No way? Isn’t natural water good?

Binghai: I'd better be more precise: the so-called N kinds of natural trace elements in natural water are really very trace. If you eat one more soybean or a piece of meat, you will get more than that. If you think that eating one more soybean is a kind of health care, then it's fine.

Niu Niu: What you mean is that spending extra money to buy this kind of natural mineral water is a waste of money?

Binghai: I just analyze it from a rational perspective, whether it is good for human health and whether there is evidence to support it. But some people are indeed more sensitive to taste. They may be more interested in the subtle taste, flavor, service, packaging, quality of water, and even the trust of the brand and the story the brand tells. So it is normal for them to be willing to spend more money to choose the products they like. After all, everyone has different needs, and I cannot use my own single dimension and standard to measure other people's preferences.

Niu Niu: Oh, yes. It’s just like when we go to a restaurant to eat. Some people go for health, some go for the taste, but more people probably go for the environment, culture, decoration, or even the story. It’s common to pay a high price for this.

Binghai: Yes, we advocate looking at things with a scientific attitude, but we cannot be "deadly rational" to deny other people's choices.

Niu Niu: I have talked so much about purchased water, but actually I usually drink water at home. Most people don’t drink packaged water at home, right? What should I do when drinking water at home?

There are many ways to drink water at home!

Niu Niu: After moving to a new home, how should I choose drinking water? Some say bottled water is convenient, some say home water purifiers are safe, but some say it is troublesome to clean the water dispenser and it is difficult to change the filter element of the water purifier. What should I choose? It's really a headache.

Binghai: This question is very simple. After listening to me, I believe you will know which choice to make.

Niu Niu: Really? Which one is the best?

Binghai: There is no "best" but only "the best is the one that suits you". If you are single or living with a partner, or renting a house in a big city, what I recommend most is to filter water with a water purifier and then boil the water for drinking.

Niu Niu: Huh? This is the first time I've heard of this method. What's the reason?

Binghai: The reason is very simple. In fact, urban drinking water is relatively clean, especially in big cities. In theory, it can be drunk directly from the water plant. If you are not sure about the chlorine added in it, you can just boil the water and drink it. However, although this is theoretically true, urban pipes may also be contaminated again (but generally do not contain toxic and harmful substances), so "filtering the water in a water purifier before boiling" takes into account cheapness, safety and convenience. This method is enough for two people to drink, and it is also convenient to move and carry. The disadvantage is that the water filtered each time is relatively small, which is only enough for a few people to drink. If you want to use water to wash fruits and vegetables, or cook, it will be stretched and inconvenient. So it is a small-scale solution suitable for one or two people, and it is based on a relatively safe and reliable water source.

Niu Niu: What if a family of five or six uses a lot of water?

Binghai: Then the most suitable one is a household direct drinking water purifier, which means that the tap water can be drunk directly after being filtered.

Niu Niu: There are many kinds of water purifiers. How should I choose?

Binghai: There are indeed many types of water purifiers, but they can be roughly divided into two categories, one is the traditional filtration method, and the other is the RO reverse osmosis filtration method. The former is cheaper in all aspects, although the effect is not as good as the latter, but if the water source is reassuring, I recommend the former.

Niu Niu: Reverse osmosis filtration is better, why is it not recommended?

Binghai: Because the cost of use is relatively high, it is mainly reflected in two aspects. First, there is a reverse osmosis filter element in the reverse osmosis filter, and its replacement cost is relatively high. But more importantly, it will produce some wastewater. The better ones on the market now also have a 1:1 wastewater volume. That is, for every liter of pure water obtained, one liter of wastewater will be discharged. And because of the discharge problem, the installation location must be considered during decoration, unlike traditional filtration, as long as there is a water inlet, it will be fine.

Niu Niu: Does reverse osmosis have no benefits? If these costs are acceptable, can reverse osmosis filtration be used?

Binghai: Of course you can. The advantage is that the water filtered by reverse osmosis is cleaner, it can be said to be extremely clean. Suppose one day the water plant can't figure it out and pours Coke into the pipes, your reverse osmosis water dispenser will also give you pure water after filtering, and it won't even be sweet. In extreme environments, or for people who have more stringent requirements and are not sensitive to price, reverse osmosis filtration is also a good choice.

Niu Niu: The discharged wastewater cannot be drunk, but it can be used for mopping the floor, watering flowers, washing clothes, etc., right?

Binghai: In theory, yes. As long as the pipe water is clean, these so-called "waste water" are not that dirty, and can indeed be reused. But believe me, this is just your beautiful idea. When you really need it, you will have to collect water, store water, and check whether there is any water in the waste water bucket when you mop the floor. You will definitely find it troublesome in the end. So don't think this is a cost-saving solution. If you want to save money, don't choose this solution. Using this means that you have higher requirements for the quality of life, and naturally the cost is higher.

Niu Niu: What are the advantages of that kind of desktop water dispenser? I see a lot of people use it?

Binghai: This type is more to meet the need of our traditional culture to drink hot water. However, I recently discovered that some new products seem to not require pipes and use RO reverse osmosis filtration technology, but there is no mention of wastewater discharge in the entire product description. It was not until I asked the customer service with doubts that they admitted that wastewater would be generated and I needed to carry a water tank to pour water every time. The actual marked 5-liter water tank capacity only had 2.5 liters of real usable capacity in the end, and then I had to pour water again.

Niu Niu: I see, I got it. So, there is no optimal solution for drinking water at home, only the one that suits you best, right?

Binghai: Yes. When facing any product, we can understand its characteristics and then choose it according to our own needs, rather than simply asking "which is the best". Many times, "one man's meat is another man's poison".

Niu Niu: By the way, you haven’t introduced bottled water yet. What kind of needs are suitable for bottled water?

Binghai: In fact, bottled water is almost not suitable for most families...

Now you know the secrets of bottled water

Niu Niu: Why are more and more people not using bottled water now, and it is usually used by companies?

Binghai: I don't recommend using bottled water at home, especially if there are no more than four people in the family. There are three reasons: First, the traditional bottled water is about 18.5 liters. According to my experience, if there are three or four people in the family, then you can only drink four bottles per month, that is, one bottle per week, so the water is not fresh. Second, bottled water dispensers are generally not "water purifiers" because bottled water itself is purified water that can be drunk directly and basically does not need further filtration, so the water dispenser itself needs to be cleaned by professionals, which is very troublesome.

Niu Niu: Wait, how many times a year does this cleaning usually take place?

Binghai: There is no strict basis, I can only use my experience to classify the situation. If you drink bottled purified water, then it is recommended to clean it every six months, and no more than once a year. If you drink natural drinking water, or so-called "mineral water", then it is recommended to clean it every three months, preferably no more than six months. In fact, if you clean it once every six months, you will have the opportunity to see the snot-like substances in the water dispenser, which is very disgusting.

Niu Niu: What about the third reason for not recommending it?

Binghai: It's about storage and replacement. A bucket of 18.5 liters of water weighs nearly 40 kilograms. Even a guy like me who is not very strong needs to work hard to replace it. If I sprain my waist, it's really not worth it. Even if I am strong or persuade the water deliveryman to help me change it, the empty bucket will still take up every inch of valuable space in my house.

Niu Niu: Why do you keep extra empty buckets? Can't you just order new ones every time you finish the water in the dispenser?

Binghai: That depends on your relationship with the water deliveryman. It depends on how long it takes for him to get to your place when you order. If it's too late, you may not have water to drink, and during this time you can only wait for him and cannot leave.

Niu Niu: We have a good relationship because we have ordered a lot. Sometimes I just put the empty bucket and water coupons at the door, and it doesn’t matter when I go out.

Binghai: But hidden prices do exist. You may buy a bucket of water for 25 yuan, and there is no delivery fee. But think about how much it costs to deliver a takeaway now? You should be able to guess how much of the 25 yuan goes to the water delivery worker. As for those small brands of water that cost 12 or 13 yuan a bucket, I can tell you an industry insider: their factory price does not exceed 3 yuan.

Niu Niu: Wow, the price is so low? Is this water drinkable?

Binghai: To be honest, most of it is drinkable. We have tested some of this water, and in terms of safety, it does not violate the relevant national standards. After all, if there is a problem with the water, they will be held responsible, and they generally will not take the initiative to harm others. But the tap water is simply sand filtered, and I sell it to you for 13 yuan a bucket. Don’t you think it’s a loss?

Niu Niu: Is there no big brand water that costs less than 13 yuan?

Binghai: Water from big brands has gone through at least two reverse osmosis processes, and the factory price is generally higher than 9 yuan. If the price is 13 yuan, the dealer can only get 4 yuan, minus the boss's money and their storefront rent, etc., the water delivery worker can only get 3 yuan? Do you think anyone is willing to deliver at this price? Therefore, if the price of the big brand water you buy is still so low, I suggest you call the official customer service hotline to verify whether the water is genuine.

Niu Niu: Are there any fake ones?

Binghai: Yes, this "fake water" is that the dealers (water stations) directly fill the barrels without going through the brand manufacturers. Now the crackdown is severe, some dealers will not fill in their own stores, but go to special places after receiving orders, let others fill and then send to customers. So the water that originally cost 9 yuan to order from the manufacturer can now be filled outside for one or two yuan. In this way, when the sales staff of the manufacturer come to check, there is not a barrel of "fake water" in the dealers, all of them are real. And they can make an extra 7 yuan per barrel by delivering N barrels each time. Isn't it great?

Niu Niu: Then the customers won’t be able to recognize it?

Binghai: Water delivery personnel are often familiar with some customers, and they know which of them are too lazy to check the anti-counterfeiting labels, and they can also "kindly" help them replace the water, so the labels and anti-counterfeiting marks are directly torn off, and the customers can't find out at all. So if there are special circumstances and you need to use bottled water at home, it is recommended to use a big brand, order water through the hotline provided by the brand, and verify the anti-counterfeiting mark in person from time to time. As for how to verify, you can call the customer service number.

Niu Niu: If it’s not suitable for use at home, can the company use bottled water?

Binghai: It is relatively better for companies to use bottled water. First, there are many people, the turnover is fast, and the water is relatively fresh. Second, the company is large and there are many places to empty the barrels. Third, the price of bottled water that a company can enjoy is much lower than that of a family because it can carry many barrels of water at a time. Finally, due to the large throughput of large companies, many businesses are willing to clean the company's water dispensers regularly. So I am not blindly denying the role of bottled water. It still has more advantages than disadvantages in some usage scenarios. Some laboratories will also order bottled distilled water. Because the bottled water of large factories is of guaranteed quality. The key is that it is indeed cheaper if used in large quantities.

Niu Niu: So, bottled water is not completely useless, nor is it that scary.

Binghai: Yes, it is not recommended for home use mainly because of the cost and risk. If it is confirmed to be a legitimate product of a big brand and avoids the disadvantages I mentioned, this solution can also be considered. For example, I have also seen some areas without piped water or inconvenient water supply, using bottled water is also very good.

Niu Niu: I see. So even if we hear some industry insider information, we can’t just generalize and analyze different situations rationally, right?

Binghai: That's right. Today we discussed bottled water purchased outside, household water use plans, and some industry insider information about barreled water. I hope everyone can face various practical problems in life rationally. If our popular science content is helpful to everyone, please forward it to those in need. Thank you.