Bottle it

Summer is just around the corner, the weather is quickly getting much warmer and the Beijing air seems even more dry than normal. Keeping hydrated is therefore a top priority in order to maintain a healthy body and lifestyle. While guzzling down gallons of bottled water is good, drinking from a multifunctional health bottle can be even better, or at least so the sellers claim. 

For sale on online shopping websites like Taobao, the bottles look the same as any other vacuum bottles on the market. The main body of the multifunctional bottle is mostly made from stainless steel, and there is a filter in the cap or the bottom of the bottle. 

However, using a filter made of clay instead of plastic or metal, they function to filter out impurities from water, while adding their own sources of goodness that offer multiple health benefits, such as reducing fatigue and constipation, tackling headaches, high or low blood pressure and even diabetes. 

Zhao Feihong, the deputy director of the Beijing Public Health Research Center of Drinking Water, told the Global Times that "some of these bottles definitely promote better health. But others might have a negative effect on the body too." 

Water works 

Open up the bottle cap and you will see a water filter placed inside that is made of clay. The clay contains various mineral substances, including a volcanic mineral that enhances the health properties of water. 

All the customer needs to do after buying the device is add water and wait. Liu Hongjun, deputy manager of Eastern Technology Corporation, a Chinese company that specializes in making healthcare promotional household products, said that you can either pour boiled, mineral or pure water into the bottle and wait for three to five minutes. Then the water will be ready to drink. 

"Today people face a lot more challenges in their daily life that affect their health. These include air pollution, long working hours and unhealthy living habits, such as little sleep and consuming unhealthy food and drink. They can unbalance the pH level in the body," Liu said. "The water from this bottle could bring it back to a normal, balanced level."

The pH rate is a measure of the acidity of an aqueous solution. Ideally humans need a perfect balance between acidic and alkaline. The minerals in this bottle balance the pH rate by reducing the acidity inside the water. 

According to the national sanitary standard for drinking water, the appropriate pH rate should be within 6.5 to 8.5, although there is some flexibility. "Drinking alkaline water is healthy for the human body as it functions to adjust the pH rate to a normal level," Zhao said.

Not crystal clear 

Despite superficially being good for the health, some products on the market can actually cause more harm than good. "Some multifunctional bottles may contain minerals that will turn the nitrate into nitrite and eventually will be no longer safe to drink," Zhao said. On top of this, they might also contain a medical stone, or maifan stone as it is sometimes named, a kind of nonmetal mineral that is used for its bacteria resistance. "One big problem for this stone is its high level of zinc, which can be toxic," Zhao explained. People should therefore buy them in expensive and recommended stores to ensure their quality.

Having been in the market for around five years, these bottles are not very popular. "One reason is that most people simply do not know about this product," explained Liu. 

Of course the fact that it has never been easy to distinguish whether the multifunctional bottles promote or decrease the health is another impediment. And then there is the expense. Prices range from around 500 ($79) to 1,000 yuan, so this is no impulse buy. 

Nor is it one that will last long. "It usually lasts about three months before the chemical effect runs out," Liu explained. 

Then there is the issue of maintenance. When you wash the bottle, you need to use white vinegar or citric acid instead of normal water. Liu also warned that the cap should not be closed when washing the bottle.

Despite the high price and the potential dangers, one bought from a reputable company does have some benefits. "It is a good health assistant, so long as it is used on top of other measures to take care of your health, rather than instead of," Zhao said.