Alkaline Ionized Water Day (Arukari Ion Sui no Hi) — "0711" reads as "onaka ni ii," meaning "good for your stomach"

What Is Alkaline Ionized Water Day?

Every year on July 11th is "Alkaline Ionized Water Day" in Japan, established by the Alkaline Ionized Water Apparatus Council and registered with the Japan Anniversary Association in 2009. The date comes from a wordplay on "0711," which reads as "onaka ni ii" — "good for your stomach" — a reference to the approved claim that alkaline ionized water helps relieve gastrointestinal symptoms. The day aims to spread accurate knowledge about alkaline ionized water and water ionizers.

A History as a Medical Device

Water ionizers in Japan have a history of being treated as medical devices rather than ordinary home appliances.

• Approval as a medical device: Research on devices that electrolyze water began in the early Showa era, and in 1966 Japan's then Ministry of Health and Welfare granted manufacturing approval for them as "medical substance generators."
• Re-examination of effects: After questions were raised about their effects in the early 1990s, an "Alkaline Ionized Water Apparatus Review Committee" was formed in 1993 to re-examine their safety and effectiveness. In 1999, results of a double-blind comparative clinical trial were reported showing usefulness for gastrointestinal symptoms.
• Today: They are now classified as controlled medical devices ("household electrolyzed water generators"), with the stated purpose of "producing drinkable alkaline electrolyzed water to improve gastrointestinal symptoms."

How Alkaline Ionized Water Is Made

Alkaline ionized water is made by electrolyzing tap water inside the ionizer.

• Electrolysis: When electricity passes through filtered water, alkaline water forms at the cathode (negative electrode) and acidic water forms at the anode (positive electrode). The alkaline water from the cathode side is the one used for drinking.
• Scope of the approved effect: The recognized effect concerns the improvement of gastrointestinal symptoms. Claims that it cures other illnesses have not been recognized, so it is wise not to take such advertising at face value.

Fun Facts About Alkaline Ionized Water

• Hydrogen is produced too: During electrolysis, hydrogen is also generated at the cathode and dissolves in the water, which is why it is sometimes called "electrolyzed hydrogen water."
• pH guideline: Drinkable alkaline ionized water is in the range of about pH 9 to 10, and alkaline electrolyzed water above pH 10 is considered unsuitable for drinking.
• Acidic water is made at the same time: The weakly acidic water from the anode is not for drinking, but the earlier approval described it as "used as an astringent for beauty purposes."
• When taking medicine: Because the effects of taking medicine with alkaline ionized water have not been confirmed, the usage notes say not to take medicine with it. People with kidney disease are advised to consult a doctor before drinking it.
• Where the name came from: Around 1979, continuous-type devices that attach directly to a faucet appeared, and the name "alkaline ionized water" is said to have come into use around then.

Ideas for Alkaline Ionized Water Day

• In the hot season, make a point of drinking water regularly before you feel thirsty.
• Look into the differences between the kinds of water you drink, such as tap water, mineral water, and filtered water.
• If you use an ionizer or water filter, check when the filter needs replacing.
• Get into the habit of checking which effects of health products are officially recognized.

A Day to Learn About Everyday Water

July 11th is a day to think about the water we drink every day. Alkaline ionized water has a history of approval and re-examination as a medical device. Today, slowly drink a glass of water and take a moment to review how you stay hydrated and how you handle the health information around you.