"The warm-water bidet type toilet seat originated in the United States, but up to the present these have not caught on at all in Europe or the U.S." says Mitsuharu Ogino, an OB-GYN physician at the Center Hospital of the National Center for Global Health and Medicine in Shinjuku.
Ogino continues: "It's been pointed out the toilets carry a risk of spreading infectious diseases, because of sanitation issues related to the nozzle and warm water."
The question posed to Dr Ogino, in conjunction with an article in Shukan Gendai (Feb 27-Mar.6), asks why Washlets, TOTO's proprietary brand that's become the generic name for such devices, have taken Japan by storm, while achieving scant success elsewhere.
A survey by the prime minister's office found that in 2020, 80.2% of Japan's households had installed such toilets, an explosive increase over the 14.2% households with Washlets in 1992.
By contrast, less than 10% of U.S. households were found to have adopted such toilets as of last year. In China, the figure was around 5% in 2019.
Dr Ogino believes the popularization of bidet-type toilets here reveals ignorance among Japanese over their potential dangers.
Kahoru Kusama, a proctologist based in Azabu, Tokyo, explains why.
"Over washing the anus risks removing the sebum, which lubricates the surface. There have been reports of problems caused by over drying of peripheral areas," says Kusama.
According to Koichiro Fujita, professor emeritus at Tokyo Medical and Dental University, our skin surface generally maintains a slightly acidic pH of between 4.5 to 6.0. The use of bidets can remove skin flora, raising pH to a neutral 7.0 or slightly above into alkaline. This leaves the body vulnerable to dermatitis and possibly invasion of staphylococcus aureus bacteria.
The transition process to become pH neutral or alkaline generally takes 10 hours, so two or more warm-water washes in the course of a single day may be enough to prevent the skin from returning to its mildly acidic state.
The aforementioned Dr Ogino says he's aware of numerous reports of people complaining of chronic cases of rectal bleeding or hemorrhoids.
Sixty-five-year-old Yuji Kawata (a pseudonym), who installed a Washlet after developing hemorrhoids, tells Shukan Gendai, "The warm water wash felt good after elimination, and I used it frequently. Afterwards I would feel the need to go again; but when I sat down, nothing would come out. From overuse I developed rectal bleeding."
Dr Kusama warns that Washlet users troubled by less serious discomforts may disregard warning signs of colon or intestinal cancer.
"In many cases, by the time they realize the problem, the cancer has already reached an advanced stage," she says.
A London-based journalist tells the magazine bidet-type toilets are seldom found in British or American homes.
"Many Europeans and Americans don't regard them as sanitary and fear risking infections from them. I don't see the likelihood of further adoption."
Shukan Gendai also approached the big three manufacturers of bidet-type toilets -- TOTO, LIXIL and Panasonic -- which control about 90% of the market. The makers referred him to the Japan Sanitary Equipment Industry Association, whose spokesperson stated, "Concerning water emitted from the toilet nozzle or present in the toilet tank, we have conducted microbiological surveys, which have confirmed the water to be safe.
"Our association is not aware of risks incurred through use of the warm water bidet toilets."
The aforementioned Dr Fujita disagrees.
"People's excessive concerns over cleanliness have become a bad influence," he says. "It should be obvious that subjecting either the anus and vagina to direct jets of warm water can create problems. We can't overlook the point that it kills off skin flora. As far as the human body is concerned, such devices are unnatural."© Japan Today