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New study shows mouthwash could trigger diabetes

24 November 2017

New study shows mouthwash could trigger diabetes

Many people use mouthwash as part of their oral hygiene routine, but a new study carried out in Harvard University showed that persistent use of over-the-counter mouth wash not only kills harmful bacteria, but it may also kill bacteria that are beneficial to our health. 

Most mouthwashes contain antibacterial agents such as triclosan, chlorohexidine, cetylpyridinium chloride, peroxide, fluoride and alcohol. KaumundiJoshipura, professor of epidemiology at Harvard stated: “Most of the antibacterial ingredients in mouthwash are not selective, In other words they do not target specific oral bacteria-instead, and these ingredients can act on a broad range of bacteria.” This means that mouthwash will also affect “good” bacteria. The use of mouthwash could impact the oral microbes’ production of nitric oxide, which in turn plays a critical role in the body’s metabolism, energy levels and sugar levels. These findingsdo relate to a study carried out in 2013 which found that using mouthwash for just a week could decrease a person’s nitrate levels by a quarter, leading to visible blood pressure spikes.

The researchers from Harvard studied 1,206 overweight individuals between the ages of 40 and 65 who were considered at risk of developing diabetes. It was found that the individuals using mouthwash at least twice a day had around a 55% greater risk of developing diabetes or dangerous blood sugar spikes within three years compared to those who used it less frequently. Mouthwash can also leave more room for harmful bacteria to thrive by killing the good bacteria.This is the first time that a study has evidenced that there is a link between what is supposedto be a beneficial oral health routine having a potentially harmful effect on the body.

The authors of the study advised sticking to one rinse a day despite their latest findings, as mouthwash can still play an important role in fighting plaque and preventing bad breath. The British Dental Association however, does not stipulate daily mouthwash use as a necessary component of proper oral healthcare and does not ensure that food build up and plaque will be removed from the teeth after rinsing with mouthwash. Department of Health however do recommendonce daily mouthwash for patients who are giving concern regarding their caries rate.The study from Harvard concluded that frequent regular use mouthwash could potentially cause diabeteshowever; more research still needs to be carried out.


Cook, J. (2017). Mouthwash may act as a trigger for diabetes, study shows. Netdoctor. Retrieved 23 November 2017, from
Joshipura, K., Muñoz-Torres, F., Morou-Bermudez, E., & Patel, R. (2017).Over-the-counter mouthwash use and risk of pre-diabetes/diabetes. Nitric Oxide, 71, 14-20.
Sarah Knapton. (2017). Mouthwash may kill beneficial bacteria in mouth and trigger diabetes, Harvard study suggests. The Telegraph. Retrieved 23 November 2017, from


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