Researchers found that using mouthwash twice a day destroys our friendly oral bacteria, which can alter blood sugar metabolism and promote diabetes. The scientists came to their intriguing findings by analyzing the data of 1,206 adults ages 40–65 who were overweight or had obesity. All adults were part of the San Juan Overweight Adults Longitudinal Study, and they were free of diabetes and major cardiovascular diseases at study baseline. The researchers suspect that mouthwash can not only destroy the bad bacteria but also “good” bacteria in the mouth that are important for the formation of nitric oxide, which is a chemical compound that helps to regulate insulin. As part of the study, participants were asked how often they used mouthwash. A total of 43 percent of the subjects said that they used mouthwash at least once daily, while 22 percent said that they used it at least twice daily. Over an average of 3 years of follow-up, the team monitored the development of prediabetes or diabetes among the 945 participants.  Compared with participants who did not use mouthwash, those who reported using mouthwash at least twice daily were 55 percent more likely to develop prediabetes or diabetes over 3 years. These findings persisted after accounting for possible confounding factors, including diet, oral hygiene, sleep disorders, medication use, fasting glucose levels, income, and education levels. There was no association between using mouthwash less than twice per day and the risk of prediabetes or diabetes, the researchers report. Given that more than 200 million people in the U.S. use mouthwash, these latest findings could be a cause for concern. The study authors caution “the indiscriminate routine use” of antibacterial mouthwash may cause more harm than good. However, it is important to note that the study is purely observational. Dec, 2017