How toxic is your mouthwash?

Have you ever wondered about the mouth wash you use and what the ingredients in it may be doing to your health? Well an increasing number of studies are showing the negative links between mouthwash and chronic health conditions like hypertension and diabetes type 2. Hypertension is a leading preventable risk factor for premature death and disability worldwide followed closely by diabetes type 2 and its complications. But don’t worry there are things you can do to help with bad breath that don’t cause long term health problems and in fact may even improve your health.

Mouthwashes has been gaining popularity and its use is often promoted or prescribed by dental health care professionals to help manage specific oral conditions. Around 60% of the US population use mouthwash one or more times weekly and a third use it daily. In 2017 almost two-thirds of the US population used mouthwash to treat dental disease or dental problems in the last seven days, and 36% used it daily. The figures are probably much the same in Australia.

Around 90% of commonly used mouthwash products contain some antibacterial ingredient, such as chlorhexidine, triclosan, cetylpyridinium chloride, alcohol, fluoride and peroxide. While this is great for helping control the nasty bacteria present in the dental plaque and controlling dental caries, periodontal diseases, and halitosis (bad breath) they also kill the good ones. Yes, we have good bacteria in your mouth as a part of your oral microbiome. The human oral cavity includes more than 700 bacterial species 1. Unfortunately, the antibacterial ingredients in mouthwash do not target just the nasty pathogens, but act on a broad spectrum of targets killing both the good ones and the bad ones.

In the mouth particular beneficial bacteria convert nitrates from foods like vegetables to nitrites which are then converted to nitric oxide (NO). Nitric oxide is an important signalling molecule which amongst other things lowers blood pressure and improves diabetes. Clinical trials suggest frequent use of mouthwashes decreases the levels of nitrate/nitrite in the body, likely through destruction of oral microbes responsible for converting nitrate to nitrite. Loss of these microbes and this chemical pathway may lead to decreased nitric oxide-bioavailability and increased blood pressure and diabetes. In one study people who used mouthwash twice/day or more had an 85% higher incidence of hypertension compared to less frequent users and a 217% increased risk compared to non-users. Pretty significant 2.

Recent studies have shown oral bacteria, particularly those belonging to the group Actinobacteria, to be inversely associated with type 2 diabetes risk. That is the more of these bacteria the lower the risk of diabetes. The same beneficial impact for hypertension of converting nitrate rich foods into nitrites by oral bacteria may have a protective role in diabetes risk and inflammation. In one study chronic over-the-counter mouthwash use twice or more daily was associated with 55% increased risk for development of pre-diabetes/diabetes over a 3-year follow-up period 2

So what is the answer?  There are safer ingredients including a mouth wash with just water, sodium bicarbonate or salt. The bicarbonate also helps to bring the mouth back to a more neutral pH so it has lots of benefits. Just as important many conditions related to bad breath are also related to reflux and a condition called silent reflux. Fixing these helps resolve some of the problems straight away. Finally, the wrong type of bacteria are promoted in the mouth through sugar and ultra-processed foods so a healthier diet may also be a breathe of fresh air.



1.Dewhirst FE, Chen T, Izard J, et al., The human oral microbiome, J. Bacteriol 192 (19) (October 2010) 5002–5017. PMC free article.

2. Blood Press. 2020 Apr; 29(2): 103–112. Published online 2019 Nov 11. doi: 10.1080/08037051.2019.1680270 PMCID: PMC7125030 NIHMSID: NIHMS1542814 PMID: 31709856. OVER-THE-COUNTER MOUTHWASH USE, NITRIC OXIDE AND HYPERTENSION RISK Kaumudi Joshipura, BDS, MS, ScD (DPH),1,2 Francisco Muñoz-Torres, MPH,1 Jeanpaul Fernández-Santiago, UG,1 Rakesh P. Patel, PhD,3 and Angel Lopez-Candales, MD4

3. Nitric Oxide. 2017 Dec 1; 71: 14–20. Published online 2017 Sep 20. doi: 10.1016/j.niox.2017.09.004 PMCID: PMC6628144 NIHMSID: NIHMS927462 PMID: 28939409 Over-the-counter mouthwash use and risk of pre-diabetes/diabetes Kaumudi J. Joshipura,a,b,*,1 Francisco J. Muñoz-Torres,a Evangelia Morou-Bermudez,c and Rakesh P. Pateld