A Surprising and Simple Way to Battle Bad Breath

When searching for the best defense against bad breath (aka halitosis), the best place to start is to understand its cause.  Setting aside foods that we all know can cause temporarily smelly breath, like members of the allium family of vegetables (garlic, onions, shallots, leeks and scallions), the major cause of disagreeable breath can be found within the mouth itself.

The main contributors by far are potent molecules derived from foods called volatile sulfur compounds (VSCs).  VSCs are chemicals that give some foods their specific flavours and odours and they can be detected by smell or taste at very low concentrations.  The sulfur-containing amino acids, methionine and cysteine, found mainly in proteins from red meat, poultry, cheese and other animal-derived foods, are the most common origins of VSCs.   The most important VSCs for causing offensive breath are hydrogen sulfide, dimethyl sulfide, dimethyl disulfide, and methyl mercaptan. (1,2,3,4,5)

Bacteria living in the mouth are the agents that actually create the odours that end up as bad breath.  These microorganisms perform the necessary step of degrading sulfur-containing amino acids into foul-smelling VSCs. VSC-producing bacteria are anaerobic, meaning that they don’t require oxygen for growth, and the fissured irregular surface of the upper back third of the tongue appears to be the favourite place for these bacteria to thrive. This area can contain as much as four times more bacteria than any other part of the mouth (6).

 

Taming Halitosis

Many aspects of the diet can help with controlling malodorous breath.

1  Eat more plants. (7)

• Higher levels of fiber in food reduces levels of VSCs in the breath and reduces its odour. Fiber is only obtained from eating whole plant-sourced foods.
• Chewing food has a self-cleaning effect in the mouth and eating foods high in fiber that require more intensive chewing produces a stronger cleaning effect.
• Some vegetables, including leafy greens, beets, carrots and celery, are high in nitrates. Nitrate-containing vegetables have been associated with decreased inflammation of the gums and better-smelling breath.

2  Eat fewer foods that include sulfur-containing amino acids. ( 8,9)

• Limit animal-sourced foods and diets high in fat and protein that promote the growth of VSC-producing bacteria.
• Avoid the keto diet, a way of eating that is very high in fat and extremely low in carbohydrates. It sours the breath simply from its production of malodourous ketone bodies. 

 3  Drink green tea. 

The freshening effect of green tea on bad breath has been known for some time.  Green tea is rich in polyphenols, part of a large group of chemicals produced by plants to provide themselves protection against environmental stresses.  Examples of the beneficial effects from catechin polyphenols are their ability to neutralize free radicals caused by exposure of a plant to stresses such as drought, UV radiation, temperature fluctuations, heavy metals and high soil salinity, thereby lessening cell damage to the plant.  Catechin polyphenols can also increase the toxicity and unpalatability of the plant itself in order to protect it against plant-eating animals or insects.  When we humans consume plants high in polyphenols we can also benefit from their protective anti-inflammatory actions.  Especially high in green tea are the polyphenols known as catechins – epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epicatechin (EC), and epigallocatechin (EGC), all of which have shown their ability to subdue and eradicate odor-producing mouth bacteria.  (10)

Studies show that green tea is very effective at reducing the production of VSCs in the mouth, thus decreasing smelly breath.  Green tea is well known for its antibacterial properties against anaerobic microorganisms which results in suppression of anaerobic bacteria, eliminating the production of VSCs.  (11)  Green tea also has the ability to down-regulate a bacterial gene that is responsible for creating the VSC, methyl mercaptan.  In addition, the zinc contained in green tea can convert VSCs into non-malodorous compounds. (4,5,12)

A 2016 study investigated the effects of green tea powder on VSCs compared to other foods claimed to control halitosis.  Green tea showed the largest reduction in concentration in the mouth of the VSCs hydrogen sulfide and methyl mercaptan. Chewing gum, mints or parsley-seed oil product did not reduce the concentration of VSCs in mouth air at any time.  (13)

A randomized double-blind placebo-controlled trial had its participants rinse their mouths twice daily for a month with a mouthwash made of green tea or a similar-looking and tasting placebo mouthwash. Results of the study showed that, after a month, foul-smelling VSCs were reduced by 40% in those using the green tea mouthwash compared to only 10% in those using the placebo mouthwash. (14)

Mouth rinses, eating mints or chewing gum might temporarily reduce offensive breath but their activity is fleeting.  The best solution for disagreeable breath is to get to the root of the problem and decrease the presence of odour-causing VSCs in the mouth.

Green tea is one of the healthiest beverages in the world.  It is anti-inflammatory and has shown benefits in many aspects of health including cardiovascular disease (15,16), obesity (17), bone health (18), cognitive performance (19,20), arthritis (21) and the prevention of cancer (15,22) and infections (23).  It contains only 2 calories, no fat, salt or sugar, and can be enjoyed as often as desired.  It can even count toward your daily recommended water intake.  Add to this its ability to freshen breath and you’ve suddenly discovered a lot of reasons to add two or three cups of green tea to your daily fluid intake.

Further information on halitosis can be found in the blog “The Quest For Sweeter Breath” published on this website on May 21, 2021.

 

SOURCES:

1  Feller, L., Blignaut, E.  Halitosis: a review.  SADJ. 2005 Feb; 60(1): 17-19.

2  McGorrin, R.J.  The Significance of Volatile Sulfur Compounds in Food Flavors: An Overview.   Chapter 1; Volatile Sulfur Compounds in Foods. Qian et al.  2011.  American Chemical Society.  https://pubs.acs.org/doi/pdf/10.1021/bk-2011-1068.ch001.

3 Tangerman, E., Winkel, E.G.  Volatile Sulfur Compounds as The Cause of Bad Breath: A Review, Phosphorus, Sulfur, and Silicon and the Related Elements. 2013. 188(4). 396-402. DOI: 10.1080/10426507.2012.736894.

4  Lodhia, P., Yaegaki, K., Khakbaznejad, A., et al. Effect of green tea on volatile sulfur compounds in mouth air. J Nutr Sci Vitaminol (Tokyo). 2008 Feb; 54(1):89-94.

5  Xi, C., Zhang, Y., Lu, H.-X., Feng, X.-P.  Factors Associated with Halitosis in White-Collar Employees in Shanghai, China.  PLoS One. 2016; 11(5): e0155592.  Doi: 10.1371/journal.pone.0155592.

 6  Hampelska, K., Jaworska, M.M., Babalska, Z.L., Karpiński, T.M. The Role of Oral Microbiota in Intra-Oral Halitosis.   J Clin Med. 2020 Aug; 9(8): 2484.  Doi: 10.3390/jcm9082484.

7   Wälti, A., Lussi, A., Seemann, R.  The effect of a chewing-intensive, high-fiber diet on oral halitosis: A clinical controlled study.  Swiss Dent J. 2016; 126(9):782-795.

8  Segal-Isaacson, .C.J., Johnson, S., et al. A randomized trial comparing low-fat and low-carbohydrate diets matched for energy and protein. Obes Res. 2004 Nov; 12 Suppl 2:130S-140S.

9  Ajibola, O.A., Smith, D., Spaněl, P., Ferns, G.A. Effects of dietary nutrients on volatile breath metabolites. Journal of Nutritional Science. 2013 ;2:e34. DOI: 10.1017/jns.2013.26.

10  Stiller, A., Garrison, K., Gurdyumov, K., Kenner, J., Yasmin, F., Yates, P., Song, B.H. From Fighting Critters to Saving Lives: Polyphenols in Plant Defense and Human Health. Int J Mol Sci. 2021 Aug 20;22(16):8995. Doi: 10.3390/ijms22168995. PMID: 34445697; PMCID: PMC8396434.

11  Liao, S., Kao, Y.H., Hiipakka, R.A. Green tea: biochemical and biological basis for health benefits. Vitam. Horm. 2001;62:1–94. Doi: 10.1016/S0083-6729(01)62001-6.

12  Tahani, B., Sabzian, R. Effect of Camellia sinensis plant on decreasing the level of halitosis: A systematic review. Dent Res J (Isfahan). 2018;15(6):379-384.

13  Porciani, P.F., Grandini, S. Effect of green tea-added tablets on volatile sulfur-containing compounds in the oral cavity. J Clin Dent. 2016;27(4):110-113.

14  Rassameemasmaung, S., Phusudsawang, P., Sangalungkarn, V. Effect of green tea mouthwash on oral malodor. ISRN Prev Med. 2013;975148.

15  Kuriyama, S., Shimazu, T., Ohmori, K., Kikuchi, N., Nakaya, N. et al. Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study. JAMA. 2006 Sep 13; 296(10):1255-1265.

16  Alexopoulos, N., Vlachopoulos, C., Aznaouridis, K., Baou, K. et al. The acute effect of green tea consumption on endothelial function in healthy individuals. Eur J Cardiovasc Prev Rehabil June 2008; 15(3):300-305.

17  Wolfram, S., Wang, Y., Thielecke, F. Anti-obesity effects of green tea: from bedside to bench. Mol Nutr Food Res. 2006 Feb; 50(2):176-187.

18  Shen, C. –L., Yeh, J.K., Cao, J., Wang, J. –S. Green tea and bone metabolism. Nutr Res. 2009 Jul; 29(7): 437–456.

19   Borgwardt, S., Hammann, F., Scheffler, K., Kreuter, M., Drewe, J., Beglinger, C. Neural effects of green tea extract on dorsolateral prefrontal cortex. European Journal of Clinical Nutrition (2012); 66: 1187–1192.

20  Schmidt, A., Hammann, F., Wölnerhanssen, B., Meyer-Gerspach, A.C., Drewe, J. et al. Green tea extract enhances parieto-frontal connectivity during working memory processing.  Psychopharmacology.  October 2014; 231(19): 3879–3888.

21  Katiyar, S.K., Raman, C. Green tea: a new option for the prevention or control of osteoarthritis. Arthritis Res Ther. 2011; 13(4): 121.

22  Lambert, J.D., Yang, C.S. Mechanisms of cancer prevention by tea constituents. J Nutr. 2003 Oct; 133(10):3262S-3267S.

23  Matsumoto, K., Yamada, H., Takuma, N., Niino, H., Sagesaka, Y.M. Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial.  BMC Complement Altern Med. 2011 Feb 21; 11: 15.