Thursday, April 26, 2012

Oral Health And Plant-Based Diets

We all know that eating a plant-based diet abundant in fruits and vegetables does wonders for our health. The reduction in the three most talked about diseases in these regards are obesity, heart disease, and diabetes. All of them can be prevented or reversed just by adopting healthy eating habits but there's another great benefit to eating wholesome, healthy foods―superb oral health!

Following a diet of whole, plant-based foods has been shown to reduce bad breath, prevent gingivitis and periodontal disease, and even reduce the risk of oral related cancers. A closer look at each one reveals why this is so.

Beating Back Bad Breath

Bad breath, also known as halitosis, is caused mainly by the formation and release of volatile sulfur compounds (VSCs) during bacterial breakdown of proteins [1]. Eighty to ninety percent of halitosis cases originate in the mouth due to the abundance of food particles left behind after eating. Bacteria, located within the oral cavity, then have a field day with feasting on these food particles. This is especially the case in individuals suffering from gingivitis and periodontal disease as these bacteria can be found hiding beneath diseased gum lines. However, the main stomping ground for these bacteria is on the back third of the top surface of the tongue. In fact, four times as many bacteria are found there than in any other part of the mouth [2].

The other 10%-20% of bad breath cases originate from sources such as infections, medication, kidney failure, liver failure, and pancreatic disease amongst other things. The putrefaction of food in the lower digestive tract is also a likely culprit in these cases. Sulfur containing gases from certain foods like garlic and onions can be absorbed into the bloodstream and make their way to the lungs where they are then exhaled through the mouth producing a foul odor. This odor can last up to three days after consuming such foods.

Obviously, one of the most important ways to eliminate bad breath is by practicing good oral hygiene habits on a daily basis. Brushing, flossing, and rinsing will help dislodge and clear much of the food particles left behind after eating, thereby reducing the amount of plaque buildup for those bacteria to feed off of. Many people forget to clean their tongue though. All bad breath sufferers should make a conscious effort every single day to brush their tongue or better yet use a tongue scraper in order to remove the accumulation of bacteria residing there.

So what about food? Everyone knows that garlic, onions, and certain spices can cause bad breath but how about other foods?

There aren't many studies looking at halitosis and specific diets but one study in particular did report more bad breath in those adhering to a very low carbohydrate (VLC) diet [3]. VLC diets are usually predominantly made up of animal fats and animal proteins. The Atkin's diet is one such diet. Dr. John McDougall gives a great explanation as to why these animal derived foods may be causing bad breath:

"Of the 20 amino acids that make up all the proteins in nature, only two contain sulfur: methionine and cysteine. Proteins with the highest content of sulfur-containing amino acids are found in red meats, poultry, cheeses, and all other animal-derived foods... If you want to drastically cut down on your sulfur intake and improve breath odor, then the most basic step for you to take is to change your diet to one based on starches, vegetables and fruits (without garlic and onions) ― and minimize your intake of animal proteins."

For good measure I would add some green tea to your diet too. Green tea exhibits antimicrobial effects and has been shown to reduce the sulfur containing compounds that cause bad breath [4].

When you've rid yourself of bad breath it means a couple of things. First, you're eating healthier which allows your body to flourish due to all the antioxidants and phytonutrients you've obtained from the fruits and vegetables you've been eating. Second, you reduce your risk of gingivitis and periodontal disease. That's because you no longer have an abundance of those foul smelling sulfur gases hanging around, especially methyl mercaptan, which has been shown to the worsen cases of gingivitis that eventually lead to periodontal disease [5]. Periodontal disease is not something any adult wants because it's the leading cause of tooth loss in people over the age of 35.

Plant-Based Diets And Oral Cancers

I've written before about the benefits of plant-based diets and reductions in cancer risk―namely breast, prostate, and colorectal cancer. But what about oral cancers? Can a plant-based diet prevent these types of cancer?

The answer to this is a resounding yes! But don't expect to swallow your fruits and veggies in the form of a pill because supplements are no match for the real thing as reported in a 2011 article published by the Journal of the American Dental Association [6]:

"Current evidence supports a diet high in fruits, vegetables and plant-based foods for the prevention of oral cancer. Dietary supplements―including vitamins and minerals―have not been shown to be effective as substitutes for a diet high in fruits and vegetables."

This wasn't the only publication touting the benefits of tasting the rainbow. Another review looking at 46 studies found a clear reduction in both oral and pharyngeal cancer risk in those individuals with the highest consumption of fruits and vegetables [7]. This reduction in risk can be at least partially attributed to the beta-carotene, vitamin C, and other selected flavonoids in these food groups. Whole grains, but not refined grains, were also associated with a lower risk of oral cancers. What really grabbed my attention was that dietary choices alone may account for up to 20-25% of all oral and pharyngeal cancers in western countries. If you're a smoker and/or a heavy drinker then the attributable risks of developing either of these two cancers increases to 85-95%! Needless to say, making healthy lifestyle choices is not just the right thing to do, it's a must if you wish to remain free of oral cancers.

I hope this post has inspired you to not only improve your eating habits and give a plant-based diet a try if you haven't done so already, but also to remind you to regularly brush, floss, AND do a little tongue scraping so those devilish, little bacteria don't turn your mouth into a sulfur manufacturing powerhouse.

Photo credits:
Germs/tooth (digitalart)
Orange (Theeradech Sanin)
Fruits&veggies (Carlos Porto)

by Dustin Rudolph, PharmD
Clinical Pharmacist




1 Feller L, Blignaut E. Halitosis: a review. SADJ. 2005 Feb;60(1):17-9. Review.
2 Yaegaki K, Coil JM. Examination, classification, and treatment of halitosis; clinical perspectives. J Can Dent Assoc. 2000 May;66(5):257-61. Review.
3 Segal-Isaacson CJ, 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-40S.
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 Ratcliff PA, Johnson PW. The relationship between oral malodor, gingivitis, and periodontitis. A review. J Periodontol. 1999 May;70(5):485-9. Review.
6 Chainani-Wu N, Epstein J, Touger-Decker R.  Diet and Prevention of Oral Cancer: Strategies for Clinical Practice. J Am Dent Assoc. 2011 Feb;142(2):166-169.
7 Lucenteforte E, Garavello W, Bosetti C, La Vecchia C. Dietary factors and oral and pharyngeal cancer risk. Oral Oncol. 2009 Jun;45(6):461-7. Epub 2008 Nov 5. Review.


  1. does this mean we should abstain from garlic? I am vegan and love to put garlic in my juices and I know it's very good for me.. with the elimination of animal products would the garlic odor be reduced?

  2. This is great! I am going to look for more studies related to plant-based diets and reduction in oral cancer and links between plant-based diets and decreased periodontal disease as well. I am a dental student and a vegan and I want to find ways to give nutritional advice to future patients that I can justify based on oral health benefits since I am not a nutritionist or a physician and therefore not qualified to give advice based on the rest of the body. I am very passionate about a plant-based diet in addressing major diseases and public health problems in our country and I want to find my role in this as a Dentist.