Following on from the earlier blog on oral microbiota and saliva, I thought it would be of use to look at some more studies associated with this mouthy topic. In particular, we will look at research relating to vegans' oral health – cavities, periodontal diseases such as gingivitis – exciting stuff like that…

The first two studies1 2 showed that vegans' teeth were more eroded and demineralised than omnivores' and also had more white spots and cavities (although the difference between vegans and the omnivore control groups in relation to cavities was not significant). Interesting though, eh? The possible reason suggested was related to the amount of "sour products (predominantly raw vegetables and fruit and tomatoes)" consumed by vegans. Maybe they simply think they are so healthy that they don't need to clean their teeth after eating. Along with flossing and rinsing, brushing teeth after eating is something I strongly advise for anyone – particularly after eating fruit. The pH was more alkaline for vegans than omnivores, which is no surprise considering the acidity of animal foods3 . And all authorities would agree that lower acidity in your body is a good thing.

As an aside, some research4 does seem to suggest that our ancient ancestors had similar problems with oral health as we do today, and they wouldn't have been consuming bars of chocolate and litres of fizzy drinks, but would certainly have been consuming lots of fibrous foods, along with fruit and veg, without the benefit of access to an Oral-B cross-action sonic electronic toothbrush. Having said this, I have to point out that there's other research5 which claims dental health was far better back in ancient times than it is now. So, we'd better leave the historical aspect of this topic for another time.

However, the above vegan dental hygiene issue is an interesting – though rather confusing finding – in light of evidence suggesting that both inflammation and saturated fat intake are linked to periodontal disease6 , and as we know, both of the latter are associated with a meat-based diet7 8 but not with a plant-based diet. Mmm, could something as simple as poor dental hygiene really be the cause of the findings in the first studies mentioned above?

Additional research9 indicated that a diet which raises cholesterol seems to be related to a higher risk of periodontitis. And we know where dietary cholesterol comes from10 . Also, a study showed that periodontal disease is associated with arterial dysfunction11 and, once again, the meat-eater's diet is the one associated with damage to the arteries12 , as well as a diet high in added oils – even olive oil13 .

So, is there any evidence to suggest that a vegan diet can reverse periodontal disease, in spite of the suggestion above that vegans appear to shoot themselves in the molar, possibly because of poor dental hygiene? Well, yes. One study14 found: "Benefits of higher intake of high-fiber foods, especially fruits, on slowing periodontal disease progression are most evident in men aged 65 and older." This association of good healthy oral hygiene and increased fibre consumption does appear to run through most if not all of the studies, and the possibility that the sort of fibrous diet eaten by vegans (if, that is, they are eating whole plant foods and not hyper-processed Quorn pies and French fries) might have an abrasive effect on teeth and possibly gums. Having said this, the first-mentioned study went to pains to state that: "The results did not reveal any direct influence of vegetarian diet on the occurrence of erosive and abrasive changes."1 I have to say that I am still unclear at this stage as to how one would establish that the prior consumption of fibrous foods would be the definitive cause for cavities and periodontal disease.

And what about oral cancer – any evidence that a plant-based diet is better than a meat-based diet at preventing this rather nasty condition? Again, yes there is. A review by the American Dental Association15 looks at this issue and concludes: "Current evidence supports a diet high in fruits, vegetables and plant-based foods for prevention of oral cancer." Interestingly, and as another aside, they continue: "Dietary supplements-including vitamins and minerals-have not been shown to be effective as substitutes for a diet high in fruits and vegetables." So much in line with evidence I mentioned in earlier blogs16 17 18 .

In conclusion, there are remaining questions to be answered regarding the relationship of a vegan diet and oral health. What can be said, though, is that the preponderance of evidence suggests a vegan diet is a better option, so long as the precaution of regular flossing and brushing is used after consuming food – advice that holds good whatever diet you eat. Dr Greger also suggests rinsing with water19 and waiting 30 minutes before brushing after eating citrus fruits20 .

An additional point that's worth making (again!) is that, when discussing research on vegetarian/vegan diets, there's always the issue about how and to what extent a non-SOS WFPBD would differ in its results if used instead of the loosely-defined vegetarian/vegan diets that could include all sorts of questionable ingredients. An example of this is a cousin of mine who has been a vegan since the age of 4 (an unusually wilful child, I fear!) The last time I met her, she expressed a dislike of most fruits and veggies and subsisted on a diet mainly consisting of chips and crisps (French fries and chips to our American cousins)!

References

  1. K. Herman, A. Czajczy'nska-Waszkiewicz, M. Kowalczyk-Zając, M. Dobrzy'nski. Assessment of the influence of vegetarian diet on the occurrence of erosive and abrasive cavities in hard tooth tissues. Postepy Hig Med Dosw (Online) 2011 65(NA):764 – 769 [↩] [↩]
  2. L. Laffranchi, F. Zotti, S. Bonetti, D. Dalessandri, P. Fontana. Oral implications of the vegan diet: Observational study. Minerva Stomatol 2010 59(11 – 12):583 – 591 [↩]
  3. J Environ Public Health. 2012; 2012: 727630. The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health? Gerry K. Schwalfenberg [↩]
  4. Human ancestors had the same dental problems as us – even without fizzy drinks and sweets [↩]
  5. Smithsonian.com: Prehistoric Humans Had Better Teeth Than We Do [↩]
  6. M. Iwasaki, M. C. Manz, P. Moynihan, A. Yoshihara, K. Muramatsu, R. Watanabe, H. Miyazaki. Relationship between saturated fatty acids and periodontal disease. J. Dent. Res. 2011 90(7):861 – 867 [↩]
  7. National Cancer Institute: Top Food Sources of Saturated Fata Among U.S. Population, 2005-2006 NHANES [↩]
  8. Harvard Medical School: Foods that fight inflammation [↩]
  9. S. Sharma, M. Lamsal, S. K. Sharma, S. R. Niraula, B. Koirala. Association of serum LDL cholesterol level with periodontitis among patients visiting a tertiary-care hospital. JNMA J Nepal Med Assoc 2011 51(183):104 – 108 [↩]
  10. Am J Public Health. 1994 May; 84(5): 799–806. Dietary sources of fats and cholesterol in US children aged 2 through 5 years. F E Thompson and B A Dennison [↩]
  11. S. Amar, N. Gokce, S. Morgan, M. Loukideli, T. E. Van Dyke, J. A. Vita. Periodontal disease is associated with brachial artery endothelial dysfunction and systemic inflammation. Arterioscler. Thromb. Vasc. Biol. 2003 23(7):1245 – 1249 [↩]
  12. Perm J. 2015 Winter; 19(1): 62–67. A Plant-Based Diet, Atherogenesis, and Coronary Artery Disease Prevention. Phillip Tuso, MD, FACP, FASN, Scott R Stoll, MD, William W Li, MD [↩]
  13. Olive Oil Injures Endothelial Cells [↩]
  14. N. Schwartz, E. K. Kaye, M. E. Nunn, A. Spiro III, R. I. Garcia. High-fiber foods reduce periodontal disease progression in men aged 65 and older: The Veterans Affairs normative aging study/Dental Longitudinal Study. J Am Geriatr Soc 2012 60(4):676 – 683 [↩]
  15. N. Chainani-Wu, J. Epstein, R. Touger-Decker. Diet and prevention of oral cancer: Strategies for clinical practice. J Am Dent Assoc 2011 142(2):166 – 169 [↩]
  16. Vitamin C Supplements vs An Apple [↩]
  17. How To Analyse the Health Claims Made for Dietary Supplements [↩]
  18. Wholism vs Reductionism – Not Just a War of Words [↩]
  19. Do Vegans Get More Cavities? By Michael Greger M.D. FACLM [↩]
  20. Plant-Based Diets: Dental Health. By Michael Greger M.D. FACLM [↩]