Vegetarian diet and oral health: a narrative review

Vegetarian diet is a type of diet based on the exclusion of all kind of meat and fish, that can be clas-sified into: vegetarian diet (no meat consumption), semivegetar-ian diet (occasional meat con-sumption), lacto-ovo-pesco-vege-tarian diet (fish consumption) and vegan diet (no animal products). Recently, this type of dietary regi-men has become popular among the eating habits of a part of the population in several countries around the world. The increase in the number of vegetarians and vegans is linked to a greater con-cern for their own health, as well as ethical, environmental and so-cial reasons. Many scientific evidences report that a plant-based diet exerts the greatest preventive effect on the risk of onset of chronic diseases such as diabetes, respects nutri-tional needs at different ages, and represents the one with the small-est ecological footprint. However, those who follow a vegetarian/ vegan diet often consume many refined and ultra-processed foods resulting in an increased likeli-hood of developing heart and metabolic diseases. Subjects who follow a plant-based diet appear to exhibit good oral health, correlating with an interest in prevention and treatment of conditions such as tooth decay and gingivitis. Some studies sug-gest a multifactorial etiology for so-called “white spot” lesions and erosions, for which dietary habits, such as plant-based diets, could play a significant etiologic role. In the context of a plant-based di-et, analysis of macronutrients and micronutrients is of paramount importance. Specifically, vegetari-ans/vegans tend to have higher intakes of vitamin C, which is im-portant in immune system de-fense processes and correlates with less severity of periodontal disease, vitamin A, which cor-relates with less periodontal dis-ease activity, and vitamin E; con-versely, a deficiency of omega-3, with less anti-inflammatory ac-tion in the acute stages of peri-odontal disease, calcium, vitamin D, and vitamin B may be ob-served. Malnutrition is a critical factor in oral mucosal health and proper functioning of the immune sys-tem. Micronutrient deficiency – including trace elements, vita-mins, and antioxidants – dysreg-ulates the host’s natural defense response by suppressing im-mune function. The same micro-nutrients also play an important role in regenerative processes against oxidative stress products in tissues. A statistically significant correla-tion is observed between squa-mous cell carcinoma develop-ment in the oral cavity and a non-vegetarian diet: a diet rich in fiber may be protective against tu-mor onset, as well as against the occurrence of leukoplakia, known to be a pre-cancerous lesion, and submucosal fibrosis. In patients with oral lichen planus, lower levels of nutrients such as calcium, vitamin D, vitamin B12, folic acid, and antioxidants such as vitamins C and E have been found; in addition, vitamin B12 deficiency has been linked to in-creased lesion severity and risk of dysplasia. A plant-based diet, if not properly planned, can induce deficiencies of the micronutrients described above: the vegan diet, even if well structured, can be included in the list of risk factors for hypovitamin-osis B12 and D.